Taxonomy
Family: Alcaligenaceae, is a new member of the alcaligenaceae family

Gyiorum (meaning “from the limbs”) was selected as the name of the species because the majority of strains were isolated from human leg wounds.

Clinical significance
Kerstersia gyiorum is an extremely rare pathogen of human infection.
It can cause chronic infection in patients mostly with underlying conditions. They are isolated from wounds, respiratory tract, urine specimens and most frequently from chronic supperative otitis media.
It can easily be misdiagnosed if proper diagnostic methods are not used.

Increased use of MALDI-TOF MS in the clinical setting may increase reporting of this atypical isolate.

Taxonomy
Family: Moraxellaceae
Formily: Moraxella
P. phenylpyruvicus

Natural habitat
They can be isolated from soil, seawater, seabirds especially penguins, fish, poultry,irradiated foods and from human clinical isolates.
It may occasionally be an opportunistic human pathogens.

Clinical significance
Can cause humans infections such asendocarditis, peritonitis, and fungating lesions of the foot, but those infections caused by this bacterium are rare.

BE AWARE that Brucella sp can be MISIDENTIFIED as P. phenylpurivicus or H. influenzae

Taxonomy
Family: Flavobacteriaceae

Natural habitat
In the environment, does not belong to the normal flora of the human being.

Clinical significance
Is mainly found in from wounds caused by animal (mostly dogs) bites.
Meningitis or septicemia has occured in patients either bitten by a dog or with continuous contact with cats.

Taxonomy
Family: Campylobacteriaceae
Formely: Arcobacter ► human infections
Genus: Aliarcobacter butzleri
- A. butzleri
- A. cryaerophilus

Natural habitats
In the intestinal tract of animals.
Man is infected by direct contact with infected animals or by consumption of contaminated water or food, especially bovine and porcine.

Clinical significance
A. butzleri has been isolated from patents with bacteremia, endocarditis, peritonitis, and diarrhea.
A. cryaerophilus isolated from patients with diarrhea and maybe underrecognized if appropriate culture conditions are not used.

Is an intracellular bacteria, which includes mycobacteria, Listeria, Legionella, Brucella, Coxiella and Rickettsia

F. tularensis is a potential BIOTERRORIST agent

F.tularensis subsp tularensis (type A) is one of the most infectious pathogen known in human medicine.
The infective dose in humans is extremely low: 25 bacteria in an aerosol.

Taxonomy
Family: Francisellaceae
F. tularensis subsp tularensis (type A) → virulent
F. tularensis subsp holartica (type B) → less virulent
F. tularensis subsp mediasiatica → moderate virulence
F. tularensis subsp novicida → low virulence

F. philomiraghia

Tularemia is a bacterial zoonotic disease of the northern hemisphere.
F.tularensis is highly virulent for humans and a range of animals such as rodents, hares and rabbits. It is transmitted to humans by arthropod bites, contact with infected animals, ingestion of contaminated water or food and inhalation infected aerosols.

There is no human to human transmission.

Clinical significance
F. tularensis subsp tularensis, can cause serious cinical manifestation and significant mortality if untreated. High fever is accompanied by progressive weakness, malaise, anorexia and loss of weight. Respiratory symptoms, including a dry cough, a sore throat and substernal pain may occur whether or not the disease is acquired by inhalation. Gastrointestinal symptoms such as nausea, vomiting and diarrhoea.

Taxonomy
Family: Pseudomonadaceae

P. monteillii belongs to the Fluorescent Group

Natural habitat
Isolated from soil, plants, water surfaces, rarely from clinical samples,
and isolated from human clinical samples like placenta, stool, bile, biological fluid, bronchial aspirate, urine and pleura fluid.

Clinical significance
Unknown, possible opportunistic pathogen.

General information
An isolate is confirmed as Salmonella when the specific O serogroup has been determined and biochemical identification has been completed

Taxonomy
Family: Enterobacteriaceae

Natural habitats
Most cases of salmonellosis are caused by food infected with Salmonella enterica, with often infects cattle and poultry, though also other animals such as domestic cats and hamsters have also been shown to be sources of infection to humans.

Raw chicken eggs and goose eggs can harbor S. enterica, initially in the egg whites, although most eggs are not infected. As the egg ages at room temperature, the yolk membrane begins to braek down and S. enterica can spread into the yolk. Refrigeration and freezing do not kill all the bacteria, but substantially slow or halt their growth.
Pasteurizing and foods irradiation are used to kill Salmonella for commercially produced foodstuffs containind raw eggs such aas ice cream.

Clinical significance
Strains of Salmonella are categorized as typhoidal and nontyphoidal.

Nontyphoidal infection
Usually cause an intestinal infection (accompanied by diarrhea, fever and abdominal cramps) that often lasts one week or longer.
They can also cause extra intestinal infections, e.g., bacteremia, urinary tract infection, or osteomyelitis, especially in immunocompromised persons.

Taxonomy
Family: Methylobacteriaceae

Natural habitat
They are isolated mostly from vegetation, but may also occasionally be found in the hospital enviroment.
Tap water has been implicated as a possible agent of transmission in hospital environment.

Methylobacterium species are a cause of health care-associated infections, including infections in immunocompromised hosts.
The ability of Methylobacterium to form biofilms and to develop resistance to high temperatures, drying, and desinfecting agents may explain the colonization of Methylobacterium in the hospital environment in e.g. endoscopes.
Due to its slow growth, it can be easily missed during microbiological surveillance of endoscope reprocessing.

They are able to utilize methanol as a sole source of carbon and energy, although this characteristic may be lost on subculture.

Clinical significance
They have been reported to cause septicemia, continous ambulatory peritoneal dialysis related peritonitis, skin ulcers, synovitis, and other infections often in immunocompromised patients, as well as pseudoinfections.

Taxonomy
Family: Pasteurellaceae

Natural habitats
Colonization of the cervix with H. ducreyi has been documented following sexual intercourse.

Clinical significance
Chancroid is a sexual transmitted disease caused by H. ducreyi which is usually characterized by the development of a single painful genital ulcer, with associated inquinal lymphadenopathy occyring 2 to 7 days following exposure.
Chancroid occurs most often in developing countries, including much of Asia, Africa, and Latin Aerica.

Epidemics of disease are associated with low socioeconomic status, poor hygiene, prostitution, and drug abuse, and commercial sex workers are believed to serve as reservoirs for H. ducreyi.

Taxonomy
Family: Enterobacteriaceae, genus: Escherichia coli, E. coli O157.H7
E. albertii, E. fergusonii, E. hermannii, E. vulneris

Origin
E. coli O157:H7 is so-named because it expresses the 157th somatic (O) antigen identified and the 7th flagellar (H) antigen.

Natural habitats
E. coli O157 is found regularly in the faeces of healthy cattle, and is transmitted to humans through contaminated food, water, and direct contact with infected people or animals.

Transmission
E. coli O157 is transmitted by food and water, directly from one person to another, and occasionally through occupational exposure.
Most foodbourne outbreaks have been traced to foods derived from cattle, especially ground beef an raw milk.

Clinical significance
Human infection is associated with a wide range of clinical illness, including asymtomatic shedding, non-bloody diarroea, haemorrhagic colitis, haemolytic uraemic syndrome, and death.

Taxonomy
Family: Methylobacteriaceae

Natural habitat
They are isolated mostly from vegetation, but may also occasionally be found in the hospital enviroment.
Tap water has been implicated as a possible agent of transmission in hospital environment.

Methylobacterium species are a cause of health care-associated infections, including infections in immunocompromised hosts.
The ability of Methylobacterium to form biofilms and to develop resistance to high temperatures, drying, and desinfecting agents may explain the colonization of Methylobacterium in the hospital environment in e.g. endoscopes.
Due to its slow growth, it can be easily missed during microbiological surveillance of endoscope reprocessing.

They are able to utilize methanol as a sole source of carbon and energy, although this characteristic may be lost on subculture.

Clinical significance
They have been reported to cause septicemia, continous ambulatory peritoneal dialysis related peritonitis, skin ulcers, synovitis, and other infections often in immunocompromised patients, as well as pseudoinfections.

Taxonomy
Family: Mycoplasmataceae
Genus: Metamycoplasma hominis
Formely: Mycoplasma hominis

Natural habitats
M. hominis lives parasitically and saphrophytically with hosts.
M. hominis plays a significant role in the microflora of men and women.

Vector and mode of transmission.
M. hominis infection is spread through vaginal intercourse, oral-to-genital contact, and vertically from mother to her infant in utero or by the colonization by the bacteria as the baby descends through the birth canal or by nosocomial acquisition through transplanted tissues

Clinical significance
M. hominis is a pathogen in humans commenly found as part of urogenital tract flora especially of women and sexually active adult males.
This bacteria cause a variety of infections which may lead to pelvic inflammatory disease, post-abortal fever, post partum fever and extragenital infections for immunodepressed humans.
It also can cause meningitis, pneumonia and abcesseses in newborn children.

It can be present in bacterial vaginosis.

Neonatal infection
Neonates, especially if preterm, are susceptible to Mycoplasma infections organisms through vertical transmission or colonization through passing the birth canal or in utero.
If the bacteria is present in the bloodstream it can access the central nervous system.
If Mycoplasma hominis and ureoplasma organisms are specifically sampled and cultured, they are of etiollogic significans in neonatal lung disease, bacteremia, and meningitis.
There are no characteristic signs and symptoms that can determine the type of pathogen present
Clinicians can consider Mycoplasma species if signs and symptoms of infections are present and if the infant does not improve with administration of beta-lactam medications.
Deaths have occurred in neonates with septicemia and meningitis caused by M. hominis.

Important
This bacteria is important due to the infections it can cause and is growing resistance to treatment, including erythromycin.

Cell wall
Mycoplasmas have a triple-layered membrane and lack a cell wall.

L-forms
The permanent lack of a cell wall barrier makes the Mycoplasma (class: Mollicutes) unique among prokaryotes and differentiates from bacterial L-forms for wich the cell wall is but a temporary reflection of enviromental conditions.

Taxonomy
Family: Pseudomonadaceae
Formerly: Chryseomonas

Natural habitat
Is an oppertunistic pathogen, found ubiquitously in damp enviroments.

Clinical significance
P. luteola is a rare cause of infections in humans.
There have been case reports of a variety of different infections, including bacteremia, cellulitis, osteomyelitis, peritonitis, endocarditis, and postsurgical meningitis.

Also infections in patients with underlying diseases or in association with foreign body.

Is an intracellular bacteria, which includes mycobacteria, Listeria, Legionella, Brucella, Coxiella and Rickettsia

Taxonomy
Family: Francisellaceae

Natural habitat
They are widely distributed in the natural environment (salty water) and is of low virulence, although it may cause disease in immunocompromised individuals.

Clinical significance
Francisella philomiragia, is of low virulence and occasionallycauses disease in immunocompromised individuals.
They may cause pneumoniae or fever with or without organ manifestation, such as meningitis or peritonitis

Human infections caused by F. philomiragia are rare and considered opportunistic infections, infecting primarily patients with underlying immunocompromissing conditions.

Taxonomy
Family: Weeksellaceae
Genus: Empedobacter falsenii
Formely: Wautersiella

Natural habitats
In the environment, does not belong to the normal flora of the human being.

Clinical significance
This organism has been isolated from clinical specimens, including blood, respiratory samples, wounds, pleural fluid,and the urinary tract, though it is an extremely rare cause of nosocomial infection, it may be significant resistant to many antibiotics, including carbapenems.

Altough infection with W. falsenii remains rare, this bacterium should not be underestimated mainly because of its natural resistance to many available antimicrobials.

Taxonomy
Family: Enterobacteriaceae

Natural habitats
Klebsiella variicola is known to associate with different plants.
Some strains have been associated with disease in humans, suggesting they may be able to serve as opportunistic pathogens of humans.

The majority of isolation of Klebsiella variicola are from sterile sites, mainly blood and urine.

Clinical significance
Proper identification of K. variicola will be critical in the further evaluation of its clinical significance as an underreported infectious agent and in the development of more tailored.

Taxonomy
Family: Helicobacteriaceae

Natural habitats
Gastrointestinal mucosa of primates and animals.

Clinical significance
Helicobacter appears to be responsible for most cases or chronic active gastritis, and is most common known cause of peptic ulcer disease.

All Vibrionaceae require Na• for growth

Taxonomy
Family: Vibrionaceae

Natural habitats
V. alginolyticus is very common in the marine ecosystem.

Clinical significance
It is most frequently isolated from ear and wound infections following seawater exposure.

V. alginolyticus has also been isolated from ocular infections.

It is occasionally isolated from diarrheal stool, but there is no evidence that it actually causes diarrhea.

Taxonomy
Family: Campylobacteriaceae

Natural habitats
In the intestinal tract of animals.
Man is infected by direct contact with infected animals or by consumption of contaminated water or food.

Clinical significance
C. fetus is primarily associated with bacteremia and extra intestinal infections during pregnancy or in the compromised host.
Although gastroenteritis does occur with this species, the incidence is probably underestimated because the organism may not grow well at 42ºC and is usually susceptible to cephalothin, an antimicrobial agent used in some common selective media for stool culture.

Taxonomy
Family: Campylobacteriaceae

Natural habitats
In the intestinal tract of animals.

Man is infected by direct contact with infected animals, gulls and other avian species, dogs, cats and chicken.

Clinical significance
C. lari has infrequently reported from humans with bacteremia and gastrointestinal and urinary tract infections.

Symptomatic infections
are usually self-limited, but relapses may occur in 5 to 10% of untreated patients.

Campylobacter infections may mimic acute appendicitis and result in unnecessary surgery.

The most common condition is enteritis, a large number of patients followed by acute colitis (enterocolitis).

Campylobacter infections may occur as acute appendicitis, which is sometimes unnecessary surgery.

The significance of the recovery of Aeromonas from stool specimens should be interpreted cautiously and must rely on both laboratory information and clinical interpretation.

Taxonomy
Family: Aeromonadaceae

Natural habitats
Aeromonas are inhabitants of aquatic ecosystems worldwide.

They don’t like saltwater.

They are also found in a wide variety of fresh produced meat (beef, poultry and pork), and dairy products (raw milk and ice cream)
And found in the gut of medical leeches and in the mouth of snakes

Clinical significance

Clinical strains formely referred to as A. sobria are in fact, A. veronii bv sobria.
This is especially important because of A. veronii bv. sobria's association with more severe, extraintestinal infections, such as septicemia and meningitis.

They are capable of causing gastroenteritis and wound infections in humans, especially those individuals with liver disease.

Aeromonas gastroenteritis ranges from an acute watery diarrhea (most common form) to dysenteric illness or chronic illness.

Stools from acute watery diarrhea are loose and erythrocytes and fecal leukocytes are absent.

Symptoms
Abdominal pain, fever, vomiting, and nausea.
Infections are usually self-limiting, but children may require hospitalization due to dehydration.

Aeromonads can also be isolated, on other sites, although blood and wounds are the most common sources

Taxonomy
Family: Pasteurellaceae

Natural habitats
H. haemolyticus is a human commensal bacterium that colonizes the nasopharynx.

Clinical significance They are closely related to the human patogen H. influenzae but has rarely been reported to cause invasive disease. They may cause disease more as a oppertunistic pathogen

The significance of the recovery of Aeromonas from stool specimens should be interpreted cautiously and must rely on both laboratory information and clinical interpretation.

Taxonomy
Family: Aeromonadaceae

Natural habitats
Aeromonas are inhabitants of aquatic ecosystems worldwide.

They don’t like saltwater.

They are also found in a wide variety of fresh produced meat (beef, poultry and pork), and dairy products (raw milk and ice cream)
And found in the gut of medical leeches and in the mouth of snakes

Clinical significance
They are capable of causing gastroenteritis and wound infections in humans, especially those individuals with liver disease.

Aeromonas gastroenteritis ranges from an acute watery diarrhea (most common form) to dysenteric illness or chronic illness.

Stools from acute watery diarrhea are loose and erythrocytes and fecal leukocytes are absent.

Symptoms
Abdominal pain, fever, vomiting, and nausea.
Infections are usually self-limiting, but children may require hospitalization due to dehydration.

A. caviae infection can even mimicinflammatory bowel disease in children.

Aeromonads can also be isolated, on other sites, although blood and wounds are the most common sources

Taxonomy
Family: Flavobacteriaceae, genus: C. canimorsus, C. cynodegmi

Natural habitats
It is a commensal bacteria in the normal gingival flora of canine and feline species.
Transmission may occur through bites, licks or even close proximity with animals.

Clinical significance
A wound infection (dog bite) with these bacteria may cause serious local problems.

Moreover, there is a high probability of a running fulminant sepsis, in wich multi-organ failure (MOF) may occur.

An isolate is confirmed as Salmonella when the specific O serogroup has been determined and biochemical identification has been completed

Taxonomy
Family: Enterobacteriaceae

Natural habitats
Humans are the only reservoir for Salmonella typhi, indicating that they are adapted to the human host; healthy carriers have been noted.

Clinical significance
Strains of Salmonella are categorized as typhoidal and nontyphoidal.

S. typhi ► typhoidal infection

Typhoid fever
Caused by Salmonella typhi, is a serious bloodstream infection, common in the developing world. Typhoid fever typically presents which a sustained debilitating high fever and headache.

Adults characteristically present without diarrhea. Illness is milder in young children, where it may manifest as nonspecific fever.

This fever has a low infectious dose (<103), and a long high variable incubation period (1 to 6 weeks)

It is transmitted through person-to-person contact or fecally contaminated food or water.

Fatal complications of typhoid most commonly occur in the second or third week of the illness.

General information
An isolate is confirmed as Salmonella when the specific O serogroup has been determined and biochemical identification has been completed

Taxonomy
Family: Enterobacteriaceae

Natural habitats
Salmonella is ubiquitous in animal populations, and human illness is usually linked to foods of animal origin.

Salmonellosis also is transmitted by direct contact with animals, by nonanimal foods, by water, and occasionally, by human contact.

Clinical significance
Strains of Salmonella are categorized as typhoidal and nontyphoidal.

Nontyphoidal infection
Usually cause an intestinal infection (accompanied by diarrhea, fever and abdominal cramps) that often lasts one week or longer.
They can also cause extra intestinal infections, e.g., bacteremia, urinary tract infection, or osteomyelitis, especially in immunocompromised persons.

Taxonomy
Family: Enterobacteriaceae

There are 4 subgroups of Shigella
- S. dysenteriaea
- S. flexneri
- S. boydii
- S. sonnei

The primary difference between E. coli and Shigella is the ability of Shigella to invade the intestinal epithelium.

Natural habitats
Humans and other large primates are the only natural reservoirs of Shigella bacteria.

Most transmission is by person-to-person spread, but infection is also caused by ingestion of contaminated food or water.

Shigellosis is most common in situations in which hygiene is compromised (e.g., child care centers, and other institutional settings).

In developing populations without running water and indoor plumbing, shigellosis can become endemic.

Sexual transmission of Shigella among men who have sex with men also occurs.

Clinical significance
They are the causative agents of bacillary dysentery.

Shigella causes bloody diarrhea (dysentery) and non-bloody diarrhea.

Shigellosis often begins with watery diarrhea accompanied by fever and abdominal cramps but may progress to classic dysentery with scant stool containing blood, mucus and pus.

Ulceration, which are restricted to the large intestine and rectum, typically do not penetrate beyond the lamina propria.
Bloodstream infections can occur but are rare.

All 4 subgroups of Shigella are capable of causing dysentery.
S. dysenteriae serotype 1, is associated with the most severe form of dysentery.

Taxonomy
Family: Pasteurellaceae
3 subspecies
- P. multocida subsp. multocida
- P. multocida subsp. septica
- P. multocida subsp. gallicida

History
Is named after Louis Pasteur (1822-1895), chemist and bacteriologist in Paris

Natural habitats
They are part of the normal flora of the respiratory tract of animals.
Through contact with these animals (licking, biting and scratching), humans can be infected, often by cats and dogs.

Clinical significance
Through contact with animals or bites especially cats or dogs the bacterium is transmitted to humans.
Arise within 48 hours painful infections erythema and swelling, the presence of pus is rare.
Infection can also occur through inhalation of the micro-organism.

Respiratory infections and urogenital infections also occur.
Complications can arise due to sepsis, meningitis, septic arthritis, peritonitis, and osteomyelitis.

Virulence
Due to the polysaccharide capsule is the Pasteurella resistant to phagocytosis.
Although some strains produce a cytotoxin its role in the pathogenesis of the disease is not clear.

Of all the P. species is P. multocida the most virulent.

There are five serogroups (A, B, D, E and F) based on the capsular antigen

Taxonomy
Family: Legionellaceae

Natural habitats
Almost all of the Legionella spp have been isolated from aqueous environmental sources.

It is assumed that the natural reservoir of all the Legionellaceae is our aqueous environment and that humans are an accidental host of the bacterium.

Environmental L. pneumophila is a facultative intracellular parasite of several different free-living amoebae, such as Acanthamoeba and Naegleria, existing in microbial consortia in biofilms and free-flowing water.

Many different Legionella spp exist in nature within free-living amoebae, and as a result, these otherwise fastidious bacteria can multiply within the amoebae and be protected from biocides.

Clinical significance
L. pneumophila serogroup 1 causes 95-98% of community-acquired Legionnaires Disease.

Infection is acquired by aerosol inhalation of contaminated water (e.g. cooling towers or aerosol generating devices), although micro aspiration may also be a mechanism of acquiring the disease.

L. pneumophila causing more than 90% of cases of Legionnaires Disease.

Legionnaires Disease,
is a type of bacterial pneumonia, caused by L. pneumophila and other Legionella spp.

The pneumonia ranges in severity from mild to fatal, with an average fatality rate of 12%.
Major risk factors for the disease include immunosuppression of the cellular immune system, cigarette smoking, use of well water, chronic heart or lung disease, and chronic renal failure.

H.influenzae was first described in 1892 by Richard Pfeiffer during an influenza pandemic.

The bacterium was mistakenly considered to be the cause of influenza until 1933 when the viral etiology of influenza became apparent.

Taxonomy
Family: Pasteurellaceae
H.influenzae 2 types
- unencapsulated
- encapsulated ► capsular antigens type (a-f)

The most virulent strain is H. influenzae type b (Hib)

Their capsule allows them to resist phagocytosis.

The unencapsulated strains are almost always less invasive; they can, however, produce an inflammatory response in humans, which can lead to many symptoms.

Natural habitats
H. influenzae belongs to the normal flora of the nasopharynx, but rarely in the oral cavity.

They may be present in the vaginal flora.

It is usually the non-encapsulated strains that are harbored as normal flora, but a minority of healthy individuals harbor H. influenzae type b (Hib) encapsulated strains in the upper respiratory tract.

These strains are opportunistic pathogens; that is, they usually live in their host without causing disease, but cause problems only when other factors (such as a viral infection, reduced immune function or chronically inflamed tissues, e.g. from allergies) create an opportunity.

Clinical significance
Naturally acquired disease caused by H. influenzae seems to occur in humans only.

In infants and young children.

H. influenzae type b (Hib) causes bacteremia, pneumonia, epiglottitis and acute bacterial meningitis.

On occasion, it causes cellulites, osteomyelitis, and infectious arthritis.

Vaccination
with Hib conjugate vaccine is effective in preventing Hib infection, but does not prevent infection with unencapsulated strains

Taxonomy
Family: Campylobacteriaceae

Natural habitats
In the intestinal tract of animals.

Man is infected by direct contact with infected animals or by consumption of contaminated water or food, especially chicken and sometimes raw milk

Clinical significance
C. jejuni and C. coli continue to be the most common Campylobacter species associated with diarrheal illness and produce clinically indistinguishable infections.

In patients with gastroenteritis caused by C. jejuni / C. coli, patients symptoms range from none to severe, including fever, abdominal cramping, and diarrhea (with or without blood/fecal white cells), that lasts several days to more than one week.

Symptomatic infections
are usually self-limited, but relapses may occur in 5 to 10% of untreated patients.

Campylobacter infections may mimic acute appendicitis and result in unnecessary surgery.

The most common condition is enteritis, a large number of patients followed by acute colitis (enterocolitis).

Campylobacter infections may occur as acute appendicitis, which is sometimes unnecessary surgery.

Guillain-Barré syndrome,
and reactive arthritis may be the result of a Campylobacter infection.

Taxonomy
Family: Campylobacteriaceae
Arcobacter
Campylobacter

Natural habitats
In the intestinal tract of animals.
Man is infected by direct contact with infected animals or by consumption of contaminated water or food, especially chicken and sometimes raw milk

Clinical significance
C. jejuni and C. coli continue to be the most common Campylobacter species associated with diarrheal illness and produce clinically indistinguishable infections.

In patients with gastroenteritis caused by C. jejuni / C. coli, patients symptoms range from none to severe, including fever, abdominal cramping, and diarrhea (with or without blood/fecal white cells), that lasts several days to more than one week.

Symptomatic infections
are usually self-limited, but relapses may occur in 5 to 10% of untreated patients.

Campylobacter infections may mimic acute appendicitis and result in unnecessary surgery.

C. jejuni is the most often recognized infection preceding the development of Guillain-Barré syndrome.

C. jejuni is in humans the most isolated.

The most common condition is enteritis, a large number of patients followed by acute colitis (enterocolitis).

Campylobacter infections may occur as acute appendicitis, which is sometimes unnecessary surgery.

Guillain-Barré syndrome,
and reactive arthritis may be the result of a Campylobacter infection.

Several Burkholderia species have been isolated from human clinical samples, but only Burkholderia cepacia complex, B. gladiola, B. mallei, B. pseudomallei are generally recognized as human pathogens.

Taxonomy
Family: Burkholderiaceae

Natural habitat
They are found in soil and surface water primarily in tropical and subtropical areas.
They have been isolated in the rice-growing regions of northeast Thailand, western Cambodia, Laos, and southern and central Vietnam. Also in northern Australia, Madagascar and Mauritius.

They can survive deep in the ground and to be rinsed during the rainy season to the surface.

Transmission
There is no person to person transmission

B. pseudomallei is acquired from the environment by inoculation through cut or abraded skin, inhalation, or ingestion.

Clinical significance
B. pseudomallei is the causative agent of the human and animal disease melioidosis.

Melioidosis
is an especially important potential travel related illness for those with CF, and persistent colonization of airways with B. pseudomallei can occur in CF despite prolonged therapy.

Infection with this organism should be considered in the differential diagnosis of any individual with a fever of unknown origin or a tuberculosis-like illness who has a history of travel to a region where B. pseudomallei infection is endemic.

Several Burkholderia species have been isolated from human clinical samples, but only Burkolderia cepacia complex, B. gladioli , B. mallei and B. pseudomallei are generally recognized as human pathogens.

Taxonomy
Family: Burkholderiaceae

Burkholderia cepacia complex includes genomospecies
B. ambifaria, B. anthina, B. arboris, B. cepacia, B. cenocepacia, B. diffusa, B. dolosa, B. latens, B. metallica, B. multivorans, B. phenazinium, B. pyrrocinia, B. seminalis, B. stabilis, B. vietnamiensis

Natural habitat
They are found in water and soil and can survive for prolonged periods in moist environments.
These bacteria can act as a powerful pesticide, capable of eliminating many soil-borne plant pathogens.

Transmission
B. cepacia complex is highly transmissible between cystic fibrosis patients and can be transferred from one CF patient to another in hospitals, health clinics, and social environments.

They are a significant risk factor for morbidity and mortality in CF.

Clinical significance
B. cepacia complex has long been recognized as an occasional opportunistic human pathogen, capable of causing a variety of infections, including bacteremia, urinary tract infection, peritonitis, and pneumonia in persons with underlying illness.

Like cystic fibrosis (CF), they are particularly susceptible to infection.

Cystic fibrosis
is a genetic, life-threatening disorder that primarily affects the digestive system and the lungs.

It is a most common potentially lethal autosomal recessive disease.

Strains of B. cepacia complex are frequently associated with aggressive pneumonia that is accompanied by rapidly fatal bacteremia.(cepacia syndrome)

Several Burkholderia species have been isolated from human clinical samples, but only Burkoldeia cepacia complex, B. gladioli , B. mallei and B. pseudomallei are generally recognized as human pathogens.

Taxonomy
Family: Burkholderiaceae

Burkholderia cepacia complex includes genomospecies
B. ambifaria, B. anthina, B. arboris, B. cepacia, B. cenocepacia, B. diffusa, B. dolosa, B. latens, B. metallica, B. multivorans, B. phenazinium, B. pyrrocinia, B. seminalis, B. stabilis, B. vietnamiensis

Natural habitat
They are found in water and soil and can survive for prolonged periods in moist environments.
These bacteria can act as a powerful pesticide, capable of eliminating many soil-borne plant pathogens.

Transmission
B. cepacia complex is highly transmissible between cystic fibrosis patients and can be transferred from one CF patient to another in hospitals, health clinics, and social environments.

They are a significant risk factor for morbidity and mortality in CF.

Clinical significance
B. cepacia complex has long been recognized as an occasional opportunistic human pathogen, capable of causing a variety of infections, including bacteremia, urinary tract infection, peritonitis, and pneumonia in persons with underlying illness.

Like cystic fibrosis (CF), they are particularly susceptible to infection.

Cystic fibrosis
is a genetic, life-threatening disorder that primarily affects the digestive system and the lungs.
It is a most common potentially lethal autosomal recessive disease.

Strains of B. cepacia complex are frequently associated with aggressive pneumonia that is accompanied by rapidly fatal bacteremia. (cepacia syndrome)

Several Burkholderia species have been isolated from human clinical samples, but only Burkoldeia cepacia complex, B. gladioli , B. mallei and B. pseudomallei are generally recognized as human pathogens.

Taxonomy
Family: Burkholderiaceae

Burkholderia cepacia complex includes genomospecies
B. ambifaria, B. anthina, B. arboris, B. cepacia, B. cenocepacia, B. diffusa, B. dolosa, B. latens, B. metallica, B. multivorans, B. phenazinium, B. pyrrocinia, B. seminalis, B. stabilis, B. vietnamiensis

Natural habitat
They are found in water and soil and can survive for prolonged periods in moist environments.
These bacteria can act as a powerful pesticide, capable of eliminating many soil-borne plant pathogens.

Transmission
B. cepacia complex is highly transmissible between cystic fibrosis patients, CF, and can be transferred from one CF patient to another in hospitals, health clinics, and social environments.

They are a significant risk factor for morbidity and mortality in CF.

Clinical significance
B. cepacia complex has long been recognized as an occasional opportunistic human pathogen, capable of causing a variety of infections, including bacteremia, urinary tract infection, peritonitis, and pneumonia in persons with underlying illness.

Like cystic fibrosis (CF), they are particularly susceptible to infection.

Cystic fibrosis
is a genetic, life-threatening disorder that primarily affects the digestive system and the lungs.

It is a most common potentially lethal autosomal recessive disease.

Strains of B. cepacia complex are frequently associated with aggressive pneumonia that is accompanied by rapidly fatal bacteremia.(cepacia syndrome)

Taxonomy
Family: Moraxellaceae

Natural habitat
They are common inhabitants of the upper respiratory tract

Clinical significance
Usually nonpathogenic and rarely infects humans

They have been reported as rare causative pathogen of infections in humans.

Brucella cultures should be handled using BSL-3 practices, with culture manipulations being done in a biological safety cabinet.

General information
Brucella from Sir David Bruce (1855-1931), microbiologist in Australia and England.

Brucellosis continues to be one of the most common laboratory-acquired infections.

Practices associated with transmission in the laboratory include unprotecting handling of specimens, sniffing of plates, mouth pipetting and exposure of the eyes, nose, or mouth to infectious aerosols.

Taxonomy
Family: Brucellaceae

Natural habitats
Brucella are facultative intracellular parasites, taking as their natural habitat a variety of animal species.

Human pathogen in order of decreasing virulence

B. melitensis - Malta fever sheep, goats, alpacas and camel
B. suis - Brucellosis pigs, swine, reindeer and caribou
B. abortus - Bang's disease cattle, camels, buffalo, yaks and horses
B. canis - Brucellosis dogs

Malditof knows only B. melitensis

Clinical significance

Transmission from human to human is very rare

Brucellosis
Although the disease can begin acutely, the beginning is usually insidious and is characterized by slight fever without local symptoms.
The fever is irregular and is accompanied with complaints of headache, malaise, fatigue, sweating and joint problems.

They can live intracellular and invade a variety of tissues.

Incubation period of 1 week to 2-3 months.

Sometimes it proceeds acutely with wavy fever (febris undulans).
They spread into the bloodstream and localize in the liver, spleen, bone and other tissues and form granulomas there.
Are therefore difficult to reach for the immune system and antibiotics.

Complications include bacterial endocarditis, nephritis, meningoencephalitis and orchitis.

The fatality rate is <1% and is mainly associated with the occurrence of bacterial endocarditis.

In non-zoonotic areas the infection proceeds possibly exacerbated by doctor's delay, probably due to a slower running diagnostics because the disease is low in the differential diagnosis.

Serology
Usually the diagnosis is established by serological testing.
Practical nature of the reasons are: it can take up to 4 weeks before a culture is positive and in practice, the patient is often already used antibiotics, so the culture is useless.

Taxonomy
Family: Alcaligenaceae

Natural habitat
B. parapertussis, once thought to be strictly a human pathogen, is also found in sheep.

The bacterium is spread by airborne droplets, its incubation period is 7-14 days.

Clinical significance
B. parapertussis causes a pertussis syndrome similar to but usually less severe than that caused by B. pertussis

While B. parapertussis may be quite prominent in isolated outbreaks, overall is account for 2-20% of Bordetella isolates.

Symptomatic
B. parapertussis infections is more commonly present as a nonspecific cough illness or bronchitis.

Mixed infections
by B. pertussis and B. parapertussis have been reported, and this should be considered when examining primary cultures from clinical specimens.

Pertussis (or whooping cough) ⇒ see B. pertussis

Taxonomy
Family: Alcaligenaceae

Natural habitats
B. pertussis is thought to be a strictly human pathogen
The bacterium is spread by airborne droplets, its incubation period is 7-14 days.

Clinical significance
B. pertussis cause pertussis, or whooping cough.

Pertussis (or whooping cough)
is an infection of the respiratory system characterized by a “whooping” sound when the person breathes in.

B. pertussis continues to circulate in population where high vaccination coverage of infants and children is achieved, because the protection induced after natural infection and vaccination decreases after several years.

Pertussis is most dangerous in infants, and most hospitalizations and death occur in this age group.
The signs and symptoms are similar to a common cold; running nose, sneezing, mild cough, and low-grade fever.
The patient becomes more contagious during the catarral stage of infection, normally two weeks after the coughing begins.

It may become airborne when the persons cough, sneezes, or laughs.

The cough is a crowing inspiratory sound characteristic of pertussis. After a spell, the patient might make a “whooping” sound when breathing in, or may vomit.

Adults have milder symptoms, such as prolonged coughing without the “whoop”.
Infants less than six month also may not have the typical whoop.

A coughing spell may last a minute or more, producing cyanosis, apnoea, and seizures.

When not in a coughing fit, the patient does not experience trouble breathing.

All Vibrionaceae require Na+ for growth

Taxonomy
Family: Vibrionaceae

Natural habitats
Marine environments

Clinical significance
V. vulnificus causes primary cellulites, septicemia, foodborne disease and wound infections.

Patients usually have predisposing conditions such as liver disease, immunosuppression, or other chronic diseases.

Patients typically present with a sudden onset of fever and chills, vomiting, diarrhea, and abdominal pain.

Secondary skin lesions
often appear, progressing to bulla formation and necrosis.

Endotoxic shock
often occurs and can rapidly lead to death.

They also cause severe wound infections, usually after trauma and exposure to marine animals or the marine environment.

All Vibrionaceae require Na• for growth

Taxonomy
Family: Vibrionaceae

Natural habitats
Marine environments

Clinical significance
V. parahaemolyticus are the leading course of foodborne intestinal infections, almost always associated with the consumption of oysters, raw fish or shellfish.

They are primarily associated with diarrhea, but it had occasionally isolated from extraintestinal sites. They causes gastroenteritis with nausea, vomiting, abdominal cramps, lowgrade fever and chills.

The diarrhea is usually watery, but can on rare occasions be bloody.

Rehydration is usually the only treatment needed, but in some severe cases the patient requires hospital admission. Antimicrobial therapy may be beneficial.

All Vibrionaceae require Na+ for growth

Taxonomy
Family: Vibrionaceae

It is divided into 3 major subgroups
1 V. cholerae-O1
⇒ 3 serovars: Inaba, Ogawa, Hikojima
⇒ 2 biotypes: El Tor and Classical
2 V. cholerae-O139
3 V. cholerae non O1

Natural habitats
Marine environments and people.
Cholera infections are most commonly acquired from drinking water in which V. cholerae is found naturally or into which the water has been polluted from the feces of an infected person.

Transmission from person to person, is rarely documented.

Clinical significance
Vibrio cholera is the only species that causes endemic, epidemic, and pandemic cholera.

They secretes cholera toxin, that causes watery diarrhea.
They ranging from asymptomatic to cholera gravis.
Symptoms include abrupt onset of watery diarrhea (a grey and cloudy liquid / rice water stools), or occasionally vomiting and abdominal cramps.

Dehydration with symptoms and signs such as thirst, dry mucous membranes, decreased skin turgor, sunken eyes, hypotension, tachycardia, renal failure, seizures, somnolence, coma and death.
The disease typically lasts from 4-6 days.

Worldwide cholera is the second leading cause of death for children under the age of 5 and at least 120.000 death are estimated to be caused by cholera each year. (source: wikipedia)

Taxonomy
Family: Neisseriaceae

Natural habitats
Inhabits soil and water in tropical and subtropical climates.

Clinical significance
Causes rarely infections in humans

Localized infections usually arise from contaminated wounds, and septicemia with multiple organ abscesses may follow.

Taxonomy
Family: Enterobacteriaceae genus: S. rubidaea

Natural habitats
They are widely distributed in nature.

Clinical significance
Rarely from clinical material

Have been isolated from humans and are usually transients or cause of opportunistic infections.

Taxonomy
Family: Morganellaceae

P. alcalifaciens
- P. rustigianii (P. alcalifaciens biogroep 3)
P. rettgeri
P. stuartii

apathogeen P. heimbachae, P. vermicola

Natural habitats
They are ubiquitous in the environment, especially water and clinical samples, such as; urine, feces, blood, wounds and throat. Also occur in animals, mammals, birds, reptiles and insects.

Clinical significance
Patients with burns are at a higher risk of Providencia wound infection, like P. stuartii and P. rettgeri
Patients who develop Providencia urinary tract infections often have long-standing dependence on an indwelling urinary catheter.

Both species (P. rettgeri more commonly than P. stuartii) have recently been implicated as etiologic agents in traveler's diarrhea, making travel history important in patients with acute-onset diarrhea.

Vomiting is common in P. rettgeri gastrointestinal infection.

Taxonomy
Family: Morganellaceae

P. alcalifaciens
- P. rustigianii (P. alcalifaciens biogroep 3)
P. rettgeri
P. stuartii

apathogeen P. heimbachae, P. vermicola

Natural habitats
They are ubiquitous in the environment, especially water and clinical samples, such as; urine, feces, blood, wounds and throat. Also occur in animals, mammals, birds, reptiles and insects.

Clinical significance
Patients who develop Providencia urinary tract infections often have long-standing dependence on an indwelling urinary catheter.

P. alcalifaciens, P. rustigianii, and P. heimbachae

Infections with these Providencia species are most likely to elicit gastrointestinal symptoms.

P. alcalifaciens infection is also associated with overseas travel.

Taxonomy
Family: Moraxellaceae
P. vulgaris
- P. penneri (= P. vulgaris genomosp 1)
- P. hauseri (= P. vulgaris genomosp 3)

Natural habitats
Proteae occur in humans, animals and the environment, especially in locations where animal protein decomposes.

Clinical significance
They were isolated from wounds, soft tissue and urine

P. vulgaris and P. penneri are easily isolated from individuals in long term care facilities and hospitals and from patients with underlying diseases or compromised immune systems.

In people with congenital or anatomic abnormality of the urinary tract or a stone in the urinary tract, are predominantly Proteus (mostly P. mirabilis) infections.
They quickly put this urea into ammonia, which creates an alkaline environment.

This can be harmful to the kidney and promotes the formation of stones materials consist of a biochemical complex, which is called struvite.

In the stone Proteus bacteria can survive despite therapy, leading to chronic UTI.

Taxonomy
Family: Enterobacteriaceae
K. pneumoniae subsp pneumoniae
K. pneumoniae subsp. ozaenae
K. pneumoniae subsp. rhinoscleromatis
K.oxytoca

Natural habitats
They are widely distributed in nature and can be found in water, soil, on plants and have been isolated from clinical samples of humans and animals.

They are part of the normal intestinal flora of humans and animals.

Clinical significance
K. pneumoniae & K. oxytoca
They are important causes of nosocomial (hospital-acquired) and community-acquired infections in humans.

They can cause a variety of infections of the urinary and respiratory tract (pneumonia).

This species can cause septicemia, peritonitis, meningitis, infections of wounds and burns.

Taxonomy
Family: Enterobacteriaceae
E. aerogenes
E. cloacae complex
- E. cloacae, E. asburiae, E. hormaechei, E. kobei, E. ludwigii
E. amnigenus I
E. cancerogenus
E. gergoviae
E. intermedium

Pathogenic to plants: E. amnigenusII, E. cowanii, E. pyrinus, E. radicincitans

Natural habitats
Can be found in soil, water, sewage, food and also on the human skin and in the intestinal tract.

Clinical significance
Enterobacter species cause a wide variety of nosocomial infections, including respiratory- and urinary tract infections, wound infections, osteomyelitis, meningitis and bacteremia.

Especially patients which are hospitalized for more than 72 hours and immunocompromised patients are at risk for an infection caused by Enterobacter.

Taxonomy
Family: Enterobacteriaceae

C. freundii complex
-- C. freundii, C. braakii, C. gilleni, C. murlinae, C. sedlakii, C. werkmanii, C. youngae
C. koseri (C. diversus)
C. amalonaticus
C. farmeri

Natural habitats
Isolated from soil, water, food, feces, urine of humans and animals.
They are commensals of the intestine.

The natural habitat of some Citrobacter species is unknown.

Clinical significance
Citrobacter species cause a wide variety of nosocomial infections, including infections of the respiratory- and urinary tract, blood, wounds, bone, meninges and other normally sterile tissues.

Especially patients which are hospitalized for more than 72 hours and neonates and immunocompromised patients are at risk for an infection caused by Citrobacter.

In many cases the infection arises from the gastrointestinal or genitourinary tract.

Taxonomy
Family: Flavobacteriaceae,
genus: C.ochracea, C.gingivalis, C.sputigena, C.haemolytica and C.granulosa

Natural Habitat
They are normal inhabitants of the human mouth

Clinical Significance
The first three are also associated with juvenile and adult periodontitis, whereas the latter two been isolated from supragingival plaque of healthy adults as well as from subgingival plaque in adult periodontitis.

All five species may cause septicemia and other infections in immunosuppressed (mainly neutrpenic) patients.

Taxonomy
Family: Enterobacteriaceae

Yersinia has 3 species of which are pathogenic for humans, namely

Y. enterocolitia, Y. pseudotuberculosis and Y. pestis

Natural habitats
Comes in all animal species, but has also been isolated from (drinking) water, soil and vegetables, also from animal products such as raw milk, cream, ice cream, beef, pigs oysters, lamb and chicken.

Clinical significance
They can cause yersiniosis in human and animals and they are a significant food-borne pathogen.

Infection usually lead to mild self-limiting enterocolitis, terminal ileitis and adenitis in humans.

Symptoms may include watery or bloody diarrhea and fever.

The infections are sometimes followed by chronic inflammatory diseases such as arthritis and erythema nodosum

Sepsis may occur with a high mortality in debilitated patients with severe underlying diseases.

Yersinia can also occur in pus of deep abscesses.

General Information
This organism is known to spontaneously develop L forms (bacteria without cell walls) which may allow its persistence in some sites

Taxonomy
Family: Leptotrichiaceae

Natural habitats
In the upper respiratory tract of rats (mice, gerbils, squirrels, ferrets, weasels and other rodents)

Clinical significance
They are pathogenic for humans and are transmitted by 2 routes
1. rat bite or contact with rat feces or saliva
►Rat-bite fever
2. ingestion of contaminated food
► Haverhill fever

The patient develop acute onset of chills, fever, headache, vomiting and often severe joint pains.

Complication can occur, including endocarditis, brain abscess, prostatitis and pancreatitis

Taxonomy
Family: Pseudomonadaceae
Genus: formerly Flavimonas

Natural habitat
Isolated from soil, water, plants and clinical specimens.
Does not belong to the human flora.

Clinical significance
Has only rarely been associated with human infections.

Infections is frequently linked to implanted or indwelling materials or to invasive procedures.

Taxonomy
Family: Enterobacteriaceae
(Plesiomonas is Greek for neighbors)

Natural habitats
Is isolated from a wide range of mammals, birds, fish, water-dwelling, reptiles and amphibians.

Clinical significance
Human P. shigelloides infections are associated with living in or travel to tropical countries and / or a history of seafood consumption; both acute diarrhea and chronic diarrhea episodes of > 2 weeks have been reported.

Most of the infections are self-limited.

Taxonomy
Family: Pseudomonadaceae
Genus: Stutzerimonas stutzeri
Formely: Pseudomonas stutzeri

Natural habitat
Occurs everywhere in soil and water. Is also found in humus, manure, straw, sewage, stagnant water, utensils in hospitals and eye makeup

Clinical significance
Infections are rare and mostly in patients with underlying disease and who have been exposed to contaminated medical instruments and solutions.

Taxonomy
Family: Pseudomonadaceae

Natural habitat
Isolated from soil, plants, water surfaces, rarely from clinical samples.

Clinical significance
Opportunistic pathogen.

General information
Its name come from the production of the soluble fluorescent pigment pyoverdin

Taxonomy
Family: Pseudomonadaceae

Natural habitat
Isolated from soil, plants, water surfaces, rarely from clinical samples.

Clinical significance
They are common course of food contamination.

In food, P. fluorescens is a common contaminant, especially since it actively enjoys lower temperatures like those found in fridges.

Dairy products are especially vulnerable to P. fluorescens contamination.

Taxonomy
Family: Pseudomonadaceae

Natural habitat
Widely distributed in nature. Isolated from soil, water, plants and clinical human specimens.
It is also found in most man-made environments throughout the world.
Because they survive in a moist environment, they can cause problems in a hospital.

Pseudomonas found in all types of aqueous solutions, including disinfectants, soap, eye drops, dialysis fluid, sink etc

Clinical significance
Is the most important pathogen of the genus Pseudomonas.
They cause a broad spectrum of infections, ranging from superficial skin lesions to sepsis.
Infections occur mainly in patients with burns, cystic fibrosis, acute leukemia, organ transplants, otitis externa ("swimmer 's ear") and intravenous drug users.
They also cause urinary tract-, lower respiratory- and eye infections.

Taxonomy
Family: Weeksellaceae

Natural habitat
In the environment, does not belong to the normal flora of the human being.

Clinical significance
Is mainly found in urine and vagina.

Taxonomy
Family: Xantomonadaceae
Formerly: Pseudomonas maltophilia, Xanthomonas maltophilia

Malditof also has S. acidaminiphila, S. nitireducens, S. rhizophilia these are apathogenic

Natural habitat
In the environment, especially water and in the water from hospitals.

Does not belong to the normal flora of the human being.

Clinical significance
It is an important pathogen of nosocomial (hospital-acquired infections) which is associated with a substantial morbidity and mortality, especially in weakened or immune compromised patients on a respirator.
They are increasingly isolated.

They have been isolated in, bacteriemia, pneumonia, UTI, eye infections, endocarditis, meningitis, peritonitis, cholangitis and soft tissue infections.

S. maltophilia is also becoming more common in CF patients.

Taxonomy
Family: Sphingomonadaceae
- S. parapaucimobilis

Malditof
All others are apathogenic

Natural habitat
In the environment, especially water and in the water from hospitals.

Does not belong to the normal flora of the human being.

Clinical significance
Virulence factor is unknown.

Transmission probably due to exposure to contaminated instruments or solutions.

Catheter-related sepsis, liquor, wound and urinary tract infections occur.

Of this genus are S. paucimobilis and S. parapaucimobilis clinically important

General information
Sphingobacterium species are capable of behaving as an opportunistic pathogen and producing severe infection in compromised patients.

Taxonomy
Family: Sphingobacteriaceae
Formerly: Flavobacterium

Natural habitat
In the environment, in food products, in an aqueous environment of a hospital, such as; the sink, incubators, water from the tap, hemodialysis systems and all kinds of aqueous solutions.

Does not belong to the normal flora of the human being.

Clinical significance
They are rarely involved in human infections.

Two species S. multivorum and S. spiritivorum have occasionally been associated with bacteremia, peritonitis and chronic respiratory infections in patients with severe underlying conditions.

General information
Sphingobacterium species are capable of behaving as an opportunistic pathogen and producing severe infection in compromised patients.

Taxonomy
Family: Sphingobacteriaceae
Formerly: Flavobacterium

Natural habitat
In the environment, in food products, in an aqueous environment of a hospital, such as; the sink, incubators, water from the tap, hemodialysis systems and all kinds of aqueous solutions.

Does not belong to the normal flora of the human being.

Clinical significance
They are rarely involved in human infections. Two species S.multivorum and S. spiritivorum have occasionally been associated with bacteremia, peritonitis and chronic respiratory infections in patients with severe underlying conditions.

Taxonomy
Family: Comamonadaceae
Formerly: Comamonas, Pseudomonas

Natural habitat
Environment, soil, water and hospital environment, does not belong to the human flora.

Clinical significance
Clinical significance is unknown. Is rarely found in patients.

Transmission probably due to exposure to contaminated instruments or solutions.

Taxonomy
Family: Burkholderiaceae
Formerly: Ralstonia

Natural habitat
They are found worldwide in the environment, water, soil, on plants, fruits and vegetables.
Because they survive in a moist environment, they can also cause problems in a hospital.

Clinical significance
Is rarely found as a cause of infection.
Are isolated from CF patients.
Still, the pathogenic role in this uncertain.

General information
In the past, its effects have often been attributed wrongly to Shewanella putrefaciens.
There has been a rising number of disease cases attributed to S. algae in the last decade, thanks to correct classification

Taxonomy
Family: Shewanellaceae / Formerly: Pseudomonas

Natural habitat
In the environment and in food products, does not belong to the normal flora of the human being.
- S. algae occurs in the vicinity of salt water
- S. putrefaciens isolated from fish, chicken, meat, fresh and saltwater.

Clinical significance
Clinical significance unknown.
Shewanella algae is of interest because of its potential to be a serious human pathogen.
It is known to cause peritonitis and obstructive pneumonia, ear infections, bacteraemia, rare occurrences of skin and soft tissue infections, bone and joint infections, and many others.

S. algae is most commonly isolated in humans

> 80% (Note errors) and is considered to be more virulent than S. putrefaciens

Taxonomy
Family: Shewanellaceae
Formerly: Pseudomonas Malitof apathogenic: S. baltica, S. fidelis, S. frigidimarina, S. profunda

Natural habitat:
In the environment and in food products, does not belong to the normal flora of the human being.
- S. algae occurs in the vicinity of salt water
- S. putrefaciens isolated from fish, chicken, meat, fresh and saltwater.

Clinical significans
Clinical significance unknown.
Is often found in mixed cultures. In cellulitis, otitis media, skin and soft tissue infections, peritonitis, respiratory- and urinary tract infections S. algae is most commonly isolated in humans
> 80% (Note errors) and is considered to be more virulent than S. putrefaciens

Taxonomy
Family: Acetobacteracea

Natural habitat
Unknown, it is rarely found in humans.

Clinical significance
Clinical significance unknown.

Most isolates from blood, wounds or urinary tract are found in immune compromised individuals.

Taxonomy
Family: Rhizobiaceae
Formely: Rhizobium
Genus: Agrobacter

Natural habitat
Environment, soil, water and plants.
They are no part of the flora of man.

Clinical significance
Transmission probably due to exposure to contaminated instruments or solutions.

Has a low virulence, except in people with lowered immunity.

Taxonomy
Family: Burkholderiaceae
Formerly Burkholderia

Natural habitat
They are found in moist environments such as soils, on plants, fruits and vegetables.
Because they survive in a moist environment, they can cause problems in a hospital.

Be isolated from CF patients.

Clinical significance
They are rarely found as a cause of infection.
The bacteria has seriously affected humans with poor health.
Several hospitals have reported outbreaks, in particular, patients with cystic fibrosis and Crohn’s Disease have been shown to be infected R. pickettii

They can cause pneumonia, meningitis, endocarditis, osteomyelitis, bacteremia and nosocomial infections.

Taxonomy
Family: Rhodobacteracea
Formerly classified as a eugenic oxidizer group 2 (EO-2)

Natural habitat
In the environment, does not belong to the normal flora of the human being.

Clinical significance
Isolated from various wounds and blood

Taxonomy
Family: Alcaligenaceae

Formerly Moraxella urethralis

Natural habitat
Unknown, can colonize the distal (bottom section) of the urethra

O. urethralis is commensal in the urogenitaliën

Clinical significance
Transmission through manipulation of catheters.

These microorganisms are usually isolated from the urinary tract and also known as cause of urosepsis.

Ochrobactrum species are closely related to Brucella species

Taxonomy
Family: Brucellaceae
Genus: Brucella anthropi
Formely: Ochrobactrum anthropi

Natural habitat
Commonly found in soil and water or in hospital environment,

Clinical significance
Cases of pathogenic O. anthropi are rare.

Infections usually take place through the use of contaminated equipment, or in the hospital wounds obtained by the application of catheters and the like.

This is probably due to the ability to attach itself to plastic. The severity of the infection which then occurs is dependent on the host. It can be a bacterieëmie, sepsis, to cause septic shock.

Taxonomy
Family: Flavobacteriaceae
previously known as Flavobacterium odoratum

Natural habitat
Commonly found in soil and water.
Water in the hospital environment is frequently suspected of carrying this organism.

Clinical significance
They are rare clinical isolates and are often not considered pathogenic.

Taxonomy
Family: Moraxellaceae

Natural habitat
Is a commensal organism of the upper respiratory tract

Clinical significance
Usually nonpathogenic.

May be involved in chronic bronchitis and upper respiratory disease and it has been found in individuals with endophtalmitis and occasionally in blood in systemic disease.

Taxonomy
Family: Moraxellaceae

Natural habitat
The natural habitat is not certain

Clinical significance
Pathogenicity uncertain

Patients with cystic fibrosis (CF) may be colonized with unusual gram-negative bacilli whose identification is difficult and clinical impact unclear.

Taxonomy
Family: Rhodospirillaceae

Relationship
I.limosus belongs to the α-proteobacteria (class), and is therefore not closely related to B.cepacia complex or P. aeruginosa

Natural habitat
The natural reservoir is yet to be discovered, but its relationship with other non-fermentative rods suggests ecological resources

Clinical significance
I. limosus is able to stay for several months in the respiratory tract of CF-patients

Just as with the P. aeruginosa is an abundant production of mucus from I. limosus favorable for a persistent chronic infection.

However, the pathogenic role of I. limosus is unclear.

Taxonomy
Family: Flavobacteriaceae
Formerly known as Flavobacterium and Chryseobacterium meningosepticum

Natural habitat
They are ubiquitous in the environment, in food products, and in an aqueous environment of the hospital, such as the sink, incubators, tapwater, or hemodialysis systems.

They are not a member of the normal human flora.

Clinical significance
The species are also a rare cause of nosocomial infections including bacteremia, pneumonia, endocarditis and meningitis, especially in immunocompromised patients.

Several studiessuggest that E. anophelis, and not E. meningoseptica, is the predominant human pathogen of this genus, but the identification of this species is difficult.

Taxonomy
Family: Flavobacteriaceae
Formerly Flavobacterium indologenes,

Apathogen: C.ginsenosidimutans, C.hagamense, C.joostei, C.oranimense, C.scophthalmum

Natural habitat
They are ubiquitous in the environment, in food products, in an aqueous environment of a hospital, such as; the sink, incubators, water from the tap, hemodialysis systems and all kind of aqueous solutions.

They are not a member of the normal human flora.

Clinical significance
Transmission through contaminated equipment or solutions.
Origin is not always known.
Almost never a clinical significance.

Described as a cause of bacteremia in immunocompromised patients or hospital infection through contaminated instruments
and has been identified as the cause of neonatal meningitis.

No transmission from human to human

B. vesicularis and B. diminuta, formely classified as members of group IV of the genus Pseudomonas, are the most frequently isolated Brevundimonas species in human infections

Taxonomy
Family: Caulobacteriaceae

B. vesicularis and B. diminuta are the only human pathogens.
Not pathogenic: B. aurantiaca, B. intermedia, B. nasdae, B. subvibrioides

Natural habitat
They are ubiquitous in the environment.
Because they survive in a moist environment, they can cause problems in a hospital.

Clinical significance
They are rarely isolated from clinical samples.

Very few cases of bacteremia have been reported, with pneumonia, infective endocarditis and spontaneous bacteria peritonitis being the most common foci of infection.

Both B. vesicularis and B. diminuta have been described as opportunistic pathogens in immunocompromised hosts

General Information
Yersinia pestis was discovered in Hong Kong in 1894 by a Swiss physician Alexandre Yersin.

He linked Y. pestis to the bubonic plague, an epidemic that ravaged Europe during the 1300s.

The organism was isolated during a outbreak in Hong Kong

Taxonomy
Family: Enterobacteriaceae
It was formerly known as Pasteurella pestis.

The closest relative is the gastrointestinalpathogen Y. pseudotuberculosis and more distantly Y. enterocolytica

Natural habitats
Yersinia pestis interacts mainly with rodents such as rats and fleas (Xenopsylla cheopsis)

Through these carriers, Yersinia pestis is able to invade human cells and create diseases.

Clinical significance
Human Y. pestis infection takes three main forms, pneumonic, septicemic and bubonic plagues.

All three forms were responsible for a number of high-mortality epidemics troughout human history, including: the sixth century's Plague of Justinian, the Black Death, which accounted for the death of at least one-third of the European population between 1347 and 1353; and the 19th century's Third Pandemic

It has now been shown that these plagues probably originated in rodent populations in China.

Yersinia pestis infections must be diagnosed quickly due to the high virulence of these organisms.
Death from pneumonic plague can occur in as little as 24 hours after the first appearance of symptoms.

Taxonomy
Family: Enterobacteriaceae genus: S. marcescens
2 subsp.- S. marcescens ssp marcescens
- S. marcescens ssp sakuensis
S. odorifera
S. liquefaciens group
- S. liquefaciens
- S. grimesii

S. plymuthica and S. rubidiaea (red pigment, rarely from clinical material)

Not pathogenic
S. entomophila, S. ficaria, S. fonticola, S. proteamaculans, S. quinivorans, S.ureilytica

Natural habitats
They are widely distributed in nature. Isolated from water, soil, foods.

Clinical significance
Serratia ssp are notorious health care-associated pathogens and colonizers

Transmission is predomiately from person to person, but medical apparatuses, intravenous fluid, and other solutions are often implicated as well.

In children, the gastrointestinal tract is a common source of infections.

Pigment
Production in S. marcescens appears to be a marker that the strain is environmental in origin and of low virulence.

Taxonomy
Family: Enterobacteriaceae
(formerly designated : Klebsiella)

R. terrigena & R. planticola (plant pathogen)

Natural habitats
They are found in water, fish, insects, nature and land.

They are commensals in the gut of humans and animals.

Clinical significance
R. ornithinolytica has the ability to convert histidine to histamine in scombroid fish.

Infection causes redness of the skin.

Scombroid food poisoning
Is a foodborne illness from eating spoiled fish.
It is often missed because it resembles an allergic reaction

The generic name Rahnella was given to honor the German-American bacteriologist Otto Rahn, and the species name aquatilis was selected because the organism is usually isolated from water.

Taxonomy
Family: Enterobacteriaceae

Natural habitats
As the name implies, they are ubiquitous in the environment, especially water, it is a water-dweller. Is also on food (meat, fresh water, fish and dairy products) plants, human and animal feces.

Clinical significance
Isolated from immunocompromised human patients, blood, sputum, wound, burn infections and bacteremia.

General information
Organisms belonging to the genus Providencia have undergone many taxonomic changes since their first description, with frequent confusion and overlap between organisms of the closely related genera Providencia, Proteus and Morganella

Taxonomy
Family: Morganellaceae

P. alcalifaciens
- P. rustigianii (P.alcalifaciens biogroep 3)
P. rettgeri
P. stuartii

apathogeen P. heimbachae, P. vermicola

Natural habitats
They are ubiquitous in the environment, especially water and clinical samples, such as; urine, feces, blood, wounds and throat.
Also occur in animals, mammals, birds, reptiles and insects.

Clinical significance
Patients with burns are at a higher risk of Providencia wound infection, like P. stuartii and P. rettgeri
Patients who develop Providencia urinary tract infections often have long-standing dependence on an indwelling urinary catheter.

Both species (P. rettgeri more commonly than P. stuartii) have recently been implicated as etiologic agents in traveler's diarrhea, making travel history important in patients with acute-onset diarrhea.

Taxonomy
Family: Enterobacteriaceae
P.vulgaris
- P.penneri (= P.vulgaris genomosp 1)
- P.hauseri (= P.vulgaris genomosp 3)

Natural habitats
Proteae occur in humans, animals and the environment, especially in locations where animal protein decomposes.

Clinical significance
They were isolated from wounds, soft tissue and urine

P. vulgaris and P. penneri are easily isolated from individuals in long term care facilities and hospitals and from patients with underlying diseases or compromised immune systems.

P. vulgaris is more susceptible to cause nosocomial infections

In people with congenital or anatomic abnormality of the urinary tract or a stone in the urinary tract, are predominantly Proteus (mostly P. mirabilis) infections.
They quickly put this urea into ammonia, which creates an alkaline environment. This can be harmful to the kidney and promotes the formation of stones materials consist of a biochemical complex, which is called struvite. In the stone Proteus bacteria can survive despite therapy, leading to chronic UTI.

Taxonomy
Family: Morganellaceae
genus Proteus mirabilis

Natural habitats
Proteae occur in humans, animals and the environment, especially in locations where animal protein decomposes.

Clinical significance
They are found in urinary tract infections and wounds.
Very often these infections are caused by their own fecal flora. P.mirabilis occurs in patients with chronic wounds, leg ulcers and decubitis. In people with congenital or anatomic abnormality of the urinary tract or a stone in the urinary tract, are predominantly Proteus infections.
They quickly put this urea into ammonia, which creates an alkaline environment.
This can be harmful to the kidney and promotes the formation of stones materials consist of a biochemical complex, which is called struvite.

In the stone Proteus bacteria can survive despite therapy, leading to chronic UTI.

was: Enterobacter agglomerans

P. agglomerans
P. dispersa (rarely)

Pathogeen voor planten
P. ananatis, P. stewartii ssp indologenes, P. stewartii ssp stewartii, P. terrae

Natural habitats
Widely distributed in nature. Isolated from human and animals stools

Clinical significance P. agglomerans can cause opportunistic infections in immune compromised patients.

General information
morganii from: Harry de Riemer Morgan (1863-1931), physician te London

Taxonomy
Family: Morganellaceae
M. morganii
- M. morganii ssp morganii
- M. morganii ssp sibonii

Natural habitats
Widely distributed in nature are normal inhabitants of the gut.

Clinical significance
Is most frequently considered a health care-associated pathogen, primarily causing urinary tract infections, though wound infections and bacteremias are also commonly encountered.
Respiratory infections are rare.

Taxonomy
Family: Enterobacteriaceae

Natural habitats
Widely distributed in nature.

Clinical significance
Pathogenicity undetermined (opportunistic pathogen).

Rarely isolated from clinical samples.

Kluyvera is a newly described genus in the family Enterobacteriaceae

Taxonomy
Family: Enterobacteriaceae
K. cryocrescens, K. ascorbata, K. georgiana, K. intermedia

Natural habitats
They are widely distributed in nature.

Clinical significance
They are infrequent opportunistic pathogens.

K. ozaenae and K. rhinoscleromais are associated with chronic diseases of the upper airways: ozena and rhinoscleroma.

Taxonomy
Family: Enterobacteriaceae
K. pneumoniae subsp pneumoniae
K. pneumoniae subsp. ozaenae
K. pneumoniae subsp. rhinoscleromatis

Clinical significance
- K. ozaenae
Occurs in ozena (a chronic disease of the nose characterized by foul smelling nasal discharge and atrophy of nasal structures) and other chronic diseases of the respiratory tract

- K. rhinoscleromatis
Causes a slowly progressing granulomatous disease of the nasal mucous membrane (rhinoscleroma)

Taxonomy
Family: Enterobacteriaceae
K. pneumoniae subsp pneumoniae
K. pneumoniae subsp. ozaenae
K. pneumoniae subsp.rhinoscleromatis
K. oxytoca

Natural habitats
They are widely distributed in nature and can be found in water, soil, on plants and have been isolated from clinical samples of humans and animals.

They are part of the normal intestinal flora of humans and animals.

Clinical significance
K. pneumoniae & K. oxytoca
They are important causes of nosocomial (hospital-acquired) and community-acquired infections in humans.

They can cause a variety of infections of the urinary and respiratory tract (pneumonia). This species can cause septicemia, peritonitis, meningitis, infections of wounds and burns.

Taxonomy
Family: Enterobacteriaceae

Natural habitats
Widely distributed in nature, water, soil, dairy products and rarely from clinical samples (feces) from humans and animals

Clinical significance
H. alvei seem to be opportunistic pathogens which produce infections in patients with underlying illness or predisposing factors.

May cause nosocomial infections associated with other bacteria, like septicemia, enteritis, urinary tract infections, pneumonia and abscesses.

Taxonomy
Family: Enterobacteriaceae,
Genus: Atlantibacter hermannii
Formely: Escherichia hermannii

Natural habitats
Widely distributed in nature, water, soil, foods and clinical samples.

Clinical significance
Most have been isolated from feces and wounds

Taxonomy
Family: Enterobacteriaceae, genus: Escherichia coli
E. albertii, E. fergusonii, E. hermannii, E. vulneris

Natural habitats
Widely distributed in nature, water, soil, foods and clinical samples.

The genus Escherichia will occupy the last part of the small intestine and the large intestine in humans and warm-blooded animals. In more than 99% of the isolates, it is a Escherichia coli.

E. coli is a good indicator of the water it is clean. (fecal contamination)

Clinical significance
They are generally located in the intestinal lumen (colon), but some strains can cause a variety of infections, enteritis, septicemia, peritonitis, urinary infections, meningitis (neonatal) etc, in humans and animals.

Taxonomy
Family: Enterobacteriaceae
E. aerogenes
E. cloacae complex
- E. cloacae, E. asburiae, E. hormaechei, E. kobei, E. ludwigii
E. amnigenus I
E. cancerogenus
E. gergoviae
E. intermedium

Pathogenic to plants: E. amnigenusII, E. cowanii, E. pyrinus, E. radicincitans

Natural habitats
Can be found in soil, water, sewage, food and also on the human skin and in the intestinal tract.

Clinical significance
Enterobacter species cause a wide variety of nosocomial infections, including respiratory- and urinary tract infections, wound infections, osteomyelitis, meningitis and bacteremia.

Especially patients which are hospitalized for more than 72 hours and immunocompromised patients are at risk for an infection caused by Enterobacter.

Taxonomy
Family: Enterobacteriaceae
Formerly known as Enterobacter sakazakii

Natural habitats
Can be found in soil, water, sewage, food, some dairy products and also on the human skin and in the intestinal tract.

Cronobacter sakazakii have also been found in powdered baby food.
The bacterium can grow at a low temperature, growth at 8 ° C has been documented.

Clinical significance
May cause significant infections in various anatomical sites.

Meningitis, necrotizing enterocolitis and sepsis associated with high mortality have been documented in especially neonates.

Taxonomy
Family: Enterobacteriaceae

C.freundii complex
-- C. freundii, C. braakii, C. gilleni, C. murlinae, C. sedlakii, C. werkmanii, C. youngae

C. koseri (C. diversus)
C. amalonaticus
C. farmeri

Natural habitats
Isolated from soil, water, food, feces, urine of humans and animals.
They are commensals of the intestine.

The natural habitat of some Citrobacter species is unknown.

Clinical significance
Citrobacter species cause a wide variety of nosocomial infections, including infections of the respiratory- and urinary tract, blood, wounds, bone, meninges and other normally sterile tissues.

Especially patients which are hospitalized for more than 72 hours and neonates andimmunocompromised patients are at risk for an infection caused by Citrobacter.

In many cases the infection arises from the gastrointestinal or genitourinary tract.

Taxonomy
Family: Alcaligenaceae

Natural habitats
Human are not natural carriers of B. bronchoseptica, which typically infects the respiratory tracts of smaller mammals (cat, dogs, rabbits etc)

Man is infected through contaminated aerosols animals, such as kennel cough.

B. bronchoseptica can persist in the environment for extended periods.

Clinical significance
They can cause infectious bronchitis, but rarely infect humans

Taxonomy
Family: Alcaligenaceae,
also former Alcaligenes odorans

Natural habitats
It is commonly found in the enviroment, soil and water.

They are also present in a hospital environment, where it is wet, such as; respirators and dialysis systems and can sometimes colonize the skin.

Clinical significance
Alcaligenes faecalis is usually a non-pathogenic bacteria that harbors in the human intestinal tract.

They are commonly found in mixed cultures, especially in diabetic ulcers of the legs and feet .

Transmission of A.faecalis probably due to exposure to contaminated instruments or solutions.

Taxonomy
Family: Pasteurellaceae, previously: Haemophilus
Genus: Aggregatibacter aphrophilus
Formerly: Haemophilus aphrophilus

Natural habitats
Occur in the mouth and oropharynx of healthy individuals.

It is a frequent member of the microflora of human dental plaque, particularly between the teeth and in the gingival pockets

Clinical significance
Has been isolated from blood, spinal fluid, peritoneum, pleura, wounds and jaw infections.

Opportunistic pathogen occasionally implicated in subacute endocarditis, brain abscesses, sinusitis, arthritis and osteomyelitis often caused by dental treatments that cause a break of the oral mucosal barrier and a temporary bactereamia.

The significance of the recovery of Aeromonas from stool specimens should be interpreted cautiously and must rely on both laboratory information and clinical interpretation.

Taxonomy
Family: Aeromonadaceae

Natural habitats
Aeromonas are inhabitants of aquatic ecosystems worldwide.

They don’t like saltwater.

They are also found in a wide variety of fresh produced meat (beef, poultry and pork), and dairy products (raw milk and ice cream)
And found in the gut of medical leeches and in the mouth of snakes

Clinical significance
They are capable of causing gastroenteritis and wound infections in humans, especially those individuals with liver disease.

Aeromonas gastroenteritis ranges from an acute watery diarrhea (most common form) to dysenteric illness or chronic illness.

Stools from acute watery diarrhea are loose and erythrocytes and fecal leukocytes are absent.

Symptoms
Abdominal pain, fever, vomiting, and nausea.

Infections are usually self-limiting, but children may require hospitalization due to dehydration.

Aeromonads can also be isolated, on other sites, although blood and wounds are the most common sources

Taxonomy
Family: Pasteurellaceae, formerly: Pasteurella ureae
Genus: Actinobacillus ureae and A. hominis

Natural habitats
A. ureae is usually a commensal in the human respiratory tract, particularly in patients with lower respiratory tract disease.

Clinical significance
They may be involved in the pathogenesis of sinusitis, bronchopneumonia, meningitis, and other infections in immunocompromised patients.

Cases are rare.

Taxonomy
Family: Alcaligenaceae
Genus: Achromobacter
Formely: Alcaligenes xylosoxidans

Natural habitat
They exist in water environment and can cause health care-associated infections and bacteremia in immunocompromised patients with indwelling catheters.

Clinical significance
It is a relatively frequent agent of infection in immunocompromised patients, causing both local and systemic infections in nosocomial settings.

They can cause infections, especially for patients with cystic fibrosis (CF).
They do not seem to have a significant impact on lung function.

They are capable of causing a wide range of infections, such as bacteremia, meningitis, pneumonia, and peritonitis.

It had also been involved in nosocomial infections attributed to contaminated disinfectans, dialysis fluids, saline solution, and water.

Taxonomy Family: Flavobacteriaceae, genus: C.ochracea, C.gingivalis, C.sputigena, C.haemolytica and C.granulosa

Natural Habitat They are normal inhabitants of the human mouth

Clinical Significance The first three are also associated with juvenile and adult periodontitis, whereas the latter two been isolated from supragingival plaque of healthy adults as well as from subgingival plaque in adult periodontitis.

All five species may cause septicemia and other infections in immunosuppressed (mainly neutrpenic) patients.

The name Acinetobacter (from the Greek akineto, "nonmotile") reflects the fact that these bacteria do not have flagella and consequently, lack swimming motility.

A. baumannii is part of the ACB complex (A. calcoaceticus and A. baumannii).

Taxonomy
Family: Moraxellaceae

Natural habitat
Acinetobacter species are widely distributed in nature and have been found in soil, sewage, water and in the hospital environment.
They are able to survive on moist and dry surfaces, and also be present in foodstuff and on the healthy human skin.

Clinical significance
A. baumannii ventilator-associated pneumonia and bloodstream infections have been documented to be associated with a high degree of mortality and morbidity.

Particular manifestations of A. baumannii are its implication in infections in soldiers that have been severly wounded in war and in victims of natural disasters.

Although severe infections with A. baumannii have been documented, Infections like, respiratory, urinary tract, wound infections, abscesses and meningitis in debilitated humans,
colonization is much more frequent than infection, and differentiation between these conditions can be difficult.

Still, although they are uncommon, community-acquired pneumonia with A. baumannii occur.

The ability of this microorganism to acquire antimicrobial multiresistance and his high capacity for survival on most environmental surfaces has led to an increase concern regarding hospital acquired infections.

A possible mechanism contributing to survival of A. baumannii is its ability to form a biofilm-like structure at the air/liquid interface, known as a pellicle.