Paenibacillus is a genus originallt included within the genus Bacillus and than reclassified as a seperate genus in 1993.
The name reflects: Latin paene means almost, so paenibacilli are literally "almost bacilli".

Taxonomy
Family: Bacillaceae

Natural habitats
Ubiquitous in nature

Clinical significance
P. chibensis is rarely associated with human infections but has been reported as an opportunistic pathogen in immunocompromised individuals.
It can cause infections such as
- bacteremia
- wound infections
although such cases are uncommon.
The clinical significance of P. chibensis remains limited, but it should be considered in atypical infections in vulnerable patients.
They could cause allergies as a result of its histamine producing properties

Paenibacillus is a genus original included within the genus Bacillus and than reclassified as a seperate genus in 1993.
The name reflects: Latin paene means almost, so paenibacilli are literally "almost bacilli".

Taxonomy
Family: Bacillaceae

Natural habitats
Ubiquitous in nature

Clinical significance
P. amylolyticus is is generally considered non-pathogenic but has been associated with rare cases of opportunistic infections, particularly in immunocompromised individuals. It can cause wound infections, bacteremia, and other soft tissue infections.
Its clinical significance is limited, but it can be an emerging pathogen in certain high-risk settings.

Paenibacillus is a genus originallt included within the genus Bacillus and than reclassified as a seperate genus in 1993.
The name reflects: Latin paene means almost, so paenibacilli are literally "almost bacilli".

Taxonomy
Family: Bacillaceae

Natural habitats
Soil and feed, for cattle and other livestock

Clinical significance
Paenibacillus pabuli clinical relevance in humans is limited, and there are few documented cases of infection or disease caused by this bacterium.
In summary, while P. pabuli may have therapeutic potential, it is not widely considered a major clinical pathogen in humans.

Paenibacillus is a genus originallt included within the genus Bacillus and than reclassified as a seperate genus in 1993.
The name reflects: Latin paene means almost, so paenibacilli are literally "almost bacilli".

Taxonomy
Family: Bacillaceae

Natural habitats
Ubiquitous in nature

Clinical significance:
Paenibacillus macerans is a bacterium that can also be associated with human infections, though these are rare.
Clinically, it has been isolated from wound infections, respiratory tract infections, and other medical conditions, particularly in immunocompromised individuals.
The clinical significance of Paenibacillus macerans mainly lies in its potential to cause opportunistic infections, but it is not typically considered a major pathogen. It may also be involved in nosocomial (hospital-acquired) infections, particularly in patients with underlying conditions or those with prolonged hospital stays.

Its antibiotic resistance profile and ability to survive in various environments make it noteworthy in clinical microbiology, especially in cases where conventional treatments fail.

B.licheniformis, B.subtilis, B. amyloliquefaciens and B.pumilus comprise the subtilis group, which has been associated with food borne gastro-enteritis

Taxonomy
Family: Bacillaceae

Natural habitats
Spores occur in soil, on bird feathers, may survive severe heat treatment

Clinical significance:
Bacillus pumilus is generally considered non-pathogenic but can occasionally cause opportunistic infections, especially in immunocompromised individuals.
Clinical significance includes:
- Wound infections: Rare cases have been reported, particularly in individuals with weakened immune systems.
- Bacteremia: It has been linked to bloodstream infections in some cases, primarily in hospitalized patients.
- Contamination: B. pumilus can also be a contaminant in clinical samples and laboratory settings.
Although rarely pathogenic, B. pumilus is of interest for its potential in industrial applications, such as in the production of enzymes.

B.licheniformis, B. amyloliquefaciens, B.subtilis and B.pumilus comprise the subtilis group, which has been associated with food borne gastro-enteritis

Taxonomy
Family: Bacillaceae

Natural habitats
Spores are widely distributed in nature.

Clinical significance:
Bacillus subtilis is generally non-pathogenic, it can occasionally be associated with opportunistic infections, particularly in immunocompromised individuals.
It is also used in biotechnology for the production of enzymes and antibiotics.
However, in rare cases, it can cause wound infections, bacteremia, or respiratory infections in vulnerable patients.

Bacillus thuringiensis is distinguished by its characteristic parasporal crystals

Taxonomy
Family: Bacillaceae
Bacillus cereus group: B. anthracis, B. cereus, B. mycoides, B. thuringiensis

Natural habitats
Endospores are widespread in soil and many other environments.
The organism had been isolated from all continents, including Antartica.

Used as bio pesticide

Clinical significance
Bacillus thuringiensis is primarily known for its use as a biopesticide due to its production of insecticidal proteins (Cry toxins).
While it is not typically pathogenic to humans, it can cause rare infections in immunocompromised individuals, such as:
- Wound infections: In individuals with weakened immune systems.
- Bacteremia: Very rarely reported in clinical settings.
B. thuringiensis is more clinically significant as a biocontrol agent in agriculture rather than as a human pathogen. Its antibiotic susceptibility and potential for causing infections are minimal in healthy individuals.

Bacillus mycoides is distinguished by its characteristic rhizoid colonies and absence of motility.

Taxonomy
Family: Bacillaceae
Bacillus cereus group: B.anthracis, B.cereus, B.mycoides, B.thuringiensis

Natural habitats
Spores are widespread, soil, water, air foods etc

Clinical significance
Bacillus mycoides is generally considered non-pathogenic but has been occasionally linked to opportunistic infections in immunocompromised individuals, including:
- Wound infections: Rare cases have been reported, often in patients with pre-existing health conditions.
- Contamination: Due to its environmental prevalence, B. mycoides can also be a contaminant in clinical specimens.

Its clinical significance is limited, and infections are relatively uncommon.
The bacterium is often susceptible to a variety of antibiotics.

Taxonomy
Family: Bacillaceae
Genus: Priestia megaterium
Formely: Bacillus megaterium

Natural habitats
Spores occur in soil, dust, water and plants.

Clinical significance
Bacillus megaterium generally non-pathogenic, it can occasionally be associated with opportunistic infections, particularly in immunocompromised individuals.
Clinical significance includes:
Infections:
- Rarely, B. megaterium can cause infections such as wound infections, bacteremia, and endocarditis.
- Contamination: It is also a potential contaminant in clinical specimens due to its environmental presence.
Infections are typically treated with antibiotics, but the organism is often susceptible to a wide range of antimicrobial agents.

B.licheniformis, B.subtilis, B. amyloliquefaciens and B.pumilus comprise the subtilis group, which has been associated with food borne gastro-enteritis

Taxonomy
Family: Bacillaceae

Natural habitats
Spores occur in soil, dust, water, may survive severe heat treatment

Clinical significance B. licheniformis is generally non-pathogenic but can be an opportunistic pathogen in immunocompromised individuals.
Clinical significance includes:
- Wound infections: Rarely, B. licheniformis can cause infections in patients with compromised immune systems.
- Bacteremia: In rare cases, it has been linked to blood infections, particularly in hospitalized patients.
- Contamination: It can also contaminate clinical samples, laboratory cultures, or medical devices due to its environmental presence.
Overall, B. licheniformis is more recognized for its industrial applications, like enzyme production, than for its role in human disease.

Taxonomy
Family: Bacillaceae
Genus: Lederbergia lentus
Formely: Bacillus lentus

Natural habitats
Is found in soil

Clinical significance
Unknown, considered nonpathogenic.

Taxonomy
Family: Bacillaceae
Genus: Niallia circulans
Formely: Bacillus circulans

Natural habitats
Spores are numerous in soil.

Clinical significance
Bacillus circulans is rarely pathogenic but can cause opportunistic infections in immunocompromised individuals, such as:

- Wound infections: Particularly in patients with compromised immune systems or underlying health conditions.
- Bacteremia: Rare cases have been reported, especially in hospitalized patients.

B. circulans is more often associated with environmental contamination in clinical samples rather than being a primary cause of infection.
It is generally susceptible to a range of antibiotics.

Taxonomy
Family: Bacillaceae

Bacillus cereus group: B. anthracis, B. cereus, B. mycoides, B. thuringiensis

Natural habitats
Soil inhabitant in sporulated form. Anthrax spores in soil can remain infectious for decades.

They are obligate pathogens.

Isolated from blood of animals and human with anthrax, animal carcasses and products and soil contaminated with spores

Clinical significance / ANTHRAX

- cutaneous anthrax
Infection occurs through a break in the skin. Following the incubation period of usually 2 to 3 days, a small papule appears, progressing over the next 24h to a ring of vesicles, with subsequent ulceration and formation of a characteristic blackened eschar.
Subsequent eschar formation may become thick and surrounded by extensive edema.
Fever and pus and pain at the side are normally absent; their presence probably indicate a secondary bacterial infection.

- gastrointestinal anthrax
The symptoms are the result of ulcerations developing primarily in the cecal and terminal ileal mucosae: vomiting, nausea and abdominal pain, accompanied by fever.

This can rapidly progress to bloody diarrhea and systemic infection

- inhalation anthrax / bioterrorism
The inhaled spores are ingested by macrophages and carried from the lungs to the lymphatic system, where the infection progresses.
During transit to lymph nodes, spores germinate into vegetative cells, begin to replicate and produce the capsule and toxins that lead to bacteremia and associated hemorrhage and necrosis.

Anthrax is high on the list of agents that could be used in biological warfare or bioterrorism.

Bacillus cereus group: B.anthracis, B.cereus, B.mycoides, B.thuringiensis

Taxonomy
Family: Bacillaceae

Natural habitats
Spores are widespread in the environment, e.g. soil, water, air or foods

Clinical significance
B. cereus is pathogenic of human and mammals, causing foodborne illness and opportunistic infections (e.g. endophtalmie, keratitis, septicemia, meningitis, endocarditis, pneumonia, osteomyelitis, urinary infections, cutaneous infections).

It is a destructive ocular pathogen.