Display:
Taxonomy Family: Streptococcaceae Streptococcus anginosus group / “S. milleri” / Lancefield Group F - S. anginosus - S. constellatus - S. intermedius Natural habitats They are regarded generally as harmless commensals of the oropharyngeal, urogenital and gastrointestinal microbiota. Clinical significance These organisms are strongly associated with abscess formation in the brain, the oropharynx, or the peritoneal cavity. The S. anginosus group has been implicated as an emerging psathogen in the respiratory tract of cystic fibrosis patients. Specific isolation site - S. anginosus - urogenital or gastrointestinal tract - S. constellatus - respiratory tract - S. intermedius - abscesses of the brain or liver
Taxonomy Family: Leuconostocaceae Natural habitats They can be isolated from plants, occasionally from milk and milk products. Clinical significance They can be isolated from the female genital tract, and the gastrointestinal tract. Infectious for humans that have surgery, antibiotic therapy, or have impared immunological systems.
A. defectiva is a fastidious organism that requires a complex medium enriched with L-cysteine or vitamin B6 as well as other unique nutritional requirements that are essential for growth. Taxonomy: Family: Aerococcaceae Genus: Abiotrophia and Granulicatella Formerly: Streptococcus defective, Nutritionally Variant Streptococci or satelliting streptococci Natural habitat They are members of normal flora of the oral cavity or upper respiratory tract as well as the intestinal tract. Clinical significance They are opportunistic pathogens, and are formally known as NVS (nutritionally variant streptococci) are normal residents of the oral cavity and are recognized as agents of endocarditis involving both native and prosthetic valves. These organisms have also been isolated from other types of infections, including ophthalmic infections, peritonitis in patients undergoing continuous ambulatory peritoneal dialysis, musculoskeletal infection, septic arthritis, and a breast implant-associated infection. Although it is rare for A. defectiva to cause endocarditis they have a greater morbidity and mortality than endocarditis caused by other streptococci due to its poor response to many antibiotics. Cases are rare.
Taxonomy Family: Lactobacillaceae Natural habitats They are commonly found in fermented vegetables, fermented dairy products and meat. They are being used as probiotic supplements in treating constipation, diarrhea, relieving stress, enhancing immune response among birds and small animals, human trials are still limited. Clinical significance P. acidilactici is the most common clinical isolate of pediococci They have been isolate from bacteremia, sepsis and hepatic abscess in compromised patients
Taxonomy Family: Streptococcaceae Streptococcus mutans group / Lancefield Group F - S. mutans - S. sobrinus (S.criceti, S.ratti, S.downei) Natural habitats Commensals of the oral cavity. Clinical significance Is the major cause of dental caries and endocarditis. S. mutans metabolizes sucrose to produce polysaccharides that help them cohere to one another forming plaque. The combination of this plaque and acids released by S. mutans leads to the breakdown / dissolve of tooth enamel resulting in dental caries. They are easily dismissed as a common non-pathogenic skin bacterial contaminant termed “diphteroid”
Taxonomy Family: Streptococcaceae Streptococcus salivarius group / Lancefield Group F - S. salivarius - S. vestibularis - S. thermophilis (no human pathogen) Natural habitats Commensals of the oral cavity, and feces Clinical significance S. vestibularis has not been clearly associated with human infections. Isolation of these species from blood cultures in asymptomatic patients often does not require antibiotic treatment, if it is due to a transient bacteremia. They can also be found as transient microbiota of the normal skin and often represent contaminants when isolated from blood cultures. At the same time these species are the most frequently isolated bacteria in bacterial endocarditis in native valve and less frequently, in prosthetic valve infections. Careful evaluation of the clinical situation is therefore crucial to correctly interpret the clinical significance. In neutropenic patients, streptococcal species from these groups are often responsible for life-threatening sepsis an pneumonia cases following immunosuppression by chemotherapy.
Taxonomy Family: Streptococcaceae Streptococcus mitis group / Lancefield Group F - S. mitis - S. cristatus - S. oralis - S. peroris - S. pneumoniae Natural habitats Commensals of the oral cavity, the gastrointestinal tract, and the female genital tract. Clinical significance Isolation of these species from blood cultures in asymptomatic patients often does not require antibiotic treatment, if it is due to a transient bacteremia. They can also be found as transient microbiota of the normal skin and often represent contaminants when isolated from blood cultures. At the same time these species are the most frequently isolated bacteria in bacterial endocarditis in native valve and less frequently, in prosthetic valve infections. Careful evaluation of the clinical situation is therefore crucial to correctly interpret the clinical significance of blood culture isolates from the S. mitis- or S. sanguinis group. In neutropenic patients, streptococcal species from these groups are often responsible for life-threatening sepsis an pneumonia cases following immunosuppression by chemotherapy.
Taxonomy Family: Streptococcaceae Streptococcus sanguinis group / Lancefield Group F - S. sanguinis - S. parasanguinis - S. gordonii Natural habitats Commensals of the oral cavity, the gastrointestinal tract, and the female genital tract. Clinical significance Isolation of these species from blood cultures in asymptomatic patients often does not require antibiotic treatment, if it is due to a transient bacteremia. They can also be found as transient microbiota of the normal skin and often represent contaminants when isolated from blood cultures. At the same time these species are the most frequently isolated bacteria in bacterial endocarditis in native valve and less frequently, in prosthetic valve infections. Careful evaluation of the clinical situation is therefore crucial to correctly interpret the clinical significance of blood culture isolates from the S. mitis- or S. sanguinis group. In neutropenic patients, streptococcal species from these groups are often responsible for life-threatening sepsis an pneumonia cases following immunosuppression by chemotherapy.
Taxonomy Family: Streptococcaceae Strepytococcus bovis group / Lancefield Group D Former name Current name S. bovis biotype I S. gallolyticus S. bovis biotype II.1 S. infantarius S. bovis biotype II.2 S. gallolyticus ssp pasteurianus Natural habitats Is part of the human gastrointestinal microbiota Clinical significance Species from this group are frequently encountered in blood cultures of patients with bacteremia, sepsis and endocarditis. The clinical significance of blood cultures growing streptococci from the S.bovis group lies in the association of S. gallolyticus ssp gallolyticus with gastrointestinal cancer and of S. gallolyticus ssp pasteurianus with meningitis.
Taxonomy Family: Streptococcaceae Streptococcus anginosus group / “S. milleri” / Lancefield Group F - S. anginosus - S. constellatus - S. intermedius Natural habitats They are regarded generally as harmless commensals of the oropharyngeal, urogenital and gastrointestinal microbiota. Clinical significance These organisms are strongly associated with abscess formation in the brain, the oropharynx, or the peritoneal cavity. The S. anginosus group has been implicated as an emerging psathogen in the respiratory tract of cystic fibrosis patients. Specific isolation site - S. anginosus - urogenital or gastrointestinal tract - S. constellatus - respiratory tract - S. intermedius - abscesses of the brain or liver
General information S. acidominimus is a member of the viridans group streptococci and is rarely pathogenic in humans making it difficult to assess its epidemiologic and clinical significance. Taxonomy Family: Streptococcaceae Natural habitats In the bovine vagina, on the skin of calves and in raw milk. Clinical significance On rare occasions, it has been associated with infections in human
Taxonomy Family: Streptococcaceae Streptococcus mitis group / Lancefield Group F - S. mitis - S. cristatus - S. oralis - S. peroris - S. pneumoniae Natural habitats Is a normal in habitant of the human upper respiratory tract, especially in children, without evidence of infection. Clinical significance They are the most frequently isolated respiratory pathogen in community-aquired pneumonia cases. They can be found in peripheral blood cultures of patients. S.pneumoniae is also a major cause of meningitis, leading to high morbidity and mortality in pediatric and adult patients. The most frequently observed infection due to S.pneumoniae is otitis media. Other infections includes sinusitis, septic arthritis, osteomyelitis, endocarditis, peritonitis, cellulitis, brain abscesses.
G. adiacens is a fastidious organism that requires a complex medium enriched with L-cysteine or vitamin B6 as well as other unique nutritional requirements that are essential for growth. Taxonomy: Family: Aerococcaceae Genus: Abiotrophia and Granulicatella Formerly: Streptococcus defective, Nutritionally Variant Streptococci or satelliting streptococci Natural habitat They are members of normal flora of the oral cavity or upper respiratory tract as well as the intestinal tract. Clinical significance They are opportunistic pathogens, and are formally known as NVS (nutritionally variant streptococci) are normal residents of the oral cavity and are recognized as agents of endocarditis involving both native and prosthetic valves. These organisms have also been isolated from other types of infections, including ophthalmic infections, peritonitis in patients undergoing continuous ambulatory peritoneal dialysis, musculoskeletal infection, septic arthritis, and a breast implant-associated infection. Although it is rare for G. adiacens to cause endocarditis they have a greater morbidity and mortality than endocarditis caused by other streptococci due to its poor response to many antibiotics. Cases are rare.
Taxonomy Family: Aerococcaceae Natural habitats They are in the air and dust and on the skin of people, and have been described as an airborn organism prevalent in occupied rooms. Aerococci could be confused with streptococci and staphylococci since they have many characteristics in common, and this may account for the fact that the presence of A. viridans has not often been reported in the hospital environment or in clinical specimens. Clinical significance A. viridans has been noted as a contaminant in clinical cultures and infrequently as a clinical significant isolate from cases of endocarditis and bacteremia.
Taxonomy Family: Aerococcaceae Natural habitats A. urinae is a rarely reported pathogen, possible due to the difficulties in the identification of the organism. Clinical significance Isolates of this species were originally isolated from the urine of (older) patients with urinary tract infections and were denoted Aerococcus-like organisms. Infections with this bacterium has likely been underestimated. A. urinae may also cause invasive infections including urosepsis, lymphadenitis, spondylodiscitis and infective endocarditis especially in elderly men with underlying urinary tract diseases.
