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.