Infectious Disease Compendium



Anaerobic gram positive rod found in the colon, oral cavity and vagina. There are over 180 species.

Epidemiologic Risks

Normal flora of gut (minor constituent) and female genital tract (major constituent). The lactobacilli in yogurt and probiotics are not the same strains found in and on the human body. The epidemiologic data does not suggest the lactobacilli in our food cause disease, the molecular biology is less forgiving (PubMed).

Bacteremia is usually from lines or abdominal sepsis and are, in order of likelihood,  Lactobacillus salivarius, followed by Lactobacillus paracasei, and Lactobacillus fermentum (PubMed).

Usually the bacteremia is NOT from probiotics.


Occasional endocarditis, UTI, line infections, and other infections where a body fluid goes into what should be a sterile space.

Take bacteremia seriously (PubMed), especially with hospital acquired or in poor hosts.

L. rhamnosus is a cause of bacteremia, often from lines and the immunoincompetent (PubMed). It is also found in probiotics. Every now and then one escapes the probiotic and into the blood (PubMed) but rare (PubMed).


Ampicillin, erythromycin, tetracycline. Add aminoglycoside if endocarditis.

Third generation cephalosporins and carbapenems also likely work.

For bacteremic infections, "Minimum inhibitory concentrations were highest for glycopeptides, cephalosporins and fluoroquinolones and were lowest for carbapenems and aminopenicillins (PubMed)."


Lactobacilli are resistant to vancomycin and often resistant to the cephalosporins and quinolones. As to their therapeutic use see probiotics.

L. casei and L. brevis are used to make sour Belgian beers.

Curious Cases

Relevant links to my Medscape blog

Back from Vacation

The Yeast Tells All

Probiotic Fail

Lack a Bacillus? Nope.

Doesn't Lack a Bacillis

Last Update: 05/01/18.