Anaerobic gram positive rod found in the colon, oral cavity and vagina.
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 ususally from lines or abdominal sepsis and are, in order of likelyhood, Lactobacillus salivarius , followed by Lactobacillus paracasei and Lactobacillus fermentum (PubMed).
Usually the bacteremia is NOT from probiotics.
L. rhamnosus is a cause of bacteremia, often from lines and the immunoincompetent (PubMed).
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.