Lactobacilli are Gram-positive, facultatively aerobic, rod-shaped bacteria that are a normal part of the human microbiota and rarely cause infections in immunocompetent hosts. Lactobacillus casei and Lactobacillus rhamnosus are the most common human pathogens within this genus and are also frequently used in probiotics. Both species are inherently resistant to vancomycin, and penicillin-sometimes in combination with aminoglycosides-remains the primary treatment for infections caused by these organisms. Management becomes particularly challenging in patients with severe penicillin allergies, such as anaphylaxis. Although daptomycin has demonstrated in vitro activity against these pathogens, clinical data on its use are limited. Here, we present a case of Lactobacillus rhamnosus endocarditis successfully treated with 6 weeks of intravenous daptomycin.
Rehan et al. (2026) studied this question.