Lactobacillus Bacteremia Following Dental Instrumentation in a Patient With a Bioprosthetic Valve

Although generally considered harmless commensals or beneficial probiotics, Lactobacillus species can act as opportunistic pathogens under certain clinical conditions. We describe a case of high-grade Lactobacillus bacteremia in a 59-year-old man with a history of aortic root dilation status post Bentall procedure and bioprosthetic aortic valve replacement. The suspected source was recent dental instrumentation. Despite negative imaging for vegetations, the patient was treated empirically for prosthetic valve endocarditis with six weeks of intravenous penicillin. This case reminds clinicians to take Lactobacillus bacteremia seriously in the proper clinical context, especially when prosthetic material is present.