Lactobacillus gasseri endocarditis on the aortic valve bioprosthesis - a case report

Lactobacillus is a genus of Gram-positive, facultative anaerobic/ microaerophilic, rod-shaped bacteria. Lactobacilli constitute a significant component of the human microbiota in the oral cavity, gastrointestinal tract and female urogenital tract. They are also widely used as probiotics. Rarely, especially in patients with impaired immunity or with structural heart disease, do Lactobacilli become the pathogen responsible for serious infections, e.g. infective endocarditis (IE).

The authors describe a case of an 80-year-old female with a past history of aortic valve replacement, mitral annuloplasty and pacemaker implantation admitted to hospital due to weakening, subfebrile state and chills. In transesophageal echocardiography vegetations on the aortic valve bioprosthesis were found, while pacemaker electrodes and mitral annulus were not involved in the endocarditis process. Bacteriological work-up revealed growth of L. gasseri. The patient was successfully treated with amoxicillin/clavulanate acid (six weeks) and with gentamycin (two weeks). No recurrence of the disease was observed during a six-month posthospital follow-up. Among different species of Lactobacillus, L. gasseri has not been reported as an IE pathogen so far. Lack of unequivocal data as to whether using probiotics may be responsible for infections, including IE, in patients with predisposing conditions.