Safety of the probiotic strain Lactobacillus plantarum DSM 9843 (= strain 299v) in an endocarditis animal model

Abstract

Objective: Lactobacilli are often considered to be beneficial or non-pathogenic to man, with small numbers of human infections being reported, including septicemia and infective endocarditis. To verify the safety of Lactobacillus plantarum DSM 9843 (= strain 299v) administration, we used a well-known endocarditis animal model. Design: Experimental study using Sprague-Dawley rats. Setting: University Hospital, Sweden. Interventions: A catheter was passed down the right common carotid artery into the lumen of the left ventricle. The catheter was tied in place and the neck incision was closed. After 48 h, 0.5 ml of a bacterial suspension was injected through the tail vein. In the endocarditis control we inoculated Staphylococcus lugdunesis CCUG 25349T (T = type strain) and L. plantarum 299v was injected in the blood in L. plantarum group. Main outcome measures: Rats were sacrificed 96 h later and samples were taken from the heart, blood and catheter for bacterial culture and Randomly Amplified Polymorphic DNA (RAPD) evaluation. Results: L. plantarum 299v was injected in the blood but no lactobacilli were found in the heart, blood or catheter after 96 h. RAPD evaluation showed that S. lugdunesis CCUG 25349T was isolated from both blood and heart. Conclusion: The results showed that L. plantarum 299v has no role in the tested endocarditis animal model, which indicates the safety of L. plantarum 299v.