Lactobacilli Infection Case Reports in the Last Three Years and Safety Implications

probiotics. However, these bacteria caused rare infections mostly in diabetic and immunocompromised subjects in presence of risk factors such as prosthetic hearth valves and dental procedures or caries. The scope of this survey was re-assessing the pathogenic potential of lactobacilli based on the infection case reports published in the last three years. In 2019, 2020 and 2021 17, 15 and 16 cases, respective-ly,.including endocarditis, bacteremia and other infections, were reported. These annual numbers are higher than observed previously. Lacticaseibacillus rhamnosus (13 cases), comprising strain GG (ATCC 53103) with established applications in healthcare, L. paracasei (7 cases), Lactobacillus acidophilus (5 cas-es), L. jensenii (5 cases), Lactiplantibacillus plantarum (3 cases), L. paraplantarum, L. delbrueckii subsp. del-brueckii, L. gasseri, L. paragasseri, Limosilactobacillus fermentum and L. reuteri (1 case each) were involved. Virulence characterization of two strains that caused infections, a derivative of L. rhamnosus GG and L.paracasei LP10266, indicated that increased biofilm forming capacity favors pathogenicity and it is determined by variable genetic traits. This survey highlighted that strains of lactobacilli able to cause infections were little characterized genet-ically. Instead, to avoid that these bacteria become a hazard, genetic stability should be periodically re-evaluated by whole genome sequencing (WGS) to ensure that only non-pathogenic variants are ad-ministered to vulnerable individuals.