Serological Variety and Antimicrobial Resistance in Salmonella Isolated from Reptiles

Salmonella enterica is one of the best adapted bacterial pathogens causing infections in a wide variety of vertebrate species. The aim of this study was to investigate the prevalence of Salmonella in different reptile species and to evaluate their serological variety and patterns of antimicrobial resistance. In total, 97 samples from 25 wild and domesticated reptile species were investigated in Lithuania. Serological variety, as well as phenotypical and genotypical resistance to antimicrobials, were investigated. Fifty isolates of Salmonella were obtained from the ninety-seven tested samples (51.5%; 95% CI 41.2−61.2). A significantly higher prevalence of Salmonella was detected in domesticated individuals (61.3%; 95% CI 50.0−71.5) compared with wild ones (18.2%; 95% CI 7.3−38.5). All isolates belonged to a single species, Salmonella enterica. Results demonstrated that reptiles carry a large variety of Salmonella serovars. Thirty-four isolates (68%) of Salmonella were resistant to at least one antimicrobial drug. The most frequent resistance of the isolates was to streptomycin (26%), cefoxitin, gentamicin, tetracycline and chloramphenicol (16%). Genes encoding resistance to tetracyclines, aminoglycosides, sulphonamides and trimethoprim were detected. No integrons that are associated with horizontal gene transfer were found. Data obtained provided knowledge about the adaptation of Salmonella in reptiles. Healthy individuals, irrespective of their origin, often carry Salmonella, including multi-resistant strains. Due to its large serological diversity, zoonotic potential and antimicrobial resistance, Salmonella in reptiles poses a risk to other animals and humans.