Characterization of plasmids form multi drug resistance salmonella infantis isolates

Aydın, Sacide Özlem
The usage and misusage of antibiotics in poultry, food-producing animals and human diseases have led to transmission of conjugative plasmids carrying antibiotic resistance genes from one microorganism to another, especially to the pathogenic bacteria. Multi-drug resistant Salmonella enterica serovar Infantis, an emerging serotype in poultry, has been spreading all around the world in a decade. Moreover, commensal microorganisms such as commensal Escherichia coli in the gut microbiota, functioning as a reservoir of antimicrobial resistance, of the warm-blooded hosts acquire antibiotic resistance by plasmid from Salmonella enterica serovars. The aim of this study was to identify the conjugative transfer of plasmids including multi-drug resistance genes from Salmonella enterica serovar Infantis to commensal susceptible E. coli in both of phenotypic and genotypic level. Salmonella Infantis isolates with different antibiotic resistance profiles involving streptomycin, sulfisoxazole, ampicillin, trimethoprim/sulfamethoxazole, kanamycin, chloramphenicol, ciprofloxacin, cephalotin, nalidixic acid and tetracycline were selected as donor bacteria (n=10), while susceptible non-pathogenic E. coli isolate was used as a recipient. Applying filter paper mating procedure was used for conjugation. Transconjugant E. coli colonies were screened by phenotypic and genotypic methods. First, yellow colonies representing transconjugant E. coli colonies were determined on the selective XLD agar containing 10 μg/ml tetracycline in phenotypic level. After that, conjugation genes (i.e., traA, traE, traL, traJ, traG, traH, traI, traM, traR, traY, rfaG, rfaI, rfaJ, rfaL and rfbP), and the incompatibility group of plasmids were screened by polymerase chain reaction (PCR) in genotypic level. This study contributes to recent and further studies related to the conjugative transmission of antibiotic resistance genes in Salmonella and E. coli, which is an arising serious problem worldwide.