Evaluation of Drug Resistance Genes in Salmonella Species Isolated from Commercial Poultry of Live Bird Markets in Islamabad Capital Territory

Abstract

Salmonella is one of most important food-born pathogen transmitted mainly through poultry. Extensive use of antimicrobial agents in animal production systems is considered as a cause of emergence of antimicrobial resistance in Salmonella and other pathogens. To analyze this fact, the study was conducted from July 2020 to July 2021 on cecal samples from apparently healthy chicken from live bird markets of different cities of Pakistan. Study was carried out with the objectives to isolate and identify drug resistant among Salmonella species from poultry and to evaluate their phenotypic and genotypic antibiotic resistance profile. This was a unique and first study of this kind to evaluate AMR through coordinated surveillance method in healthy poultry across the country. In this regard a total of 763 caecal samples from poultry were processed for the presence of Salmonella spp. following standard isolation protocols. Out of 763 samples, 268 (35%) samples were tested positive for Salmonella spp. From 268 positive isolates, 173 were analyzed through antimicrobial susceptibility test and all were observed to be resistant to multiple antibiotics with highest level of resistance against Penicillin (100%), Clindamycin (100%), Streptomycin Tetracycline Teicoplanin (100%), Linezolid (100%), Nalidixic Acid (95%), Tetracycline (93%) and Streptomycin (90%). On the other hand, almost all isolates were susceptible to piperacillin/tazobactum. Out of 173 isolates analyzed for phenotypic antimicrobial resistance profile, 24 were further analyzed for genotypic antimicrobial resistance profile for the detection of genes through conventional polymerase chain reaction (PCR) and results were correlated with phenotypic profile. The study concluded that there is high multidrug resistance in Salmonella which may be increased with time due to miss-sue and over-use of antibiotics on farm and therapeutic level, poor husbandry practices, and fluctuation in standard recommended dosage of antibiotics. This may be leading to selection pressure on Salmonella spp. to acquire and retain resistance genes and causing a major threat. It is hereby recommended to aware farmers and other poultry related stakeholders about controlled use of antibiotics, good husbandry and slaughtering practices to avoid contamination with multidrug resistant Salmonella spp., and to find new mechanisms and solutions to cope with this high level of antibiotic resistance to treat both animals and human food-borne illness. Key words: Salmonella, antimicrobial resistance, isolation and identification, phenotypic antimicrobial resistance profile, genotypic antimicrobial resistance profi