Antibiotic Resistance Pattern and Distribution of Resistance Genes in Salmonella Isolated from Chicken and Duck Eggs in Chhattisgarh, India

Background: Salmonella is recognized as the most prevalent bacterial cause of foodborne diseases worldwide and animal-sourced foods have been reported as a common source of Salmonella infections among humans. Methods: The commercial chicken eggs, backyard chicken eggs, and duck eggs samples, 60 each, were processed for isolation and identification of Salmonella. All Salmonella isolates were further tested for resistance against six different antibiotics. The prevalence of virulence and antimicrobial resistance genes in the Salmonella isolates was determined by PCR. Result: A total of 28 Salmonella isolates were recovered with an overall prevalence of 15.6% and out of them, 11.1% and 4.4% were from eggshell and egg content, respectively. All the isolates were found sensitive to Gentamicin however maximum resistance was observed against Cefotaxime. PCR results revealed that 100% of the isolates were carrying the invA gene however stn gene was detected in 78.6% of isolates. Among presumptively identified β-lactam-resistant Salmonella isolates, 100% and 50% isolates harbored blaTEM and blaCTX-M genes, respectively whereas none of the isolates contained the blaSHV gene. All tetracycline-resistant isolates harbored the tetA gene whereas none of the isolates carried the tetB gene. 100% of fluoroquinolone-resistant isolates were carrying the gyrA gene however parC gene was present only in 60% of isolates. These results indicate that drug-resistant Salmonella spp. were prevalent in eggs sold in the study area which can pose a serious public health problem.