Genetic analysis of multidrug resistant Salmonella isolated from broiler chickens

Abstract

Salmonellosis is a major problem for the poultry industry, and this problem represents a critical food safety hazard. Resistance to antimicrobial agents within nontyphoidal Salmonellae is a serious problem. The present study aimed to analyze genetically some β-lactamase resistance genes and some virulence associated genes in Salmonella isolates from broiler chicken. Five hundred samples were collected from diseased broiler chickens of different ages (3-6 weeks) from different farms in Assiut Governorate in Egypt during the period from January 2015 to December 2015. Bacteriological examination showed that 26 Salmonella isolates were recovered with a prevalence rate of 5.2% Serotyping of Salmonella isolates showed that S. Enteritidis S. Typhimurium, and S. Kentuky were identified at rates of 50%, 30.8% and 19.2%, respectively. Results of antibiogram showed that 18 Salmonella isolates (92.3%) were multidrug resistant. All isolates were screened for the presence of 2 β-lactamase resistance genes (blaCTX and blaCMY) as well as 3 virulence genes (stn, invA and hilA) using multiplex PCR. The overall prevalences were 53.9% for blaCTX and 34.6% for blaCMY. Meanwhile, stn, invA and hilA genes were found in 96.2%, 100% and 84.7% of isolates, respectively.