Occurrence of Multidrug-Resistant Salmonella Enterica in Retail Chicken Meat and Development of A Six Genes-Based Multiplex PCR as An Alternative Diagnostic Method

Abstract

This study was aimed to develop a rapid discriminatory PCR-based assay for detection and differentiation the most common Salmonella serovars in chicken meat and their products. Definite six target genes were selected for their ability to give unique results in a simple multiplex PCR assay to identify Salmonella typhimurium, Salmonella kentucky and Salmonella enteritidis with multidrug resistance properties. Three hundred chicken meat samples were analyzed using conventional methods. The isolates were identified, serotyped and tested against 16 antibiotics. Isolated Salmonella serovars were further analyzed for the presence of six target genes (invA, avrA, stn, fliC, stm and sefA) using two multiplex PCR assays. 2.5, 0.5 and 0.5% of raw chicken meat were positive for S. typhimurium, S. kentucky and S. enteritidis, respectively. All isolates were resistant, at least, to three antibiotics. Multiplex PCR gave 284 bp (invA), 422 bp (avrA) and 617 bp (stn) fragments belonging to the genus Salmonella, and additional three fragments of 559 bp (fliC), 915 bp (stm) and 310 bp (sefA) which allowed distinct identification of S. typhimurium, S. kentucky and S. enteritidis. The developed six genes-based multiplex PCR in this study is a potential alternative method for discrimination of the most common serotypes of Salmonella. Practical Applications We developed a six genes-based multiplex PCR for effective discrimination of the most common foodborne Salmonella serovars with multidrug resistance prosperities. Although there are few studies about the incidence of Salmonella in retail meat in Egypt, our study is the first one in Alexandria (on the Mediterranean Sea in the north central part) about multidrug-resistant (MDR) serovars of Salmonella in retail chicken meat and their products. If we analyze all these findings to see the potential risk assessments in this region, our study could be a leading report in near future.