Rapid detection and characterization of Salmonella enterica serovars by multiplex polymerase chain reaction assay

Abstract

Multiplex polymerase chain reaction (PCR) was used for molecular typing of Salmonella enterica serovars in Egypt. During the summer of 2010, a total of 1075 samples were collected from cattle, sheep and poultry farms to be subjected for isolation of Salmonella (290 rectal swabs from cattle, 335 rectal swabs from sheep and 450 cloacal swabs from poultry). Bacteriological examination revealed the isolation of 68 Salmonella belonging to 13 different Salmonella serovars. The most common serovars were Salmonella Typhimurium (16 isolates), Salmonella Enteritidis (13 isolates), Salmonella Kentucky (eight isolates) and Salmonella Arizona (seven isolates). Other serovars typed were Salmonella Heidelberg (four), Salmonella Cerro (four), Salmonella Gallinarum (three), Salmonella Virginia (three), Salmonella Paratyphi-A (three), Salmonella Dublin (two), Salmonella Agona (two), Salmonella Hadar (two) and Salmonella Bardo (one). The results of molecular techniques highlight the usefulness of the multiplex PCR for the rapid detection of the two serotypes of Salmonella from field samples especially after pre-enrichment on Rappaport-Vassiliadis (RV) media. Moreover, detecting S. Typhimurium and S. Enteritidis by this assay was carried out within two days as opposed to five to six days by the bacteriological and serological methods.

Key words: Multiplex polymerase chain reaction (PCR), Salmonella Enteritidis, Salmonella Typhimurium, Egypt.