Phenotypic and Genotypic Characterization of Listeria Monocytogenes Isolated from Different Sources

The aim of this study was to determine the differences concerning phenotypic and genotypic characters of L.monocytogenes isolated from different sources (100 meat, 100 offals, 100 fish and 100 ready to eat foods -RTE- which is represented by luncheon) on the basis of pathogenicity and antibiotic resistance. To achieve this aim, bacteriological examination was done according to ISO 11290 amendment 2004.then confirmed by biochemical reactions and serotyping, then antimicrobial susceptibility testing which indicates the presence of multidrug resistance isolates. Biofilm binding activity of the isolated L.monocytogenes isolates showed that three isolates had strong binding activity, two isolates showed moderate binding activity and one isolate was weak/non biofilm producer. The molecular characterization was done by detection of class1 integron and for pathogenicity by detection of the presence of hlyA gene which encodes listeriolysin of L.monocytogenes then sequencing of the resulted PCR product to determine the difference between the isolates. The confirmation of results was done by SYBR green Real-time PCR.