DETECTION OF SALMONELLA SEROVARS AND THEIR COMMON VIRULENCE GENES FROM DIFFERENT CHICKEN BREEDING SYSTEMS

Wael Said El Shafey, Mohammed Farouq Hashim, Ahmed Abo-Elmagd Bekheet and Madiha Salah Ibrahim*

ABSTRACT

The present study investigated the occurrence, antibiotic sensitivity patterns, and virulence gene profiling of Salmonella serovars in chicken farms in Behaira governorate, Egypt. Three hundred samples including chicken's internal organs, cloacal swabs, litter samples and eggs were examined for the presence of Salmonella by standard microbiological techniques. All Salmonella isolates were tested for their sensitivity against 11 antibiotics and subjected to virulence genotyping by polymerase chain reaction (PCR). The overall isolation percentage of Salmonella was 13%. The prevalence of Salmonella was 6.8% in broilers, 42.3% in layers, 0% in breeders and cloacal swabs, 6.5% in litter and 15.6% in eggs. Four different serovars were found, with the predominant one being Salmonella enteritidis. Salmonella isolates were sensitive to most of the tested antibiotics, but they exhibited absolute resistance against ampicillin and cefotaxime. PCR investigation of invA, mgtC, sopB and bcfC virulence genes in 8 Salmonella isolates revealed that all tested genes were expressed in all examined isolates. These results would greatly help in understanding the prevalence of virulence genes and antibiotic sensitivity among Salmonella serovars in chicken.

Keywords: PCR, Salmonella, Serotypes, Virulence Genes.