The present study was aimed to investigate the prevalence of multidrug resistant S. enteritidis in broiler chicken flocks (n=15)suffering from diarrhea during the period of 2015 in El-Beheira governorate. A total of 210 tissue swabs (liver, intestine, spleen and gall bladder) were aseptically collected, processed and plated onto XLD agar medium. Only five (2.4%) isolates were identified as Salmonella using conventional biochemical methods and PCR assay based on invA gene. Out of 5 Salmonella isolates, 4 (80%) were identified as S. enteritidis using PCR assay based on sefA gene.Antimicrobial susceptibility testing revealed that all isolates of S. enteritidis were multi-resistant to two or more antimicrobial agents. Resistance tosulfisoxazole was common across all isolates. Furthermore, two (50%) penicillin-resistant isolates were tested positive for blaTEM gene using PCR assay. In addition, β-lactamase activity of these isolates was assessed on penicillin-sensitive strain of S. aureus (ATCC29213). Sensitivity of S. aureus to penicillin was significantly decreased in the presence of beta-lactamase-producing S.enteritidis in comparison with control group. The current study necessitates further exploration of genetic elements related to antibiotic resistance and underlines the need to track the evolution of β-lactamases in S. entritidis isolates in Egypt.
Key words: Key words:Salmonella enteritidis, β-lactamase, PCR, Egypt.