Identification and Characterization of Salmonella Species Isolated from Broiler Chickens

Salmonellosis is one of the most important problems in poultry industry and a critical food safety hazard. In the present study the prevalence of avian Salmonellosis was studied in different farms of broiler chickens in Beni Suef Governorate, Egypt during the period from January to April 2020. A total of 140 samples were taken from slaughtered diseased or freshly dead broiler chickens aged from one to 35 days. Bacteriological examination revealed that 7.14% of the samples were Salmonella positive. Serotyping of Salmonella isolates showed that S. kentucky, S. blegdam and S. virchow were recognized at rates of 40%, 30% and 30%, respectively. Antimicrobial susceptibility test revealed that all salmonella isolates were multidrug resistant (MDR). All isolates were resistant to oxytetracycline (100%) while 90% were resistant to amoxicillin-clavulanic acid, cefotaxime, sulfamethoxazole- trimethoprim and norofloxacin.  On the other hand, 80% of isolates were sensitive to fosfomycin and nitrofurantoin. Results of screening of some MDR isolates by multiplex PCR for detection of some virulence genes showed that all the tested isolates (100%) had invA, stn, spvC genes meanwhile pefA was not detected in any isolate.