Bacillus cereus is one of the opportunistic foodborne bacteria producing food poisoning producing severe economic loss and representing a high risk to the human. The contamination of poultry feed with Bacillus cereus produces gastric damage and facilitates other bacterial infections. For these reasons, fresh fecal matters were collected from poultry farms located in 3 Egyptian Governorates (Giza, Gharbia, and Dakahlia) to isolate and identify Bacillus cereus, determine their susceptibility to different antimicrobial agents, and examine their virulence and resistance factors. Eleven B. Cereus out of 50 examined samples was isolated with a percentage of (11/50, 22%) and subjected to confirmation using the VITEK2 instrument. Disc diffusion tests showed that all isolates were resistant to trimethoprim-sulfamethoxazole, imipenem, cefotaxime, ampicillin, amoxicillin/clavulanic acid, and penicillin G and sensitive to chloramphenicol, gentamicin, and ciprofloxacin. The molecular characterizations of virulence and resistance factors revealed the detection of targeting the groEL gene in all isolates (100%). The toxin gene profiling showed the existence of the nhe gene (90.9%) and the hbl genes (18.18%). The ces and cytk genes were not detected in the examined isolates. Two antimicrobial resistance genes were detected in the examined isolates with (33.33%) for the tetA gene and (45.45%) for bla gene. Therefore, it was concluded that the isolation of B. cereus carrying genes responsible for antimicrobial resistance and toxins production in broiler farms, represents major threats for human health and poultry industry. So that control programs of biosecurity should be implemented in poultry farms to mitigate the losses of B. cereus infection.
Key words: Bacillus cereus, chicken farms
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