Advances in Animal and Veterinary Sciences

Research Article
Adv. Anim. Vet. Sci. 7(s2): 123-128
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Ibrahim H. Amer, Esmat I. Awad, Salah F. Abd El-Aal, Rania M. Kamal, Reem M. Algendy*

Food Control Deptartment, Faculty of Veterinary Medicine, Zagazig University, Egypt.

Abstract | Bacillus cereus (B. cereus) is an aerobic spore-forming bacterium that has a great public health hazards due to its high distribution in the environment, especially in dairy products in addition to its production to toxins. A total of 25 each of raw and pasteurized milk samples were examined for the presence of B. cereus. Microscopic examination, biochemical tests followed by detection of virulence genes and the antimicrobial susceptibility patterns of recovered B. cereus isolates were performed. From 37 samples that yielded bacillus like growth, there were 15 positives for B. cereus group. All Gram-positive B. cereus isolates were positive for glucose utilization test but were negative for indole test. The distribution of emetic cereulide gene (ces) among the examined isolates was 66.67% (10 ΜΈ 15), while the enterotoxigenic non haemolytic gene (nhe) was not detected in any of the tested isolates. B. cereus isolates showed an absolute resistance to penicillin (10 U) (100%), followed by ampicillin (10 mg) (93.33%), cefoxitin (30 mg) and amoxicillin (20 mg) (80% each). The isolates were susceptible to enrofloxacin (5 mg) and erythromycin (15 mg) (100 % each), vancomycin (30 mg) (93.33%) and doxycycline (30 mg) (80%). In conclusion, the presence of toxigenic and resistant B. cereus in raw milk and pasteurized milk samples indicates a potential risk to food safety and, therefore, monitoring of the dairy items is suggested.

Keywords | Bacillus cereus, Virulence genes, Enterotoxigenic gene, Cereulide gene, Antibiotic susceptibility