Prevalence of virulent Bacillus cereus isolated from different food samples in the Egyptian markets

Bacillus cereus is a common, widely found contaminant mostly found in soil. It is known as a food-borne pathogen that can be detected in various food types and causes emetic and diarrheal illnesses in humans. This research examined 200 food samples of various food products including rice, starch, flavors, milk and dairy products, fruits, herbs, and ready-to-eat foods. Examination revealed 50 samples (25%) of the total sample were contaminated with B. cereus. Antibiotic susceptibility, detection of hemolytic (hbl), emetic (ces), and nonhemolytic (nhe) genes were conducted for each isolate. The findings indicated that all B. cereus isolates were resistant to β-lactam antibiotics (ampicillin, penicillin-G), with 38% of the isolates being resistant to vancomycin, which raises serious concerns about the spread of antibiotic resistance in the environment. Analysis revealed that non-hemolytic genes were detected as 94% for nheA, 100% for nheB and 86% for nheC. Hemolytic genes were detected in lower percent with 66% for hblA, 64% for nblB and 48% for nblD, while the emetic ces gene was present in 6% of all isolates. This study demonstrates the frequency of virulent B. cereus in food samples found in markets and emphasizes the need of utilizing both conventional and molecular approaches to identify virulent B. cereus in food.