Characterization and antibiotic susceptibility pattern of Bacillus cereus isolates from fried soyabean cake in Zaria, Nigeria

A total of one hundred and fifty fried soyabean cake samples were collected from different vendors in various parts of Zaria, Kaduna state and were assessed for the presence of Bacillus cereus. 84 out of the total 150 were positive for B. cereus given a prevalence of 56%. All the samples tested contained more than 105 cfu/g of the bacterium with a mean count value of 7.8±7.1 log cfu/g. Isolates were tested for enterotoxin production using the BCET-RPLA kit and 90% of the isolates were found to possess the L2 fraction of the HBL components. All enterotoxic B. cereus isolates were found to be susceptible to Amikacin (30µg), Ciprofloxacin (5µg), Gentamicin (10µg) and Tetracycline (30µg). 100% resistance was observed against Ampicillin (10µg) and Oxacillin (1µg). The percentage resistance to Bacitracin (10µg), Chloramphenicol (30µg), Erythromycin (15µg) and Vancomycin (30µg) of the enterotoxic isolates are 56%, 33%, 39% and 44% respectively.