Ecopathological Features of Bacillus Cereus Food Poisoning in Anambra State, Nigeria

Abstract

This study was conducted to determine the level of contamination of Bacillus cereus in Nigeria local cooked /boiled foods in Anambra State, Nigeria. One hundred and ninety (190) different types of extra human samples made up of 10 each ready to eat cooked/boiled foods were randomly purchased from local food vendors and restaurants. Eighty (80) human diarrheal stools from patients suspected of food poisoning attending clinics and laboratories and fifty control stool from human volunteers were also examined for the presence of Bacillus cereus. The extra human samples were first homogenized in 1% peptone, incubated at 37^oc for 24hours and then sub cultured on to freshly prepared blood, MacConkey, and Polymyxin B agar plates while a direct stool culture on the above agar plates were also done. Bacillus cereus was identified using cultural characteristics, Gram staining reaction, spore staining reaction for the presence of lipid globules which is specific for Bacillus cereus, some biochemical tests and polymerase chain reaction (PCR). Animal studies results revealed pathological involvement of the liver. Antibiotic sensitivity tests were carried out using agar diffusion methods. Bacillus cereus was detected in 44(23.4%) of 190 extra human samples. Bacillus cereus was isolated in ready to eat cooked/boiled foods, 20(33.3%) of 90 cooked/boiled foods, soup category 10(20%) of 50 soup samples, 15(30%) of 50 steamed wrapped foods samples. No Bacillus cereus was isolated from stew sample while 4(40%) of 10 samples each of abacha (African salad, breadfruit (ukwa), boiled palm nut oil soup (akwu), plantain pudding (ukpogede) were positive for Bacillus cereus.  Bacillus cereus was isolated in 15(18.5%) of 80 diarrheal stool samples and 4(8%) of 50 control stool. 42 (95.45%) of Bacillus cereus isolated were positive for the enterotoxins while 2(4.55%) all from cooked rice were negative. The Bacillus cereus isolated were 100% resistant to ampiclox. The results of this study showed that Bacillus cereus is a common contaminant of Nigerian’s local foods and food products and is mainly of the enterotoxin (diarrheal type).

Keywords: Ecopathology, Bacillus cereus, Food poisoning, Enterotoxin