Prevalence, antibiogram pattern and virulence genes profile of bacillus cereus isolated from buffalo milk

Abstract

In Egypt, the buffalo’s milk is greatly consumed on a large population scale, due to its nutrition quality and palatability, so there is a needing to ensure its microbiological quality especially for food borne pathogens to be safe for human consumption. The current study was conducted on a total of 85 solitary collected raw buffalo’s milk samples at El-Giza Governorate. The cultural examination revealed that Bacillus cereus was isolated in 11 samples by (12.94%). The biochemical examination of the 11 isolates exhibited predominant two different biotypes 2 and 5. The antibiogram manner exposed that all isolates were sensitive to gentamicin, neomycin and ciprofloxacin, less sensitive to tetracycline (87.5%) vancomycin (81.25%) and erythromycin (81.25%), intermediate to ampicillin (56.25%) and polymyxin (43.75%) while the eleven isolates were resistant to both amoxicillin and penicillin G (100%). The multiplex PCR was carried out to assess conservative gene 16S rDNA gene, ces (cereulide encoding gen) and entFM (enterotoxin-encoding gene) among the eleven isolates. The procured data demonstrated that only ten isolates amplified the targeted 16S rDNA product 964 bp (90.9%). On the other side, there were six isolates showed amplicons of average molecular size 486 bp (54.54%) while two isolates amplified 1271 bp (18.18%), which targeted entFM and ces respectively. The obtained data proposed that raw buffalo’s milk may considered a source of public health concern toxigenic B. cereus which may be implemented in food-borne illness.