High risk of potential diarrheagenic Bacillus cereus in diverse food products in Egypt

Abstract

Bacillus cereus is one of the important foodborne pathogens that can be found in various foodstuffs; causing diarrheal and/or emetic syndromes. This study aimed to evaluate the prevalence, antimicrobial susceptibility profile, pathogenic potential, and genotypic diversity of B. cereus isolated from diverse food products from markets in Cairo, Egypt. A total of 39 out of 165 food samples were positive for B. cereus (detection rate of 24%) with a contamination level ranged from 2 to 6 log CFU/g and a higher incidence of > 3 log bacterial count. Antimicrobial susceptibility testing showed that B. cereus isolates were fully sensitive to all tested antimicrobial agents except β-lactams. The pathogenic potential of the 39 B. cereus isolates was assessed by detecting and profiling the secreted virulence or toxin encoding genes including the chromosomal-carried genes hblA , bceT , plc , sph , nheA , entFM , cytK associated with the diarrheal syndrome and the plasmid-carried ces gene associated with the emetic syndrome. The most frequently detected genes were hblA , nheA and entFM . All isolates harbored more than one of the diarrheal enterotoxins encoding genes with the genetic profile hblA-bceT-nheA-entFM-cytK-plc-sph was the most prevalent (in 20/39 isolates). The emetic toxin ces was not detected at all. ERIC-based analysis of the 20 B. cereus isolates harboring the prevalent genetic profile revelated that they were genetically distinct. In conclusion, the findings of this study provide useful information for public health management and serve as a warning of the potential risk of diarrheagenic B. cereus in diverse food products. Therefore, the consideration to extensively study the epidemiology of this food pathogen in Egypt is warranted. Additionally, strict procedures should be applied to monitor, protect, and safely handle food products, particularly ready to eat foodstuffs that are usually consumed without heat treatment.