Gene detection and toxin production evaluation of hemolysin BL of Bacillus cereus isolated from milk and dairy products marketed in Brazil

Abstract

Bacillus cereusis an ubiquitous, spore-forming bacteria that can survive pasteurization and the majority of the heating processes used in the dairy industry. Besides, it is a pathogen responsible for different types of food poisoning. One type of foodborne disease caused by B.cereusis the diarrheal syndrome, which is caused by the ingestion of vegetative cells producing toxins in the small intestine. One virulence factor for the diarrheal syndrome is the toxin hemolysin BL (HBL), a three-component protein formed by the L1, L2 and B components. In order to evaluate the presence of diarrheal strains isolated from milk and dairy products, 63 B. cereus isolates were obtained from 260 samples of UHT milk, pasteurized milk and powdered milk, sold in commercial establishments and from different brands. The isolates were subjected to the Polymerase Chain Reaction (PCR) for the detection of the encoding genes for the L1, L2 and B components and the toxin production capacity were evaluated with an immunoassay. A total of 23 [36.5%] isolates were identified carrying simultaneously the three tested genes, from which, 20 [86.9%] showed toxigenic capacity. 26 [41.3%] isolates did not carry any of genes tested and the other 14 [22.2%] were positive for one or two of them. The results showed a high toxigenic capacity among the B. cereus isolates able to produce the HBL, indicating a potential risk for consumers.

Detection of emetic toxin (ces) gene and antimicrobial susceptibility of Bacillus cereus isolates from Iranian traditional dairy products

“…In this study, from a total 150 samples of dairy products, 16 samples (10.66%) were contaminated to B. cereus. These results are somewhat in accordance with the ndings of Reyes et al (2013) who reported that from 260 samples of milk and dairy products, 24.23% were contaminated to this bacterium (Reis et al 2013).…”

Plant Compounds Enhance the Assay Sensitivity for Detection of Active Bacillus cereus Toxin

“…However, this in vivo methodology raises ethical concerns with regard to the use of experimental animals. Sensitive, rapid, and specific methods such as the polymerase chain reaction (PCR) assays have been used [ 18 , 19 ], but these indirect methods measure B. cereus genes and thus do not detect toxin gene expression. Also, the PCR-based assays do not provide a direct measurement of the toxin level and do not distinguish between live and dead organisms and active and inactive toxins.…”

Biological Toxins and Bioterrorism

“…They are mainly associated with rice dishes, occasionally pasta, meat, or vegetable dishes, dairy products, soups, sauces, and sweet pastry products (Reis et al 2014). They are mainly associated with rice dishes, occasionally pasta, meat, or vegetable dishes, dairy products, soups, sauces, and sweet pastry products (Reis et al 2014).…”

“…Both diseases have mild manifestation and, in most cases, are self-limited, although severe cases resulting in the death of the patient have been reported (Reis et al 2013). Both diseases have mild manifestation and, in most cases, are self-limited, although severe cases resulting in the death of the patient have been reported (Reis et al 2013).…”