Bacillus Cereus in Eggshell: Enterotoxigenic Profiles and Biofilm Production

Abstract

A study was carried out with the objective of determining the presence of Bacillus cereus in eggshells commercialized in Mexico, the enterotoxigenic profile of the isolated strains, and the production of biofilms in different materials as well as in the eggshell. 1000 chicken eggs from four commercial brands were collected from markets and supermarkets located in the city of Chilpancingo, Mexico. Bacillus cereus was isolated from the eggshell. The molecular identification was by amplification of the gyrB gene and the enterotoxigenic profiles by the amplification of the cytK, ces, nheABC, and hblABD genes, in addition to the amplification of the tasA and sipW genes associated with the production of biofilms. In different materials and in eggshells, the production of biofilms was evaluated. The microbiological and molecular analysis of B. cereus yielded a frequency of 5.5% (55/1000), this was higher in brand III (11.6%, p=0.0001) and white eggshell (7.6%, 38/500, p≤0.001) and by marketing source, it was similar between market (5.2% / 26/500) and supermarket (5.8%, 29/500). The most common was the toxigenic profile A (23/55). Biofilm production is high in PVC in relation to other materials (p<0.0001), and the frequency of the related genes tasA and sipW was 72.7% and 40% respectively; the highest production was related to the tasA gene; in eggshell, most of the strains (54/55) were able to produce biofilm. Strains of B. cereus with toxigenic potential circulate and persist in this product, which shows the need for sanitary regulation in the country.