Biofilm Production by Enterotoxigenic Strains of Bacillus cereus in Different Materials and under Different Environmental Conditions

Abstract

Foodborne illnesses, such as infections or food poisoning, can be caused by bacterial biofilms present in food matrices or machinery. The production of biofilms by several strains of Bacillus cereus on different materials under different culture conditions was determined, as well as the relationship of biofilms with motility, in addition to the enterotoxigenic profile and candidate genes that participate in the production of biofilms. Biofilm production of B. cereus strains was determined on five materials: glass, polystyrene, polyethylene, polyvinylchloride (PVC), PVC/glass; in three culture media: Phenol red broth, tryptic soy broth, and brain heart infusion broth; in two different temperatures (37 °C and 25 °C), and in two different oxygen conditions (oxygen and CO2 tension). Furthermore, the strains were molecularly characterized by end-point polymerase chain reaction. Motility was determined on semi-solid agar. The B. cereus strains in this study were mainly characterized as enterotoxigenic strains; statistically significant differences were found in the PVC material and biofilm production. Motility was positively associated with the production of biofilm in glass/PVC. The sipW and tasA genes were found in two strains. The results of this study are important in the food industry because the strains carry at least one enterotoxin gene and produce biofilms on different materials

Genetic diversity of enterotoxigenic Bacillus cereus strains in coriander in southwestern Mexico

“…However, in this study, the production of biofilms was low, and as the frequency of the sipW and tasA genes. In a previous study, we found a differential distribution of the sipW and tasA genes according to the origin of the B. cereus strains, finding a high frequency in strains from eggs compared to strains from other foods ( Adame-Gómez et al, 2020 ).…”

“…In brief, cells from one colony were suspended in sterile water, heated at 95 °C for 3 min, and then placed on ice. After centrifugation, the supernatant was used as template for the molecular identification and toxin profile ( Adame-Gómez et al, 2020 ).…”

Bacillus cereus in the Artisanal Cheese Production Chain in Southwestern Mexico

“…B. cereus BC133 strain was used as a positive control for nhe amplification. This strain was previously isolated and characterized in the laboratory from infant formula powdered [ 42 ].…”

“…The production of biofilms was carried out with 1 mL of BHI broth in glass tubes (CLS99447161, Merck, Darmstadt, Germany) containing 50 μL of a 24 h culture. They were incubated for 48 h, and washed three times with phosphate-buffered saline or PBS 1X (NaCl 137 mM, KCl 2.7 mM, Na 2 HPO 4 10 mM, KH 2 PO 4 1.8 mM, pH 7.2); 1 mL of safranin was added and homogenized for 15 min, three washes with PBS solution were performed, and it was determined from the visual observation of a ring stained by the dye [ 42 ].…”

Peer Review #1 of "Genetic diversity of enterotoxigenic Bacillus cereus strains in coriander in southwestern Mexico (v0.1)"

“…In brief, cells from one colony were suspended in sterile water, heated at 95ºC for 3 min, and then placed on ice. After centrifugation, the supernatant was used as template for the molecular identification and toxin profile (Adame-Gómez et al, 2020). The differentiation of B. cereus group was targeted on gyrB gene, and the toxin gene profiles from nheABC, hblABD, ces, and cytK gene.…”