Occurrence and Characterization of the Pathogenic Potential of Bacillus cereus in Vending Machines from Southern Italy.

Bacillus cereus is a ubiquitous spore-forming bacterium associated with foodborne illness. Although frequently detected as a contaminant in food-processing environments, the presence of specific virulence-associated genes may be relevant to food safety. Pathogenicity is mainly associated with production of emetic and diarrheal toxins. In a previous survey assessing the hygienic and sanitary conditions of vending machines in the Campania Region (Italy), B. cereus was the predominant pathogenic microorganism recovered. The present study aimed to characterize the virulence-associated gene profiles of DNA extracts from these B. cereus-positive samples to assess their potential pathogenicity-related and food-safety relevance. A total of 221 samples, including finished products (cappuccino), powdered ingredients (e.g., milk and coffee), and surface swabs, were collected. B. cereus was detected in 51.6% (114/221) samples using the nhe gene for species identification. The virulence-associated genes cwpFM, cytK, hblD, and ces, among the most frequently associated with foodborne illness, were investigated by end-point Polymerase Chain Reaction (PCR). The prevalence was 67% for cwpFM, 54% for cytK, 53% for hblD, and 11% for ces. These findings reveal virulence- and persistence-associated genetic markers in B. cereus-positive vending machine samples, highlighting the need for effective hygiene measures, improved sanitation, and enhanced monitoring.