ABSTRACT
AIMS: The aim of this study was to evaluate the performance of immunodetection methods and PCR analysis of enterotoxigenic Bacillus cereus strains. METHODS AND RESULTS: Eighty-eight enterotoxigenic B. cereus group strains linked to food-borne outbreaks and illnesses were studied with 30 exclusivity nonenterotoxigenic strains including Bacillus amyoliquifaciens, Bacillus subtilis, Staphylococcus aureus, Salmonella and Escherichia coli for this assessment. The PCR results showed 80% agreement with immunoassays for the Nhe target and 84% for the Hbl product. All exclusivity strains were PCR and serologically negative. CONCLUSIONS: PCR has proven to be a valuable tool when used in conjunction with immunoassays to quickly identify enterotoxigenic B. cereus group strains. SIGNIFICANCE AND IMPACT OF THE STUDY: This study assessed the utility of rapid methods to characterize enterotoxigenic profiles of B. cereus group strains. The identification of enterotoxigenic bacteria and any associated toxins detected from food products is essential in food defense programs as public health officials search for methods to rapidly and accurately screen a global food supply.
Subject(s)
Bacillus cereus/isolation & purification , Enzyme-Linked Immunosorbent Assay , Food Microbiology , Polymerase Chain Reaction , Bacillus/genetics , Bacillus cereus/genetics , Bacterial Proteins/analysis , Bacterial Proteins/genetics , Bacterial Toxins/analysis , Bacterial Toxins/genetics , Enterotoxins/genetics , Hemolysin Proteins/analysis , Hemolysin Proteins/genetics , HumansABSTRACT
Staphylococcus aureus pathogenicity islands (SaPIs) are mobile elements that are induced by a helper bacteriophage to excise and replicate and to be encapsidated in phage-like particles smaller than those of the helper, leading to high-frequency transfer. SaPI mobilization is helper phage specific; only certain SaPIs can be mobilized by a particular helper phage. Staphylococcal phage 80α can mobilize every SaPI tested thus far, including SaPI1, SaPI2 and SaPIbov1. Phage 80, on the other hand, cannot mobilize SaPI1, and Ï11 mobilizes only SaPIbov1. In order to better understand the relationship between SaPIs and their helper phages, the genomes of phages 80 and 80α were sequenced, compared with other staphylococcal phage genomes, and analyzed for unique features that may be involved in SaPI mobilization.
