Diagnostic real-time PCR assays for the detection of emetic Bacillus cereus strains in foods and recent food-borne outbreaks.
نویسندگان
چکیده
Cereulide-producing Bacillus cereus can cause an emetic type of food-borne disease that mimics the symptoms provoked by Staphylococcus aureus. Based on the recently discovered genetic background for cereulide formation, a novel 5' nuclease (TaqMan) real-time PCR assay was developed to provide a rapid and sensitive method for the specific detection of emetic B. cereus in food. The TaqMan assay includes an internal amplification control and primers and a probe designed to target a highly specific part of the cereulide synthetase genes. Additionally, a specific SYBR green I assay was developed and extended to create a duplex SYBR green I assay for the one-step identification and discrimination of the two emesis-causing food pathogens B. cereus and S. aureus. The inclusivity and exclusivity of the assay were assessed using a panel of 100 strains, including 23 emetic B. cereus and 14 S. aureus strains. Different methods for DNA isolation from artificially contaminated foods were evaluated, and established real-time assays were used to analyze two recent emetic food poisonings in southern Germany. One of the food-borne outbreaks included 17 children visiting a day care center who vomited after consuming a reheated rice dish, collapsed, and were hospitalized; the other case concerned a single food-poisoning incident occurring after consumption of cauliflower. Within 2 h, the etiological agent of these food poisonings was identified as emetic B. cereus by using the real-time PCR assay.
منابع مشابه
Detection of emetic Bacillus cereus by real-time PCR in foods.
The simplex real-time PCR assays based on the TaqMan probe and SYBR green I, which target cereulide synthetase genes (ces genes) were used for rapidly, reliably and sensitively identifying the emetic strains from among Bacillus cereus strains isolated from different sources. Only the emetic strains showed positive reactions to the real-time PCR assays, but all examined strains of diarrheal B. c...
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عنوان ژورنال:
- Applied and environmental microbiology
دوره 73 6 شماره
صفحات -
تاریخ انتشار 2007