Aims:  To investigate the prevalence and genotypic/phenotypic characters of emetic toxin‐producing Bacillus cereus strains isolated from sporadic food poisoning cases in Korea. Methods and Results:  The prevalence of emetic B. cereus was determined in 56 899 stool samples from sporadic food poisoning cases in Korea between 2004 and 2006. We assessed toxin profiles, phenotypic traits and antibiotic resistance. The molecular subtyping was ascertained using an automated repetitive sequence‐based PCR (rep‐PCR) system, DiversiLab™, with these emetic strains isolated from sporadic food poisoning cases and other emetic strains isolated from an outbreak and food samples. Emetic B. cereus was present in 0·012% of sporadic food poisoning cases. The prevalence of nheABC, hblCDA, cytK and entFM enterotoxin genes among emetic strains was 100, 14·3, 14·3 and 100%, respectively. Most emetic strains were negative for salicin hydrolysis (100%), starch fermentation (85·7%) and haemolysis (85·7%). One emetic isolate, VK7, exhibited several unique traits, such as harbouring the hbl gene and ability to hydrolyse starch. All isolated strains were highly resistant to β‐lactam antibiotics. All emetic strains except VK7 exhibited an identical rep‐PCR banding pattern, while nonemetic strains were classified into various pulsotypes. Conclusions:  Most emetic strains except one isolate exhibited similar genotypic/phenotypic traits and subtyping pattern. Automatic rep‐PCR (DiversiLab™) may be used to discriminate emetic strains from nonemetic strains, although we could not distinguish between most emetic strains using that. Significance and Impact of the Study:  Result of this study may contribute an extended database on the prevalence and toxigenic traits of emetic B. cereus strains isolated from Korea.

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