Prevalence, phenotypic traits and molecular characterization of emetic toxin-producing Bacillus cereus strains isolated from human stools in Korea

Abstract

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.

Characterization of Escherichia coli–Producing Extended-Spectrum β-Lactamase (ESBL) Isolated from Chicken Slaughterhouses in South Korea

“…Subtyping patterns were analyzed using the Pearson correlation statistical methods in the DiversiLabÔ software. We scored isolates as indistinguishable if they had a high percentage of similarity (>97%), as described elsewhere (Healy et al, 2008;Chon et al, 2012).…”

Occurrence and characterization of toxigenic Bacillus cereus in food and infant feces

“…Six commercially antibiotic disks were used (Oxoid): vancomycin (30 mg/mL), clindamycin (2.0 mg/mL), erythromycin (15 mg/ mL), gentamicin (10 mg/mL), oxacillin (1.0 mg/mL) and penicillin (10 units). All Mueller-Hinton plates were incubated at 34 C for 18-24 h [19].…”

“…All isolates were grown in brain heart infusion broth (Oxoid) for 18 h at 34 C followed by spreading on Mueller-Hinton agar (Oxoid) [19] . Six commercially antibiotic disks were used (Oxoid): vancomycin (30 mg/mL), clindamycin (2.0 mg/mL), erythromycin (15 mg/ mL), gentamicin (10 mg/mL), oxacillin (1.0 mg/mL) and penicillin (10 units).…”

Prevalence and antimicrobial resistance of <i>Bacillus cereus</i> isolated from beef products in Egypt

“…The antibiotic susceptibility testing was performed using the disc diffusion method (Chon et al, 2012). All the isolates were grown in brain heart infusion broth (Oxoid) for 18 hrs at 34 o C and then spread on MuellerHinton agar (Oxoid, UK) and left for 15 minutes.…”

“…All the isolates were grown in brain heart infusion broth (Oxoid) for 18 hrs at 34 o C and then spread on MuellerHinton agar (Oxoid, UK) and left for 15 minutes. Then, eight commercial antibiotic discs (Oxoid, UK) were used: penicillin (10 units), oxacillin (1.0 mg/ml) vancomycin (30 mg/m), clindamycin (2.0 mg/ml), erythromycin (15 mg/ml), gentamicin (10 mg/ml), Ciprofloxacin (5μg) and Ceftriaxone (30 μg), and the plates were then incubated at 37 °C for 18-24 hrs (Chon et al, 2012).…”