Analysis of 97 emetic Bacillus cereus strains in prepackaged pastries in Taizhou City from 2020 to 2022

Abstract

ObjectiveTo understand the diarrhea-type virulence genes， the antimicrobial resistance and the molecular typing of emetic Bacillus cereus from the pre-packaged pastries in Taizhou City.MethodsThe Polymerase Chain Reaction （PCR） method was used to identify the vomiting strains of 97 Bacillus cereus strains which were isolated from pre-packaged pastries in Taizhou and detecte whether the vomiting strains carry diarrhea virulence genes. The sensitivity of the vomiting strains to 19 antibiotics was tested by disk diffusion method， and the molecular typing was carried out by multilocus sequence typing technique.ResultsThe results showed that five emetic Bacillus cereus stains were detected of 97 Bacillus cereus strains and divided into ST 26 and ST 1186 two types. Non-hemolytic enterotoxin gene nhe， enterotoxin genes entFM and bceT were the main diarrhea-type virulence genes of the five strains. The five strains were completely resistant to penicillin， ampicillin and cefotaxime. The resistance rates to cotrimoxazole， rifampicin and cefazolin were 80%（4/5）， 40%（2/5） and 20%（1/5）， respectively. The sensitivity rates of amoxicillin， clindamycin and cefoxitin were 40%（2/5）， 80%（4/5） and 80%（4/5）， respectively， and they were completely sensitive to other antibiotics.ConclusionThis study showed that the detection rate of vomiting Bacillus cereus in pre-packaged pastries in Taizhou was 5.2%（5/97）， ST 26 was the main type， there were a variety of diarrhea-type virulence genes in the five vomiting Bacillus cereus strains.

Keywords

• emetic bacillus cereus
• pre-packaged pastry
• virulence gene
• antimicrobial resistance
• multilocus sequence typing