Development of a Domestic Alternative Positive Control Strain to Bacillus cereus ATCC 14579 for Microbial Assays.

Abstract

Most positive control strains in microbial assays are sourced from abroad. Bacillus cereus ATCC 14579 is used as the positive control strain in microbial assays described in the Manual for the Detection of Foodborne Pathogens at Outbreaks and the FDA's Bacteriological Analytical Manual method. This study aimed to identify a domestically isolated strain from the Ministry of Food and Drug Safety (MFDS) to replace B. cereus ATCC 14579. A total of 323 strains from the MFDS were collected, and gene-targeted polymerase chain reaction and biochemical tests were performed to characterize candidate strains. Sixty-one candidate strains showing identical biochemical and molecular characteristics to ATCC 14579 were further subjected to whole-genome sequencing. Comparative genetic analyses using MLST, SNP distance, and OrthoANI revealed that B. cereus MFDS 1004972 shared the same sequence type, exhibited SNP distance of fewer than 10 SNPs, and showed 100% ANI with ATCC 14579. Therefore, B. cereus MFDS 1004972 is proposed as a suitable domestic alternative to the imported strain.