Molecular Detection Revealed the Presence of TEM, VIM, and CTX Metallo-Beta-Lactamase Genes in Bacillus Cereus from Milk Powder Formula

This study sought to molecularly determine the presence of TEM-1, VIM, and CTX Metallo Beta-Lactamase (MBL) genes in Bacillus cereus isolated from selected infant formula specimens, and 30 were designated for advanced analysis. Suspected colonies of B. cereus were obtained from the samples and subjected to morphological and biochemical characterization to confirm their identity as B. cereus isolates. Antibiotic susceptibility testing. This study was executed in alignment with the guidelines established by the Clinical and Laboratory Standards Institute (CLSI). To identify MBL genes, we implemented a phenotypic confirmatory test on Mueller Hinton agar to ensure reliable identification fortified with clavulanic acid was implemented. The detection of MBL genes was evidenced by an inhibition zone increase exceeding 5 mm on the plate with clavulanic acid relative to the plate lacking this supplement. For molecular detection, PCR was used to identify the MBL genes in the isolated strains. Among the 30 PCR-tested samples, 28 were found to harbor the TEM-1 gene, indicating its presence in the B. cereus isolated from the infant formula samples. However, none of the isolates tested positive for the VIM or CTX MBL genes. In conclusion, infant dry milk is identified as a conducive environment for B. cereus growth, and the TEM-1 gene is frequently present in the strains derived from these samples. However, the lack of detection of VIM and CTX genes indicates that these resistance genes are not widespread in the isolated B. cereus from infant powder milk.