Molecular Detection of Metallo-β-lactamase Genes blaIMP, blaVim,‎ ‎and blaSPM-1‎ in Bacillus cereus Strains Isolated from Infant Milk Powder Samples

Background: Infant milk powder (IMP) is a very suitable medium for the growth of ‎micro-organisms such as Bacillus cereus. B. cereus is a spore-producer that can ‎survive easily during the pasteurization process to cause some health problems. Objectives: This study was carried out to determine the antibiotic resistance pattern of B. ‎cereus isolates producing metallo-β-lactamase (MBL) enzymes in IMP samples‏.‏ Methods: After preparing 50 samples of IMP, they were cultured to detect the presence of B. cereus. The Kirby-Bauer method was used to determine antibiotic susceptibility and the DDST method to phenotypically detect MBL enzymes. MBL genes blaVIM, blaSMP-1, and blaIMP were genotypically examined in the isolates by the PCR method. Results: Most samples of IMP had a high level of contamination with B. cereus when compared to national and international standards. The highest percentage of resistance was related to ceftazidime and oxacillin (100%) and the lowest resistance to tetracycline (21.4%) and ciprofloxacin (26.3%). All B. cereus isolates were the producers of MBL in the DDST test. None of the isolates was positive for the blaSPM gene. Of the other MBL genes, the blaVIM gene was seen in all isolates (100%) and the blaIMP gene in 16 isolates (84.21%). Conclusions: Antibiotic resistance is on the rise in the study region due to the production of MBL enzymes. Among MBL-producing isolates, the frequency of the blaVIM gene was more than that of blaIMP and blaSPM-1.