Prevalence, antibiotic-resistance properties and enterotoxin gene profile of bacillus cereus strains isolated from milk-based baby foods

Abstract

Purpose: To investigate the prevalence, distribution of enterotoxins and antibiotic resistance of B. cereus in milk-based infant foods. Methods: Three-hundred milk-based infant foods were collected and immediately transferred to the laboratory. Samples were cultured and B. cereus isolates were also confirmed using polymerase chain reaction (PCR)-based detection of gyrB gene. B. cereus strains were subjected to disk diffusion and PCR-based detection of enterotoxigenic genes. Results: Prevalence of B. cereus in infant foods was 3 %. Contamination was in the range of 12.5 – 41.5 CFU/g. Brand D had the highest prevalence of B. cereus (6.2 %). NheA (88.8 %), nheC (55.5 %) and entFM (55.5 %) were the most commonly detected enterotoxigenic genes. Bacteria showed the highest prevalence of resistance against penicillin (100 %), tetracycline (77.7 %) and oxacillin (66.6 %). Prevalence of resistance against two antibiotics were 100 %. Conclusion: Considerable prevalence of resistant and toxigenic B. cereus and high consumption of milk-based infant foods in Iran, represent an important public health issue which should be considered for further preventive approaches.