Phenotypic Characterization and Antibiotic Resistance of Bacillus cereus Isolated from Local Infant Corn Flour Sold in Daloa Markets (Côte d’Ivoire)

Abstract

Obtaining corn flour as a complementary food for infants is done by artisanal methods by women, which could compromise their hygienic quality. The objective of this work was to determine the presence of Bacillus cereus in corn flour intended for infant consumption. Ninety samples of corn flour were collected from vendors in the markets of Lobia, Orly, Abattoir du grand marché in Daloa (Côte d’Ivoire). These samples were cultured on Mossel agar and incubated at 30°C for 24 hours. Lecithinase-positive colonies, a total of 150, were extracted. Biochemical tests were then carried out, including Gram staining, catalase test, glucose and mannitol fermentation, followed by motility analysis and Simmons citrate utilization. Confirmation of the isolates with the MALDITOF test was carried out. An antibiogram was performed to assess the resistance of Bacillus cereus strains to the various selected antibiotics. A total of 85 strains, or 56.67%, were identified as Bacillus cereus. Of the remaining 65 isolates, 44 strains, or 29.33%, were Bacillus subtilis ssp. subtilis, and 21 strains, or 14.00%, were Bacillus velezensis. The antibiogram revealed multiple resistances ranging from 2 to 9 antibiotics depending on the strain. It is worth noting high resistance to beta-lactams, with high rates (60%) for imipenene and 53.33% for amoxicillin + clavulanic acid (Amc). The uncontrolled use of antibiotics in the food environment poses a serious public health problem because it causes multiple resistance in Bacillus cereus strains.