DETERMINATION OF THE PHYLOGENETIC RELATEDNESS OF CRONOBACTER SPP. ISOLATED FROM POWDERED INFANT FORMULA RETAILED IN NIGERIA USING PAN–GENOMIC DNA MICROARRAY

Cronobacter spp. are emerging, opportunistic, food-borne pathogens associated with infections like meningitis, necrotizing enterocolitis and septicaemia in premature and immunocompromised neonates and infants. The phylogenetic relatedness of three Cronobacter species isolated from powdered infant formula retailed in Nigeria was carried out using a Pan-Genomic DNA Microarray constituting 19,287 independent genes representing 15 Cronobacter genomes and 18 plasmids and 2,371 virulence genes of phylogenetically related Gram-negative bacteria. The hybridization results showed that Cronobacter malonaticus (CS14) and Cronobacter sakazakii (CS17 and CS124) clustered with powdered infant formula environmental and clinical strains of C. malonaticus and C. sakazakii isolated from countries like Jordan, Czech Republic, Ireland and USA with a significant relatedness greater than 80%. The sequence types of C. malonaticus CS14 was ST303 and C. sakakakii CS17 and CS124 were ST304 and ST296, respectively. Some virulence genes (integrase of Shigella flexnerri bacteriophage X, hypothetical protein z1655, dihydrofolate reductase, and formate acetyltransferase 1) were detected in CS124 and CS17. Adequate regulatory measures should be applied to monitor imported and locally produced powdered infant formulae to prevent contamination with Cronobacter spp. and other food borne pathogens to ensure the safety of vulnerable neonates and infants.