Molecular detection of Enterobacter spp. and other related species in powdered milk infant formula and milk powder

Abstract A total of 60 powdered milk infant formula and milk powder samples were obtained from different localities in Qena Governorate, Egypt, to be evaluated for presence of Enterobacter and closely related species using FDA procedure. Ten out of 60 samples were contaminated with Enterobacter spp. and other Enterobacteriaceae. The obtained isolates were biochemically identified as Enterobacter spp., Klebsiella pneumoniae , Escherichia coli , Citrobacter spp. Further characterization was performed using 16S rRNA sequence analysis; it was a pivotal to confirm the identity of the isolates especially in imprecise identification of phenotypic method in some isolates like Enterobacter hormaechei , Klebsiella quasipneumoniae, and Acinetobacter vivianii. Results revealed the contamination of powdered milk infant formula with E. hormaechei which makes it a matter of concern. According to the best of our knowledge, Enterobacter hormaechei and Klebsiella quasipneumonia were isolated for the first time in Egypt. The phylogenetic analysis proved the close relation between our isolates in amplification of partial 16S rRNA gene. Practical applications As many neonates depend on powdered infant formula in their feeding as well as milk powder is a fundamental component of many infants diet, our study evaluated these products for the presence of pathogens of safety concern. This study focused on Enterobacteriaceae family members other than Salmonella and Cronobacter sakazakii using 16S rRNA gene for identification and differentiation of the closely related species.