Cronobacter sakazakii was isolated from Used and Retail Powdered Infant Formulas (PIF) and Opened-vended Powdered Milk (OVPM) samples using standard methods comprising Enterobacteriaceae Enrichment Broth and HARDYCHROM sakazakii medium. The antibiotics susceptibility results showed that out of the forty-four (44) of the Cronobacter sakazakii isolates tested, 44 (100%) was sensitive to Ciprofloxacin, 27 (61.36%) to Gentamycin and 17 (38.64%) to Streptomycin in that order. The killing rate showed that Ciprofloxacin and Gentamycin killed Cronobacter sakazakii completely after 240 minutes with antibiotics mean and standard error of mean values of 1.18±0.00 and 2.40±0.03. Of the common antibiotics available, only Ciprofloxacin and Gentamycin were able to kill Cronobacter sakazakii completely at 240 minutes. Hence, both Ciprofloxacin and Gentamycin were bactericidal and they can be used for killing Cronobacter sakazakii ingested through contaminated Used and Retail Powdered Infant Formulas (PIF) and Opened-vended Powdered Milk (OVPM).
Keywords: Cronobacter sakazakii, Powdered Infant Formulas, Antibiotics susceptibility, Killing rate