title: The phenotypic and genotypic characterization of Enterobacter sakazakii strains from infant formula milk.
abstract: Enterobacter sakazakii is an emerging foodborne pathogen associated with severe diseases in neonates. Infant formula milk (IFM) has been identified as one of the major contaminated sources and a transmission vehicle. To determine the phenotypic and genotypic characterization of this pathogen, 22 E. sakazakii strains isolated from IFM by an FDA-recommended method and PCR on the alpha-glucosidase gene were subtyped by random amplified polymorphic DNA (RAPD)-PCR, enterobacterial repetitive intergenic consensus (ERIC)-PCR, and antibiotic resistance patterns. At a similarity threshold of 80%, 16 ERIC-PCR fingerprint types were identified with a discriminatory power (D) of 0.933, and 18 RAPD-PCR types were identified with D of 0.973. Resistance to 9 antibiotics tested by disk diffusion assay revealed 6 antibiotic resistance patterns with D of 0.749. The comparison of characterization indicated that RAPD-PCR and ERIC-PCR have high discriminatory power showing genetic diversity of E. sakazakii isolates, and ERIC-PCR patterns showed a closer correlation than RAPD-PCR patterns to phenotypic characterization and the brands of IFM. Overall, the ERIC-PCR typing method could be used for tracing sources of E. sakazakii isolates in the food chain.
authors.affiliation: Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China. yeyw04@mails.gucas.ac.cn
authors.forename: Y
authors.initials: Y
authors.lastname: Ye
authors.forename: Q
authors.initials: Q
authors.lastname: Wu
authors.forename: X
authors.initials: X
authors.lastname: Xu
authors.forename: X
authors.initials: X
authors.lastname: Yang
authors.forename: X
authors.initials: X
authors.lastname: Dong
authors.forename: J
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002417:Cattle; D044083:Cronobacter sakazakii / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000235:genetics; D005838:Genotype; D006801:Humans; D007223:Infant; D041943:Infant Formula; D008826:Microbial Sensitivity Tests; D008892:Milk / Q000382:microbiology*; D010641:Phenotype; D016133:Polymerase Chain Reaction; D019105:Random Amplified Polymorphic DNA Technique
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial