title: Detection and prevalence of pathogenic Yersinia enterocolitica in refrigerated and frozen dairy products by duplex PCR and dot hybridization targeting the virF and ail genes.
abstract: Pathogenic Yersinia enterocolitica is involved in yersiniosis through expression of chromosome-borne or plasmid-borne virulence factors. Yersinia enterocolitica is a cold-tolerant pathogen frequently isolated from refrigerated or frozen foods. However, little attention has been focused on the prevalence of pathogenic Y. enterocolitica in refrigerated or frozen dairy samples in China. In this study, we developed a new duplex PCR targeting the plasmid-borne virF gene and chromosome-borne ail gene for detection of pathogenic Y. enterocolitica isolates. We established a detection limit for the duplex PCR of 6.5 × 10(2)cfu/mL in artificially contaminated dairy samples. In addition, the duplex PCR could detect directly 4.5 to 5.7 cfu of Y. enterocolitica in 5 mL of brain heart infusion broth after 6 h of enrichment at 28 °C. A newly developed dot hybridization assay further confirmed specificity of the duplex PCR for detection of virulent Y. enterocolitica. Furthermore, 13 Y. enterocolitica and 5 pathogenic strains, from 88 commercial frozen or refrigerated dairy products, were detected successfully by the China National Standard method (GB/T4789.8-2008) and the duplex PCR, respectively. Finally, biotypes and serotypes of pathogenic Y. enterocolitica strains were further characterized. The duplex PCR developed here is reliable for large-scale screening, routine monitoring, and risk assessment of pathogenic Y. enterocolitica in refrigerated or frozen dairy products.
authors.affiliation: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, 230009, China. Electronic address: yeyingwang04@126.com.
authors.forename: Y W
authors.initials: YW
authors.lastname: Ye
authors.affiliation: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, 230009, China.
authors.forename: N
authors.initials: N
authors.lastname: Ling
authors.affiliation: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, 230009, China.
authors.forename: Y J
authors.initials: YJ
authors.lastname: Han
authors.affiliation: State Key Laboratory of Applied Microbiology, South China (the Ministry-Province Joint Development), Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou, 510070, China. Electronic address: wuqp203@163.com.
authors.forename: Q P
authors.initials: QP
authors.lastname: Wu
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D002681:China; D003080:Cold Temperature; D004269:DNA, Bacterial / Q000235:genetics; D003611:Dairy Products / Q000382:microbiology*; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D057230:Limit of Detection; D009693:Nucleic Acid Hybridization; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D037521:Virulence Factors / Q000235:genetics; D015008:Yersinia enterocolitica / Q000235:genetics / Q000302:isolation & purification*
chemical_list: C069712:Ail protein, Yersinia enterocolitica; D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial; D037521:Virulence Factors
keywords: dot hybridization; duplex PCR; pathogenic Yersinia enterocolitica; refrigerated or frozen dairy products