title: Detection of Yersinia enterocolitica in milk powders by cross-priming amplification combined with immunoblotting analysis.
abstract: Yersinia enterocolitica (Y. enterocolitica) is frequently isolated from a wide variety of foods and can cause human yersiniosis. Biochemical and culture-based assays are common detection methods, but require a long incubation time and easily misidentify Y. enterocolitica as other non-pathogenic Yersinia species. Alternatively, cross-priming amplification (CPA) under isothermal conditions combined with immunoblotting analysis enables a more sensitive detection in a relatively short time period. A set of specific displacement primers, cross primers and testing primers was designed on the basis of six specific sequences in Y. enterocolitica 16S-23S rDNA internal transcribed spacer. Under isothermal condition, amplification and hybridization were conducted simultaneously at 63°C for 60 min. The specificity of CPA was tested for 96 different bacterial strains and 165 commercial milk powder samples. Two red lines were developed on BioHelix Express strip for all of the Y. enterocolitica strains, and one red line was shown for non-Y. enterocolitica strains. The limit of detection of CPA was 10(0)fg for genomic DNA (1000 times more sensitive than PCR assay), 10(1) CFU/ml for pure bacterial culture, and 10(0) CFU per 100 g milk powder with pre-enrichment at 37°C for 24 h. CPA combined with immunoblotting analysis can achieve highly specific and sensitive detection of Y. enterocolitica in milk powder in 90 min after pre-enrichment.
authors.affiliation: Key Laboratory of Food Nutrition and Safety, Ministry of Education of China, Tianjin University of Science and Technology, Tianjin 300457, China; Food, Nutrition, and Health Program, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Food, Nutrition, and Health Program, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
authors.forename: Shaolong
authors.initials: S
authors.lastname: Feng
authors.affiliation: School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Yulong
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Food Nutrition and Safety, Ministry of Education of China, Tianjin University of Science and Technology, Tianjin 300457, China. Electronic address: s.wang@tust.edu.cn.
authors.forename: Shuo
authors.initials: S
authors.lastname: Wang
authors.affiliation: Food, Nutrition, and Health Program, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada. Electronic address: xiaonan.lu@ubc.ca.
authors.forename: Xiaonan
authors.initials: X
authors.lastname: Lu
mesh_terms: D000818:Animals; D017931:DNA Primers / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D005516:Food Microbiology; D006801:Humans; D015151:Immunoblotting / Q000379:methods; D008892:Milk / Q000382:microbiology*; D009693:Nucleic Acid Hybridization / Q000379:methods; D016133:Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity; D015009:Yersinia Infections / Q000382:microbiology*; D015008:Yersinia enterocolitica / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D017931:DNA Primers; D021903:DNA, Ribosomal Spacer
keywords: 16S–23S rDNA internal transcribed spacer; Cross-primer amplification; Food safety; Immunoblotting analysis; Yersinia enterocolitica