title: Comparison of culture, multiplex, and 5' nuclease polymerase chain reaction assays for the rapid detection of Yersinia enterocolitica in swine and pork products.
abstract: Bacteriological culture was compared with multiplex and fluorogenic (TaqMan) polymerase chain reaction (PCR) assays for the detection of attachment invasion locus (ail)-bearing Yersinia enterocolitica in market weight swine, chitterlings, and ground pork. The TaqMan assay detected 1 pg of purified Y. enterocolitica DNA, whereas conventional gel-based PCR detected I ng of the same. The presence of ail-bearing Y. enterocolitica was tested in pork and feces artificially inoculated with Y. enterocolitica strain NADC 5561. The sensitivity limits of culture, multiplex, and TaqMan PCR assays were 4 x 10(3), 4 x 10(2), and 0.4 CFU/g, respectively, for the artificially inoculated pork. The sensitivity limits were 4 x 10(2), 4 x 10(2), and 0.4 CFU/g, respectively, for feces after a 48-h enrichment in a Yersinia selective broth. By the culture method, Y. enterocolitica was not detected in any of the swine specimens (n = 2,403) examined. By contrast, it was detected in 48 (2%) of the swine samples screened using the multiplex PCR and in 656 (27.2%) of these samples using the TaqMan assay. Using the culture method, Y. enterocolitica was detected in 8% of chitterling samples (n = 350) and in none of the ground pork samples (n = 350). It was identified in 27% of the chitterling samples using multiplex PCR and in 79% of these samples using the TaqMan assay. Ten percent of the ground pork samples contained Y. enterocolitica, as determined by the multiplex PCR, and 38% based on the TaqMan assay. The results suggest that pork products harbor more ail-bearing Y. enterocolitica than selected organs of freshly slaughtered hogs and that the TaqMan assay is more sensitive than either the multiplex PCR or traditional culture methods.
authors.affiliation: Pre-Harvest Food Safety and Enteric Diseases Research Unit, National Animal Disease Center, USDA, Agriculture Research Service, Ames, Iowa 50010, USA.
authors.forename: S
authors.initials: S
authors.lastname: Boyapalle
authors.forename: I V
authors.initials: IV
authors.lastname: Wesley
authors.forename: H S
authors.initials: HS
authors.lastname: Hurd
authors.forename: P G
authors.initials: PG
authors.lastname: Reddy
mesh_terms: D000818:Animals; D015373:Bacterial Typing Techniques; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000032:analysis*; D004768:Enterotoxins; D005243:Feces / Q000382:microbiology; D005456:Fluorescent Dyes; D008461:Meat Products / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D013552:Swine; D019914:Taq Polymerase; D015008:Yersinia enterocolitica / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D004269:DNA, Bacterial; D004768:Enterotoxins; D005456:Fluorescent Dyes; D019914:Taq Polymerase