title: Detection of Yersinia enterocolitica O:3 in faecal samples and tonsil swabs from pigs using IMS and PCR.
abstract: Dilutions of faecal samples spiked with Yersinia enterocolitica O:3 were analysed using immunomagnetic separation (IMS) followed by PCR. In 10% faecal dilutions with added Y. enterocolitica cells, the limit of detection was 200 cells g-1 faeces. Faecal samples from 38 pigs were analysed by IMS-PCR in parallel with detection and quantification of Y. enterocolitica O:3 using cold pre-enrichment culturing. Of the 15 culture-positive samples, only two were detected with IMS-PCR. These two samples contained 40-400 Y. enterocolitica O:3 cells g-1 faeces; the highest level found in the investigation. This indicated that the low sensitivity of IMS-PCR was due to low amounts of cells in the faecal samples. Swab samples from 195 pig tonsils, taken on a slaughterline were examined using IMS-PCR and culture detection. Of 164 culture-positive samples, 60 were positive with IMS-PCR. In addition, IMS-PCR was positive for three culture-negative samples. Forty-five of the samples were further examined by IMS-PCR after 7-10 d of cold pre-enrichment. All 31 culture-positive samples as well as five culture-negative samples were detected by IMS-PCR. From these data it can be concluded that IMS-PCR can be used to detect Y. enterocolitica O:3 cells after pre-enrichment, but direct detection needs further optimization of the sample preparation procedures.
authors.affiliation: RVAU Centre for Food Research, Biotechnological Institute, Lyngby, Denmark.
authors.forename: H N
authors.initials: HN
authors.lastname: Rasmussen
authors.forename: O F
authors.initials: OF
authors.lastname: Rasmussen
authors.forename: H
authors.initials: H
authors.lastname: Christensen
authors.forename: J E
authors.initials: JE
authors.lastname: Olsen
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D005069:Evaluation Studies as Topic; D005243:Feces / Q000382:microbiology; D018189:Immunomagnetic Separation / Q000379:methods*; D008969:Molecular Sequence Data; D014066:Palatine Tonsil / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D013552:Swine; D015008:Yersinia enterocolitica / Q000302:isolation & purification*
chemical_list: D017931:DNA Primers