Evaluation of culture methods for rapid screening of swine faecal samples for Yersinia enterocolitica O : 3 biotype 4

In two studies, seven different culture protocols were compared to test naturally contaminated faecal samples from pigs for isolation of Y. enterocolitica serotype O; 3/biotype 4( n = 70 and n = 79). Four of the protocols were based on the Nordic Committee on Food Analysis (NMKL protocols), while three protocols were based on a rapid and selective method (here called ITC protocols). The protocols differed mainly in time of pre-enrichment (1, 10 and 24 d) and enrichment (2, 10, 24 d) and the type of selective enrichment media (ITC vs. MRB). The sensitivity of the rapid ITC protocol (24% and 9%) was comparable with the lengthy NMKL-protocols (16% and 11%), while the results of direct plating after 3 h (4%) and the extended enrichment in ITC-broth (4%) were very low. In addition, there was a marked reduction in the number of false positive plates in the short selective protocol (62% vs. 12%). The results indicate possibilities of shortening the culture methods by replacing most of the biochemical tests with an agglutination test based on a monoclonal antibody.