Comparative study of culture methods to detect Yersinia enterocolitica serogroup O3 on swine tongues.

Swine tongues were used as a model for evaluation of culture methods for Y. enterocolitica O3. The following three methods were used: Method A consisting of primary culture on DC, McConkey, CIN and SSD agar with additional long-term cold enrichment in PBS and/or selenite broth. Method B--2 min, treatment of samples with 0.5 per cent KOH solution followed by the same cultivation as above and Method C--"cold shock" i.e. incubation of swabs without any medium at -20 degrees C overnight and then inoculated in selenite broth and/or PBS. Methods B and C were approximately twice as effective as Method A. The percentage of detectability ranged from 70 to 90 per cent. CIN agar yielded 20 of 23 positive results when compared with other solid media. A total of 247 smears from pig tongues yielded 60 positive Y. enterocolitica O3 isolations i.e. 27 per cent on average.