COMPARISON OF THE VITEK, API 20E AND GENE-TRAK(R) SYSTEMS FOR THE IDENTIFICATION OF YERSINIA-ENTEROCOLITICA

The current improvements in nucleic acid hybridization technology prov ide new techniques for the identification of micro-organisms. One such technique is the Gene-trak(R) DNA hybridization system (Framingham, M A, USA), which was introduced in 1983. The objective for this study wa s to evaluate the new Gene-trak(R) Yersinia enterocolitica kit in comp arison with the API 20E and Vitek systems. A total of 101 strains incl uding 18 reference non-Yersinia strains from the authors' stock cultur e collection and 83 suspected positive isolates from CIN agar were tes ted. Of these 83 isolates, 40 were identified as Y. enterocolitica aft er incubation at 37 degrees C for 24 h with the API 20E system; 37 str ains were identified at 30 degrees C for 48 h. The Gene-trak(R) method gave positive results with 39 strains. The Vitek system gave positive results with 27 strains. With the Gene-trak(R) method, Y. enterocolit ica was detectable in mixed cultures provided that the numbers of cfu ml(-1) were equal to or above 10(6) Y. enterocolitica ml(-1). Although enrichment procedures are still needed, the system provides a quick d etection of these food-borne pathogens.