Background: Yersinia enterocolitica is an important pathogen in temperate climates. The heterogeneity of the microorganisms covered by this denomination has a made grouping and identification schemes necessary.
Methods: A series of 150 different, consecutive isolates from patients with diarrheic syndrome living in an urban area with a population of approximately 500,000 inhabitants, were studied in order to evaluate their biochemical, antigenic and sensitivity characteristics.
Results: There was a high degree of uniformity among the strains isolated, 144 (96%) of which were identified as Yersinia enterocolitica sensu stricto, biotype 4, serotype 0:3. These strains presented, almost invariably, the same susceptibility pattern, being sensitive to amoxicillin/clavulanic acid, piperacillin, cefamandole, cefoxitin, gentamicin, amikacin, tetracycline and cotrimoxazole, and highly resistant to ampicillin, ticarcillin and cephazotin. In addition, 5 strains of Yersinia frederiksenii were isolated. The biochemical, epidemiological and sensitivity characteristics of these strains differed from those invariably found in the rest of the isolates.
Conclusions: The data obtained in this study, shown a high degree of uniformity in the strains of Yersinia enterocolitica isolated in our area in recent years, with regard to both their biochemical characteristics and their sensitivity patterns. The isolations of the other biogroups may be regarded as extremely infrequent in the stool culture of patients with diarrhea treated in our hospitals.