Human carriage of Yersinia spp

Examination of faecal specimens for the presence of Yersinia spp. during a 1-year period yielded isolations from 3.5% of patients. Salmonella spp., Campylobacter spp. and Shigella spp. were isolated from 2.5%, 2.8% and 0.34% of patients respectively. Most isolates belonged to Y. enterocolitica biotype 1 (53%) and Y. frederikseni (39%). The most frequently encountered serotypable strains were serotypes O 5.27 and O 6.30. Serotype O 3, the commonly recognised pathogenic strain, was not isolated in this survey. A strong association between Yersinia excretion and the age group 1-14 years was demonstrated. Although biotype-1 strains and Y. frederikseni have not previously been thought to be pathogenic, clinical significance could be attributed to the presence of Yersinia spp. in almost 90% of patients aged 15 years or more, and in over 50% of patients in the younger age groups.