Epidemiology and Infection

Evaluation of pulsed-field gel electrophoresis of genomic restriction fragments in the discrimination of Yersinia enterocolitica O[ratio]3

a1 National Public Health Institute, Department of Enteric Pathogens, Mannerheimintie 166, 00300 Helsinki, Finland
a2 National Veterinary and Food Research Institute, Department of Food Microbiology, PO Box 358, 00280 Helsinki, Finland


One hundred and six Yersinia enterocolitica serogroup O[ratio]3, biotype 4 isolated from human and porcine samples in 1984 and in the years 1993–5 were examined by pulsed-field gel electrophoresis (PFGE). The genomic profiles produced by the enzymes NotI and XbaI were studied. Sixteen (A–P) and 8 (1·8) different pulsotypes were obtained, respectively. By combining the pulsotypes produced by both NotI and XbaI 24 different types were distinguished. The two major types, designated as A1 and B1, comprised 36% of all strains tested. The proportions of pulsotypes A1 and B1 were, 35·9 and 25·6%, respectively, among strains isolated in 1984. The corresponding figures among the strains isolated in 1993–5 were 35·8 and 41·8%. Nine pulsotypes were found only in 1984 and nine only in 1993–5. The proportions of the major pulsotypes, A1 and B1, in human isolates were 42·9 and 35·7% and in porcine isolates 22·2 and 36·1% respectively. Six types were found among both human and porcine isolates, 8 only among human strains and 10 only among porcine strains.

(Accepted June 18 1998)

c1 Author for correspondence.