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One hundred thirty-three strains of Pasteurella haemolytica of both biotypes (90 and 43 strains of biotypes A and T, respectively) and almost all the serotypes were subjected to ribotyping, random amplified polymorphic DNA (RAPD) analysis, and pulsed-field gel electrophoresis (PFGE) analysis for epidemiological purposes. A total of 15 patterns recorded as ribotypes HA to HO were found for the P. haemolytica biotype A strains, with ribotypes HA, HC, and HD being encountered most often (66 strains [74%]); and 20 ribotypes, designated HA′ to HT′, that were clearly distinct from those observed for biotype A strains were observed for strains of biotype T. RAPD analysis generated a total of 44 (designated Rp1 to Rp44) and 15 (designated Rp1′ to Rp 15′) unique RAPD patterns for biogroup A and biogroup T, respectively. Analysis of the data indicated that a given combined ribotype-RAPD pattern could be observed for biotype A strains of different serotypes, whatever the zoological or geographic origin, whereas this was not the case for biotype T strains. PFGE appeared to be more efficient in strain discrimination since selected strains from various zoological or geographical origins harboring the same ribotype-RAPD group were further separated into unique entities.

Pre‐treatment of a 5‐h enrichment culture with an automated immunoconcentration (ICE) system greatly improved the isolation of Escherichia coli O157:H7 from spiked heifer faecal samples. Enrichment samples plated directly onto sorbitol MacConkey agar (SMAC) and SMAC agar supplemented with cefixime and potassium tellurite (CT‐SMAC) showed recovery rates of 8% and 56%, respectively. However, after ICE treatment, E. coli O157:H7 was recovered from 92% of the samples on SMAC and 100% on CT‐SMAC. Immunoconcentration analysis of heifers' faecal samples collected from a slaughter‐house in France, during March to June 1998, showed that 1% (three of 300) was positive for E. coli O157:H7. Phenotypic and genotypic analysis showed that all three isolates carried both the O157 and H7 antigens, did not ferment sorbitol or had β‐glucuronidase activity and carried trait virulence factors for E. coli O157:H7 (uidA allele, eaeA and pO157 plasmid). However, only one strain was toxigenic and this strain produced a single toxin, namely verotoxin 2.

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Thlrty-two faecal samples from various pet chelonians were bacteriologically examined using various combinations of selective media for Salmonella detection. Strains identified as Salmonella were clustered by rRNA gene restriction pattern (ribotyping) analysis prior to serological typing. The combination of selenite broth and Rambach or .Ta/monella-Sb&elJa agars gave the maximum rate of Salmonella recovery. Of the 32 samples examined, 13 (40°/), were positive for Salmonella. Five serovars were identified, Muenchen, Rubislaw, Newport, Ferruch and a non-motile 0:4,5,12, with Salmonella Muenchen the most common. This result indicates that biochemical characterization combined with ribotyping prior to serotyping can contribute to .Talmonel/a detection on a large scale.