Restriction fragment length polymorphism for the identification of Campylobacter jejuni-isolates.

Companion animals ("pets") are occasionally carriers of organisms pathogenic for man. In the present, study fecal samples of clinically inapparent animals with direct contact to 204 patients, suffering from campylobacter enteritis, were investigated for C. jejuni or C. coli (CJC). CJC positive animals were seen in the environment of only five patients (= 2.4%). By comparison of biotypes and serotypes of thermostable and thermolabile antigens from human and animal isolates no clear epidemiological relationship could be deduced. Using chromosomal DNA of the strains, genetic identity of the isolates was studied for HaeIII-restriction fragment length polymorphism (RFLP), applying a biotinylated commercial CJ probe. The probe was found to be specific for most CJ strains and revealed a pattern of one to four bands. In contrast to biotyping no identity of patient strains and animal isolates was seen in three cases; one case with different biotypes had identical RFLP patterns; one patient CJ strain did not show any pattern with the CJ probe. Serotypes were identical for a larger number of animal strains but differed in HaeIII RFLP and vice versa. Comparing the results from the different technological approaches it seems impossible to give a clear statement on the epidemiology of campylobacter infections or carrier state by biotyping alone. It is concluded that DNA RFLP patterns are a useful additional tool, but for epidemiological analysis a set of different methods should be used.