The application of genotyping techniques to the epidemiological analysis ofCampylobacter jejuni

Abstract

SUMMARYCampylobacter jejuni serogroup reference strains and collections of sporadic and outbreakassociated isolates were examined for restriction fragment length polymorphisms (RFLPs), using C. jejuni random chromosomal and 16S rRNA gene probes. A collection of 48 Penner (HS) and 14 Lior (HL) serogroup reference strains, plus 10 clinical isolates, generated 35 RFLP and 26 ribotype patterns. In combination the two loci generated 48 distinct genotypes. Both probes were able to differentiate between certain random isolates of the same HS/HL serogroups but greater discrimination was obtained with RFLP than with ribotyping.

Genotyping of Campylobacter spp

“…PFGE typing of members of several serogroups identified by the Lior typing scheme has revealed little, if any, correlation (87,88). Similarly, identical ribopatterns can be obtained for members of multiple HL antigen serotypes (40).…”

“…C. jejuni serotype HS1, HS2, and HS4 isolates exhibited considerable genetic diversity within the serogroups as determined by both PFGE (28,73) and fla typing (9, 68) and, to a lesser extent, by ribotyping and RAPD analysis (20,28,40,73). A comparison of RAPD fingerprinting and HS antigen serotyping results suggested that sometimes there can be correlations between the data obtained with these two typing schemes (55); however, such correlations are unpredictable (1,36).…”

“…The enzymes used in ribotyping studies for chromosomal digestion also vary considerably; PstI, HaeIII, HindIII, and PvuII have been used alone, in pairs, or even in combinations consisting of three enzymes (19,28,35,40,70,72,74,80). The differences in the restriction enzymes and probes used generally hamper direct comparisons of the ribotype profiles obtained in different laboratories.…”

“…First, rehybridization of the Southern blots with probes for other hypervariable regions of the chromosome can be used to increase the level of discrimination. This approach has been used with a polymorphic lambda clone insert (40,41). Using this probe alone resulted in discriminatory power that was greater than the discriminatory power obtained with the ribosomal probe, probably because the former probe contained a longer insert.…”

“…Some laboratories perform preliminary screening by serotyping, but this approach may disguise some clonal relationships that are obvious only when genotyping is used. The genotyping methods whose value has been proven in outbreak investigations include ribotyping (40,72), PFGE (28,80,88), fla typing (60), and RAPD analysis (30,38). Outbreak-related C. upsaliensis isolates have also been identified by using PFGE (31).…”