Distinct genotypes of human and canine isolates of Campylobacter upsaliensis determined by 16S rRNA gene typing and plasmid profiling

Abstract

The utility of combined 16S rRNA (rrs) gene restriction fragment length polymorphism and plasmid profiles to differentiate between and within Campylobacter upsaliensis of human and canine origin was examined. Fourteen distinct rrs gene restriction fragment length polymorphs consisting of bands sized between 1.9 and 4.8 kb were observed. The copy number of the 16S rRNA gene was three in most strains of C. upsaliensis. Plasmids were found in almost 60% of the strains; ranging in size from 1.5 to 100 kb, they gave 15 distinct plasmid profiles. All isolates from humans contained one or more plasmids, as did strains isolated from dogs with sporadic diarrhea. The two commonest 16S ribotypes were divided into eight and nine subgroups by plasmid profiling. The genotyping of canine isolates from three veterinary surveys detected both multiple infections and reinfection of dogs. Except for one, each of the isolates from humans constituted a single and unique 16S ribotype, and these more frequently carried plasmids than did canine strains. Ribotypes of human strains were not found among canine isolates. These results suggest that host-specific genotypic differences may exist among strains of C. upsaliensis, for example, intraspecific clones or clone complexes pathogenic for humans.

Campylobacter upsaliensis : Waiting in the Wings

“…Nonetheless, the transmission of C. upsaliensis from animals to humans remains to be conclusively proven. A recent study by Stanley et al provides evidence against dog-to-human transmission of C. upsaliensis (82). In this study C. upsaliensis isolates from humans had a conserved 16S rRNA ribotype, which is not found among canine strains.…”

“…A number of investigators (23,82) commented on the relative frequency of plasmids isolated from strains of C. upsaliensis (60 to 93%), which is considerably more frequent than the plasmid carriage of other campylobacters such as C. jejuni. Plasmid carriage appears to be more common among C. upsaliensis strains isolated from humans (82). However, there has been no systematic structural or functional study of these extrachromosomal genetic elements.…”

Pulsed-field gel electrophoresis indicates genotypic heterogeneity among Campylobacter upsaliensis strains

“…In recent reports, Goossens et al [20] and Stanley et al [21] have assessed the usefulness of a number of molecular-based typing methods for investigating the epidemiology of C upsaliensis. However, the use of PFGE was not reported in these studies.…”

Molecular subtyping scheme for serotypes HS1 and HS4 of Campylobacter jejuni

“…rDNA polymorphisms (ribotypes) have previously been examined in C. jejuni with general purpose probes consisting of 16 plus 23S rRNA and intergenic regions (4,(11)(12)(13). Ribotyping has also been done with specific PCR-generated 16S rRNA gene probes, giving data which can be related directly to gene copy number as well as epidemiological typing (16,17). Pulsedfield gel electrophoresis (PFGE) has been applied to several strains of C. jejuni as a tool for chromosome mapping (3,8), and it was further shown to have potential epidemiological application in a study of 12 strains (20).…”