Investigation of Food and Environmental Exposures Relating to the Epidemiology of Campylobacter coli in Humans in Northwest England

Abstract

This study uses multilocus sequence typing (MLST) to investigate the epidemiology of Campylobacter coli in a continuous study of a population in Northwest England. All cases of Campylobacter identified in four Local Authorities (government administrative boundaries) between 2003 and 2006 were identified to species level and then typed, using MLST. Epidemiological information was collected for each of these cases, including food and recreational exposure variables, and the epidemiologies of C. jejuni and C. coli were compared using case-case methodology. Samples of surface water thought to represent possible points of exposure to the populations under study were also sampled, and campylobacters were typed with multilocus sequence typing. Patients with C. coli were more likely to be older and female than patients with C. jejuni. In logistic regression, C. coli infection was positively associated with patients eating undercooked eggs, eating out, and reporting problems with their water supply prior to illness. C. coli was less associated with consuming pork products. Most of the cases of C. coli yielded sequence types described elsewhere in both livestock and poultry, but several new sequence types were also identified in human cases and water samples. There was no overlap between types identified in humans and surface waters, and genetic analysis suggested three distinct clades but with several "intermediate" types from water that were convergent with the human clade. There is little evidence to suggest that epidemiological differences between human cases of C. coli and C. jejuni are a result of different food or behavioral exposures alone.

Expanded Multilocus Sequence Typing and Comparative Genomic Hybridization of Campylobacter coli Isolates from Multiple Hosts

“…Our surmise above regarding the potential source of human infections is in agreement with recent studies of C. jejuni and C. coli which find chicken meat as the most likely source of human infection for both species of Campylobacter (50,59). This analysis is also in agreement with other studies suggesting that campylobacteriosis due to C. coli infection is less commonly associated with consumption of pork products (35,52). Earlier studies have also implicated waterfowl as a possible source of water infection (e.g., reference 40), but generally, this evidence has centered primarily on C. jejuni; our analysis provides a probable similar connection for wild birds and water involving C. coli.…”

“…C. coli and C. jejuni also tend to differ in their relative prevalences in animal host species and various environmental sources (4,48,58), and there is some evidence that both taxa may include groups of host-specific putative ecotype strains (7,36,38,39,52,56). At present, there is only a single draft genome sequence available for C. coli, and there are no microarray comparative genomic hybridization data for C. coli strains.…”

Genotypes and Antibiotic Resistances of Campylobacter jejuni and Campylobacter coli Isolates from Domestic and Travel-Associated Human Cases

“…The C. jejuni isolates showed much higher diversity than the C. coli isolates, as indicated by the distribution of the strains within different clonal complexes (CCs). Of the investigated C. coli strains, 95.0% could be assigned to CC828, confirming a higher clonality within this species (17,24,26).…”

Campylobacter sequence typing databases: applications and future prospects

“…Although these studies show no association of particular genotypes with virulence, different clonal complexes are prevalent at different times, with the ST-45 and ST-283 complexes more common in the summer. There is evidence that genotypes change over time but that this is a gradual process, with relatively small changes in the frequencies of different clonal complexes affecting humans year-on-year (Bessell et al, 2012;Cody et al, 2012;McCarthy et al, 2012;Sopwith et al, 2010). Some differences are apparent in the epidemiology of human infection with C. jejuni and C. coli, but the reasons for this are unclear (Sopwith et al, 2010).…”

“…There is evidence that genotypes change over time but that this is a gradual process, with relatively small changes in the frequencies of different clonal complexes affecting humans year-on-year (Bessell et al, 2012;Cody et al, 2012;McCarthy et al, 2012;Sopwith et al, 2010). Some differences are apparent in the epidemiology of human infection with C. jejuni and C. coli, but the reasons for this are unclear (Sopwith et al, 2010). In conclusion, most human disease is caused by Campylobacter genotypes found in retail food, especially chicken meat, with relatively small changes in genotypes over shorter periods of time, except for a seasonal signal in some, but not all genotypes.…”