Campylobacter populations in wild and domesticated Mallard ducks (Anas platyrhynchos)

Abstract

Identifying the Campylobacter genotypes that colonize farmed and wild ducks will help to assess the proportion of human disease that is potentially attributable to the consumption of duck meat and environmental exposure to duck faeces. Comparison of temporally and geographically matched farmed and wild ducks showed that they had different Campylobacter populations in terms of: (i) prevalence, (ii) Campylobacter species and (iii) diversity of genotypes. Furthermore, 92.4% of Campylobacter isolates from farmed ducks were sequence types (STs) commonly associated with human disease, in contrast to just one isolate from the wild ducks. Only one ST, ST-45, was shared between the two sources, accounting for 0.9% of wild duck isolates and 5% of farmed duck isolates. These results indicate that domestic ‘niche’ as well as host type may affect the distribution of Campylobacter, and that husbandry practises associated with intensive agriculture may be involved in generating a reservoir of human disease associated lineages.

The Evolution ofCampylobacter jejuniandCampylobacter coli

“…In the same way that species occupy different hosts, the genetic substructure within species can also be related to ecology. Within C. coli, the majority of isolates from clinical samples and agricultural animals belong to clade 1 with clades 2 and 3 C. coli more commonly associated with waterfowl and environmental sources that have, presumably, been contaminated by them (Sheppard et al 2010a;Colles et al 2011). There is also a strong host -genotype relationship at the MLST clonal complex, ST, and allele levels, particularly within C. jejuni (Miller et al 2006;McCarthy et al 2007;Sheppard et al 2010b).…”

Campylobacter sequence typing databases: applications and future prospects

“…The Campylobacter isolates recovered after slaughter from one free-range broiler crop were more similar to those recovered from retail chicken meat than to isolates obtained from the live flock before slaughter, implying that production processes have an important impact on the differential survival of Campylobacter genotypes . There is increasing evidence that a number of clonal complexes are agriculturally associated and dominant throughout poultry production, and thus commonly reach the human consumer via this route Müllner et al, 2010;Sheppard et al, 2011b).…”

“…The differentiation of Campylobacter populations isolated from diverse wild bird species is particularly striking (Colles et al, 2008a(Colles et al, , 2011bOgden et al, 2009;Sheppard et al, 2011b). C. jejuni populations isolated from more than 400 samples from wild starlings and geese sampled in the same geographical location provide a typical example, having no STs in common, and being more than 60 % different using F ST , a measure of genetic differentiation, or gene flow (Colles et al, 2008a).…”

“…C. jejuni populations isolated from more than 400 samples from wild starlings and geese sampled in the same geographical location provide a typical example, having no STs in common, and being more than 60 % different using F ST , a measure of genetic differentiation, or gene flow (Colles et al, 2008a). There is evidence that some clonal complexes, in particular the ST-21 and ST-45 complexes, are 'multihost' genotypes which can be isolated from a wide variety of agricultural and environmental sources (Table 1) Sheppard et al, 2011b). These genotypes remain a challenge in attribution and epidemiological analysis, and may require higherresolution genotyping than seven-locus MLST.…”

“…A small number of host-associated multidrug-resistant C. coli genotypes have been identified in association with the US turkey production industry (D'Lima et al, 2007). In addition, it has been shown that wild mallard ducks were colonized by C. coli that grouped into two clades which were distinct from the agriculture-associated ST-828 and ST-1150 clonal complexes (Colles et al, 2011b). After 10 years of MLST, novel STs for both Campylobacter species are now most often isolated from environmental sources such as water and wildlife, including rabbits, badgers, bank voles and even slugs, suggesting that the diversity of the Campylobacter population as a whole is far from exhaustively sampled but that we have a reasonable picture for human and agricultural isolates French et al, 2005;Kwan et al, 2008b;Lévesque et al, 2008;Sproston et al, 2010;Williams et al, 2010).…”