A repeated cross‐sectional study of the epidemiology of Campylobacter and antimicrobial resistant Enterobacteriaceae in free‐living Canada geese in Guelph, Ontario, Canada

Abstract

From May through October 2016, we conducted a repeated cross‐sectional study examining the effects of temporal, spatial, flock and demographic factors (i.e. juvenile vs. adult) on the prevalence of Campylobacter and antimicrobial resistant Enterobacteriaceae among 344 fresh faecal samples collected from Canada geese (Branta canadensis) from four locations where birds nested in Guelph, Ontario, Canada. The overall prevalence of Campylobacter among all fresh faecal samples was 9.3% and was greatest in the fall when these birds became more mobile following the nesting season. Based on 40 gene comparative genomic fingerprinting (CGF40), the increase in prevalence noted in the fall was matched by an increase in the number of unique CGF40 subtypes identified. Resistance to colistin was detected most commonly, in 6% of Escherichia coli isolates, and was highest in the late summer months. All colistin‐resistant isolates were negative for the mcr‐1 to mcr‐5 genes; a chromosomal resistance mechanism (PmrB) was identified in all of these isolates. The prevalence of samples with E. coli exhibiting multi‐class resistance or extended spectrum beta‐lactamase was low (i.e. <2% of samples). The intra‐class correlation coefficients, estimated from the variance components of multilevel logistic regression models, indicated that the shedding of Campylobacter and antimicrobial resistant E. coli among geese within a flock (i.e. birds collected from the same site on the same day) was moderately correlated. Spatial, temporal, and spatiotemporal clusters identified using the spatial scan statistic, largely supported the findings from our multi‐level models. Salmonella was not isolated from any of the fresh faecal samples collected suggesting that its prevalence in this population of birds was very low.

Molecular Characterization and Antimicrobial Susceptibility of C. jejuni Isolates from Italian Wild Bird Populations

“…Our results are in line with a recent study demonstrating the existence of certain sub lineages of ST-45 forming genetically isolated clades containing C. jejuni strains with extremely similar genomes regardless of time and location of sampling [27]. In addition to the highly mobile nature of many wild bird species to disseminate bacteria in the environment [32], the World Health Organization in 2017 (World Health Organization, 2017) showed that many of these microorganisms exhibited resistance to antimicrobials considered of highest importance to human medicine [37,38]. Interestingly, C.jejuni strains isolated in this study showed a moderate percentage resistance to tetracycline, to ciprofloxacin and nalidixic acid, suggesting that the antimicrobial resistance could be acquired by horizontal gene transfer [39] or, to the usage antibiotics as a therapeutic agent in dairy cattle and poultry farms [40].…”

Generalizability and comparability of prevalence estimates in the wild bird literature: methodological and epidemiological considerations

“…Repeat cross-sectional studies performed across multiple seasons, while holding the methods and location(s) fixed, allow for broader generalizability in comparison with data obtained from birds in a single or limited number of seasons. Given the evidence of seasonal variation in the carriage of a number of pathogenic organisms by wild birds (Campylobacter, Salmonella, and E. coli and associated AMR; Girdwood et al, 1985;Morabito et al, 2001;Broman et al, 2002;Kirk et al, 2002;Colles et al, 2009;Hughes et al, 2009;Hald et al, 2016;Vogt et al, 2018Vogt et al, , 2019, it may be problematic to compare prevalence estimates from studies which sampled birds in different seasons. Data from repeat cross-sectional studies that represent multiple seasons may be of use in assessing the Animal Health Research Reviews seasonality of the carriage of certain microorganisms and can thereby support or undermine the comparability of certain prevalence estimates from different seasons.…”

“…Of the sample of articles discussed in this subsection, a small number of studies reported how isolates with intermediate susceptibility were handled. Two studies retained such isolates as intermediates (Shobrak and Abo-Amer, 2014;Vidal et al, 2017), another reclassified the isolates as susceptible (Pinto et al, 2015), and in our previous work we classified all intermediates as resistant (Vogt et al, 2018(Vogt et al, , 2019. Recognition of the various factors that influence MDR definitions has resulted in recent efforts to develop a standard definition of MDR that is internationally recognized, in order to facilitate comparisons between studies (Magiorakos et al, 2012).…”

“…We discuss this issue here as it has received little attention in the wild bird literature and represents a fairly straightforward way in which future work in this area can be improved. At the time of writing this review, few studies were found that controlled for clustering in the relevant wild bird literature (Hughes et al, 2009;Vogt et al, 2018Vogt et al, , 2019.…”

“…Another study categorized season based on biological relevance, and considered a mild-weather reproductive season (March–September) and a cold-weather non-reproductive season (October–February; Morabito et al ., 2001). In our previous research, when samples were collected between May and October, we used three different categories of season (early summer, late summer, fall) in order to equally distribute our observations among those categories and to facilitate subsequent statistical analyses (Vogt et al ., 2019).…”