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Cluster Analysis of Campylobacter jejuni Genotypes Isolated from Small and Medium‐Sized Mammalian Wildlife and Bovine Livestock from Ontario Farms
Author(s) -
Viswanathan M.,
Pearl D. L.,
Taboada E. N.,
Parmley E. J.,
Mutschall S. K.,
Jardine C. M.
Publication year - 2017
Publication title -
zoonoses and public health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.87
H-Index - 65
eISSN - 1863-2378
pISSN - 1863-1959
DOI - 10.1111/zph.12294
Subject(s) - dendrogram , upgma , livestock , biology , veterinary medicine , wildlife , logistic regression , campylobacter jejuni , population , genotype , genetics , ecology , gene , statistics , environmental health , medicine , genetic diversity , mathematics , bacteria
Summary Using data collected from a cross‐sectional study of 25 farms (eight beef, eight swine and nine dairy) in 2010, we assessed clustering of molecular subtypes of C. jejuni based on a Campylobacter ‐specific 40 gene comparative genomic fingerprinting assay ( CGF 40) subtypes, using unweighted pair‐group method with arithmetic mean ( UPGMA ) analysis, and multiple correspondence analysis. Exact logistic regression was used to determine which genes differentiate wildlife and livestock subtypes in our study population. A total of 33 bovine livestock (17 beef and 16 dairy), 26 wildlife (20 raccoon ( Procyon lotor ), five skunk ( Mephitis mephitis ) and one mouse ( Peromyscus spp.) C. jejuni isolates were subtyped using CGF 40. Dendrogram analysis, based on UPGMA , showed distinct branches separating bovine livestock and mammalian wildlife isolates. Furthermore, two‐dimensional multiple correspondence analysis was highly concordant with dendrogram analysis showing clear differentiation between livestock and wildlife CGF 40 subtypes. Based on multilevel logistic regression models with a random intercept for farm of origin, we found that isolates in general, and raccoons more specifically, were significantly more likely to be part of the wildlife branch. Exact logistic regression conducted gene by gene revealed 15 genes that were predictive of whether an isolate was of wildlife or bovine livestock isolate origin. Both multiple correspondence analysis and exact logistic regression revealed that in most cases, the presence of a particular gene (13 of 15) was associated with an isolate being of livestock rather than wildlife origin. In conclusion, the evidence gained from dendrogram analysis, multiple correspondence analysis and exact logistic regression indicates that mammalian wildlife carry CGF 40 subtypes of C. jejuni distinct from those carried by bovine livestock. Future studies focused on source attribution of C. jejuni in human infections will help determine whether wildlife transmit Campylobacter jejuni directly to humans.