Comparison of temporally and geospatially related populations of Campylobacter jejuni from chickens and environmental waters

Authors: Meinersmann, Richard - Rick; Berrang, Mark

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/20/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The relationship of Campylobacter jejuni found in chickens to those found in environmental waters, either as a reservoir, a source or the downstream deposition of the organisms, is still an open question. In the years 2012 and 2013, we collected 67 isolates of C. jejuni from chicken ceca collected at a slaughter plant in northeast Georgia, USA, and 39 isolates of C. jejuni collected from a variety of surface water locations in the same watershed. The isolates were subjected to whole genome sequencing and the data used for core genome multi-locus sequence typing (cgMLST). Cluster analysis showed that there were four distinct populations; the majority of the chicken isolates and the majority of the water isolates formed distinct populations and smaller populations from chickens and water were also distinct but less distant from each other than the major populations were. Calculation of fixation statistics (Fst) showed that all the populations were significantly distinct and analyses of Fst on a locus-by-locus basis of pairings of each of the populations showed that greater than 90% of the loci were differentiated by population. In the smaller sub-populations, approximately 63% of the loci were differentiated according to source. Ribosomal protein genes were generally less diverse than the other loci and less likely to show differentiation. Only 26 genes (~ 2%) showed clear differentiation of both chicken sub-populations from both water sub-populations. There may have been a bias for membrane protein genes in that group, but there was no clear physiologic profile of the differentiating loci. Thus, there appears to be little migrations of C. jejuni genetic material between chickens and environmental waters and their differentiation does not show clear evidence of selection, i.e. differentiation is probably due to isolation and genetic drift.