Epidemiological comparison of Campylobacter jejuni isolates from Poland and Spain combining MLST and antimicrobial resistance whole genome analyses

OHEJP Project: DISCoVeR Campylobacteriosis caused by Campylobacter jejuni remains the most important food-borne zoonosis in the EU, mostly associated to poultry products (1). Here, we compare C. jejuni isolates from humans and poultry recovered from Poland and Spain, to determine to what extent these two distant countries share antimicrobial resistance markers (RMs) and MLST types, as suggested by previous research (2). In total, 83 Polish (15 humans, 68 broilers) and 222 Spanish isolates (146 humans, 62 broilers previously sequenced, 14 broilers newly sequenced) from 2010 to 2018 were included in the study. Human strains were recovered from faeces of hospital sporadic cases and broiler isolates were collected at abattoirs. Whole genome sequencing (Illumina) was used to identify the main RMs and MLST profiles, and the latter were analysed for clustering using the Minimum Spanning Tree (MST) algorithm (Bionumerics). The Polish MST showed two well defined clonal complexes (CCs) (ST-6411, ST-353), of mainly broiler strains with little ST variation, whereas five main CCs (ST-443, ST-353, ST-21, ST-45, ST-828), of broiler and human strains with more distant STs were found in the Spanish MST. Polish isolates from both sources and Spanish broiler isolates harboured rep34 gene plasmid replicons. Plasmid encoded resistance gene cat(pC194) was identified in a Polish broiler isolate. This country comparison has disclosed that the clonal structure on the Polish MST and its associated AMR plasmid findings suggest acquisition of genes by horizontal transfer, whereas a more vertical resistance mechanism can be inferred from the Spanish MST, helping to understand the epidemiology of the problem.Poster for OHEJP ASM 2022 Conference (11-13 April 2022, Orvieto, Italy