Genomic analysis of the diversity, antimicrobial resistance and virulence potential of Campylobacter jejuni and Campylobacter coli strains from a private health care center in central Chile

Campylobacter jejuni and Campylobacter coli are the leading causes of human gastroenteritis in the developed world and an emerging threat in developing countries. There is increasing evidence that the incidence of campylobacteriosis in Chile and other South American countries is greatly underestimated, mostly due to the lack of adequate diagnostic methods. Accordingly, there is limited genomic and epidemiological data from these countries, leaving an important knowledge gap in our understanding of the population structure, virulence potential, and antimicrobial resistance profiles of clinical Campylobacter strains.

We recently published the whole-genome sequences of a collection of 68 C. jejuni and 12 C. coli strains isolated from patients with enteric infections during a 2-year period (2017-2019) attending Clinica Alemana in Santiago, Chile. In the present study, we sequenced an additional C. jejuni genome and performed a genome-wide analysis of the genetic diversity, virulence, and antimicrobial resistance potential of these 81 strains. cgMLST analysis identified a high genetic diversity of C. jejuni as well as 13 novel STs and alleles in both C. jejuni and C. coli. Pangenome and virulome analyses showed a differential distribution of virulence factors, including both plasmid and chromosomally encoded T6SSs and T4SSs.

Resistome analysis predicted widespread resistance to fluoroquinolones, but a low rate of erythromycin resistance. This study provides valuable genomic and epidemiological data and highlights the need for larger genomic epidemiology studies to better understand the genetic diversity, virulence potential and antimicrobial resistance of human clinical Campylobacter strains in South America.