Virulence Traits of Inpatient Campylobacter jejuni Isolates, and a Transcriptomic Approach to Identify Potential Genes Maintaining Intracellular Survival

Abstract

There are still major gaps in our understanding of the bacterial factors that influence the outcomes of human Campylobacter jejuni infection. The aim of this study was to compare the virulence-associated features of 192 human C. jejuni strains isolated from hospitalized patients with diarrhoea (150/192, 78.1%), bloody diarrhoea (23/192, 11.9%), gastroenteritis (3/192, 1.6%), ulcerative colitis (3/192, 1.5%), and stomach ache (2/192, 1.0%). Traits were analysed with genotypic and phenotypic methods, including PCR and extracellular matrix protein (ECMP) binding, adhesion, and invasion capacities. Results were studied alongside patient symptoms, but no distinct links with them could be determined. Since the capacity of C. jejuni to invade host epithelial cells is one of its most enigmatic attributes, a high throughput transcriptomic analysis was performed in the third hour of internalization with a C. jejuni strain originally isolated from bloody diarrhoea. Characteristic groups of genes were significantly upregulated, outlining a survival strategy of internalized C. jejuni comprising genes related (1) to oxidative stress; (2) to a protective sheath formed by the capsule, LOS, N-, and O-glycosylation systems; (3) to dynamic metabolic activity supported by different translocases and the membrane-integrated component of the flagellar apparatus; and (4) to hitherto unknown genes.

Survival of Campylobacter jejuni in Amoebae enhances subsequent invasion of mammalian cells

“…Our results show differences in invasiveness and survival capabilities between the range of the C. jejuni strains tested. Interestingly, these results are similar to previous studies that correlated invasiveness and survivability of C. jejuni is both bacterial strain and host cell-dependent [25-28]. In our amoebae model, the greater survivability of C. jejuni within A. castellanii seems to be a host susceptibility factor rather than being bacterial induced.…”

Genomic Characterization of Fluoroquinolone-Resistant Thermophilic Campylobacter Strains Isolated from Layer Chicken Feces in Gangneung, South Korea by Whole-Genome Sequencing

“…To control Campylobacter-related infections, it is necessary to understand virulence factors and molecular mechanisms contributing to pathogenesis [11,12]. WGS data from different pathogenic and non-pathogenic mutant strains have been used to classify virulence gene clusters linked to pathogenicity [13].…”

Foodborne Pathogen Campylobacter

“…Our aim to further understand the pathogenicity and physiology of Campylobacter has been pursued by a number of research groups. Kovács et al [8] investigate the virulence traits of inpatient C. jejuni isolates and apply a transcriptomic approach to identify potential genes maintaining a role in intracellular survival. Characteristic groups of genes were identified as significantly upregulated, outlining a survival strategy of internalised C. jejuni, comprising genes related (1) to oxidative stress; (2) to a protective sheath formed by the capsule, LOS, N-, and O-glycosylation systems; (3) to dynamic metabolic activity supported by different translocases and the membrane-integrated component of the flagellar apparatus; and (4) to hitherto unknown genes.…”