So close and yet so far — Molecular microbiology ofCampylobacter fetussubspecies

Abstract

Campylobacter fetus comprises two subspecies, C. fetus subsp. fetus and C. fetus subsp. venerealis, which are considered emerging pathogens in humans and animals. Comparisons at the genome level have revealed modest subspecies-specific variation; nevertheless, these two subspecies show distinct host and niche preferences. C. fetus subsp. fetus is a commensal and pathogen of domesticated animals that can be transmitted to humans via contaminated food. The clinical features of human infection can be severe, especially in impaired hosts. In contrast, C. fetus subsp. venerealis is a sexually transmitted pathogen essentially restricted to cattle. Infections leading to bovine venereal campylobacteriosis cause substantial economic losses due to abortion and infertility. Recent genome sequencing of the two subspecies has advanced our understanding of C. fetus adaptations through comparative genomics and the identification of subspecies-specific gene regions predicted to be involved in pathogenesis. The most striking difference between the subspecies is the highly subspecies-specific association of a pathogenicity island in the C. fetus subsp. venerealis chromosome. The inserted region encodes a Type 4 secretion system, which contributes to virulence properties of this organism in vitro. This review describes the main differences in epidemiological, phenotypic, and molecular characteristics of the two subspecies and summarizes recent advances towards understanding the molecular mechanisms of C. fetus pathogenesis.

Campylobacter fetus impairs barrier function in HT‐29/B6 cells through focal tight junction alterations and leaks

“…Also, as already observed in prior studies, Cf can translocate via the paracellular pathway between confluent cells without affecting barrier function or transmigrate through focal leaks, as described here. The process of cellular invasion by the bacterium in Cf or C. jejuni infection is more effective from the basolateral side of the epithelium, with the prerequisite of bacterial subvasion (the term subvasion means paracellular transmigration followed by invasion into the cells from the basal compartment) . Cytotoxicity of Campylobacter spp.…”

“…The process of cellular invasion by the bacterium in Cf or C. jejuni infection is more effective from the basolateral side of the epithelium, with the prerequisite of bacterial subvasion (the term subvasion means paracellular transmigration followed by invasion into the cells from the basal compartment). 9,36,37 Cytotoxicity of Campylobacter spp. is often attributed to their cytolethal distending toxin (CDT), which can induce cell death.…”

“…6 Moreover, Cf is found also in the bloodstream during infection, with the consequence of sepsis, and the infection can lead to abortion in pregnant women. [7][8][9] Pathomechanisms that are responsible for the clinical characteristics of the Campylobacter infection have been partially described for C. jejuni and C. coli, as well as for C. concisus. Studies on Cf have been conducted over the last five decades, 10 and the information on Cf pathology continues to accumulate, as another complete genome sequence of C. fetus subsp.…”

Draft Genome Sequence of Campylobacter fetus MMM01, Isolated from a Chronic Kidney Disease Patient with Sepsis

“…fetus and C. fetus subsp. venerealis , which cause several kinds of diseases in humans and animals ( 1 , 2 ). The ecological niches of these subspecies are different, and they can be isolated from a variety of different hosts ( 3 , 4 ).…”

“…The ecological niches of these subspecies are different, and they can be isolated from a variety of different hosts ( 3 , 4 ). Cases of bacteremia in humans, particularly immunocompromised individuals, due to C. fetus have been reported in recent years in several parts of the world ( 2 ). Here, we report the draft genome sequence of C. fetus MMM01 isolated from the blood of a 60-year-old patient with type II diabetes and chronic kidney disease.…”