Occurrence of the invasion associated marker (iam) in Campylobacter jejuni isolated from cattle

Abstract

BackgroundThe invasion associated marker (iam) has been detected in the majority of invasive Campylobacter jejuni retrieved from humans. Furthermore, the detection of iam in C. jejuni isolated from two important hosts, humans and chickens, suggested a role for this marker in C. jejuni's colonization of multiple hosts. However, no data exist regarding the occurrence of this marker in C. jejuni isolated from non-poultry food-animals such as cattle, an increasingly important source for human infections. Since little is known about the genetics associated with C. jejuni's capability for colonizing physiologically disparate hosts, we investigated the occurrence of the iam in C. jejuni isolated from cattle and assessed the potential of iam-containing cattle and human isolates for chicken colonization and human cell invasion.ResultsSimultaneous RAPD typing and iam-specific PCR analysis of 129 C. jejuni isolated from 1171 cattle fecal samples showed that 8 (6.2%) of the isolates were iam-positive, while 7 (54%) of human-associated isolates were iam-positive. The iam sequences were mostly heterogeneous and occurred in diverse genetic backgrounds. All iam-positive isolates were motile and possessed important genes (cadF, ciaB, cdtB) associated with adhesion and virulence. Although certain iam-containing isolates invaded and survived in INT-407 cells in high numbers and successfully colonized live chickens, there was no clear association between the occurrence, allelic sequence, and expression levels of the iam and the aforementioned phenotypes.ConclusionsWe show that the prevalence of iam in cattle C. jejuni is relatively lower as compared to isolates occurring in humans and chickens. In addition, iam was polymorphic and certain alleles occur in cattle isolates that were capable of colonizing and invading chickens and human intestinal cells, respectively. However, the iam did not appear to contribute to the cattle-associated C. jejuni's potential for invasion and intracellular survival in human intestinal cells as well as chicken colonization.

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

“…High prevalence of cadF (100%), iamA (99%), docA (90%), and ciaB (87%) in our strain collection highlighted the potential importance of these genes in C. jejuni pathogenesis and survival. This was indicated in previous genetic studies examining their presence among poultry, cattle and human isolates [7,8,89,90]. CdtABC, cadF, docA, and iamA were detected in 98%-100%, 98%-100%, 94%, and 1.6%-92% of the human isolates, respectively [7,8,89,90].…”

“…This was indicated in previous genetic studies examining their presence among poultry, cattle and human isolates [7,8,89,90]. CdtABC, cadF, docA, and iamA were detected in 98%-100%, 98%-100%, 94%, and 1.6%-92% of the human isolates, respectively [7,8,89,90]. The hcp gene, coding for the Type VI secretion system (T6SS), was recently suggested as a potential new player.…”

Aerotolerance and multilocus sequence typing among <i>Campylobacter jejuni</i> strains isolated from humans, broiler chickens, and cattle in Miyazaki Prefecture, Japan

“…C. jejuni is a gram-negative, rod spiral-shaped, microaerophilic bacterium found in the gastrointestinal tracts of various animals [16]. In particular, poultry and cattle are considered as the common sources for human infection [17, 36]. C. jejuni can also be isolated from farms and natural environments [8, 10, 18].…”

Campylobacteriosis: A Global Threat

“…North America United States of America: The incidence of reported Campylobacter disease in industrialized countries, like United States, has risen steadily over the past 2 decades with most reported cases being sporadic. In 2013 from five Campylobacter out breaks, mostly outbreaks were associated with raw milk consumption [20]. Moreover, presence of active food borne surveillance system estimates that one out of 30 cases were reported.…”