Genomic and Phenotypic Characterisation of Campylobacter jejuni Isolates From a Waterborne Outbreak

Abstract

Campylobacter infections are the leading cause of bacterial gastroenteritis. In Europe, over 246,000 cases are confirmed annually. Infections are often transmitted via contaminated food, such as poultry products, but water may be the source of infection as well. The aim of this study was to characterise a selection of Campylobacter jejuni human isolates, together with a water isolate, from a waterborne outbreak in Norway in 2019, including human isolates from early, mid-, and late epidemic. The isolates were characterised with whole-genome sequencing, analysing the expression of putative virulence genes and demonstrating the pathogenic potential in an in vitro adhesion model using HT-29 cells. All isolates belonged to the multilocus sequence type 1701 and ST45 clonal complex. In the genomic analysis, the water isolate clustered somewhat separately from the human isolates. There was some variation between the human isolates, but the water isolate seemed to display the greatest pathogenic potential, demonstrated by the highest levels of virulence gene expression, adhesion to epithelial cells and IL-8 induction. These results suggest that the water isolate of the study has potential to cause human infections, and that some bacterial changes due to host or environmental adaptation, may occur during a waterborne Campylobacter epidemic. This is, to the best of our knowledge, the first study on C. jejuni isolates from a waterborne outbreak, including both human isolates and a water isolate, characterised with genomic and phenotypic approaches.

Campylobacter concisus from chronic inflammatory bowel diseases stimulates IL-8 production in HT-29 cells

“…Although wells infected with HC isolates produced the lowest amount of IL-8 in the present study, the difference was not statistically different from CC, LC, UC, CD and D isolates. Furthermore, C. jejuni produced higher levels of IL-8 than all C. concisus isolates; a control isolate chosen due to its well-known pathogenic effects in in vitro settings [ 20 , 21 ]. Nevertheless, despite that C. concisus may be considered a commensal based on these observations, the bacterium still stimulates the innate immune system in a non-specific way and thereby hypothetically plays a part in mucosal inflammation if abundant in the gut microbiota.…”

Genomic Relatedness, Antibiotic Resistance and Virulence Traits of Campylobacter jejuni HS19 Isolates From Cattle in China Indicate Pathogenic Potential

“…Because campylobacteriosis is often associated with contaminated food products and exposure to animals, whole-genome sequencing (WGS) might become the preferred typing method, and analysis of isolates from various sources should be a major component of studying disease ecology and epidemiology ( Park et al, 2020 ). At present, WGS has been considered the most informative and discriminative typing method to examine the genomic characteristics of Campylobacter isolates with high resolution ( Davies et al, 2020 ), allowing for comprehensive phylogenetic analyses of numerous traits associated with virulence or antibiotic resistance ( Fiedoruk et al, 2019 ). Our previous epidemiological research revealed that the GBS maker serotype HS19 was significantly more prevalent in isolates from cattle than other animal populations circulating in China.…”

A Case of Pseudoappendicitis Caused by Campylobacter Enteritis Diagnosed by Gram Staining and Direct Microscopic Investigation of Stool Specimen

“…Their helical shape and long polar flagella allow them to move quickly and survive within the mucosal layer of the gastrointestinal tract [1]. Campylobacter infection usually begins in the jejunum and ileum and progresses distally to affect the cecum and colon [2].…”

“…The route of infection is often unknown, but it can be caused by oral ingestion of raw or undercooked meat or food secondarily contaminated with raw meat [ 1 ]. After an incubation period of approximately three days, infections are established mainly in the colon and rectum [ 2 ]. The disease is found worldwide, regardless of the climate.…”

“…Definitive diagnostic techniques include stool culture and nucleic acid amplification testing, including reverse transcription polymerase chain reaction. Fecal microscopy and Gram staining are also available but are not performed effectively [ 2 ]. In this case, a young woman with a chief complaint of fever was quickly diagnosed using fecal microscopy and Gram staining.…”