pVir and Bloody Diarrhea in<i>Campylobacter jejuni</i>Enteritis
Bibliographic record
Abstract
The plasmid pVir may play a role in the virulence of Campylobacter jejuni, a leading cause of bacterial gastroenteritis.The pVir plasmid was identified in 17% of 104 C. jejuni clinical isolates studied and was significantly associated with the occurrence of blood in patient stool, a marker of invasive infection.The pVir plasmid was not associated with greater occurrence of diarrhea, fever, pain, vomiting, or need for patient hospitalization.Isolates containing pVir were also associated with the presence of a tetracycline-resistance plasmid, but pVir did not transfer with tetracycline-resistance plasmids to recipient strains of C. jejuni.The association of pVir and bloody stool suggests that pVir may be clinically relevant in C. jejuni infections.C ampylobacter jejuni is a major foodborne pathogen and a leading cause of bacterial gastroenteritis (1,2).Infection with C. jejuni can result in a wide array of clinical symptoms, including diarrhea, fever, abdominal pain, and vomiting, as well as bloody stool with severe invasive infection (3).Various virulence factors, which allow for adherence, colonization, and invasion of the intestinal epithelium, have been proposed to contribute to the pathogenesis of C. jejuni (4).Potential virulence components include flagella (5,6), invasion proteins (7), and toxins (8,9).Although the genome of C. jejuni has been sequenced (10), its mechanisms of pathogenicity remain poorly understood (11).A number of bacterial enteric pathogens contain plasmids that contribute to pathogenesis, including Shigella sp.(12), Salmonella sp.(13), and enteropathogenic Escherichia coli (14).No evidence was seen for the involvement of plasmids in the virulence of C. jejuni until Bacon et al. (15) identified plasmid pVir in strain 81-176.pVir is an ≈37.5-kbplasmid that contains components of a type IV secretion system (T4SS) (15,16) known to be important for the virulence of a number of major bacterial pathogens (17).Bacon et al. (15) suggested that the pVir plasmid is important in vitro for both adherence and invasion of intestinal epithelial cells in culture.In a survey of fresh clinical isolates of C. jejuni from Thailand, 10% (n = 58) contained pVir (15).C. jejuni gastroenteritis is primarily self-limiting and is usually treated by supportive therapy (fluid and electrolyte replacement) (3).Erythromycin is the drug of choice for treating severe clinical infections with C. jejuni (18), and fortunately the prevalence of erythromycin resistance has remained low (19).Worldwide, tetracycline resistance in C. jejuni is high: 56% in Canada (20) and up to 95% in Thailand (21).In Alberta, Canada, only 8.6% of human clinical isolates were tetracycline-resistant in 1981 (22).In C. jejuni, tetracycline resistance is primarily mediated by plasmids that carry the tet(O) gene (23,24).The Tet(O) protein binds to the bacterial ribosome and displaces tetracycline (25,26).The aim of this study was to investigate the prevalence of the pVir plasmid in C. jejuni isolated from clinical specimens in Alberta and the relationship of pVir to the clinical expression of the disease in gastroenteritis. Materials and Methods Source of C. jejuni IsolatesWe obtained a random sample of 104 human isolates of C. jejuni (fresh and frozen at -70°C in double-strength skim milk) cultured from stool samples from 1999 to 2002 at the University of Alberta Hospital and Provincial Laboratory for Public Health (Microbiology) in Edmonton, Alberta, Canada, for this study.All stool specimens were routinely cultured for enteric pathogens tested according to standard laboratory protocols.Most C. jejuni isolates were from northern Alberta and represented ≈10% pVir and Bloody Diarrhea in Campylobacter jejuni Enteritis
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".