Tove Ejlertsen

Increased Short- and Long-Term Risk of Inflammatory Bowel Disease After Salmonella or Campylobacter Gastroenteritis

BACKGROUND & AIMS Various commensal enteric and potentially pathogenic bacteria may be involved in the pathogenesis of inflammatory bowel diseases (IBD). We compared the risk of IBD between a cohort of patients with documented Salmonella or Campylobacter gastroenteritis and an age- and gender-matched control group from the same population in Denmark. METHODS We identified 13,324 patients with Salmonella/Campylobacter gastroenteritis from laboratory registries in North Jutland and Aarhus counties, Denmark, from 1991 through 2003, and 26,648 unexposed controls from the same counties. Of these, 176 exposed patients with IBD before the infection, their 352 unexposed controls, and 80 unexposed individuals with IBD before the Salmonella/Campylobacter infection were excluded. The final study cohort of 13,148 exposed and 26,216 unexposed individuals were followed for up to 15 years (mean, 7.5 years). RESULTS A first-time diagnosis of IBD was reported in 107 exposed (1.2%) and 73 unexposed individuals (0.5%). By age, gender, and comorbidity adjusted Cox proportional hazards regression analysis, the hazard ratio (95% confidence interval) for IBD was 2.9 (2.2-3.9) for the whole period and 1.9 (1.4-2.6) if the first year after the Salmonella/Campylobacter infection was excluded. The increased risk in exposed subjects was observed throughout the 15-year observation period. The increased risk was similar for Salmonella (n = 6463) and Campylobacter (n = 6685) and for a first-time diagnosis of Crohns disease (n = 47) and ulcerative colitis (n = 133). CONCLUSIONS In our population-based cohort study with complete follow-up, an increased risk of IBD was demonstrated in individuals notified in laboratory registries with an episode of Salmonella/Campylobacter gastroenteritis.

Serological and molecular evidence of Rickettsia helvetica in Denmark.

Recent seroepidemiological studies and examinations of Ixodes ricinus ticks in Europe have demonstrated the presence of an emerging tick-borne infection with Rickettsia helvetica. We conducted a serosurvey in 168 Danish patients seropositive for borreliosis reflecting their exposure to I. ricinus ticks. A total of 21 patients (12.5%) had positive antibody titres to R. helvetica including 4 cases of seroconversion. None of the samples were positive for antibodies to Ehrlichia. We conclude that in humans exposed to I. ricinus ticks in Denmark the risk of acquiring rickettsial infection is for the first time demonstrated. In the same region of Denmark we collected 570 I. ricinus ticks from various sources, and examinations by PCR for Rickettsia were performed. Positive reactions were obtained in 23 ticks (4%), and R. helvetica was identified in all 13 of those for which sequencing was performed.

Bacteraemia as a result of Campylobacter species: a population-based study of epidemiology and clinical risk factors

Invasive disease as a result of Campylobacter is rarely reported. We reviewed 46 cases of blood stream infection with Campylobacter in a Danish population with complete follow-up. The incidence was 2.9 per 1 million person-years with a peak incidence in the age group above 80 years. In the population, the ratio of notified bacteraemia/enteritis patients with Campylobacter infection was 0.004. Patients with bacteraemia were older and had higher comorbidity, e.g. alcoholism, immunosuppression, previous gastrointestinal surgery or HIV infection. We found 26% of blood isolates resistant to ciprofloxacin. The length of hospitalization was significantly longer in bacteraemia patients, whereas the outcome was favourable with 28-day mortality of 4% in bacteraemia patients and 1% in enteritis patients. None of the bacteraemia patients relapsed within 365-day follow-up.

Oral and Fecal Campylobacter concisus Strains Perturb Barrier Function by Apoptosis Induction in HT-29/B6 Intestinal Epithelial Cells

Campylobacter concisus infections of the gastrointestinal tract can be accompanied by diarrhea and inflammation, whereas colonization of the human oral cavity might have a commensal nature. We focus on the pathophysiology of C. concisus and the effects of different clinical oral and fecal C. concisus strains on human HT-29/B6 colon cells. Six oral and eight fecal strains of C. concisus were isolated. Mucus-producing HT-29/B6 epithelial monolayers were infected with the C. concisus strains. Transepithelial electrical resistance (Rt) and tracer fluxes of different molecule size were measured in Ussing chambers. Tight junction (TJ) protein expression was determined by Western blotting, and subcellular TJ distribution was analyzed by confocal laser-scanning microscopy. Apoptosis induction was examined by TUNEL-staining and Western blot of caspase-3 activation. All strains invaded confluent HT-29/B6 cells and impaired epithelial barrier function, characterized by a time- and dose-dependent decrease in Rt either after infection from the apical side but even more from the basolateral compartment. TJ protein expression changes were sparse, only in apoptotic areas of infected monolayers TJ proteins were redistributed. Solely the barrier-forming TJ protein claudin-5 showed a reduced expression level to 66±8% (P<0.05), by expression regulation from the gene. Concomitantly, Lactate dehydrogenase release was elevated to 3.1±0.3% versus 0.7±0.1% in control (P<0.001), suggesting cytotoxic effects. Furthermore, oral and fecal C. concisus strains elevated apoptotic events to 5-fold. C. concisus-infected monolayers revealed an increased permeability for 332 Da fluorescein (1.74±0.13 vs. 0.56±0.17 10−6 cm/s in control, P<0.05) but showed no difference in permeability for 4 kDa FITC-dextran (FD-4). The same was true in camptothecin-exposed monolayers, where camptothecin was used for apoptosis induction. In conclusion, epithelial barrier dysfunction by oral and fecal C. concisus strains could mainly be assigned to apoptotic leaks together with moderate TJ changes, demonstrating a leak-flux mechanism that parallels the clinical manifestation of diarrhea.

High incidence of Campylobacter concisus in gastroenteritis in North Jutland, Denmark: a population-based study

The incidence of non-thermophilic Campylobacter species was assessed in an unselected population-based study in a mixed urban and rural community in North Jutland, Denmark. In a 2-year study period, 11,314 faecal samples from 8302 patients with gastroenteritis were cultured with supplement of the filter method. We recovered a high incidence of Campylobacter concisus (annual incidence 35/100,000 inhabitants), almost as high as the common Campylobacter jejuni/coli. In contrast, there was a very low incidence of other non-thermophilic Campylobacter species, such as Campylobacter upsaliensis. Campylobacter concisus was, unlike C. jejuni/coli, found more frequently among small children (<1 year) and the elderly (≥ 65 years). Around 10% of the patients with C. consisus had co-infections dominated by Clostridium difficile and Salmonella enterica, whereas co-infections occurred in about 5% of C. jejuni/coli patients. We observed a seasonal variation in C. jejuni/coli with a peak incidence in late summer months and autumn, whereas there was an almost constant monthly prevalence of C. concisus. Among patients participating in a questionnaire sub-study, there was a higher degree of close contacts with animals, especially dogs, as well as a higher travel exposure among C. jejuni/coli patients compared with C. concisus patients. We did not culture any C. concisus in stool samples from a small cohort of healthy individuals. Future studies have to focus on the clinical follow-up and the long-term risk of inflammatory bowel diseases in C. concisus-positive patients. We conclude that there is a high incidence of C. concisus in Denmark.

Multiple hospital outbreaks of vanA Enterococcus faecium in Denmark, 2012–13, investigated by WGS, MLST and PFGE

OBJECTIVES In Denmark, the incidence of vancomycin-resistant Enterococcus faecium (VREfm) has increased since 2012. The aim of this study was to investigate the epidemiology and clonal relatedness of VREfm isolates in Danish hospitals in 2012-13 using WGS. The second aim was to evaluate if WGS-based typing could replace PFGE for typing of VREfm. METHODS A population-based study was conducted including all VREfm isolates submitted for national surveillance from January 2012 to April 2013. All isolates were investigated by WGS, MLST and PFGE. RESULTS One-hundred and thirty-two isolates were included. The majority of the isolates were from clinical samples (77%). Gastroenterology/abdominal surgery (29%) and ICUs (29%) were the predominant departments with VREfm. Genomics revealed a polyclonal structure of the VREfm outbreak. Seven subgroups of 3-44 genetically closely related isolates (separated by <17 SNPs) were identified using WGS. Direct or indirect transmission of VREfm between patients and intra- and inter-regional spreading clones was observed. We identified 10 STs. PFGE identified four major clusters (13-43 isolates) and seven minor clusters (two to three isolates). The results from the typing methods were highly concordant. However, WGS-based typing had the highest discriminatory power. CONCLUSIONS This study emphasizes the importance of infection control measures to limit transmission of VREfm between patients. However, the diversity of the VREfm isolates points to the fact that other important factors may also affect the VREfm increase in Denmark. Finally, WGS is suitable for typing of VREfm and has replaced PFGE for typing of VREfm in Denmark.

Severity of infection and seasonal variation of non-typhoid Salmonella occurrence in humans.

Non-typhoid Salmonella infections may present as severe gastroenteritis necessitating hospitalization and some patients become septic with bacteraemia. We hypothesized that the seasonal variation of non-typhoid Salmonella occurrence in humans diminishes with increased severity of infection. We examined the seasonal variation of non-typhoid Salmonella infections in three patient groups with differing severity of infection: outpatients treated for gastroenteritis (n=1490); in-patients treated for gastroenteritis (n=492); and in-patients treated for bacteraemia (n=113). The study was population-based and included all non-typhoid Salmonella patients in a Danish county from 1994 to 2003. A periodic regression model was used to compute the peak-to-trough ratio for the three patient groups. The peak-to-trough ratios were 4.3 [95% confidence interval (CI) 3.6-5.0] for outpatients with gastroenteritis, 3.2 (95% CI 2.4-4.2) for in-patients with gastroenteritis, and 1.6 (95% CI 1.0-2.8) for in-patients with bacteraemia. We conclude that the role of seasonal variation diminishes with increased severity of non-typhoid Salmonella infection.

Trends in occurrence of antimicrobial resistance in Campylobacter jejuni isolates from broiler chickens, broiler chicken meat, and human domestically acquired cases and travel associated cases in Denmark.

Campylobacter jejuni is a frequent cause of bacterial gastroenteritis. Often it causes self-limiting disease but severe or prolonged cases may require antimicrobial treatment. The agricultural use of antimicrobial agents selects for resistance among C. jejuni which is transmitted to humans via food. In Denmark, the use of fluoroquinolones in animal husbandry has been restricted since 2003. The purpose of the present study was to look at trends in occurrence of resistance among C. jejuni from broiler chickens, broiler chicken meat and human domestically acquired or travel associated cases. From 1997 through 2007, C. jejuni isolates were obtained from The Danish Integrated Antimicrobial Resistance Monitoring and Research Programme (DANMAP) and susceptibility tested for ciprofloxacin, erythromycin, nalidixic acid, and tetracycline. Erythromycin resistance was at a low level in all the reservoirs during the study period. Resistance to ciprofloxacin, nalidixic acid and tetracycline was significantly higher in C. jejuni from imported broiler chicken meat compared to Danish broiler chicken meat. In domestically acquired human C. jejuni isolates, resistance to ciprofloxacin and nalidixic acid was for most years significantly higher compared to the level found in isolates from Danish broiler chicken meat, whereas the resistance level was similar to the level found in isolates from imported broiler chicken meat. Imported broiler chicken meat may therefore contribute to the high level of ciprofloxacin and nalidixic acid resistance in C. jejuni isolates from domestically acquired human infections. In 2006 and 2007, the occurrence of resistance to ciprofloxacin, nalidixic acid and tetracycline was significantly higher in travel associated C. jejuni isolates compared to isolates acquired domestically. Even though the use of fluoroquinolones is restricted for animal use in Denmark, Danes are still often infected by fluoroquinolone resistant C. jejuni from imported chicken meat or by travelling.

Evaluation of fecal calprotectin in Campylobacter concisus and Campylobacter jejuni/coli gastroenteritis

Abstract Calprotectin (CP) is a calcium-binding cytosolic neutrophil protein and the concentration in feces reflects the migration of neutrophils into the gut lumen. Testing for fecal CP (f-CP) in patients with negative cultures for enteric pathogens is widely accepted as a useful screening tool for identifying patients who are most likely to benefit from endoscopy for suspected inflammatory bowel disease (IBD) with the assumption that a negative f-CP is compatible with a functional disorder. Campylobacter concisus has recently been reported to have a high incidence in the Danish population almost equal to Campylobacter jejuni and Campylobacter coli and has been reported to cause prolonged watery diarrhea. However, isolation of C. concisus from feces requires the filter method in a hydrogen-enriched microaerobic atmosphere, which is not commonly used in the laboratory, and the diagnosis may consequently be missed. The aim of this study was to evaluate the f-CP levels, as a marker for the intestinal inflammation in C. jejuni/coli- and C. concisus-infected patients. The authors found a high concentration of f-CP (median 631: IQR 221–1274) among 140 patients with C. jejuni/coli infection, whereas the f-CP level among 99 C. concisus-infected patients was significantly lower (median 53: IQR 20–169). The data correlate to the severe inflammatory gastroenteritis seen in patients infected with C. jejuni/coli, whereas C. concisus-infected patients have a much lower intestinal inflammation which could be compared with viral gastroenteritis. Nevertheless, clinicians should be aware of C. concisus infection, especially in patients with prolonged mild diarrhea, in the differential diagnosis to IBD.

Morbidity and mortality of elderly patients with zoonotic Salmonella and Campylobacter: A population-based study

OBJECTIVES To evaluate the impact of age and comorbidity on the risk and prognosis of zoonotic Salmonella and Campylobacter gastroenteritis in elderly individuals. METHODS Registry-based study comprising all first-time zoonotic Salmonella/Campylobacter gastroenteritis infections in two Danish counties from 1991 through 2003. Cases were elderly (>or=65 years) Salmonella/Campylobacter patients. Younger Salmonella/Campylobacter patients and age and gender matched individuals were reference persons. RESULTS There were 13,324 Salmonella/Campylobacter patients (including 1226 elderly patients) and 26,648 matched reference persons. Elderly Salmonella/Campylobacter patients had more comorbidity than their matched reference persons (OR [95% CI]: 1.56 [1.35-1.80]) and comorbidity adjusted mortality rate ratios (95% CI) were 11.4 (5.1-25.4), 1.9 (1.4-2.6), and 1.3 (0.9-1.9) at day 0-30, 31-180, and 181-365, respectively. The differences in crude 365-day mortality increased with age when Salmonella/Campylobacter patients and reference persons without comorbidity were compared. The independent impact of age was less clear for individuals with comorbidity. There were no differences in comorbidity or survival between non-hospitalized elderly patients and their matched reference persons. CONCLUSIONS Elderly hospitalized Salmonella/Campylobacter patients had higher comorbidity and 1-year mortality than the background population. The excess 30-day mortality elucidated the prognostic role of the Salmonella/Campylobacter infection per se.