Jørgen Engberg

Fresh Chicken as Main Risk Factor for Campylobacteriosis, Denmark

Increased consumption of fresh poultry in Denmark has contributed substantially to the increasing incidence of human campylobacteriosis.

Virulence Factors for Hemolytic Uremic Syndrome, Denmark

We present an analysis of strain and patient factors associated with the development of bloody diarrhea and hemolytic uremic syndrome (HUS) among Shiga toxin-producing Escherichia coli (STEC) patients registered in Denmark in a 6-year period. Of 343 STEC patients, bloody diarrhea developed in 36.4% and HUS in 6.1%. In a multivariate logistic regression model, risk factors for bloody diarrhea were the eae and stx2 genes, O groups O157 and O103, and increasing age. Risk factors for HUS were presence of the stx2 (odds ratio [OR] 18.9) and eae (OR undefined) genes, being a child, and having bloody diarrhea. O group O157, although associated with HUS in a univariate analysis (OR 4.0), was not associated in the multivariate analysis (OR 1.1). This finding indicates that, rather than O group, the combined presence of the eae and stx2 genes is an important predictor of HUS.

Quinolone-resistant Campylobacter infections: risk factors and clinical consequences.

We integrated data on quinolone and macrolide susceptibility patterns with epidemiologic and typing data from Campylobacter jejuni and C. coli infections in two Danish counties. The mean duration of illness was longer for 86 patients with quinolone-resistant C. jejuni infections (median 13.2 days) than for 381 patients with quinolone-sensitive C. jejuni infections (median 10.3 days, p = 0.001). Foreign travel, eating fresh poultry other than chicken and turkey, and swimming were associated with increased risk for quinolone-resistant C. jejuni infection. Eating fresh chicken (of presumably Danish origin) was associated with a decreased risk. Typing data showed an association between strains from retail food products and broiler chickens and quinolone-sensitive domestically acquired C. jejuni infections. An association between treatment with a fluoroquinolone before stool-specimen collection and having a quinolone-resistant C. jejuni infection was not observed.

Phylogenetic evidence for the acquisition of ribosomal RNA introns subsequent to the divergence of some of the major Tetrahymena groups.

Previous work has demonstrated the presence of a self‐splicing intron in the large subunit ribosomal RNA coding region in some strains of the ciliate protozoan Tetrahymena. Sequence comparisons of the intron regions from six Tetrahymena species showed these to fall into three homology groups. In an attempt to evaluate the evolutionary origins of the intervening sequences, we have now determined complete small subunit ribosomal RNA gene sequences from 13 species of Tetrahymena and the absolute number of nucleotide differences between the sequences was used to construct a phylogenetic tree. This phylogeny was consistent with the groupings suggested by comparisons of other biochemical characters including cytoskeletal proteins, isozyme analyses, and restriction maps of complete rRNA transcription units. The homology groupings that were based upon the intron sequence data do not agree with the relationships inferred from the small subunit rRNA sequence data. These observations are taken to indicate that the intron character has been acquired independently in different species at a stage later than the branching out of the species.

Antibody Responses to Campylobacter Infections Determined by an Enzyme-Linked Immunosorbent Assay: 2-Year Follow-Up Study of 210 Patients

ABSTRACT An enzyme-linked immunosorbent assay (ELISA) was adapted to measure immunoglobulin G (IgG), IgM, and IgA classes of human serum antibody toCampylobacter jejuni and Campylobacter coli. Heat-stable antigen, a combination of C. jejuni serotype O:1,44 and O:53 in the ratio 1:1, was used as a coating antigen in the ELISA test. A total of 631 sera from 210 patients with verifiedCampylobacter enteritis were examined at various intervals after infection, and a control group of 164 sera were tested to determine the cut-off for negative results. With a 90th percentile of specificity, IgG, IgM, and IgA showed a sensitivity of 71, 60, and 80%, respectively. By combining all three antibody classes, the sensitivity was 92% within 35 days after infection, whereas within 90 days after infection, a combined sensitivity of 90% was found (IgG 68%, IgM 52%, and IgA 76%). At follow-up of the patients, IgG antibodies were elevated 4.5 months after infection but exhibited a large degree of variation in antibody decay profiles. IgA and IgM antibodies were elevated during the acute phase of infection (up to 2 months from onset of infection). The antibody response did not depend on Campylobacter species or C. jejuniserotype, with the important exception of response to C. jejuni O:19, the serotype most frequently associated with Guillain-Barré syndrome. All of the patients infected with this serotype had higher levels of both IgM (P = 0.006) and IgA (P = 0.06) compared with other C. jejuni and C. coli serotypes.

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.

Genetic relatedness among Campylobacter jejuni serotyped isolates of diverse origin as determined by numerical analysis of amplified fragment length polymorphism (AFLP) profiles

Aims:  To use amplified fragment length polymorphism (AFLP) analysis to evaluate the genetic relatedness among 254 Campylobacter jejuni reference and field strains of diverse origin representing all defined ‘Penner’ serotypes for this species.

Absence of Clonality of Campylobacter jejuni in Serotypes Other Than HS:19 Associated with Guillain-Barré Syndrome and Gastroenteritis

Guillain-Barré syndrome (GBS) is recognized as a complication that occurs after Campylobacter infection. Certain Penner serotypes, such as HS:19, are linked particularly to GBS in some parts of the world, and there is good evidence for restricted genetic diversity in these isolates. However, GBS also occurs after Campylobacter infection due to other serotypes. Therefore, we asked whether Campylobacter jejuni non-HS:19 serotypes associated with GBS have a clonal structure and differ from strains isolated from patients with Campylobacter gastroenteritis. A worldwide selected population of C. jejuni non-HS:19 strains associated with GBS and gastroenteritis was analyzed by use of multilocus enzyme electrophoresis, automated ribotyping, pulsed-field gel electrophoresis, and flagellin gene typing. The results show that these isolates represent a heterogenic population and do not constitute a unique population across serotypes. No epidemiologic marker for GBS-associated strains was identified.

Active ulcerative colitis associated with low prevalence of Blastocystis and Dientamoeba fragilis infection

Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark, Department of Gastroenterology, Hvidovre University Hospital, Copenhagen, Denmark, Department of Clinical Microbiology, Slagelse Hospital, Slagelse, Denmark, Department of Clinical Microbiology, Hvidovre University Hospital, Copenhagen, Denmark, and National Food Institute, Technical University of Denmark, Copenhagen, Denmark

The prevalence and clinical significance of intestinal parasites in HIV-infected patients in Denmark

Abstract To investigate the prevalence and clinical significance of intestinal parasites in human immunodeficiency virus (HIV)-infected patients, faecal specimens from 96 HIV-infected patients were submitted to microbiological analyses, including microscopy and polymerase chain reaction for protozoa and enteropathogenic bacteria. Results of microbiological analyses were compared with self-reported gastrointestinal complaints collected using a validated questionnaire. Thirty-two (33%) patients were positive for parasites. However, opportunistic parasites (Isospora and Cryptosporidium) were detected in only 2 instances. Entamoeba dispar was detected in 10 cases, 9 of which represented men who have sex with men (MSM). Despite generally low HIV RNA loads and high CD4+ T-cell counts, 42% of the 76 patients reporting symptoms complained of diarrhoea, 31% of whom were parasite-positive. The presence of diarrhoea was not associated with the presence or absence of parasites; neither was it associated with receiving highly active anti-retroviral therapy (HAART) in general, or protease inhibitors (PI) in particular. A CD4+ T-cell count <200 cells/mm3 was not associated with parasitic infection or with diarrhoea. The data show that diarrhoea is a common symptom among HIV-infected patients in Denmark, but do not indicate that the diarrhoea is due to intestinal parasites.