Epidemiology of gastrointestinal infections: lessons learned from syndromic testing, Region Zealand, Denmark

The aim of this study was to investigate the value of syndromic diagnostic testing for a better understanding of the epidemiology of gastrointestinal infections in Denmark. Here we evaluated the QIAstat-Dx® Gastrointestinal (GI) Panel 1 assay on 18,610 fecal samples requested for analysis for enteric pathogens in Region Zealand, Denmark, in 1 year (October 1, 2021, to September 30, 2022). In total, 6905 (37%) samples were detected positive for one or more diarrhoeal bacteria, viruses, and protozoa. The most common bacterial, viral, and parasitic pathogens detected with the QIAstat-Dx® Gastrointestinal Panel 1 were EPEC (in patients ≥ 2 years of age) (n = 1420 (20.6%)), rotavirus (n = 948 (13.7%)), and Cryptosporidium spp. (n = 196 (2.84%)). We identified a large diversity in infections likely reflecting substantial differences in the epidemiology including origin of infections, mode of transmission, seasonality, age-dependent susceptibility to disease, severity, and travel history. All pathogens were detected as both single and coinfections. Viral infections peaked in March with a positive rate of 31.6%, and bacterial infections peaked in August with a positive rate of 35.3%. ETEC, Shigella/EIEC, EAEC, and P. shigelloides were most related to travel activity, and coinfections were frequent. The distribution of Ct values varied significantly between the pathogens, with the lowest Ct values (median 17-18) observed in astrovirus, adenovirus, and rotavirus. Our results highlight the value of providing extensive diagnostic testing on fecal samples for sufficient detection of relevant diarrhoeal pathogens for optimal clinical care.

Imported spring onions related to the first recorded outbreak of enteroinvasive Escherichia coli in Denmark, November to December 2021

Between November and December 2021, the first ever recorded outbreak of enteroinvasive Escherichia coli in Denmark occurred at national scale. We describe the investigation of this outbreak, which was initially recognised in early December 2021. A total of 88 cases (58 female; 30 male) with a median age of 52 years (range: 0-91) were detected by PCR-based diagnostic methods. Case ascertainment was complicated by current culture-free diagnostic procedures, with only 34 cases confirmed by culture, serotyping and whole genome sequencing. Isolates from cases grouped into two serotypes (O136:H7 and O96:H19), which was supported by whole-genome-sequence-phylogeny, also yielding two clusters. Interviews of 42 cases and traceback investigation pointed towards consumption of ready-to-eat salads as the outbreak cause. While the ready-to-eat salads comprised different vegetables, imported spring onions were the only common ingredient and thus the likely source. Environmental investigations failed to recover outbreak strains. This report highlights the value of fast typing (here O-typing) to confirm cases in an outbreak situation. Timely communication and data sharing are also important, and were facilitated by the national collaboration between relevant laboratories, the public health institute and the veterinary and food administration. High hygiene standards for imported fresh vegetables intended for ready-to-eat products are essential.

The incidence of laboratory-confirmed cases of enteric pathogens in Denmark 2018: a national observational study

BACKGROUND

Only a subset of enteric pathogens is under surveillance in Denmark, and knowledge on the remaining pathogens detected in acute gastroenteritis is limited. Here, we present the one-year incidence of all enteric pathogens diagnosed in Denmark, a high-income country, in 2018 and an overview of diagnostic methods used for detection.

METHODS

All 10 departments of clinical microbiology completed a questionnaire on test methods and provided 2018-data of persons with positive stool samples with Salmonella species, Campylobacter jejuni/coli, Yersinia enterocolitica, Aeromonas species, diarrheagenic Escherichia coli (Enteroinvasive (EIEC), Shiga toxin-producing (STEC), Enterotoxigenic (ETEC), Enteropathogenic (EPEC), and intimin-producing/attaching and effacing (AEEC)), Shigella species., Vibrio cholerae, norovirus, rotavirus, sapovirus, adenovirus, Giardia intestinalis, Cryptosporidium species, and Entamoeba histolytica.

RESULTS

Enteric bacterial infections were diagnosed with an incidence of 229.9 cases/100,000 inhabitants, virus had an incidence of 86/100,000 and enteropathogenic parasites of 12.5/100,000. Viruses constituted more than half of diagnosed enteropathogens for children below 2 years and elderly above 80 years. Diagnostic methods and algorithms differed across the country and in general PCR testing resulted in higher incidences compared to culture (bacteria), antigen-test (viruses), or microscopy (parasites) for most pathogens.

CONCLUSIONS

In Denmark, the majority of detected infections are bacterial with viral agents primarily detected in the extremes of ages and with few intestinal protozoal infections. Incidence rates were affected by age, clinical setting and local test methods with PCR leading to increased detection rates. The latter needs to be taken into account when interpreting epidemiological data across the country.

Correlation of High Seawater Temperature with Vibrio and Shewanella Infections, Denmark, 2010-2018

During 2010-2018 in Denmark, 638 patients had Vibrio infections diagnosed and 521 patients had Shewanella infections diagnosed. Most cases occurred in years with high seawater temperatures. The substantial increase in those infections, with some causing septicemia, calls for clinical awareness and mandatory notification policies.

Sentinel surveillance and epidemiology of Clostridioides difficile in Denmark, 2016 to 2019

BackgroundSince 2008, Danish national surveillance of Clostridioides difficile has focused on binary toxin-positive strains in order to monitor epidemic types such as PCR ribotype (RT) 027 and 078. Additional surveillance is needed to provide a more unbiased representation of all strains from the clinical reservoir.AimSetting up a new sentinel surveillance scheme for an improved understanding of type distribution relative to time, geography and epidemiology, here presenting data from 2016 to 2019.MethodsFor 2─4 weeks in spring and autumn each year between 2016 and 2019, all 10 Danish Departments of Clinical Microbiology collected faecal samples containing toxigenic C. difficile. Isolates were typed at the national reference laboratory at Statens Serum Institut. The typing method in 2016-17 used tandem-repeat-sequence typing, while the typing method in 2018-19 was whole genome sequencing.ResultsDuring the study period, the sentinel surveillance scheme included ca 14-15% of all Danish cases of C. difficile infections. Binary toxin-negative strains accounted for 75% and 16 of the 20 most prevalent types. The most common sequence types (ST) were ST2/13 (RT014/020) (19.5%), ST1 (RT027) (10.8%), ST11 (RT078) (6.7%), ST8 (RT002) (6.6%) and ST6 (RT005/117) (5.1%). The data also highlighted geographical differences, mostly related to ST1 and temporal decline of ST1 (p = 0.0008) and the increase of ST103 (p = 0.002), ST17 (p = 0.004) and ST37 (p = 0.003), the latter three binary toxin-negative.ConclusionSentinel surveillance allowed nationwide monitoring of geographical differences and temporal changes in C. difficile infections in Denmark, including emerging types, regardless of binary toxin status.

Verification of analytical bacterial spectrum of QIAstat-Dx® GI V2 and Novodiag® Bacterial GE+ V2-0 diagnostic panels

Background

Implementing multiplex PCR or syndromic panel-based testing platforms to detect microbial species that cause acute diarrhoea may guide patient management more effectively and efficiently.

Objectives

To assess and compare the performance of two syndromic panel-based testing systems, QIAstat-Dx^® Gastrointestinal Panel V2 (QGI) and the Novodiag^® Bacterial GE+ V2-0 (NGE).

Methods

The QGI and NGE panels include 16 and 14 bacterial gastrointestinal pathogens, respectively. The performance of the panels was tested retrospectively using 141 positive clinical stool specimens, External Quality Assessment (EQA) panels and spiked faecal specimens.

Results

For Campylobacter jejuni and coli (n = 20), Salmonella (n = 24), Shigella (n = 13), Yersinia enterocolitica (non-1A biotypes) (n = 8), Clostridioides difficile (n = 24) and Vibrio parahaemolyticus (n = 2), QGI correctly verified 19/20, 20/24, 13/13, 8/8, 23/24 and 2/2, whereas NGE correctly verified 20/20, 17/24, 13/13, 8/8, 14/24 and 1/2. Among diarrhoeagenic Escherichia coli (n = 29), QGI reported one Shiga toxin-producing E. coli (STEC) stx1a O26:H11 as STEC serotype O157:H7 and NGE failed on one enteropathogenic E. coli, one enteroaggregative E. coli and one STEC (stx2e). Y. enterocolitica biotype 1A (non-pathogenic) (n = 6) were all positive in QGI, but negative in NGE.

Conclusions

Both QGI and NGE testing panels can improve laboratory workflow and patient management by providing user-friendly platforms that can rapidly detect a number of targets with one specimen. QGI was significantly more sensitive in identifying C. difficile. Both methods had suboptimal detection of Salmonella and this needs to be examined further. The short hands-on time and turnaround time are of value for on-demand testing and use in a high-throughput setting.

Randomised clinical trial: a 12-strain bacterial mixture versus faecal microbiota transplantation versus vancomycin for recurrent Clostridioides difficile infections

BACKGROUND

A defined bacterial mixture could be a safer alternative to faecal microbiota transplantation (FMT).

AIMS

To compare the efficacy of a 12-strain mixture termed rectal bacteriotherapy with either FMT or vancomycin for recurrent Clostridioides difficile infection (CDI) in an open-label 3-arm randomised controlled trial.

METHODS

We screened all individuals positive for C difficile from May 2017 to March 2019. Persons with laboratory-confirmed recurrent CDI were included. Before FMT and rectal bacteriotherapy, we pre-treated with vancomycin for 7-14 days. Rectal bacteriotherapy was applied by enema on three consecutive days and FMT by enema once with possible repetition for two to three infusions within 14 days. The vancomycin group was treated for 14 days with additional five weeks of tapering for multiple recurrences. The primary outcome was clinical cure within 90 days. A secondary outcome was 180-day all-cause mortality.

RESULTS

Participants in the FMT group (n = 34) were cured more often than participants receiving vancomycin (n = 31), 76% vs 45% (OR 3.9 (1.4-11.4), P < 0.01) or rectal bacteriotherapy (n = 31), 76% vs 52% (OR 3.0 (1.1-8.8), P = 0.04). Rectal bacteriotherapy and vancomycin performed similarly (P = 0.61). The mortality rate was 6% in the FMT group, 13% in the bacteriotherapy group and 23% in the vancomycin group. FMT tended to reduce mortality compared with vancomycin, OR 0.2 (0.04-1.12), P = 0.07.

CONCLUSIONS

Rectal bacteriotherapy appears as effective as vancomycin but less effective than 1-3 FMTs. FMT by enema with 1-3 infusions is superior to vancomycin for treating recurrent C difficile infections and might reduce mortality.

Whole-Genome Sequencing to Detect Numerous Campylobacter jejuni Outbreaks and Match Patient Isolates to Sources, Denmark, 2015-2017

In industrialized countries, the leading cause of bacterial gastroenteritis is Campylobacter jejuni. However, outbreaks are rarely reported, which may reflect limitations of surveillance, for which molecular typing is not routinely performed. To determine the frequency of genetic clusters among patients and to find links to concurrent isolates from poultry meat, broiler chickens, cattle, pigs, and dogs, we performed whole-genome sequencing on 1,509 C. jejuni isolates from 774 patients and 735 food or animal sources in Denmark during 2015–2017. We found numerous clusters; 366/774 (47.3%) clinical isolates formed 104 clusters of >2 isolates. A total of 41 patient clusters representing 199/366 (54%) patients matched a potential source, primarily domestic chickens/broilers. This study revealed serial outbreaks and numerous matches to concurrent food and animal isolates and highlighted the potential of whole-genome sequencing for improving routine surveillance of C. jejuni by enhancing outbreak detection, source tracing, and potentially prevention of human infections.

Disease-Specific Enteric Microbiome Dysbiosis in Inflammatory Bowel Disease

Inflammatory Bowel disease (IBD) is traditionally divided into Crohn's disease (CD) and ulcerative colitis (UC). UC is a relapsing non-transmural inflammatory disease that is restricted to the colon and is characterized by flare-ups of bloody diarrhea. CD is a chronic, segmental localized granulomatous disease that can affect any part of the entire gastrointestinal tract. Ileo-anal pouch is a procedure restoring functionality of the rectum after a colectomy. IBD is a multifactorial disease and flares of IBD are probably triggered by changes in the intestinal microbiota followed by an abnormal immune response. In this study, we aim to analyze the intestinal bacterial diversity in IBD patients during various stages of disease compared with healthy controls. Permission for human experiments and recruitment of participants was obtained from the Ethic Committee for Copenhagen County hospitals (Permission no. KA-03019, Permission no. KA-20060159). Stools from 26 healthy controls, 42 CD, 38 UC and 18 pouch patients were collected. Stool DNA extraction was performed using Qiagen, DNA mini stool kit Denmark. DGGE-PCR amplifying the V2-V3 region of 16S-rDNA gene of the bacteria was amplified by universal primers HDA1 and HDA2. Analysis of DGGE was performed blinded using BioNumerics version 7.5. After normalization, a DGGE gel band matching was performed. The similarities between profiles were calculated with a ranked Pearson correlation coefficient based on the band matching results using band intensities. Simpson's index of diversity and Pielou's species evenness were calculated. Based on the Shannon Diversity Index, UC patients had lower species diversity and bacterial evenness in comparison to healthy persons, p < 0.05. However, only CD and disease pouch patients had lower species diversity compared to those with inactive disease and healthy controls. Well-functioning pouch patients had decreased species evenness in comparison to diseased pouch patients and control group. During the active disease stage in CD and pouch, the patients have a low bacterial diversity in their gut when compared to the inactive stage. In UC patients, a generally low diversity was observed at all stages of the disease compared to healthy controls.

Characterization of Diarrheagenic Enteroaggregative Escherichia coli in Danish Adults-Antibiotic Treatment Does Not Reduce Duration of Diarrhea

Enteroaggregative Escherichia coli (EAEC) is frequently isolated from sporadic cases of diarrhea and in outbreaks of gastroenteritis in several regions of the world. The pathophysiology of EAEC continues to be enigmatic, and the efficacy of antibiotic treatment in EAEC-associated diarrhea has been discussed. Since the level of antibiotic resistance is increasing, it is essential to restrict the use of antibiotics to prevent further resistance development. We aimed to investigate EAEC strains in adult Danish patients suffering from diarrhea and from healthy controls. We examined the antibiotic resistance in EAEC strains, the clinical response to antibiotic treatment in EAEC diarrheal cases, and the distribution of virulence genes in diarrheal cases. The EAEC strains were collected from patients suffering from diarrhea in a Danish multicenter study. A medical doctor interviewed the patients by using a questionnaire regarding gastrointestinal symptoms, exposures, and use of antibiotic and over-the-counter antidiarrheal drugs. Follow-up was performed after 3–5 months to inquire about differential diagnosis to gastrointestinal disease. A multiplex polymerase chain reaction characterized virulence genes in diarrheal cases. Finally, the level of antibiotic resistance was examined by using the disc diffusion method. Asymptomatic carriage of EAEC in the adult Danish population was rare, in contrast to findings in healthy Danish children. The duration of diarrhea was not shortened by antibiotic treatment, specifically ciprofloxacin treatment, or by over-the-counter antidiarrheal drugs. Follow-up revealed no pathology in diarrheal patients apart from irritable bowel syndrome in two patients. A high number of patients suffered from long-term diarrhea, which was associated with the enterotoxin EAST-1 and a high virulence factor score. A high level of antibiotic resistance was observed and 58% of the EAEC strains were multidrug resistant. Multidrug resistance was most pronounced in cases of travelers' diarrhea, and it was seen that antibiotic treatment did not reduce the duration of diarrhea.

Novel multiplex format of an extended multilocus variable-number-tandem-repeat analysis of Clostridium difficile correlates with tandem repeat sequence typing

Subtyping of Clostridium difficile is crucial for outbreak investigations. An extended multilocus variable-number tandem-repeat analysis (eMLVA) of 14 variable number tandem repeat (VNTR) loci was validated in multiplex format compatible with a routine typing laboratory and showed excellent concordance with tandem repeat sequence typing (TRST) and high discriminatory power.

Psychometric scores and persistence of irritable bowel after Campylobacter concisus infection

OBJECTIVE

Gastroenteritis with Campylobacter concisus is an emerging infection, but the risk of irritable bowel syndrome (IBS) following it is unknown.

MATERIAL AND METHODS

In a prospective, community-based study of gastroenteritis with C. concisus and C. jejuni/coli, we invited adult patients to participate in a questionnaire study, including IBS symptoms and psychometric scores, at baseline and at 6 months. We estimated adjusted RR (RRadj) (for age, sex and comorbidity) for IBS as the primary outcome.

RESULTS

The development of IBS symptoms at 6 months was reported in 26/106 (25%) patients with C. concisus infection, and in 30/162 (19%) of C. jejuni/coli patients. The baseline predictors for IBS in C. concisus infection were high anxiety scores (RRadj 2.0; 95% CI 1.1-3.6, p<0.05), chills (RRadj 1.9; 95% CI 1.0-3.6, p<0.05), headache (RRadj 2.5; 95% CI 1.1-6.0, p<0.05), dizziness (RRadj 2.6; 95% CI 1.2-5.8, p<0.05) and muscle ache (RRadj 3.6; 95% CI 1.4-8.9, p<0.01). For all Campylobacter patients (n=268), we confirmed previous reports of anxiety (RRadj 2.0; 95% CI 1.3-3.1), depression (RRadj 2.3; 95% CI 1.3-4.0) and high somatization scores (RRadj 3.0; 95% CI 1.5-6.0) as predictors for post-infectious IBS (PI-IBS).

CONCLUSIONS

Gastroenteritis with C. concisus carries a 25% risk of IBS at 6-month follow-up. The risk factors for IBS are chills, headache, dizziness and muscle ache in the acute stage, as well as preexisting high psychometric scores for anxiety. Our findings suggest that psychological factors play a role in the development of PI-IBS.

Comparison of polycarbonate and cellulose acetate membrane filters for isolation of Campylobacter concisus from stool samples

One thousand seven hundred ninety-one diarrheic stool samples were cultivated for Campylobacter spp. We found a high prevalence of Campylobacter concisus with use of a polycarbonate filter (n = 114) compared to a cellulose acetate filter (n = 79) (P < .0001). The polycarbonate filter is superior to the commonly used cellulose acetate filter for detection of C. concisus.

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

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.

Short-term and medium-term clinical outcomes of Campylobacter concisus infection

There are only sparse data on the short-term and medium-term clinical impacts of Campylobacter concisus infection. A clinical study was performed during a 2-year period to determine the clinical manifestations in C. concisus-positive adult patients. A case patient was defined as an adult patient (≥18 years) with a C. concisus-positive stool sample during the study period. Clinical data were obtained with use of a questionnaire supplemented with the patients' medical records, if any. The short-term and medium-term clinical manifestations in these patients were compared with those of patients with Campylobacter jejuni/Campylobacter coli infection. One hundred and seventy-four C. concisus patients and 196 C. jejuni/C. coli patients participated in the study. Patients with pre-existing inflammatory bowel disease or microscopic colitis or enteric co-infection were excluded from review of the clinical manifestations. Comparison of the short-term clinical manifestations in 139 C. concisus patients with those in 187 C. jejuni/C. coli patients showed a significantly lower prevalence of fever, chills, mucus and blood in stools, and weight loss. However, 80% of C. concisus patients, but only 32% of C. jejuni/C. coli patients, had diarrhoea for >2 weeks. After a 6-month follow-up period, 12% of C. concisus patients were diagnosed with microscopic colitis, whereas no C. jejuni/C. coli patients were diagnosed with non-infective colitis. Irritable bowel symptoms were common in both groups at follow-up. C. concisus infection seems to cause a milder course of acute gastroenteritis than C. jejuni/C. coli infection, but is associated with more prolonged diarrhoea.

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.

A waterborne outbreak with a single clone of Campylobacter jejuni in the Danish town of Køge in May 2010

BACKGROUND

In Denmark, large-scale waterborne outbreaks are rare. This report describes the investigation of an outbreak that occurred in the town of Køge in May 2010.

METHODS

The epidemiological investigation consisted of hypothesis generating telephone interviews, followed by a cohort study among approximately 20,000 residents using an online questionnaire. Odds ratios were calculated for exposures including the number of glasses of tap water consumed. Geographical spreading was assessed using a geographical information system. The microbiological investigation included cultures of stool samples and flagellin-typing. In the environmental investigation, water samples were tested for Escherichia coli and coliform counts and for DNA of Campylobacter, Enterococcus, and Bacteroides. During the outbreak investigation a water boiling order was enforced, as tap water was considered a potential source.

RESULTS

Of 45 patients with laboratory confirmed Campylobacter infection in the municipality of Køge in May, 43 lived in the area covered by the central water supply. Of 61 patients with laboratory confirmed Campylobacter jejuni by 8 June, 50 shared a common flagellin gene type--flaA type 36 (82%). The epidemic curve from the cohort study showed a wave of diarrhoea onset from 14 to 20 May (n = 176). Among these patients, the development of diarrhoea was associated with drinking tap water with a dose-response pattern (linear increase by 2 glasses: odds ratio 1.40, 95% confidence interval 1.16-1.70). No bacterial DNA was found in water samples.

CONCLUSIONS

These findings indicated a point source contamination of tap water with a single clone of C. jejuni which likely occurred on 12-13 May. The water boiling order was lifted on 18 June.

Seroreactivity to E. coli outer membrane protein C antibodies in active inflammatory bowel disease; diagnostic value and correlation with phylogroup B2 E. coli infection

BACKGROUND

Several serologic tests, including anti-outer membrane porin C antibody (Omp C), are used for screening and as marker of disease course in inflammatory bowel diseases (IBD). Our aim was to investigate possible differences in Omp C level in patients with active and inactive IBD compared to controls.

METHODS

All blood samples were tested for Omp C. Disease activity was evaluated by Harvey Bradshaw Index, Simple Clinical Activity Index and Modified Pouchitis Disease Activity Index.

RESULTS

Blood samples were collected from 113 patients and 60 controls. Patients with active IBD did not have a higher level of Omp C than patients in remission. Surprisingly, in patients with active Crohn's disease a significantly lower level of Omp C was found compared with patients with inactive Crohn's disease (p < 0.05). All other groups among patients with IBD did have a significantly higher level of Omp C, compared with controls, including patients with acute gastroenteritis (p < 0.05). Although IBD patients with phylogroup B2 E. coli cultured from their fecal samples, were more likely to have a positive Omp C test (p < 0.05), this could not explain the low Omp C level in the subgroup of patients with active Crohn's disease.

CONCLUSIONS

Omp C titer was not raised in patients with active IBD compared with patients in remission. In addition, there was no difference in Omp C level in patients with active Crohn's disease compared with controls. These observations do not support the use of Omp C serology testing, either in disease activity assessment, or in screening for active Crohn's disease.

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 (R^t) 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 R^t 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.

Outbreak of listeriosis caused by infected beef meat from a meals-on-wheels delivery in Denmark 2009

An outbreak of listeriosis in Denmark occurred in May 2009. Multilocus variable number of tandem repeats analysis typing, later confirmed by pulsed-field gel electrophoresis typing, showed that isolates from eight patients had identical patterns and were distinguishable from Listeria monocytogenes isolates from other Danish patients. Seven out of eight patients had received a meal with beef from the same meals-on-wheels delivery catering company 3 weeks prior to onset of disease. Two patients died of their infection. Large-scale delivery of precooked meals to a vulnerable population represents a threat if proper measures against listeriosis are not taken.

Comparative analysis of antibiotic resistance and phylogenetic group patterns in human and porcine urinary tract infectious Escherichia coli

Urinary tract infections (UTIs) are one of the most common infectious diseases in humans and domestic animals such as pigs. The most frequent infectious agent in such infections is Escherichia coli. Virulence characteristics of E. coli UTI strains range from highly virulent pyelonephritis strains to relatively benign asymptomatic bacteriuria strains. Here we analyse a spectrum of porcine and human UTI E. coli strains with respect to their antibiotic resistance patterns and their phylogenetic groups, determined by multiplex PCR. The clonal profiles of the strains differed profoundly; whereas human strains predominantly belonged to clonal types B2 and D, these were not seen among the porcine strains, which all belonged to the E. coli clonal groups A and B1. Contrary to the human strains, the majority of the porcine strains were multidrug resistant. The distinct profiles of the porcine strains suggest selective pressure due to extensive antibiotic use.

[Salmonella typhi--time to change empiric treatment]

In the present case series report we describe seven recent cases of typhoid fever. All the patients were travellers returning from Pakistan, where typhoid is endemic. Salmonella typhi isolated from the patients by blood culture were reported as intermediary susceptible to fluoroquinolones in six out of seven cases. We recommend that empiric treatment of suspected cases of typhoid fever includes a third generation cephalosporin such as ceftriaxon. Furthermore, the present report stresses the importance of typhoid vaccination of travellers to areas where typhoid is endemic.

Systematic serotyping and riboprinting of Campylobacter spp. improves surveillance: experiences from two Danish counties

In order to monitor the distribution of subtypes of Campylobacter and to identify clusters, 975 isolates of Campylobacter spp., obtained from human infections occurring in two Danish counties, were studied during a 1-year period. The isolates were characterised by Penner serotyping and automated ribotyping. Pulsed-field gel electrophoresis (PFGE) profiling was used to confirm clustering of identical serotypes and ribotypes. The 975 isolates were divided into 48 serotypes, 210 ribotypes and 277 serotype-ribotype combinations. The overall distribution of serotypes and ribotypes was similar between the two counties. After taking into account the rare or common occurrence of subtypes, a model identified 43 clusters of subtypes during the study period. Clustered isolates represented 28% (273/975) of the study population, with clusters containing between three and 20 isolates. PFGE confirmed the validity of selected clusters identified by serotyping and ribotyping. The observed clustering of Campylobacter isolates, with identical types in time and place, indicates that common-source outbreaks of campylobacteriosis are more common than is usually thought.

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.

We report the findings of a case-control study of risk factors for sporadic cases of human campylobacteriosis in Denmark. In 3 different analytical models, the main domestic risk factor identified was eating fresh, unfrozen chicken. Specifically, 28 of 74 domestically acquired case-patients were exposed to fresh chicken compared with 21 of 114 controls (multivariate matched odds ratio 5.8; 95% confidence interval 2.1–15.9). In contrast, a risk from eating other poultry, including previously frozen chicken, was only indicated from borderline significant 2-factor interactions. The marked increase in consumption of fresh, unfrozen poultry in Denmark during the 1990s likely contributed substantially to the increasing incidence of human campylobacteriosis in this period.

Most Campylobacter subtypes from sporadic infections can be found in retail poultry products and food animals

The subtypes of Campylobacter isolates from human infections in two Danish counties were compared to isolates from retail food samples and faecal samples from chickens, pigs and cattle. During a 1-year period, 1285 Campylobacter isolates from these sources were typed by two methods: 'Penner' heat-stable serotyping and automated ribotyping (RiboPrinting). C. jejuni was the dominating species, but C. coli was more prevalent among food and chicken isolates (16%) compared to human isolates (4%). In total, 356 different combined sero-ribotypes (subtypes) were found. A large subtype overlap was seen between human isolates and isolates from food (66%), chickens (59%) and cattle (83%). This was verified by PFGE typing of 212 isolates representing selected subtypes. All frequent (n>3) subtypes found in food were also present in humans. Sixty-one per cent of the isolates from domestically acquired infections had subtypes that were also found in food as opposed to 31% of travel-associated infections. The results showed differences in the various Campylobacter populations, e.g. the Danish population as reflected in the domestically acquired infections and the Danish-produced food was more uniform than the isolates originating from outside the country. The study shows that most C. jejuni subtypes found in poultry food samples, broiler chickens, and cattle were represented in the domestically acquired cases, indicating that C. jejuni from these reservoirs are likely sources of human infections in Denmark.

Invasive listeriosis in Denmark 1994-2003: a review of 299 cases with special emphasis on risk factors for mortality

Listeriosis is a rare, but serious, foodborne infection which, in the invasive form, presents as bloodstream (BS) infection, an infection of the central nervous system (CNS), a maternofetal infection or a focal infection. The disease is notifiable in Denmark. This paper reviews the results of the Danish surveillance of invasive listeriosis from 1994 to 2003, excluding maternofetal cases. In total, 299 invasive cases of listeriosis were reported. Two-thirds of the cases were caused by isolates of serogroup 1/2, and one-third by serogroup 4. Most (70%) cases had conditions known to predispose to listeriosis. More patients with BS infection were predisposed because of concurrent underlying illness than were patients with CNS infection. Half of the patients were aged > 70 years, and 21% died of the disease. There was no change in the case fatality rate (CFR) during the 10-year period. The CFR was identical for men and women. BS and CNS infection caused the same incidence of mortality, but no mortality was observed in patients with focal infections at normally sterile body sites. In a multivariate analysis, isolates belonging to serogroup 4 were associated with a higher CFR than were isolates of serogroup 1/2. In patients aged < 70 years, underlying conditions predisposing to disease were related strongly to mortality, which was not the case in patients aged > 70 years. The underlying conditions associated most strongly with mortality in the younger age group were non-haematological malignancies.

Campylobacter concisus: an evaluation of certain phenotypic and genotypic characteristics

The clinical relevance of Campylobacter concisus in gastrointestinal disease has not been determined definitively. This study investigated the phenotypic and genotypic characteristics of 39 C. concisus isolates from Danish patients with diarrhoea, three isolates from healthy individuals and the type strain. A cytolethal distending toxin (CDT)-like effect on Vero cells was observed in 35 (90%) isolates from patients with diarrhoea, in all three isolates from healthy individuals and in the type strain. Analysis of SDS-PAGE protein profiles and PCR amplification of 23S rDNA assigned the isolates into two distinct, but discordant groups. Automated ribotyping (RiboPrinting) identified 34 distinct patterns among the 43 isolates, but cluster analysis did not separate isolates from patients with diarrhoea from isolates from healthy patients. Random amplified polymorphic DNA (RAPD) analysis with three primers identified 37 unique profiles, but requires further evaluation. The isolates obtained from healthy carriers were distinguished by cluster analysis from the isolates obtained from patients with diarrhoea. All the isolates were susceptible to 11 antimicrobial agents tested. Overall, there was considerable variability between the C. concisus isolates, but there were no clear phenotypic or genotypic differences between isolates from patients with diarrhoea and isolates from healthy carriers. Further evidence is needed to support the possible role of C. concisus as a human enteric pathogen.

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.

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.

METHODS AND RESULTS

Field strains (n = 207) from human diarrhoea and diverse animal and environmental sources were collected mainly through a National surveillance programme in Denmark and serotyped by use of the established 'Penner' scheme. Genetic relationships among these isolates, and the archetypal serotype reference strains, were assessed by numerical analysis of AFLP profiles derived from genomic DNA. Extensive genetic diversity was seen among the strains examined; however, 43 groups of isolates were identified at the 92% similarity (S-) level. Thirteen groups contained isolates from a single host, possibly representing genotypes of 'low risk' to human health. The remaining 30 groups contained isolates from humans, chickens and associated food products, cattle, sheep, turkeys, ostriches and/or dogs. Strains assigned to serotypes 2, 6/7, 11 and 12 formed major clusters at the 77.6% S-level. Most other serotypes did not form homogeneous clusters.

CONCLUSIONS

High-resolution genotyping applied to strains from a comprehensive range of sources provides evidence for multiple sources of sporadic C. jejuni infection. The results suggest that public health protection measures should be directed at all foods of animal origin.

SIGNIFICANCE AND IMPACT OF THE STUDY

The genetic relatedness among all 'Penner' serotypes of C. jejuni is assessed by AFLP analysis. In addition, further evidence of epidemic and host-specific clones of C. jejuni is provided.

A case-control study of risk factors for sporadic campylobacter infections in Denmark

A case control study comprising 282 cases and 319 matched controls was conducted in Denmark during 1996-7. Two estimates of the odds ratio (OR) were determined for each risk factor with and without 'protective factors' fitted into the final model. Consumption of undercooked poultry (OR 4.5; 8.2), consumption of red meat at a barbecue (OR 2.3; 4.1), consumption of grapes (OR 1.6; 2.8) and drinking unpasteurized milk (OR 2.3; 11.8) were identified as risk factors in both models. Frequent consumption of pork chops (OR 4.4) and daily contact with domestic animals and pets were identified as risk factors in one of the two models only. Finally, foreign travel was found to be a significant risk factor (OR 2.5). Seasonal and regional interaction was observed for several risk factors and the time elapsed from interviewing of cases to interviewing of controls seemed to influence the effect of certain seasonal dependent risk factors.

Genotypic and serotypic stability of Campylobacter jejuni strains during in vitro and in vivo passage

The stability of four typing methods and the sero- and genotypic stability of three Campylobacter jejuni strains were evaluated after subculturing 50 times in triplicate and after colonising mice for up to 26 days. The employed methods were Penner heat-stable serotyping; automated ribotyping (RiboPrinting) using HaeIII restriction enzyme; pulsed-field gel electrophoresis (PFGE) using SmaI, SalI and KpnI; and random amplified polymorphic DNA analysis (RAPD) using primers 1254, 1281 and HLWL85. No changes in any of the DNA profiles or in the reactions to heat-stable antigens were identified among these strains after the in vitro and in vivo passages. However, one isolate became untypeable with RAPD after passage in one of the mice. In addition, eleven other C. jejuni strains of four different serotypes were subcultured ten times to screen for instability. Neither of these showed instability using PFGE and serotyping. Furthermore, three of four strains previously identified as unstable, showed to consist of mixed cultures, which explains the reported profile changes. The results indicate that the applied typing methods are reliable and applicable for typing of Campylobacter isolates from different sources over time, and that many C. jejuni strains are genetically stable as tested by these methods.

Molecular population genetic analysis of Campylobacter jejuni HS:19 associated with Guillain-Barré syndrome and gastroenteritis

Infection with Campylobacter jejuni serotype HS:19 is associated with the development of Guillain-Barré syndrome (GBS). To determine whether a particular HS:19 clone is associated with GBS, multilocus enzyme electrophoresis (MLEE) was used to analyze a worldwide collection of isolates. There were 34 electropherotypes (ETs) in 3 phylogenetic clusters among 83 C. jejuni isolates. Cluster I contained all HS:19 strains, and a single ET (ET4) accounted for most HS:19 strains. HS:19 strains did not occur in any of the other clusters. ET4 contained isolates from different geographic locations, indicating global spread of this clone. Furthermore, ET4 contained isolates from patients with uncomplicated enteritis and GBS, as well as isolates from animal sources. The results of this study show that HS:19 strains comprise a clonal, although not monomorphic, population, which is distinct from non-HS:19 strains within C. jejuni. A unique clone associated with GBS was not identified by use of MLEE.

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.

Comparison of genotypes and serotypes of Campylobacter jejuni isolated from Danish wild mammals and birds and from broiler flocks and humans

The incidence of human infection with Campylobacter jejuni is increasing in most developed countries and the reason for this is largely unknown. Although poultry meat is considered to be a major source, it is evident that other reservoirs exist, possibly common to humans and poultry. Environmental sources are believed to be important reservoirs of Campylobacter infection in broiler chicken flocks. We investigated the potential importance of wildlife as a source of infection in commercial poultry flocks and in humans by comparing the serotype distributions, fla types, and macrorestriction profiles (MRPs) of C. jejuni isolates from different sources. The serotype distribution in wildlife was significantly different from the known distributions in broilers and humans. Considerable sero- and genotype diversity was found within the wildlife collection, although two major groups of isolates within serotype O:12 and the O:4 complex were found. Common clonal lines among wildlife, chicken, and/or human isolates were identified within serotype O:2 and the O:4 complex. However, MRPs of O:12 and O:38 strains isolated from wildlife and other sources indicated that some clonal lines propagated in a wide selection of animal species but were not detected in humans or broilers in this study. The applied typing methods successfully identified different clonal groups within a strain collection showing large genomic diversity. However, the relatively low number of wildlife strains with an inferred clonal relationship to human and chicken strains suggests that the importance of wildlife as a reservoir of infection is limited.

Antimicrobial resistance of thermophilic Campylobacter

Campylobacter has become the leading cause of zoonotic enteric infections in developed and developing countries world-wide. Antimicrobial resistance has emerged among Campylobacter mainly as a consequence of the use of antimicrobial agents in food animal production. Resistance to drugs of choice for the treatment of infections, macrolides and fluoroquinolones has emerged as a clinical problem and interventions to reduce this are recommended. Resistance to fluoroquinolones and macrolides is mediated by chromosomal mutations. Resistance to other relevant antimicrobial agents, mediated by acquired resistance genes, has not become widespread so far. However, resistance genes originating from both Gram-positive and Gram-negative bacterial species have been found, showing the potential for acquired resistance to emerge in Campylobacter.

Antibody responses to Campylobacter infections determined by an enzyme-linked immunosorbent assay: 2-year follow-up study of 210 patients

An enzyme-linked immunosorbent assay (ELISA) was adapted to measure immunoglobulin G (IgG), IgM, and IgA classes of human serum antibody to Campylobacter 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 verified Campylobacter 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. jejuni serotype, 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.

Quinolone and macrolide resistance in Campylobacter jejuni and C. coli: resistance mechanisms and trends in human isolates

The incidence of human Campylobacter jejuni and C. coli infections has increased markedly in many parts of the world in the last decade as has the number of quinolone-resistant and, to a lesser extent, macrolide-resistant Campylobacter strains causing infections. We review macrolide and quinolone resistance in Campylobacter and track resistance trends in human clinical isolates in relation to use of these agents in food animals. Susceptibility data suggest that erythromycin and other macrolides should remain the drugs of choice in most regions, with systematic surveillance and control measures maintained, but fluoroquinolones may now be of limited use in the empiric treatment of Campylobacter infections in many regions.

CGRP and adrenomedullin receptor populations in human cerebral arteries: in vitro pharmacological and molecular investigations in different artery sizes

The aim of the present study was to determine functional and molecular characteristics of receptors for calcitonin gene-related peptide (CGRP) and adrenomedullin in three different diameter groups of lenticulostriate arteries. Furthermore, the presence of perivascular neuronal sources of CGRP was evaluated in these arteries. In the functional studies, in vitro pharmacological experiments demonstrated that both CGRP and adrenomedullin induce alpha-CGRP-(8-37) sensitive vasodilation in artery segments of various diameters. The maximal amounts of vasodilation induced by CGRP and adrenomedullin were not different, whereas the potency of CGRP exceeded that of adrenomedullin by 2 orders of magnitude. Significant negative correlations between artery diameters and maximal responses were demonstrated for CGRP and adrenomedullin. In addition, the potency of both peptides tended to increase in decreasing artery diameter. In the molecular experiments, levels of mRNAs encoding CGRP receptors and receptor subunits were compared using reverse transcriptase polymerase chain reactions (RT-PCR). The larger the artery, the more mRNA encoding receptor activity-modifying proteins 1 and 2 (RAMP1 and RAMP2) was detected relative to the amount of mRNA encoding the calcitonin receptor-like receptor. By immunohistochemistry, perivascular CGRP containing nerve fibres were demonstrated in all the investigated artery sizes. In conclusion, both CGRP and adrenomedullin induced vasodilation via CGRP receptors in human lenticulostriate artery of various diameter. The artery responsiveness to the CGRP receptor agonists increased with smaller artery diameter, whereas the receptor-phenotype determining mRNA ratios tended to decrease. No evidence for CGRP and adrenomedullin receptor heterogeneity was present in lenticulostriate arteries of different diameters.

Evaluation of phenotypic and genotypic methods for subtyping Campylobacter jejuni isolates from humans, poultry, and cattle

Six methods for subtyping of Campylobacter jejuni were compared and evaluated with a collection of 90 isolates from poultry, cattle, and sporadic human clinical cases as well as from a waterborne outbreak. The applied methods were Penner heat-stable serotyping; automated ribotyping (RiboPrinting); random amplified polymorphic DNA typing (RAPD); pulsed-field gel electrophoresis (PFGE); restriction fragment length polymorphisms of the flagellin gene, flaA (fla-RFLP); and denaturing gradient gel electrophoresis of flaA (fla-DGGE). The methods were evaluated and compared on the basis of their abilities to identify isolates from one outbreak and discriminate between unrelated isolates and the agreement between methods in identifying clonal lines. All methods identified the outbreak strain. For a collection of 80 supposedly unrelated isolates, RAPD and PFGE were the most discriminatory methods, followed by fla-RFLP and RiboPrinting. fla-DGGE and serotyping were the least discriminative. All isolates included in this study were found to be typeable by each of the methods. Thirteen groups of potentially related isolates could be identified using a criterion that at least four of the methods agreed on clustering of isolates. None of the subtypes could be related to only one source; rather, these groups represented isolates from different sources. Furthermore, in two cases isolates from cattle and human patients were found to be identical according to all six methods.

Dynamic effects of self-efficacy on smoking lapse and relapse

Self-efficacy (SE) is thought to be critical to success in smoking cessation both as an individual difference and as a dynamic process after a quit attempt. In this study, 214 smokers used palm-top computers to record day-to-day variations in SE during 4 weeks after quitting. SE remained at high and stable levels prior to a 1st lapse but decreased and became more variable thereafter. The authors used event history models with time-varying covariates to assess the effect of daily SE on lapse and relapse risk. Daily SE measures predicted an initial lapse on the subsequent day. However, this relationship was accounted for by stable baseline differences in SE (assessed by questionnaire), rather than by day-to-day dynamics in SE. Progression from 1st lapse to relapse was also examined. In this instance, daily SE predicted subsequent relapse risk, even when baseline SE and concurrent smoking were accounted for, suggesting the importance of SE dynamics for this stage of the relapse process.

Cloning and characterization of the gene encoding the highly expressed ribosomal protein l3 of the ciliated protozoan Tetrahymena thermophila. Evidence for differential codon usage in highly expressed genes

We have cloned and characterized the cDNA and the macronuclear genomic copy of the highly conserved ribosomal protein (r-protein) L3 of Tetrahymena thermophila. The r-protein L3 is encoded by a single copy gene interrupted by one intron. The organization of the promoter region exhibits features characteristic of ribosomal protein genes in Tetrahymena. The codon usage of the L3 gene is highly biased. A thorough analysis of codon usage in Tetrahymena genes revealed that genes could be categorized into two classes according to codon usage bias. Class A comprises r-protein genes and a number of other highly expressed genes. Class B comprises weakly expressed genes such as the conjugation induced CnjB and CnjC genes, but surprisingly, this class also contains abundantly expressed genes such as the genes encoding the surface antigens SerH3 and SerH1. Codon usage is slightly more restricted in class A than in class B, but both classes exhibit distinct and different codon usage biases. Class A genes preferentially use C and U in the silent third codon positions, whereas class B genes preferentially use A and U in the silent third codon positions. The analysis suggests that two different strategies have been employed for optimization of codon usage in the A+T-rich genome of Tetrahymena.

Use of proteoliposomes to generate phage antibodies against native AMPA receptor

To isolate antibodies against ionotropic glutamate receptors (GluRs), we prepared a phage antibody library from mice immunized with proteoliposomes containing purified alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), a selective GluRD receptor. Specific binders were selected by repeated rounds of affinity panning against immobilized GluRD liposomes. Using this approach, we obtained a panel of high-affinity antibody fragments that immunoprecipitated both recombinant and native GluRD receptors, but not GluR6, a kainate receptor subunit with a 40% sequence similarity. The antibody fragments showed subunit selectivity, some being strictly specific for GluRD, whereas others also recognized the GluRB and GluRC but not GluRA subunits. Further experiments indicated that the epitopes recognized were conformational in nature and reside in the N-terminal extracellular 400-residue X domain of GluRD. Our results suggest that proteoliposomes, in combination with phage display technology, provide an effective tool for the generation of high-affinity conformation-sensitive monoclonal antibodies against predetermined membrane proteins.

Prevalence of Campylobacter, Arcobacter, Helicobacter, and Sutterella spp. in human fecal samples as estimated by a reevaluation of isolation methods for Campylobacters

The aims of this study were to investigate the prevalence of campylobacteria including Campylobacter jejuni subsp. jejuni (C. jejuni) and Campylobacter coli in human clinical samples and in samples from healthy individuals and to reevaluate the efficacies of conventional selective methods for isolation of Campylobacter spp. Two charcoal-based selective media, modified charcoal cefoperazone deoxycholate agar (mCCDA) and cefoperazone-amphotericin-teicoplanin (CAT) agar, were compared with Skirrow's blood-based medium and with a filter method (filter) applied to a yeast-enriched blood agar. A total of 1,376 specimens were tested on all four media, and the percentages of thermophilic Campylobacter-positive specimens isolated on Skirrow's medium, filters, CAT agar, and mCCDA were 82, 83, 85, and 95%, respectively. When additional samples were processed with the three selective media, mCCDA recovered significantly more thermophilic Campylobacter spp. than Skirrow's medium (P = 0.0034). No significant difference between Skirrow's medium and CAT agar was observed in this study. Another six taxa were identified, namely, Campylobacter concisus, Campylobacter curvus-like bacteria, Arcobacter butzleri, Arcobacter cryaerophilus, Helicobacter cinaedi, and Sutterella wadsworthensis. Most of these strains were isolated after 5 to 6 days of incubation by use of the filter technique. This paper provides evidence for the existence of S. wadsworthensis in human feces from clinical cases of gastrointestinal disorders and in feces from a healthy individual. Furthermore, C. concisus was isolated from a large number of diarrheal cases, particularly those at the extremes of age, but was additionally isolated from the feces of healthy people. Further investigations to establish the role of C. concisus and S. wadsworthensis in enteric disease is needed. We conclude that a range of campylobacteria may cause infections in Denmark.