Development of an LPS-based ELISA for diagnosis of Yersinia enterocolitica O:3 infections in Danish patients: a follow-up study.

BACKGROUND: The bacterium Yersinia enterocolitica causes gastroenteritis in humans. The study aimed to develop a diagnostic enzyme-linked immunosorbent assay (ELISA) for detection of Yersinia enterocolitica O:3 LPS antibodies in sera from Danish patients with suspected Yersinia enterocolitica O:3 gastrointestinal infection. As a part of this, antibody decay profiles after culture confirmed Yersinia enteritis were studied. RESULTS: An ELISA using Yersinia enterocolitica O:3 LPS as the coating antigen was developed for measuring IgA, IgG and IgM specific antibodies. A longitudinal collection of 220 sera drawn between 20 and 1053 days after onset of symptoms from 85 adult Danish patients with verified Yersinia enteritis were examined. A control group of 100 sera from healthy Danish blood-donors were analysed in order to determine the cut-off for interpretation of results. Serum samples from 62 out of 81 patients who delivered either the first or the second sample were found positive for specific antibodies against Yersinia enterocolitica O:3 LPS (77%). For samples collected within 60 days after onset of symptoms (n = 48) sensitivities of 58%, 42% and 79% for IgA, IgG and IgM antibodies were found. A sensitivity of 81% was found for these samples when using the definition of a positive result in either IgA, IgG or IgM as a combined positive. All samples received up to 36 days after onset of symptoms (n = 10) were found to be positive using this definition. For the period 61 to 90 days after onset of symptoms (n = 32), a combined sensitivity of 63% was found. The antibody levels as well as decay profiles for the three different immunoglobulin classes for the individual patients exhibited a large degree of variation. CONCLUSIONS: Using a definition of positive as a positive result for either IgA, IgG or IgM antibodies, a diagnostic sensitivity of 81% was achieved for samples received within 60 days after onset of symptoms. In particular, the levels of specific IgM antibodies were elevated. In comparison, the standard tube-agglutination assay achieved a sensitivity of 60% on the same samples. The sensitivity of the ELISA decreased the longer the duration of time since onset of symptoms. The ELISA was highly specific for Yersinia when testing sera from individuals with confirmed gastrointestinal infections by other bacteria. Moreover, the knowledge gained from this longitudinal study of antibody decay profiles can be used in future epidemiological studies of seroprevalence.

The role of Campylobacter jejuni cytolethal distending toxin in gastroenteritis: toxin detection, antibody production, and clinical outcome.

The role of Campylobacter jejuni cytolethal distending toxin (CDT) on clinical outcome after gastroenteritis was investigated. Clinical data, blood serum samples, and Campylobacter spp. isolated, from each of 30 patients were collected over a period of 6 months. The CDT encoding genes, cdtABC, characterized by PCR, revealed that all but one of the C. jejuni strains had the wild-type sequence. Sequencing of cdtABC from this strain showed two major deletions. From all of the strains, CDT titers were determined, and toxin neutralizing antibodies were documented using an in vitro assay. Three of the thirty clinical isolates, including the one with the mutant cdtABC coding genes, did not have a detectable CDT activity. Analyzing the relationship between CDT titer, serum neutralization of CDT, and the clinical outcome showed that campylobacteriosis caused by CDT-negative strains was clinically indistinguishable from that of patients infected with an isolate that produced high levels of CDT. These results suggest that CDT does not solely determine severity of infection and clinical outcome.

Determination of new cutoff values for indirect immunofluorescence antibody test for Q fever diagnosis in Denmark.

Q fever is a ubiquitous zoonosis caused by Coxiella burnetii. The disease is emerging in many parts of the world, likely because of increased awareness and availability of better diagnostics. The diagnosis is primarily based on serology. Because the prevalence of the disease varies worldwide, the establishment of local cutoff values is needed. A baseline for antibodies against C. burnetii in Denmark was defined by testing sera from healthy Danish volunteers using a commercially available immunofluorescence antibody test. Cross-reactivity was studied on sera obtained from patients experiencing clinically related diseases. The cutoff titers suggested by the manufacturer were found to result in very low specificity of the test. The specificity was, however, effectively increased by using cutoff titers based on the local baseline and equal to immunoglobulin M (IgM) phase I > or =128, IgM phase II > or =256, IgG phase I > or =512, and IgG phase II > or =1024.

Sialylation of Campylobacter jejuni lipo-oligosaccharides is associated with severe gastro-enteritis and reactive arthritis.

We used various genotyping methods to identify bacterial genetic markers for development of arthritic symptoms following Campylobacter enteritis. We genotyped a collection of population derived Campylobacter strains, with detailed information on clinical characteristics, including arthritic symptoms. Besides using whole genome screening methods, we focused on the lipo-oligosaccharide (LOS) gene locus in which marker genes for developing post-Campylobacter neurological disease are present. Patients with arthritic symptoms were more frequently infected with Campylobacter jejuni strains with a class A LOS locus. We also found that patients who were infected with a C. jejuni strain containing sialic acid-positive LOS (class A, B or C) more frequently had bloody diarrhoea and a longer duration of symptoms. Furthermore, the IgM antibody response against Campylobacter was stronger in patients with a sialic acid containing LOS. Ganglioside auto-antibodies were observed in a small number of patients following infection with a class C strain. We conclude that sialylation of C. jejuni LOS is not only a risk factor for development of post-infectious symptoms, but is also associated with increased severity of enteric disease.

Listeria monocytogenes: maternal-foetal infections in Denmark 1994-2005.

Maternal-foetal infection by Listeria monocytogenes is a rare complication in pregnancy. In the period 1994-2005, 37 culture-confirmed cases of maternal-foetal Listeria monocytogenes infections were reported in Denmark. We examined 36 patients' files in order to evaluate risk factors, clinical and laboratory findings, response to therapy, and outcome for maternal-foetal listeriosis. Patient data and bacteriological findings were divided into 2 groups for comparison: 1 group with children born alive (n=24) and another group with abortion or stillbirth (n=12). 23 of the 36 children survived the acute infection, as did all the mothers. The mothers were generally only mildly affected by the infection. In contrast, among the children born alive, 15 were diagnosed with bacteraemia/septicaemia, 3 children with pneumonia, 3 with neonatal meningitis, and 3 were unaffected. Despite the high frequency of illness only 1 of the live-born children died from the infection and none of the surviving children showed signs of permanent damage at the time they were discharged from hospital. Listeriosis during pregnancy is a serious threat to the unborn child. One-third of culture-confirmed cases of maternal-foetal infections resulted in abortion or stillbirth; however, the prognosis for live-born children is good, even in severely ill newborns.

A comparison of self-reported joint symptoms following infection with different enteric pathogens: effect of HLA-B27.

OBJECTIVE: We conducted a case-case comparison study to estimate the attack-rate of reactive joint pain (JPrea) following intestinal infections, and evaluated whether the susceptibility and severity of joint symptoms was associated with the tissue-type HLA-B27. METHODS: Consecutive patients with positive fecal culture for Salmonella, Campylobacter, Yersinia, Shigella, and E. coli were addressed by questionnaires inquiring about gastrointestinal (GI) symptoms and the occurrence of joint pain in a previously healthy joint within 4 weeks after onset of infection. A blood sample was requested for HLA-B27 typing. RESULTS: Of 3146 patients invited, 2105 (67%) responded to the survey questionnaire. The triggering infections were Campylobacter, 1003; Salmonella, 619; E. coli, 290; Shigella, 102; and Yersinia, 91. JPrea was reported by 294 subjects: Campylobacter, 131 (13.1%); Salmonella, 104 (16.8%); Yersinia, 21 (23.1%); Shigella, 10 (9.8%); and E. coli, 28 (9.7%). There was a significant association between severity of gastroenteritis and development of arthralgia (p = 0.001). The odds ratio (OR) for JPrea in an HLA-B27-positive individual was 2.62 (95% CI 1.67-3.93) for the entire group. A significant association between JPrea and HLA-B27 was found for Salmonella, Shigella, and Yersinia; not, however, for Campylobacter and E. coli. HLA-B27-positive patients had a significantly increased risk for severe joint symptoms. CONCLUSION: Our study shows that JPrea after GI infection is positively correlated to severity of GI symptoms. HLA-B27 is not associated with joint pain after Campylobacter. Intestinal E. coli seems to be an arthritogenic pathogen. A significant association between HLA-B27 and severity of joint pain was observed.

No serological evidence for rickettsial diseases among Danish elite orienteerers.

A series of sudden unexpected cardiac deaths among Swedish elite orienteerers in the 1980s have resulted from the combination of infectious diseases and physical exercise. Studies in the late 1990s have pointed to Chlamydia and Barontella, which both had a high seroprevalence among Swedish elite orienteerers. We conducted a case-control study aimed to elucidate the serologic prevalence of rickettsial diseases among Danish elite orienteerers. Ticks are known as vectors for some rickettsial diseases. None of the orienteerers had a positive antibody titer against any of the tested Rickettsia despite a very high frequency of tick bites in this group.

[Salmonella infections acquired from exotic pets]. / Salmonella-infektioner erhvervet fra eksotiske kaeledyr.

The majority of non-typhoidal Salmonella infections are foodborne, with undercooked eggs, chicken and red meat being the most important sources. Transmission from exotic pets, reptiles in particular, may account for 3-5% of human Salmonella cases. We describe a case of S. Saintpaul infection in an eight-month-old infant. A food source was unlikely because the infant was fed from a percutaneous endoscopic gastrostomy tube and the food tested negative for Salmonella. The family kept pet turtles, and S. Saintpaul with indistinguishable pulsed field gel electrophoresis patterns was isolated from the turtle water. The infant's older sister, who had contact with the turtles, had had gastroenteritis and may have served as the vehicle of transmission.

Risk factors for diarrhea among children in an industrialized country.

BACKGROUND: Risk factors for childhood diarrhea in industrialized countries are not well characterized, although diarrhea remains an important cause of morbidity. METHODS: We conducted a case-control study of 422 cases and 866 controls over 22 months in Denmark. We selected cases among children under 5 years of age with diarrhea. Age-matched healthy controls were selected from the background population using a population register. Parents were interviewed about possible exposures and underlying conditions. In addition, stool samples from both cases and controls were analyzed for viruses, parasites, and bacteria. We analyzed risk factors for diarrhea in general and for diarrhea of a viral, bacterial, or "unknown" etiology using logistic regression. RESULTS: The following factors were independently associated with an increased risk of diarrhea: recent foreign travel, contact with symptomatic persons (particularly in daycare centers), hospitalization, contact with a dog with diarrhea, private daycare, consumption of products containing formula milk, unemployment and low educational status of parents, and prior diagnosis of several types of atopic diseases. In a pathogenic-specific analysis of diarrhea of bacterial (73 patients), viral (88), or "unknown" (222) etiology, the major risk factor for viral diarrhea was contact with symptomatic persons. For bacterial diarrhea, foreign travel and socioeconomic factors were the main risk factors. CONCLUSIONS: Viral diarrhea appears to be transmitted predominantly from person to person, whereas bacterial diarrhea appears to be primarily foodborne. A substantial portion of the diarrheal episodes may be of noninfectious etiology. Limiting child-to-child transmission of disease in daycare centers may substantially reduce the disease burden.

Etiology of diarrhea in young children in Denmark: a case-control study.

Infectious gastroenteritis is one of the most common diseases in young children. To clarify the infectious etiology of diarrhea in Danish children less than 5 years of age, we conducted a 2-year prospective case-control study. Stools from 424 children with diarrhea and 870 asymptomatic age-matched controls were examined, and their parents were interviewed concerning symptoms. Rotavirus, adenovirus, and astrovirus were detected by enzyme-linked immunosorbent assay, and norovirus and sapovirus were detected by PCR. Salmonella, thermotolerant Campylobacter, Yersinia, Shigella, and Vibrio spp. were detected by standard methods. Shiga toxin-producing (STEC), attaching-and-effacing (A/EEC), enteropathogenic (EPEC), enterotoxigenic, enteroinvasive, and enteroaggregative Escherichia coli were detected by using colony hybridization with virulence gene probes and serotyping. Parasites were detected by microscopy. Overall, a potential pathogen was found in 54% of cases. More cases than controls were infected with rotavirus, Salmonella, norovirus, adenovirus, Campylobacter, sapovirus, STEC, classical EPEC, Yersinia, and Cryptosporidium strains, whereas A/EEC, although common, was not associated with illness. The single most important cause of diarrhea was rotavirus, which points toward the need for a childhood vaccine for this pathogen, but norovirus, adenovirus, and sapovirus were also major etiologies. Salmonella sp. was the most common bacterial pathogen, followed by Campylobacter, STEC, Yersinia, and classical EPEC strains. A/EEC not belonging to the classical EPEC serotypes was not associated with diarrhea, underscoring the importance of serotyping for the definition of EPEC.

Antimicrobial treatment of asymptomatic carriers of verocytotoxin-producing Escherichia coli: an empiric study.

Antimicrobial treatment of acute infection caused by verocytotoxin toxin-producing Escherichia coli (VTEC) is controversial due to risk of inducing haemolytic uraemic syndrome. We review the treatment of 9 persons who experienced serious social problems due to prolonged, asymptomatic carriage of non-O157 VTEC. Eradication of VTEC was successful and without complications.

Low seroprevalence of bartonella species in danish elite orienteers.

In the 1990s, studies were conducted to investigate 16 episodes of sudden unexpected cardiac death (SUCD) among Swedish elite orienteers during the period from 1979 to 1992. A case control study revealed that a significantly higher proportion of Swedish elite orienteers were B. elizabethae seropositive compared to controls. The aim of our study, designed as a case-control study, was to determine whether similarly high rates of B. elizabethae seropositivity were present among Danish elite orienteers. Cases were 43 elite orienteers; controls were 159 blood donors and 63 elite indoor sportsmen. All participants were tested for antibodies against B. henselae, B. quintana and B. elizabethae using immunofluorescent antibody tests. Surprisingly, Bartonella antibodies were only detected in sera from 5 persons: B. henselae from 1 elite orienteer, 1 handball player and 1 blood donor. B. elizabethae antibodies were detected in 1 handball player and 1 basketball player. We found no association between elite orienteers and the prevalence of Bartonella antibody positivity. This is in contrast to the Swedish study, and might be explained by the use of different serological methods in the 2 studies; to determine whether it is a true difference, a new study is needed.

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 the O group, the combined presence of the eae and stx2 genes is an important predictor of HUS.

Bartonella henselae causing severe and protracted illness in an otherwise healthy person.

Bartonella henselae is an emerging pathogen capable of causing severe disease. We report a case of severe protracted illness in an otherwise healthy police dog handler. The patient recovered slowly after antibiotic treatment. This case report emphasizes the importance of considering B. henselae infections in patients with fever of unknown origin.