Serology in chronic Q fever is still surrounded by question marks.

Detection of antibodies using immunofluoresence tests (IFAT) is recommended for diagnosis of chronic Q fever, but other commercial antibody assays are also available. We compared an enzyme-linked immunosorbent assay (ELISA) (Virion/Serion) and a complement fixation test (CFT) (Virion/Serion) for the detection of Coxiella burnetii IgG phase I and IgA phase I in early- and follow-up serum samples from patients with chronic Q fever, diagnosed according to an algorithm that involves IFAT. For this, we tested sera of 49 patients, including 30 proven, 14 probable and five possible chronic Q fever cases. Sensitivity of CFT for diagnosis of chronic Q fever was suboptimal (85 %), as eight patients, including five with chronic Q fever, tested negative at time of diagnosis, whereas IgG phase I antibodies were detected in these five patients by ELISA. Sensitivity of ELISA was higher, although three probable patients were missed. No differences in ELISA IgA phase I detection between proven chronic Q fever and probable were observed; instead possible patients were in majority IgA negative (60 %). Serological examination using ELISA and CFT in follow-up sera from 26 patients on treatment was unsatisfactory. Like IFAT, all kinetic options were possible: decreasing, remaining stable or even increase during time. This study demonstrated that the sensitivity of CFT-based phase I antibody detection is low and therefore not recommended for diagnosis of chronic Q fever. Based on our results, serological follow-up to guide treatment decisions was of limited value.

Evaluation of commonly used serological tests for detection of Coxiella burnetii antibodies in well-defined acute and follow-up sera.

In this study, we compared Coxiella burnetii IgG phase I, IgG phase II, and IgM phase II detection among a commercially available enzyme-linked immunosorbent assay (ELISA) (Virion/Serion), an indirect fluorescent antibody test (IFAT) (Focus Diagnostics), and a complement fixation test (CFT) (Virion/Serion). For this, we used a unique collection of acute- and convalescent-phase sera from 126 patients with acute Q fever diagnosed by positive Coxiella burnetii PCR of blood. We were able to establish a reliable date of onset of disease, since DNA is detectable within 2 weeks after the start of symptoms. In acute samples, at t = 0, IFAT demonstrated IgM phase II antibodies in significantly more sera than did ELISA (31.8% versus 19.7%), although the portion of solitary IgM phase II was equal for IFAT and for ELISA (18.2% and 16.7%, respectively). Twelve months after the diagnosis of acute Q fever, 83.5% and 62.2% of the sera were still positive for IgM phase II with IFAT and ELISA, respectively. At 12 months IFAT IgG phase II showed the slowest decline. Therefore, definitive serological evidence of acute Q fever cannot be based on a single serum sample in areas of epidemicity and should involve measurement of both IgM and IgG antibodies in paired serum. Based on IgG phase II antibody detection in paired samples (at 0 and 3 months) from 62 patients, IFAT confirmed more cases than ELISA and CFT, but the differences were not statically significant (100% for IFAT, 95.2% for ELISA, and 96.8% for CFT). This study demonstrated that the three serological tests are equally effective in diagnosing acute Q fever within 3 months of start of symptoms. In follow-up sera, more IgG antibodies were detected by IFAT than by ELISA or CFT, making IFAT more suitable for prevaccination screening programs.

Vascular complications of Q-fever infections.

INTRODUCTION: Coxiella burnetii is a strict intracellular pathogen causing Q fever, a worldwide zoonosis with an extensive animal reservoir. Chronic Q fever infections are frequently associated with cardiovascular complications, mainly endocarditis, and also aortic aneurysms and vascular-graft infection. We present four cases of chronic Q fever infections and associated vascular complications, and review the literature to identify major symptoms and assess the prevalence, treatment and outcome in these challenging patients. MATERIALS AND METHODS: The demographic and clinical data of four patients presenting at our unit were analysed. PubMed was searched to identify articles describing patients with chronic Q-fever-associated vascular complications. RESULTS: Combining our own with the published experience, 58 cases (49 male) of chronic Q-fever-associated vascular complications were identified. The average age of the patients was 64 years (range: 30-83 years). As many as 26 patients had vascular graft infections (25 Dacron/polytetrafluoroethylene (PTFE), one homograft) and 32 had infected aneurysms. The majority of these patients presented with fever (n = 40) and/or pain (n = 43). Weight loss and fatigue were seen in 25 and 14 patients, respectively. Aneurysm rupture, aorto-enteric fistulae and lower-limb embolisation were seen in nine, four and four patients, respectively. Concurrent endocarditis was seen in two patients, whereas, for 15 cases, this information was not available. Patients were treated with antibiotics for an average of 23 months (range 1-54 months). Treatment of infected vascular segments was described in 50 patients. Ten patients were treated conservatively whilst 40 underwent resection of the infected vessel and reconstruction with a graft. Major surgical complications (graft infection, n = 3;aorto-enteric fistula, n = 2; bleeding, n = 1; anastomotic leakage, n = 1; aortic dissection, n = 1; vertebral osteomyelitis, n = 3; graft thrombosis, n = 1; renal failure, n = 2; and pneumonia, n = 1) were reported in 11 cases (21%) and were not specified in 13. The overall mortality was 24% (14/58). Seven (18%) surgically treated patients died. Six of them died within 6 months of surgery and one patient at 3 years' follow-up. Seven out of 10 of the conservatively treated patients died within 3 years of diagnosis. CONCLUSION: Aneurysms associated with Q-fever infections tend to be complicated, requiring challenging surgical corrections, and long-term antibiotic treatment. Major complications and mortality rates are significant, especially in conservatively treated patients.

[Successful culture of Chlamydia pneumoniae in 2 asymptomatic patients]. / Succesvolle kweek van Chlamydia pneumoniae bij twee asymptomatische patiënten.

In two women, partners of 41 and 36 years old, positive cultures of Chlamydia pneumoniae were repeatedly obtained from the throat. Both individuals were asymptomatic during the period described. Eradication was not achieved despite treatment with doxycycline. C. pneumoniae on the basis of serological data is considered a common cause of respiratory tract infections. However, this micro-organism has only been isolated in the Netherlands once. Carrier status has been described in the literature, although its frequency is unknown.