Q fever endocarditis in Israel and a worldwide review

Insights from genomic analysis of a novel Coxiella burnetii strain isolated in Israel

The diagnosis of Q fever is challenging due to nonspecific symptoms and negative standard blood culture results. Serological testing through immunofluorescence assay (IFA) is the most commonly used method for diagnosing this disease. Polymerase chain reaction (PCR) tests can also be used to detect bacterial DNA if taken at an appropriate time. Once the presence of bacteria is confirmed in a sample, an enrichment step is required before characterizing it through sequencing. Cultivating C. burnetii is challenging as it can only be isolated by inoculation into cell culture, embryonated eggs, or animals. In this article, we describe the isolation of C. burnetii from a valve specimen in Vero cells. We conducted genome sequencing and taxonomy profiling of this isolate and were able to determine its taxonomic affiliation. Furthermore, Multispacer sequence typing (MST) analysis suggests that the infection originated from a local strain of C. burnetii found around northern Israel and Lebanon. This novel strain belongs to a previously described genotype MST6, harboring the QpRS plasmid, never reported in Israel.

The Prognostic Value of Serology in Persistent Q Fever Infection

Background: Q fever has significant consequences for patients with persistent localized infection. A combination of doxycycline with hydroxychloroquine, for at least 18-24 months, is the first-line therapy. The use of serology as a prognostic marker during therapy is controversial. Methods: A retrospective, observational cohort study in two outpatient clinics in northern Israel. All adults with persistent Q fever (2015-2021) were included in the study. Clinical failure was defined as relapse or death related to Q fever after end of treatment (EOT). Serological cure was defined as phase 1 IgG ≤800 or a four-fold decrease at EOT. Results: Twenty-two patients were included in the study, with a median follow up of 40 months (IQR = 28.5-63.5), and median treatment duration of 28.5 months (IQR = 21.8-50.5). Clinical cure occurred in 18 patients (82%), serological cure in 10 (45%). Phase 1 IgG at presentation was significantly higher in the clinical failure group (median 9600 vs. 3200 in the clinical cure group, p = 0.019), and at 6-12 months after EOT (median 6400 vs. 800 respectively, p = 0.03). Phase 1 IgG levels at 1 year and EOT were similar in both groups. Positive phase 2 IgM after one year of therapy correlated with clinical failure (p = 0.038), but not at EOT or after EOT. Conclusion: Phase 1 IgG levels at presentation, phase 2 IgM at 1 year, and Phase 1 IgG 6-12 months after EOT were associated with clinical failure in patients with persistent Q fever.

Cross-Sectional Study of Q Fever Seroprevalence among Blood Donors, Israel, 2021

We evaluated Q fever prevalence in blood donors and assessed the epidemiologic features of the disease in Israel in 2021. We tested serum samples for Coxeilla burnetii phase I and II IgG using immunofluorescent assay, defining a result of >200 as seropositive. We compared geographic and demographic data. We included 1,473 participants; 188 (12.7%) were seropositive. The calculated sex- and age-adjusted national seroprevalence was 13.9% (95% CI 12.2%-15.7%). Male sex and age were independently associated with seropositivity (odds ratio [OR] 1.6, 95% CI 1.1-2.2; p = 0.005 for male sex; OR 1.2, 95% CI 1.01-1.03; p<0.001 for age). Residence in the coastal plain was independently associated with seropositivity for Q fever (OR 1.6, 95% CI 1.2-2.3; p<0.001); residence in rural and farming regions was not. Q fever is highly prevalent in Israel. The unexpected spatial distribution in the nonrural coastal plain suggests an unrecognized mode of transmission.

Coxiella burnetii in Dromedary Camels (Camelus dromedarius): A Possible Threat for Humans and Livestock in North Africa and the Near and Middle East?

The "One Health" concept recognizes that human health is connected to animal health and to the ecosystems. Coxiella burnetii-induced human Q fever is one of the most widespread neglected zoonosis. The main animal reservoirs responsible for C. burnetii transmission to humans are domesticated ruminants, primarily goats, sheep, and cattle. Although studies are still too sparse to draw definitive conclusions, the most recent C. burnetii serosurvey studies conducted in herds and farms in Africa, North Africa, Arabian Peninsula, and Asia highlighted that seroprevalence was strikingly higher in dromedary camels (Camelus dromedarius) than in other ruminants. The C. burnetii seroprevalence in camel herds can reach more than 60% in Egypt, Saudi Arabia, and Sudan, and 70 to 80% in Algeria and Chad, respectively. The highest seroprevalence was in female camels with a previous history of abortion. Moreover, C. burnetii infection was reported in ticks of the Hyalomma dromedarii and Hyalomma impeltatum species collected on camels. Even if dromedary camels represent <3% of the domesticated ruminants in the countries of the Mediterranean basin Southern coast, these animals play a major socioeconomic role for millions of people who live in the arid zones of Africa, Middle East, and Asia. In Chad and Somalia, camels account for about 7 and 21% of domesticated ruminants, respectively. To meet the growing consumers demand of camel meat and milk (>5 million tons/year of both raw and pasteurized milk according to the Food and Agriculture Organization) sustained by a rapid increase of population (growth rate: 2.26-3.76 per year in North Africa), dromedary camel breeding tends to increase from the Maghreb to the Arabic countries. Because of possible long-term persistence of C. burnetii in camel hump adipocytes, this pathogen could represent a threat for herds and breeding farms and ultimately for public health. Because this review highlights a hyperendemia of C. burnetii in dromedary camels, a proper screening of herds and breeding farms for C. burnetii is urgently needed in countries where camel breeding is on the rise. Moreover, the risk of C. burnetii transmission from camel to human should be further evaluated.

New insights in Coxiella burnetii infection: diagnosis and therapeutic update

Introduction: Coxiella burnetii infection is still challenging physicians, mainly because no international coordination has been stated to standardize the therapeutic strategy and improve the clinical outcomes.Areas covered: Based on the recent knowledge on Q fever, we review here the clinical practices from Q fever diagnosis to therapy. We searched PubMed and Google Scholar to perform the qualitative synthesis.Expert opinion: Four major critical points are highlighted in this review. The first point is that Q fever diagnosis has been reviewed in the light of the new diagnosis tools, including molecular biology, transthoracic echocardiography, and 18F-FDG-PET/CT-scan imaging. Q fever diagnosis results from the presence of a microbiological criterion in addition to a lesional criterion. Second, the identification of the anticardiolipin antibodies as a novel biological predictive marker for acute Q fever complications (hemophagocytic syndrome, acute Q fever endocarditis, alithiasic cholecystitis, hepatitis, and meningitis). Third, the observation of a coincidence between Q fever and non-Hodgkin lymphoma that has made persistent C. burnetii infection a risk of non-Hodgkin lymphoma. Finally, we expose here the close follow-up we proposed from the French National Reference Center for patients with Q fever infection to detect relapse and complications.

Screening for Q Fever during Other Bacterial Endocarditis in Endemic Areas: Our Experience with Three Patients

Endocarditis is not a usual manifestation of acute Q fever. There is an ongoing debate about the need to screen patients for valvular diseases after acute Q fever. We present, for the first time, three patients with bacterial endocarditis from different aetiologies and a simultaneous diagnosis of acute Q fever. All were treated with prolonged antimicrobial treatment, and none of them developed a persistent Q infection. We suggest screening patients with endocarditis from other aetiologies to Q fever.

Chronic Q fever-related complications and mortality: data from a nationwide cohort

OBJECTIVES

Chronic infection with Coxiella burnetii (chronic Q fever) can cause life-threatening conditions such as endocarditis, infected vascular prostheses, and infected arterial aneurysms. We aimed to assess prognosis of chronic Q fever patients in terms of complications and mortality.

METHODS

A large cohort of chronic Q fever patients was assessed to describe complications, overall mortality and chronic Q fever-related mortality. Chronic Q fever-related mortality was expressed as a case fatality rate (number of chronic Q fever-related deaths/number of chronic Q fever patients).

RESULTS

Complications occurred in 166 of 439 (38%) chronic Q fever patients: in 61% of proven (153/249), 15% of probable (11/74), and 2% of possible chronic Q fever patients (2/116). Most frequently observed complications were acute aneurysms (14%), heart failure (13%), and non-cardiac abscesses (10%). Overall mortality was 38% (94/249) for proven chronic Q fever patients (median follow-up 3.6 years) and 22% (16/74) for probable chronic Q fever patients (median follow-up 4.7 years). The case fatality rate was 25% for proven (63/249) chronic Q fever patients and 4% for probable (3/74) chronic Q fever patients. Overall survival was significantly lower in patients with complications, compared to those without complications (p <0.001).

CONCLUSIONS

In chronic Q fever patients, complications occur frequently and contribute to the mortality rate. Patients with proven chronic Q fever have the highest risk of complications and chronic Q fever-related mortality. Prognosis for patients with possible chronic Q fever is favourable in terms of complications and mortality.

Endocarditis in the Mediterranean Basin

Infective endocarditis is a severe disease with high mortality. Despite a global trend towards an increase in staphylococcal aetiologies, in older patients and a decrease in viridans streptococci, we have observed in recent studies great epidemiologic disparities between countries. In order to evaluate these differences among Mediterranean countries, we performed a PubMed search of infective endocarditis case series for each country. Data were available for 13 of the 18 Mediterranean countries. Despite great differences in diagnostic strategies, we could classify countries into three groups. In northern countries, patients are older (>50 years old), have a high rate of prosthetic valves or cardiac electronic implantable devices and the main causative agent is Staphylococcus aureus. In southern countries, patients are younger (<40 years old), rheumatic heart disease remains a major risk factor (45–93%), viridans streptococci are the main pathogens, zoonotic and arthropod-borne agents are frequent and blood culture–negative endocarditis remains highly prevalent. Eastern Mediterranean countries exhibit an intermediate situation: patients are 45 to 60 years old, the incidence of rheumatic heart disease ranges from 8% to 66%, viridans streptococci play a predominant role and zoonotic and arthropod-borne diseases, in particular brucellosis, are identified in up to 12% of cases.

Q Fever: an old but still a poorly understood disease

Q fever is a bacterial infection affecting mainly the lungs, liver, and heart. It is found around the world and is caused by the bacteria Coxiella burnetii. The bacteria affects sheep, goats, cattle, dogs, cats, birds, rodents, and ticks. Infected animals shed this bacteria in birth products, feces, milk, and urine. Humans usually get Q fever by breathing in contaminated droplets released by infected animals and drinking raw milk. People at highest risk for this infection are farmers, laboratory workers, sheep and dairy workers, and veterinarians. Chronic Q fever develops in people who have been infected for more than 6 months. It usually takes about 20 days after exposure to the bacteria for symptoms to occur. Most cases are mild, yet some severe cases have been reported. Symptoms of acute Q fever may include: chest pain with breathing, cough, fever, headache, jaundice, muscle pains, and shortness of breath. Symptoms of chronic Q fever may include chills, fatigue, night sweats, prolonged fever, and shortness of breath. Q fever is diagnosed with a blood antibody test. The main treatment for the disease is with antibiotics. For acute Q fever, doxycycline is recommended. For chronic Q fever, a combination of doxycycline and hydroxychloroquine is often used long term. Complications are cirrhosis, hepatitis, encephalitis, endocarditis, pericarditis, myocarditis, interstitial pulmonary fibrosis, meningitis, and pneumonia. People at risk should always: carefully dispose of animal products that may be infected, disinfect any contaminated areas, and thoroughly wash their hands. Pasteurizing milk can also help prevent Q fever.

Q Fever endocarditis: does serology predict outcome?

Q fever is an ubiquitous zoonosis caused by Coxiella burneti, an intracellular bacterium that can produce acute or chronic infections in humans. These forms are characterized by different evolution, serological profile and treatment that must be very long to achieve a cure in chronic forms. However, the serological profile for diagnosis and the real value of serology for predicting outcome are controversial, and management dilemmas for many patients with Q fever infection are continuously emerging. In this article, we describe in a comprehensive manner the different clinical presentations of the disease, making a critical overview of the evidence for serological predictions. We also take a broad view of new available diagnostic techniques and finally, we give recommendations for treatment.

Guidelines for the diagnosis and antibiotic treatment of endocarditis in adults: a report of the Working Party of the British Society for Antimicrobial Chemotherapy

The BSAC guidelines on treatment of infectious endocarditis (IE) were last published in 2004. The guidelines presented here have been updated and extended to reflect developments in diagnostics, new trial data and the availability of new antibiotics. The aim of these guidelines, which cover both native valve and prosthetic valve endocarditis, is to standardize the initial investigation and treatment of IE. An extensive review of the literature using a number of different search criteria has been carried out and cited publications used to support any changes we have made to the existing guidelines. Publications referring to in vitro or animal models have only been cited if appropriate clinical data are not available. Randomized, controlled trials suitable for the development of evidenced-based guidelines in this area are still lacking and therefore a consensus approach has again been adopted for most recommendations; however, we have attempted to grade the evidence, where possible. The guidelines have also been extended by the inclusion of sections on clinical diagnosis, echocardiography and surgery.

Q Fever Presenting As Recurrent, Culture-negative Endocarditis with Aortic Prosthetic Valve Failure: A Case Report and Review of the Literature

The present report describes a case of recurrent, culture-negative endocarditis presenting with aortic prosthetic valve dysfunction in a 62-year-old man who required four valve replacement surgeries. On each occasion, he presented with valve failure. Fever was only documented during his first presentation. Furthermore, no vegetations were detectable on his aortic valve at transesophageal echocardiography. On the occasion of his most recent presentation, a detailed history of animal exposure - including hunting and skinning deer, moose and other large animals with his bare hands - was the only clue to his diagnosis. Serum antibodies against Coxiella burnetii were strongly positive, and C burnetii DNA was detected by polymerase chain reaction from his resected aortic valve tissue. Q fever is a worldwide zoonotic infection with diverse reservoirs. This diagnosis should be considered when evaluating unexplained prosthetic valve dysfunction, particularly in the setting of animal exposure.

Q fever: clinical manifestations and treatment

Public awareness and advances in the diagnostic approach to Q fever have provided important information on epidemiological and clinical aspects of this zoonosis. Coxiella burnetii infection exhibits various acute or chronic clinical forms, and infection during pregnancy may jeopardize the integrity of the fetus. The presentation of infection is often nonspecific and this hinders prompt diagnosis. Therapeutic regimens vary, and treating Q fever during pregnancy and childhood is often challenging. Increasing clinical experience with C. burnetii infections has helped create treatment protocols and follow-up algorithms that have considerably improved management and prognosis. Vaccines are available, although their use is still limited.

Long-term outcome of Q fever endocarditis: a 26-year personal survey

BACKGROUND

Q fever endocarditis caused by Coxiella burnetii is a potentially fatal disease characterised by a chronic evolution. To assess the long-term outcome and identify prognostic factors for mortality, surgical treatment, and serological changes in Q fever endocarditis, we did a retrospective study in the French National Referral Centre.

METHODS

Patients included were diagnosed with Q fever endocarditis at our centre from May, 1983, to June, 2006, and followed up for a minimum of 3 years for each patient, history and clinical characteristics were recorded with a standardised questionnaire. Prognostic factors associated with death, surgery, serological cure, and serological relapse were assessed by Cox regression analysis. Excised heart valve analysis was assessed according to duration of treatment.

FINDINGS

104 patients were identified for inclusion in the study, although one was lost to follow-up; median follow-up was 100 months (range 37-310 months). 18 months of treatment was sufficient to sterilise the valves of all the patients except three, and 2 years of treatment sterilised all valves except one. In a multivariate Cox regression analysis, the major determinants associated with mortality were age (hazard ratio 1.11, 95% CI 1.05-1.18, p=0.003), stroke at diagnosis (7.09, 2.00-25.10, p=0.001), endocarditis on a prosthetic valve (6.04, 1.47-24.80, p=0.044), an absence of a four-times decrease of phase I IgG and IgA at 1 year (5.69, 1.00-32.22, p=0.049), or the presence of phase II IgM at 1 year (12.08, 3.11-46.85, p=0.005). Surgery was associated with heart failure (2.68, 1.21-5.94, p=0.015) or a cardiac abscess (4.71, 1.64-13.50, p=0.004). The determinants of poor serological outcome were male sex (0.47, 0.26-0.86, p=0.014), a high level of phase I IgG (0.65, 0.45-0.95, p=0.027), and a delay in the start of treatment with hydroxychloroquine (0.20, 0.04-0.91, p=0.037). Factors associated with relapse were endocarditis on a prosthetic valve (21.3, 2.05-221.86, p=0.01) or treatment duration less than 18 months (9.69, 1.08-86.72, p=0.042).

INTERPRETATION

The optimum duration of treatment with doxycycline and hydroxychloroquine in Q fever endocarditis is 18 months for native valves and 24 months for prosthetic valves. This duration should be extended only in the absence of favourable serological outcomes. Patients should be serologically monitored for at least 5 years because of the risk of relapse.

FUNDING

French National Referral Centre for Q Fever.

Prophylaxis after exposure to Coxiella burnetii

Postexposure prophylaxis may avert Q fever illness and death when the probability of exposure is above the population-specific threshold point.

Coxiella burnetii is a category B bioterrorism agent. We numerically evaluated the risks and benefits from postexposure prophylaxis (PEP) after an intentional release of C. burnetii to the general population, pregnant women, and other high-risk populations. For each group, we constructed a decision tree to estimate illness and deaths averted by use of PEP/100,000 population. We calculated the threshold points at which the number of PEP-related adverse events was equal to the cases averted. PEP was defined as doxycycline (100 mg 2×/day for 5 days), except for pregnant women, where we assumed a PEP of trimethoprim-sulfamethoxazole (160 mg/800 mg 2×/day) for the duration of the pregnancy. PEP would begin 8–12 days postexposure. On the basis of upper-bound probability estimates of PEP-related adverse events for doxycycline, we concluded that the risk for Q fever illness outweighs the risk for antimicrobial drug–related adverse events when the probability of C. burnetii exposure is >7% (pregnant women using trimethoprim-sulfamethoxazole = 16%).

An economic evaluation of increased uptake in Q fever vaccination among meat and agricultural industry workers following implementation of the National Q Fever Management Program

INTRODUCTION

Q fever is a serious but vaccine-preventable infectious disease that predominantly affects those working in the meat and agricultural industries. In October 2000, the Commonwealth Government introduced the National Q Fever Management Program. This economic evaluation assesses the cost-effectiveness and cost-utility of improved vaccine uptake among meat and agricultural industry workers.

METHODS

Separate analyses were conducted for meat and agricultural industry workers. Clinical and epidemiological data used to create the models were obtained from published sources. Markov modelling was used to estimate the impact of Q fever vaccination uptake on the direct costs and outcomes of Q fever over a 20-year period.

RESULTS

Increasing vaccine uptake from 65% to 100% among meat industry workers results in an incremental cost per life year gained of $20,002, and a cost per QALY of $6,294. Increasing vaccine uptake from zero to 20% among agricultural industry workers results in an incremental cost per life year gained of $24,950, and a cost per QALY of $7,984. Including some indirect costs in the form of Workcover payments results in cost savings for both industry groups.

CONCLUSION

The results of this evaluation indicate that public health strategies to enhance the uptake of Q fever vaccine among high-risk workers potentially provides excellent value for the money invested.

Point: antibiotic therapy is not the answer for patients with persisting symptoms attributable to lyme disease

It is not well understood why some patients develop a subjective syndrome that includes considerable fatigue, musculoskeletal aches, and neurocognitive dysfunction after receiving standard antibiotic courses for the treatment of Lyme disease. Some practitioners use the term "chronic Lyme disease" and order prolonged courses of oral and parenteral antibiotics, believing that persistent infection with Borrelia burgdorferi is responsible. However, well-performed prospective studies have found neither evidence of chronic infection nor a benefit worthy of long-term antibiotic therapy for these patients. Such extended antibiotic therapy poses hazards and cannot be viewed as acceptable. The term "chronic Lyme disease" should be discarded as misleading; rather, the term "post-Lyme disease syndrome" better reflects the postinfectious nature of this condition. Further research is necessary to understand possible mechanisms of these chronic symptoms following Lyme disease as well as to find effective therapies.

German guidelines for the diagnosis and management of infective endocarditis

This Gudelines are the translation of the German Guidelines for the Diagnosis and Management of Infective Endocarditis, which were prepared by the Working Group on Infective Endocarditis of the Paul-Ehrlich-Society and the German Society for Cardiology, Heart, and Circulatory Research in cooperation with the Deutsche Gesellschaft für Thorax-, Herz und Gefässchirurgie (DGTHG; German Society for Thorax-, Cardiac-, and Vascular Surgery), the Deutsche Gesellschaft für Infektiologie (DGI; German Society for Infectious Diseases), the Deutsche Gesellschaft für Internistische Intensivmedizin und Notfallmedizin (DGIIN; German Society for Internal Intensive Care Medicin and Emergency Medicine), the Deutsche Gesellschaft für Hygiene und Mikrobiologie (DGHM; German Society for Hygiene and Microbiology) and the Deutsche Gesellschaft für Innere Medizin (DGIM; German Society for Internal Medicine) (Naber CK et al. [S2 Guideline for diagnosis and therapy of infectious endocarditis] Z Kardiol. 2004;93:1005-21). The Guidelines provide recommendations for the diagnosis and management of infective endocarditis.

Q fever endocarditis: a case report and review of the literature

The case of a 31-year-old man from Alberta diagnosed with Q fever endocarditis is presented. To the authors' knowledge, this is the first case of Q fever endocarditis diagnosed in the province of Alberta. The patient had undergone open valvulotomy for congenital aortic stenosis as an infant. He presented with congestive heart failure secondary to severe aortic regurgitation and underwent mechanical aortic valve replacement. Early failure of the mechanical prosthesis and numerous laboratory abnormalities prompted an investigation for endocarditis, which was initially negative. Markedly positive serology eventually established the diagnosis of chronic Q fever. The patient subsequently underwent a second aortic valve replacement following initiation of appropriate antimicrobials directed against Coxiella burnetii. The present report reviews the clinical presentation and diagnosis of Q fever endocarditis. It highlights the insidious and nonspecific nature of the presenting symptoms, and emphasizes the use of serology for diagnosis. Increased awareness and earlier diagnosis can significantly decrease the morbidity and mortality associated with this disease.

Q fever endocarditis masquerading as Mixed cryoglobulinemia type II. A case report and review of the literature

Background

The clinical manifestations of Q fever endocarditis are protean in nature. Mixed cryoglobulinemia type II is rarely a facet of the presenting clinical manifestations of Q fever endocarditis.

Case presentation

We report a case of a 65-year-old pensioner with such an association and review the literature. As transesophageal echocardiograms are usually normal and blood cultures are usually negative in Q fever endocarditis, many of the manifestations (fever, rash, glomerulonephritis/evidence of renal disease, low serum C4 complement component, presence of mixed type II cryoglobulin, constitutional symptoms as arthralgias and fatigue) can be attributed to Mixed cryoglobulinemia type II per se. The use of Classic Duke Endocarditis Service criteria does not always suffice for the diagnosis of Q fever.

Conclusion

The application of the modified criteria proposed by Fournier et al for the improvement of the diagnosis of Q fever endocarditis will help to reach the diagnosis earlier and thus reduce the high mortality of the disease. We would like to stress the importance of ruling out the diagnosis of Q fever endocarditis in cases of mixed type II cryoglobulinemia.

Blood culture-negative endocarditis in a reference center: etiologic diagnosis of 348 cases

To identify the current etiologies of blood culture-negative infective endocarditis and to describe the epidemiologic, clinical, laboratory, and echocardiographic characteristics associated with each etiology, as well as with unexplained cases, we tested samples from 348 patients suspected of having blood culture-negative infective endocarditis in our diagnostic center, the French National Reference Center for Rickettsial Diseases, between 1983 and 2001. Serology tests for Coxiella burnettii, Bartonella species, Chlamydia species, Legionella species, and Aspergillus species; blood culture on shell vial; and, when available, analysis of valve specimens through culture, microscopic examination, and direct PCR amplification were performed. Physicians were asked to complete a questionnaire, which was computerized. Only cases of definite infective endocarditis, as defined by the modified Duke criteria, were included. A total of 348 cases were recorded-to our knowledge, the largest series reported to date. Of those, 167 cases (48%) were associated with C. burnetii, 99 (28%) with Bartonella species, and 5 (1%) with rare, fastidious bacterial agents of endocarditis (Tropheryma whipplei, Abiotrophia elegans, Mycoplasma hominis, Legionella pneumophila). Among 73 cases without etiology, 58 received antibiotic drugs before the blood cultures. Six cases were right-sided endocarditis and 4 occurred in patients who had a permanent pacemaker. Finally, no explanatory factor was found for 5 remaining cases (1%), despite all investigations.Q fever endocarditis affected males in 75% of cases, between 40 and 70 years of age. Ninety-one percent of patients had a previous valvulopathy, 32% were immunocompromised, and 70% had been exposed to animals. Our study confirms the improved clinical presentation and prognosis of the disease observed during the last decades. Such an evolution could be related to earlier diagnosis due to better physician awareness and more sensitive diagnostic techniques. As for Bartonella species, B. quintana was recorded more frequently than B. henselae (53 vs 17 cases). For 18 patients with Bartonella endocarditis, the responsible species was not identified. Species determination was achieved through culture and/or PCR in 49 cases and through Western immunoblotting in 22. Comparison of B. quintana and B. henselae endocarditis revealed distinct epidemiologic patterns. The 2 cases due to T. whipplei reflect the emerging role of this agent as a cause of infective endocarditis. Because identification of the bacterium was possible only through analysis of excised valves by histologic examination, PCR, and culture on shell vial, the prevalence of the disease might be underestimated. Among patients who received antibiotic drugs before blood cultures, 4 cases (7%) were found to be associated with Streptococcus species (2 S. bovis and 2 S. mutans) through 16S rDNA gene amplification directly from the valve, which shows the usefulness of this technique in overcoming the limitations of previous antibiotic treatment. Right-sided endocarditis occurred classically in young patients (mean age, 36 yr), intravenous drug users in 50% of cases, and suffering more often from embolic complications. Finally, 5 cases without etiology or explaining factors were all immunocompetent male patients with previous aortic valvular lesions, and 3 of the 5 presented with an aortic abscess. Further investigations should be focused on this group to identify new agents of infective endocarditis.

Pseudoepidemic of Q Fever at an Animal Research Facility

Serum samples from people exposed to sheep at a research facility were evaluated by a commercial laboratory and resulted in an overall Coxiella burnetii seroprevalence of 75%. We interviewed individuals to determine exposure history and compatible illness, and retested their sera. Analysis indicated that the commercial laboratory was misinterpreting its results; when corrected, the seroprevalence dropped to 27%. Test kits of the brand used by the commercial laboratory gave equivalent results to the in-house CDC assay when tested in parallel at CDC. Upon final analysis, only the attending veterinarian was confirmed as a Q fever case. This event resulted in increased risk reduction protocols at the research facility and improved public health communication among health authorities. This pseudoepidemic resulted from a lapse in laboratory quality control for testing. Similar errors can be avoided through standardization and improved review of laboratory procedures.

Guidelines for the antibiotic treatment of endocarditis in adults: report of the Working Party of the British Society for Antimicrobial Chemotherapy

The BSAC Guidelines on Endocarditis were last published in 1998. The Guidelines presented here have been updated and extended to reflect changes in both the antibiotic resistance characteristics of causative organisms and the availability of new antibiotics. Randomized, controlled trials suitable for the development of evidenced-based guidelines in this area are still lacking, and therefore a consensus approach has again been adopted. The Guidelines cover diagnosis and laboratory testing, suitable antibiotic regimens and causative organisms. Special emphasis is placed on common causes of endocarditis, such as streptococci and staphylococci, however, other bacterial causes (such as enterococci, HACEK organisms, Coxiella and Bartonella) and fungi are considered. The special circumstances of prosthetic endocarditis are discussed.

Q fever (coxiellosis): epidemiology and pathogenesis

Q fever is a widespread zoonosis caused by the Gram-negative bacterium Coxiella burnetii. Aborting domestic ruminants are the main sources of human infection but the reservoir of infection is extremely wide. In humans, Q fever may occur as acute pneumonia, hepatitis or flu-like illness or may take a severe chronic form, characterized by endocarditis, chronic hepatitis and chronic fatigue syndrome. In animals, the main clinical manifestation is late abortion. Infection with C. burnetii can be diagnosed using cultural, serological and genetic methods but because the organism is potentially dangerous and requires specialized skills only specialist laboratories are capable of undertaking diagnostic tests. This paper provides a brief overview of the epidemiology and pathogenesis of Q fever (coxiellosis).

Measurement of the antibiotic susceptibility of Coxiella burnetii using real time PCR

The objective of this study was to determine MICs of antibiotics for two reference strains of Coxiella burnetii using real time quantitative PCR. The method was very sensitive and specific and allowed the evaluation of the doubling time of Nine Mile and Q212 strains: 37 and 15 h, respectively. Dose response curves of antibiotics were used to determine MICs. Those of doxycycline, fluoroquinolone compounds and rifampicin were in the range 1-4 mg/l. Telithromycin was the most effective macrolide compound with MICs of 1-2 mg/l. The results confirmed previous reports on the accuracy of this new method for the determination of the antibiotic susceptibility of C. burnetii and could be used for the screening of new drugs.

Doxycycline and chloroquine as treatment for chronic Q fever endocarditis

Endocarditis is a rare but severe complication of Q fever, an infectious disease caused by the intracellular pathogen Coxiella burnetii. Heart involvement is the most common clinical presentation of chronic Q fever, and it occurs almost invariably in patients with previous valvular disease or artificial valves, and in the immunocompromised host. The optimal treatment of Q fever endocarditis is still today debated, and recommended duration of treatment varies from one year to one's lifespan. A case of chronic Q fever endocarditis is described in a patient with biological prosthetic aortic valve and aortic homograft, successfully treated with doxycycline and chloroquine for 2 years.

Changing clinical presentation of Q fever endocarditis

Fifteen cases of Q fever endocarditis that occurred in 1999-2000 in southern France are described and compared with 15 cases from the same area reported in 1987. Significant decreases were found in the prevalences of heart failure, hepatomegaly, inflammatory syndrome, anemia, leukopenia, and abnormal liver function test results in patients who had Q fever endocarditis after 1997. This was probably the result of a reduction in the delay before diagnosis of the disease and of the use of novel, effective antibiotic regimens.

Clinically and histologically silent Q fever endocarditis accidentally diagnosed by PCR

A case of Q fever endocarditis was diagnosed in a patient with no sign of active endocarditis by performing PCR targeting eubacterial 16S rDNA on the resected mitral valve. The diagnosis was confirmed by detection of high levels of anti-Coxiella burnetti antibodies, positive immunohistologic analysis of the valve tissue with specific antibodies and culture of C. burnetti from the valve tissue. As this patient had an unexplained aggravation of valve dysfunction, we recommended routine serologic testing for C. burnetti to allow the diagnosis of Q fever endocarditis at a very early stage.

Q fever 1985-1998. Clinical and epidemiologic features of 1,383 infections

In order to describe the clinical features and the epidemiologic findings of 1,383 patients hospitalized in France for acute or chronic Q fever, we conducted a retrospective analysis based on 74,702 sera tested in our diagnostic center, National Reference Center and World Health Organization Collaborative Center for Rickettsial Diseases. The physicians in charge of all patients with evidence of acute Q fever (seroconversion and/or presence of IgM) or chronic Q fever (prolonged disease and/or IgG antibody titer to phase I of Coxiella burnetii > or = 800) were asked to complete a questionnaire, which was computerized. A total of 1,070 cases of acute Q fever was recorded. Males were more frequently diagnosed, and most cases were identified in the spring. Cases were observed more frequently in patients between the ages of 30 and 69 years. We classified patients according to the different clinical forms of acute Q fever, hepatitis (40%), pneumonia and hepatitis (20%), pneumonia (17%), isolated fever (17%), meningoencephalitis (1%), myocarditis (1%), pericarditis (1%), and meningitis (0.7%). We showed for the first time, to our knowledge, that different clinical forms of acute Q fever are associated with significantly different patient status. Hepatitis occurred in younger patients, pneumonia in older and more immunocompromised patients, and isolated fever was more common in female patients. Risk factors were not specifically associated with a clinical form except meningoencephalitis and contact with animals. The prognosis was usually good except for those with myocarditis or meningoencephalitis as 13 patients died who were significantly older than others. For chronic Q fever, antibody titers to C. burnetii phase I above 800 and IgA above 50 were predictive in 94% of cases. Among 313 patients with chronic Q fever, 259 had endocarditis, mainly patients with previous valvulopathy; 25 had an infection of vascular aneurysm or prosthesis. Patients with endocarditis or vascular infection were more frequently immunocompromised and older than those with acute Q fever. Fifteen women were infected during pregnancy; they were significantly more exposed to animals and gave birth to only 5 babies, only 2 with a normal birth weight. More rare manifestations observed were chronic hepatitis (8 cases), osteoarticular infection (7 cases), and chronic pericarditis (3 cases). Nineteen patients were observed who experienced first a documented acute infection, then, due to underlying conditions, a chronic infection. To our knowledge, we report the largest series of Q fever to date. Our results indicate that Q fever is a protean disease, grossly underestimated, with some of the clinical manifestations being only recently reported, such as Q fever during pregnancy, chronic vascular infection, osteomyelitis, pericarditis, and myocarditis. Our data confirm that chronic Q fever is mainly determined by host factors and demonstrate for the first time that host factors may also play a role in the clinical expression of acute Q fever.

Q fever

Q fever is a zoonosis with a worldwide distribution with the exception of New Zealand. The disease is caused by Coxiella burnetii, a strictly intracellular, gram-negative bacterium. Many species of mammals, birds, and ticks are reservoirs of C. burnetii in nature. C. burnetii infection is most often latent in animals, with persistent shedding of bacteria into the environment. However, in females intermittent high-level shedding occurs at the time of parturition, with millions of bacteria being released per gram of placenta. Humans are usually infected by contaminated aerosols from domestic animals, particularly after contact with parturient females and their birth products. Although often asymptomatic, Q fever may manifest in humans as an acute disease (mainly as a self-limited febrile illness, pneumonia, or hepatitis) or as a chronic disease (mainly endocarditis), especially in patients with previous valvulopathy and to a lesser extent in immunocompromised hosts and in pregnant women. Specific diagnosis of Q fever remains based upon serology. Immunoglobulin M (IgM) and IgG antiphase II antibodies are detected 2 to 3 weeks after infection with C. burnetii, whereas the presence of IgG antiphase I C. burnetii antibodies at titers of >/=1:800 by microimmunofluorescence is indicative of chronic Q fever. The tetracyclines are still considered the mainstay of antibiotic therapy of acute Q fever, whereas antibiotic combinations administered over prolonged periods are necessary to prevent relapses in Q fever endocarditis patients. Although the protective role of Q fever vaccination with whole-cell extracts has been established, the population which should be primarily vaccinated remains to be clearly identified. Vaccination should probably be considered in the population at high risk for Q fever endocarditis.

Long term vascular complications of Coxiella burnetii infection in Switzerland: cohort study

OBJECTIVE

To evaluate the range of long term vascular manifestations of Coxiella burnetii infection.

DESIGN

Cohort study in Switzerland of people affected in 1983 by the largest reported outbreak of Q fever and who were followed up 12 years later. Follow up information about possible vascular disease and endocarditis was obtained through a mailed questionnaire and death certificates.

SETTING

Val de Bagnes, a rural Alpine valley in Switzerland.

PARTICIPANTS

2044 (87%) of 2355 people who had serum testing for Coxiella burnetii infection in 1983: 1247 were classed as not having been infected, 411 were classed as having been acutely infected, and 386 were classed as having been infected before 1983.

MAIN OUTCOME MEASURES

Relative risk controlled for age and sex and 12 year risk of vascular diseases and endocarditis among infected participants as compared with those who had never been infected.

RESULTS

The 12 year risk of endocarditis or venous thromboembolic disease was not increased among those who had been acutely infected. The 12 year risk of arterial disease was significantly higher among those who had been acutely infected (7%) as compared with those who had never been infected (4%) (relative risk 2.2, 95% confidence interval 1.4 to 3.6). Specifically, there was an increased risk of developing a cerebrovascular accident (relative risk 3.7, 1.6 to 8.4) and cardiac ischaemia (relative risk 1.9, 1.04 to 3.4). 12 year mortality was significantly higher among the 411 people who had been acutely infected in 1983 (9.7%; age adjusted relative risk 1.8, 1.2 to 2.6) when compared with the 1247 participants who had remained serologically negative in 1983 (7.0%).

CONCLUSIONS

Coxiella burnetii infection may cause long term complications including vascular disease.

Q fever endocarditis revisited

A diagnosis of Q fever endocarditis was made in 7 patients, 6 with predisposing factors and 3 with occupational risk factors. Prompt recognition of Coxiella burnettii endocarditis is required when clinical signs of endocarditis such as fever, anaemia, elevated liver transaminases, congestive cardiac failure are accompanied by negative blood cultures. Serological evidence of elevated antibody titres to Phase I and Phase II antigens of Coxiella burnettii are diagnostic. Prolonged antimicrobial therapy combined with surgery has resulted in the marked reduction of mortality from 50 per cent of 17 per cent when Q fever endocarditis is revisited almost 20 yr later.