Vascular Complications of Q-fever Infections

Homemade pericardial bifurcated graft for Q fever-infected abdominal aortic aneurysm open repair: a case report

Q fever is a zoonotic infection caused by Coxiella burnetii. In rare cases, it can lead to vascular complications, including infected aneurysms. Successful treatment involves surgery and antibiotics, but there is no established consensus or clear recommendation for the choice of material graft. We report a case of abdominal aortic aneurysm infected by C. burnetii treated by open surgery with complete resection of the aneurysm and homemade bovine pericardial bifurcated graft reconstruction and long-term antibiotherapy using doxycycline. One year postoperatively, the patient had no sign of persistent infection or vascular complication. Moreover, C. burnetii immunoglobulins titers decreased 6 months postoperatively.

Dissecting aortitis in a goat associated with Pasteurella multocida and Staphylococcus spp infection

Reports of primary cardiovascular disease in goats are rare and most commonly include ventricular septal defect, valvular endocarditis, traumatic pericarditis, ionophore poisoning and nutritional cardiomyopathies. We now report the pathological findings in a 67 kg, 6-year-old, adult female Boer goat that presented with neurological signs (ie, head pressing, unsteadiness and paddling) and hyperthermia 2 days prior to death. Lack of therapeutic response to meloxicam and penicillin‒streptomycin and poor prognosis led to euthanasia of the animal. At necropsy, the main findings included severe aortic dissection with luminal thrombosis and stenosis, and pulmonary congestion and oedema. Histological examination of the aorta revealed severe chronic granulomatous and fibrosing dissecting aortitis with mineralization. Bacterial culture of the affected aortic segment resulted in isolation of a profuse growth of Pasteurella multocida and a moderate growth of Staphylococcus spp. Histopathological findings in the central nervous system were consistent with neurolisteriosis.

Coxiella burnetii Femoro-Popliteal Bypass Infection: A Case Report

Cardiovascular infections are the most severe and potentially lethal among the persistent focalized Coxiella burnetii infections. While aortic infections on aneurysms or prostheses are well-known, with specific complications (risk of fatal rupture), new non-aortic vascular infections are increasingly being described thanks to the emerging use of 18-fluorodeoxyglucose positron emission tomography (18F-FDG PET-scan). Here, we describe an infection of a femoro-popliteal bypass that would not have been diagnosed without the use of PET-scan. It is well-known that vascular prosthetic material is a site favorable for bacterial persistence, but the description of unusual anatomical sites, outside the heart or aorta, should raise the clinicians' awareness and generalize the indications for PET-scan, with careful inclusion of the upper and lower limbs (not included in PET-scan for cancer), particularly in the presence of vascular prostheses. Future studies will be needed to precisely determine their optimal management.

Clinical and biological diagnosis and follow-up of patients treated for endovascular infections due to Coxiellaburnetii

The objective of this study was to evaluate the effectiveness of the recommended treatment for endovascular infections due to Coxiella burnetii. This single-center retrospective study was conducted in 13 patients with endovascular infection due to C. burnetii between January 2001 and December 2020 for a definite or possible endovascular infection due to C. burnetii with a minimum follow-up of 18 months post-infection. Clinical and biological data, including serology, blood and tissue PCR results, doxycycline and hydroxychloroquine assays were collected. Among the 13 patients, 11 had endocarditis (8 definite and 3 possible) and 2 had a vascular infection. At the time of diagnosis, fever was present in only 46% of cases. In case of endocarditis, 73% of patients had a pathological echocardiography. Biologically, the CRP level was low (52 mg/l ± 44). Autoimmune antibodies (antinuclear factor, neutrophil anticytoplasm) were present in 23% of patients. At the time of diagnosis, tissue PCR was very sensitive (100%) unlike blood or serum (29%). Blood levels of doxycycline and hydroxychloroquine were within expected values. Only one patient experienced treatment failure at two years, requiring surgery. For the 7 patients whose phase I IgG titres fell below 1/800, a minimum of 18 months of treatment was necessary. In the long term, the clinical and biological cure was 100% and 92% respectively, underlining the importance of monitoring the serum dosages of doxycycline and hydroxychloroquine. Given its sensitivity, tissue PCR could be added to the major Duke criteria.

Primary and subsequent secondary aorto-enteric fistulae in the setting of chronic Q fever

We report the case of an 80-year-old male with stage three kidney disease, who survived a primary aorto-enteric fistula (AEF) in the setting of chronic Q fever after presenting with melena and syncope. His initial surgical treatment included endovascular aortic repair. Type 2 endoleak was present post-operatively. Six months later, he was diagnosed with a secondary AEF after syncope and large volume hematemesis. He was definitively treated with an open explant of his stent, repair of the duodenum and bilateral axillofemoral bypass. Two years later, he remains active and independent on life-long antibiotics.

Spinal infection caused by Coxiella burnetii

BACKGROUND

Spinal infection caused by Coxiella burnetii is rare and difficult to diagnose. Here we reported a case of spinal infection from Coxiella burnetii detected by the metagenomic next-generation sequencing (mNGS).

CASE PRESENTATION

A 66-year-old male farmer with no medical history reported severe sharp low back pain, numbness and lower limb weakness for three years. Magnetic resonance imaging (MRI) revealed bone destruction and spinal cord compression within L1 and L2. mNGS testing showed that the inspected specimen collected from spinal lesion was detected positively for Coxiella burnetii. After receiving the combined treatment of antibiotic therapy and surgical intervention, the patient recovered well, and the sagittal MRI showed that vertebral edema signals disappeared and the graft of bone fused 16 months after surgery.

CONCLUSION

The mNGS may be benefit for early diagnosis and intervention of non-specific spinal infection, and future studies should validate its effectiveness for clinical use in spinal infections. Additionally, antibiotic therapy combined with surgical intervention plays an important role on the treatment of spinal infection caused by Coxiella burnetii.

Open repair of a Coxiella burnetii-associated abdominal aortic endovascular stent graft infection with a cryopreserved allograft using visceral artery pump perfusion

Coxiella burnetii, the causative organism of Q fever, has been increasingly reported to be associated with infections of abdominal aortic aneurysms and endovascular stent grafts. We have added to the current literature by presenting a case of the surgical management of chronic Q fever that had infected a prior aortic endovascular stent graft placed for a contained rupture of an infrarenal aortic aneurysm in a 68-year-old woman. We presented our case of the surgical management of the excision and explantation of the infected aorta and stent graft, with reconstruction of the aorta using a cryopreserved aortic graft and visceral artery pump perfusion.

Differences in local immune cell landscape between Q fever and atherosclerotic abdominal aortic aneurysms identified by multiplex immunohistochemistry

Background:

Chronic Q fever is a zoonosis caused by the bacterium Coxiella burnetii which can manifest as infection of an abdominal aortic aneurysm (AAA). Antibiotic therapy often fails, resulting in severe morbidity and high mortality. Whereas previous studies have focused on inflammatory processes in blood, the aim of this study was to investigate local inflammation in aortic tissue.

Methods:

Multiplex immunohistochemistry was used to investigate local inflammation in Q fever AAAs compared to atherosclerotic AAAs in aorta tissue specimen. Two six-plex panels were used to study both the innate and adaptive immune systems.

Results:

Q fever AAAs and atherosclerotic AAAs contained similar numbers of CD68⁺ macrophages and CD3⁺ T cells. However, in Q fever AAAs, the number of CD68⁺CD206⁺ M2 macrophages was increased, while expression of GM-CSF was decreased compared to atherosclerotic AAAs. Furthermore, Q fever AAAs showed an increase in both the number of CD8⁺ cytotoxic T cells and CD3⁺CD8^-FoxP3⁺ regulatory T cells. Finally, Q fever AAAs did not contain any well-defined granulomas.

Conclusions:

These findings demonstrate that despite the presence of pro-inflammatory effector cells, persistent local infection with C. burnetii is associated with an immune-suppressed microenvironment.

Funding:

This work was supported by SCAN consortium: European Research Area - CardioVascualar Diseases (ERA-CVD) grant [JTC2017-044] and TTW-NWO open technology grant [STW-14716].

OUTCOME IN PATIENTS AFTER AUTOLOGOUS FEMORAL VEIN RECONSTRUCTION FOR PRIMARY AORTIC INFECTION AND AORTIC GRAFT INFECTION: A CASE SERIES

OBJECTIVES

For surgical treatment of primary aortic infection and aortic graft infection, in situ reconstruction with autologous vein(s) has the lowest rates of re-infection and of graft thrombosis. In this study, we have assessed the outcome after autologous femoral vein reconstruction in patients with aortic (graft) infection and we provide insights into the specific technical surgical considerations of the procedure.

METHODS

In this retrospective single-center study, all patients who underwent autologous femoral vein reconstruction because of primary aortic infection or aortic graft infection between January 2012 and January 2020 were included. The primary outcome parameter was 30-day mortality.

RESULTS

Twenty-nine patients with autologous femoral vein reconstruction for a primary aortic infection (n = 3) or aortic graft infection (n = 26) were included. An aorto-enteral fistula was detected in 13 patients (49%). Venous reconstruction of the aorta was performed with a single femoral vein in 17 patients (59%), and two femoral veins in 12 patients (41%). Thirty-day mortality was 17%. Relapse of infection occurred in two patients (7%) and no amputations were needed. One year after surgery, only three patients (10%) still needed stockings and after two years none of the patients used stockings.

CONCLUSIONS

Central aortic reconstruction with femoral veins is a durable solution for primary aortic and aortoiliac graft infections with a low incidence of reinfections, amputations, and venous hypertension.

Molecular diagnosis of Coxiella burnetii in culture negative endocarditis and vascular infection in South Korea

BACKGROUND

Q fever endocarditis is a major cause of culture-negative endocarditis. The role of Coxellia burnetii is underestimated because it is difficult to diagnose. We investigated the significance of C. burnetii as the cause of culture-negative endocarditis and vascular infection by examining blood and tissue specimens using serological testing and polymerase chain reaction (PCR).

METHODS

All patients with infective endocarditis or large vessel vasculitis were prospectively enrolled at a tertiary-care hospital from May 2016 through September 2020. Q fever endocarditis and vascular infection were diagnosed based on: (1) positive PCR for a cardiac valve or vascular tissue, (2) positive PCR for blood or phase I immunoglobulin G (IgG) ≥ 6400, or (3) phase I IgG ≥ 800 and < 6400 with morphologic abnormality. PCR targeted C. burnetii transposase gene insertion element IS1111a.

RESULTS

Of the 163 patients, 40 (25%) had culture-negative endocarditis (n = 35) or vascular infection (n = 5). Of the 40 patients, 24 (60%) were enrolled. Eight (33%) were diagnosed with Q fever endocarditis or vascular infection. Of these 8 patients, 6 had suspected acute Q fever endocarditis or vascular infection with negative phase I IgG. Six patients were not treated for C. burnetii, 4 were stable after surgery. One patient died due to surgical site infection after 5 months post-operatively and one died due to worsening underlying disease.

CONCLUSIONS

Approximately one-third of patients with culture-negative endocarditis and vascular infection was diagnosed as Q fever. Q fever endocarditis and vascular infection may be underestimated in routine clinical practice in South Korea.KEY MESSAGEQ fever endocarditis and vascular infection may be underestimated in routine clinical practice, thus, try to find evidence of C. burnetti infection in suspected patients by all available diagnostic tests including PCR.

Development of High-Throughput Multiplex Serology to Detect Serum Antibodies against Coxiella burnetii

The causative agent of Q fever, the bacterium Coxiella burnetii (C. burnetii), has gained increasing interest due to outbreak events and reports about it being a potential risk factor for the development of lymphomas. In order to conduct large-scale studies for population monitoring and to investigate possible associations more closely, accurate and cost-effective high-throughput assays are highly desired. To address this need, nine C. burnetii proteins were expressed as recombinant antigens for multiplex serology. This technique enables the quantitative high-throughput detection of antibodies to multiple antigens simultaneously in a single reaction. Based on a reference group of 76 seropositive and 91 seronegative sera, three antigens were able to detect C. burnetii infections. Com1, GroEL, and DnaK achieved specificities of 93%, 69%, and 77% and sensitivities of 64%, 72%, and 47%, respectively. Double positivity to Com1 and GroEL led to a combined specificity of 90% and a sensitivity of 71%. In a subgroup of seropositives with an increased risk for chronic Q fever, the double positivity to these markers reached a specificity of 90% and a sensitivity of 86%. Multiplex serology enables the detection of antibodies against C. burnetii and appears well-suited to investigate associations between C. burnetii infections and the clinical manifestations in large-scale studies.

Coxiella burnetii vascular graft infection

Q fever, a zoonotic infection caused by Coxiella burnetii, can present with a wide spectrum of clinical manifestations. The organism is typically transmitted from sheep, goats, or cattle to humans via contaminated aerosols. On average, 1–5% of patients with acute Q fever will develop chronic infection months to decades after their primary infections. We report a case of a chronic vascular graft infection due to Coxiella burnetii in a 61-year-old man without direct exposure to animals who presented with recurrent fever. Indium-111-labeled white blood cell scan with single-emission positron computed tomography demonstrated findings suggesting a graft infection. C. burnetii phase I and phase II IgG antibody titers were > 1:32,768 and polymerase chain reaction performed on the explanted graft was positive for C. burnetii. Q fever should be considered in the differential diagnosis of vascular infections in patients who have a pre-existing lesion such as an aneurysm, or vascular prosthesis even in the absence of a history of direct animal exposure.

High Prevalence and New Genotype of Coxiella burnetii in Ticks Infesting Camels in Somalia

Coxiella burnetii is the causative agent of Q fever. It can infect animals, humans, and birds, as well as ticks, and it has a worldwide geographical distribution. To better understand the epidemiology of C. burnetii in Somalia, ticks infesting camels were collected from five different regions, including Bari, Nugaal, Mudug, Sool, and Sanaag, between January and March 2018. Collected ticks were tested for C. burnetii and Coxiella-like endosymbiont DNA by using IS1111, icd, and Com1-target PCR assays. Moreover, sequencing of the 16S-rRNA was conducted. Molecular characterization and typing were done by adaA-gene analysis and plasmid-type identification. Further typing was carried out by 14-marker Multi-Locus Variable-Number Tandem Repeats (MLVA/VNTR) analysis. The investigated ticks (n = 237) were identified as Hyalomma spp. (n = 227, 95.8%), Amblyomma spp. (n = 8, 3.4%), and Ripicephalus spp. (n = 2, 0.8%), and 59.1% (140/237) of them were positive for Coxiella spp. While Sanger sequencing and plasmid-type identification revealed a C. burnetii that harbours the QpRS-plasmid, MLVA/VNTR genotyping showed a new genotype which was initially named D21. In conclusion, this is the first report of C. burnetii in ticks in Somalia. The findings denote the possibility that C. burnetii is endemic in Somalia. Further epidemiological studies investigating samples from humans, animals, and ticks within the context of "One Health" are warranted.

Coxiella burnetii Antibody Prevalence and Risk Factors of Infection in the Human Population of Estonia

Q fever is an emerging health problem in both humans and animals. To estimate the prevalence of Coxiella burnetii (C. burnetii) antibodies in the Estonian population, we analyzed plasma samples from 1000 individuals representing the general population and 556 individual serum samples from five population groups potentially at a higher risk (veterinary professionals, dairy cattle, beef cattle, and small ruminant stockbreeders and hunters). Additionally, 118 dairy cow bulk tank milk samples were analyzed to establish the infection status of the dairy cattle herds and the participating dairy cattle keepers. Questionnaires were used to find the potential risk factors of exposure. The effects of different variables were evaluated using binary logistic regression analysis and mixed-effects logistic analysis. The prevalence in veterinary professionals (9.62%; p = 0.003) and dairy cattle farmers (7.73%; p = 0.047) was significantly higher than in the general population (3.9%). Contact with production animals in veterinary practice and being a dairy stockbreeder in C. burnetii positive farms were risk factors for testing C. burnetii seropositive (p = 0.038 and p = 0.019, respectively). Results suggest that C. burnetii is present in Estonia and the increased risk of infection in humans is associated with farm animal contact.

Should Acute Q-Fever Patients be Screened for Valvulopathy to Prevent Endocarditis?

Background

Echocardiographic screening of acute Q-fever patients and antibiotic prophylaxis for patients with cardiac valvulopathy is considered an important approach to prevent chronic Q-fever-related endocarditis. During a large Q-fever epidemic in the Netherlands, routine screening echocardiography was discontinued, raising controversy in the international literature. We followed a cohort of acute Q-fever patients to estimate the risk for developing chronic Q-fever, and we evaluated the impact of screening in patients who were not yet known to have a valvulopathy.

Methods

The study population consisted of patients diagnosed with acute Q-fever in 2007 and 2008. We retrospectively reviewed all screening echocardiographs and checked for development of chronic Q-fever 8 years after the acute episode. Risks of developing chronic Q-fever in relation to the presence or absence of valvulopathy were analyzed with logistic regression.

Results

The cohort included 509 patients, of whom 306 received echocardiographic screening. There was no significant difference (P-value = .22) in occurrence of chronic Q-fever between patients with a newly detected valvulopathy (2/84, 2.4%) and those with no valvulopathy (12/202, 5.9%). Two patients with a newly detected valvulopathy, who did not receive antibiotic prophylaxis, developed chronic Q-fever at a later stage.

Conclusions

We found no difference in outcome between patients with and without a valvulopathy newly detected by echocardiographic screening. In retrospect, the 2 above-mentioned patients could have benefitted from antibiotic prophylaxis, but its omission must be weighed against the unnecessary large-scale and long-term use of antibiotics that would have resulted from universal echocardiographic screening.

Risk of chronic Q fever in patients with cardiac valvulopathy, seven years after a large epidemic in the Netherlands

BACKGROUND

From 2007 through 2010, a large epidemic of acute Q fever occurred in the Netherlands. Patients with cardiac valvulopathy are at high risk to develop chronic Q fever after an acute infection. This patient group was not routinely screened, so it is unknown whether all their chronic infections were diagnosed. This study aims to investigate how many chronic Q fever patients can be identified by routinely screening patients with valvulopathy and to establish whether the policy of not screening should be changed.

METHODS

In a cross-sectional study (2016-2017) in a hospital at the epicentre of the Q fever epidemic, a blood sample was taken from patients 18 years and older who presented with cardiac valvulopathy. The sample was tested for IgG antibodies against phase I and II of Coxiella burnetii using an immunofluorescence assay. An IgG phase II titre of ≥1:64 was considered serological evidence of a previous Q fever infection. An IgG phase I titre of ≥1:512 was considered suspicious for a chronic infection, and these patients were referred for medical examination.

RESULTS

Of the 904 included patients, 133 (15%) had evidence of a previous C. burnetii infection, of whom 6 (5%) had a chronic infection on medical examination.

CONCLUSIONS

In a group of high-risk patients with a heart valve defect, we diagnosed new chronic Q fever infections seven years after the epidemic, emphasizing the need for screening of this group to prevent complications in those not yet diagnosed in epidemic areas.

Serological evidence of Coxiella burnetii infection in cattle and farm workers: is Q fever an underreported zoonotic disease in Ecuador?

Background: Q fever is an underreported zoonotic disease of cattle and men in most countries of the world. Very little information about the prevalence of Coxiella burnetii infection in animals and humans comes from South and Central America and systematic studies are lacking. Methods: A seroprevalence survey for Q fever amongst cattle, farm workers and students was conducted in Ecuador using a commercial ELISA kit. Results: Survey results showed an unexpectedly high prevalence of Coxiella burnetii antibodies in dairy cattle (43%) and in farm workers (34%). In addition, a clinical case in a human of acute Q fever in the convalescent stage was detected. Conclusion: We conclude that the disease is endemic in Ecuador but is overlooked by medical and laboratory personnel. Q fever should be considered a public health issue in Ecuador and further research into the clinical relevance of this infection is recommended.

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.

Non-diagnostic anti-C. burnetii phase I IgG titres: Should they be discarded in elderly patients?

BACKGROUND

High anti-Coxiella burnetii phase I IgG titres are associated with chronic Q fever; an infectious disease with high mortality. Prognostic significance of lower or medium IgG phase I titres remain uncertain. The aim of this study was to explore this issue in a high-risk population.

METHODS

Sero-epidemiological and prospective study of 456 hospitalised patients aged 65 and older (Burgos; Spain). Serum IgG antibody phase I and II were determined by immunofluorescence assay.

RESULTS

A lower or medium IgG phase I titres (<1:1024) was observed in 180 (39.4%) patients. Atherosclerotic cardiovascular disease was associated with these titres, but not the traditional risk factors of chronic Q fever (cardiac valve disease, and vascular grafts or valvular prosthesis) (adjusted OR 1.75, 95% CI 1.18-2.61). Lower or medium IgG phase I titres were also associated with decreased survival at 30 months follow-up in patients with atherosclerotic cardiovascular disease (but not in the total sample) after adjusting for others comorbidities: IgG phase I titres≥1:32 (HR 1.77; 95% CI 1.14 4-2.74), ≥1:64 (HR 1.90; 95% CI 1.21-2.99)-3.25), and ≥1:128 (HR 2.00; 95% CI 1.23-3.25).

CONCLUSION

Lower or medium IgG phase I titres against C. burnetii, even the lowest, should not be discarded in elderly patients with atherosclerotic cardiovascular disease. Serological follow-up should be recommended in this group of patients.

Surveillance for Q Fever Endocarditis in the United States, 1999-2015

Background

Q fever is a worldwide zoonosis caused by Coxiella burnetii. In some persons, particularly those with cardiac valve disease, infection with C. burnetii can cause a life-threatening infective endocarditis. There are few descriptive analyses of Q fever endocarditis in the United States.

Methods

Q fever case report forms submitted during 1999-2015 were reviewed to identify reports describing endocarditis. Cases were categorized as confirmed or probable using criteria defined by the Council for State and Territorial Epidemiologists (CSTE). Demographic, laboratory, and clinical data were analyzed.

Results

Of 140 case report forms reporting endocarditis, 49 met the confirmed definition and 36 met the probable definition. Eighty-two percent were male and the median age was 57 years (range, 16-87 years). Sixty-seven patients (78.8%) were hospitalized, and 5 deaths (5.9%) were reported. Forty-five patients (52.9%) had a preexisting valvulopathy. Eight patients with endocarditis had phase I immunoglobulin G antibody titers >800 but did not meet the CSTE case definition for Q fever endocarditis.

Conclusions

These data summarize a limited set of clinical and epidemiological features of Q fever endocarditis collected through passive surveillance in the United States. Some cases of apparent Q fever endocarditis could not be classified by CSTE laboratory criteria, suggesting that comparison of phase I and phase II titers could be reexamined as a surveillance criterion. Prospective analyses of culture-negative endocarditis are needed to better assess the clinical spectrum and magnitude of Q fever endocarditis in the United States.

Both Major Histocompatibility Complex Class I (MHC-I) and MHC-II Molecules Are Required, while MHC-I Appears To Play a Critical Role in Host Defense against Primary Coxiella burnetii Infection

To understand the role of class I major histocompatibility complex (MHC-I) and class II MHC (MHC-II) antigen presentation pathways in host defense against Coxiella burnetii infection, we examined whether MHC-I or MHC-II deficiency in mice would significantly influence their susceptibility to virulent C. burnetii Nine Mile phase I (NMI) infection. The results indicate that NMI infection induced more severe disease in both MHC-I-deficient and MHC-II-deficient mice than in wild-type (WT) mice, while only MHC-I-deficient mice developed a severe persistent infection and were unable to control bacterial replication. These results suggest that both MHC-I-restricted CD8⁺ T cells and MHC-II-restricted CD4⁺ T cells contribute to host defense against primary C. burnetii infection, while MHC-I-restricted CD8⁺ T cells appear to play a more critical role in controlling bacterial replication. Additionally, although NMI infection induced more severe disease in TAP1-deficient mice than in their WT counterparts, TAP1 deficiency in mice did not significantly influence their ability to eliminate C. burnetii This suggests that C. burnetii antigen presentation to CD8⁺ T cells by the MHC-I classical pathway may depend only partially on TAP1. Furthermore, granzyme B deficiency in mice did not significantly alter their susceptibility to C. burnetii infection, but perforin-deficient mice were unable to control host inflammatory responses during primary C. burnetii infection. These results suggest that perforin, but not granzyme B, is required for C. burnetii antigen-specific cytotoxic CD8⁺ T cells to control primary C. burnetii infection.

A case of giant cell arteritis associated with culture-proven Coxiella burnetii aortitis

A case of proven Coxiella burnetii aortitis, possibly associated with giant cell arteritis (GCA), is reported. A 72-year-old man, who is a hunter, presented with weight loss, fever, jaw claudication, and hardened temporal arteries associated with a persistent inflammatory syndrome and arteritis of the whole aorta, including the brachiocephalic arteries, as seen on ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography. The diagnosis of GCA was retained, and treatment with prednisolone was started. Given the aneurysm of the abdominal aorta, the patient underwent replacement of the abdominal aorta with an allograft. Histology showed intense chronic arteritis attributed to atherosclerosis with dissection. However, Coxiella burnetii infection was confirmed by serology and then by culture and molecular biology on the surgical specimen. A combination of hydroxychloroquine and doxycycline was added to tapered prednisolone and the outcome was favourable.

Q Fever Presented as a Large Retroperitoneal Pseudotumoral Mass

Background

Q fever is an infection caused by Coxiella burnetii, an intracellular organism. Acute infection is most often a benign and asymptomatic process; however, some individuals may go on to develop subacute and persistent localized symptomatic Q fever. As such, the clinical and histopathologic findings of Q fever are widely variable and may be missed if clinical suspicion is not high.

Case Presentation

Herein we report the first case of C. burnetii infection presenting as an isolated retroperitoneal mass. A 61-year-old male underwent axillary-bifemoral bypass surgery. His postoperative course was complicated by the discovery of a large retroperitoneal mass.

Conclusion

Clinical and histopathologic findings of Coxiella burnetii infection are variable and can be deceiving. These are often nonspecific, especially in its persistent localized infectious stages.

CXCL9, a promising biomarker in the diagnosis of chronic Q fever

Background

In the aftermath of the largest Q fever outbreak in the world, diagnosing the potentially lethal complication chronic Q fever remains challenging. PCR, Coxiella burnetii IgG phase I antibodies, CRP and ¹⁸F–FDG-PET/CT scan are used for diagnosis and monitoring in clinical practice. We aimed to identify and test biomarkers in order to improve discriminative power of the diagnostic tests and monitoring of chronic Q fever.

Methods

We performed a transcriptome analysis on C. burnetii stimulated PBMCs of 4 healthy controls and 6 chronic Q fever patients and identified genes that were most differentially expressed. The gene products were determined using Luminex technology in whole blood samples stimulated with heat-killed C. burnetii and serum samples from chronic Q fever patients and control subjects.

Results

Gene expression of the chemokines CXCL9, CXCL10, CXCL11 and CCL8 was strongly up-regulated in C. burnetii stimulated PBMCs of chronic Q fever patients, in contrast to healthy controls. In whole blood cultures of chronic Q fever patients, production of all four chemokines was increased upon C. burnetii stimulation, but also healthy controls and past Q fever individuals showed increased production of CXCL9, CXCL10 and CCL8. However, CXCL9 and CXCL11 production was significantly higher for chronic Q fever patients compared to past Q fever individuals. In addition, CXCL9 serum concentrations in chronic Q fever patients were higher than in past Q fever individuals.

Conclusion

CXCL9 protein, measured in serum or as C. burnetii stimulated production, is a promising biomarker for the diagnosis of chronic Q fever.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2656-6) contains supplementary material, which is available to authorized users.

From Q Fever to Coxiella burnetii Infection: a Paradigm Change

Coxiella burnetii is the agent of Q fever, or "query fever," a zoonosis first described in Australia in 1937. Since this first description, knowledge about this pathogen and its associated infections has increased dramatically. We review here all the progress made over the last 20 years on this topic. C. burnetii is classically a strict intracellular, Gram-negative bacterium. However, a major step in the characterization of this pathogen was achieved by the establishment of its axenic culture. C. burnetii infects a wide range of animals, from arthropods to humans. The genetic determinants of virulence are now better known, thanks to the achievement of determining the genome sequences of several strains of this species and comparative genomic analyses. Q fever can be found worldwide, but the epidemiological features of this disease vary according to the geographic area considered, including situations where it is endemic or hyperendemic, and the occurrence of large epidemic outbreaks. In recent years, a major breakthrough in the understanding of the natural history of human infection with C. burnetii was the breaking of the old dichotomy between "acute" and "chronic" Q fever. The clinical presentation of C. burnetii infection depends on both the virulence of the infecting C. burnetii strain and specific risks factors in the infected patient. Moreover, no persistent infection can exist without a focus of infection. This paradigm change should allow better diagnosis and management of primary infection and long-term complications in patients with C. burnetii infection.

Chronic Q Fever in Alberta: A Case of Coxiella burnetii Mycotic Aneurysm and Concomitant Vertebral Osteomyelitis

Chronic Q fever is a potentially life-threatening infection from the intracellular, Gram-negative Coxiella burnetii. It presents most commonly as endocarditis or vascular infection in people with underlying cardiac or vascular disease. We discuss a case of a 67-year-old male with Coxiella burnetii vascular infection of a perirenal abdominal aortic graft. The patient had a history of an abdominal aortic aneurysm (AAA) repair 5 years earlier. He presented with a 12 × 6 × 8 cm perirenal pseudoaneurysm and concomitant L1, L2, and L3 vertebral body discitis. He underwent an open repair which revealed a grossly infected graft perioperatively. Q fever serology revealed phase I serological IgG titer of 1 : 2048 and phase II 1 : 1024 consistent with chronic Q fever. Polymerase chain reaction (PCR) on infected vascular tissue was positive for C. burnetii. The patient was started on doxycycline and hydroxychloroquine with good clinical response and decreasing serological titers. Recognizing chronic Q fever is a difficult task as symptoms are nonspecific, exposure risk is difficult to ascertain, and diagnosis is hidden from conventional microbiological investigations. Its recognition, however, is critical as C. burnetii is inherently resistant to standard empiric therapies used in cardiovascular infections.

Psoas abscess and chronic Q fever: a contiguous or hematogenous complication? A case report and literature review

Few cases of psoas abscesses (PA) during chronic Q fever have been reported, and the route of transmission remains unknown. Here, we report a new case and have performed a systematic literature review to determinate the spreading route of this complication. Medline, EMBASE and Web of Science were searched. Local spreading was supported by endocarditis exclusion, evidence of vascular infection and absence of distantly infected sites. Among 275 retrieved references, 179 were initially rejected, and 85 additional references were rejected after full-text review. A total of 11 studies, reporting 13 cases, were included. Additionally, we reported one new case. A total of 14/14 cases reached Q fever vascular infection diagnostic criteria, and 7/14 provided adequate evidence supporting a causal relationship between Q fever vascular infection and PA. All patients presented aorta defects. In conclusion, Q fever PA results from the spreading of a local infection and occurs specifically in patients presenting a vascular graft or an abdominal aortic aneurysm.

Secondary Aortoesophageal Fistula Associated With Aneurysmal Graft Infection by Coxiella burnetii

Aortoesophageal fistula is a rare and serious condition that carries a high mortality rate. We present a case of overt gastrointestinal bleeding from an aortoesophageal fistula in a patient with chronic infection of an endovascular prosthesis with Coxiella burnetii.

Surgical and Antimicrobial Management of a Thoracic Aortic Aneurysm Due to Q Fever: A Case Report and Brief Review

Coxiella burnetii, the etiologic agent of Q fever, has been associated with vascular infection and aneurysm formation. We report the case of a 36-year-old woman from Iraq who presented with long-standing malaise as well as vague chest and shoulder discomfort and was found to have a saccular aneurysm of the descending thoracic aorta. Serology assays were positive for chronic C burnetii infection. She was treated with successful aneurysm resection and aortic replacement with a rifampin-impregnated Maquet Hemashield (TM) Dacron interposition graft interposition graft in addition to 18 months of doxycycline and hydroxychloroquine. The patient is without evidence of recurrent infection on follow-up at 3 years. To our knowledge, this is the first case of aortic aneurysm secondary to Q fever reported in the United States. We review the diagnosis, surgical management, antibiotic therapy, and surveillance of a thoracic aortic aneurysm secondary to Q fever.

Chronic Q fever diagnosis— consensus guideline versus expert opinion

Literature-based consensus guideline is more sensitive and easier to use in clinical practice.

Chronic Q fever, caused by Coxiella burnetii, has high mortality and morbidity rates if left untreated. Controversy about the diagnosis of this complex disease has emerged recently. We applied the guideline from the Dutch Q Fever Consensus Group and a set of diagnostic criteria proposed by Didier Raoult to all 284 chronic Q fever patients included in the Dutch National Chronic Q Fever Database during 2006–2012. Of the patients who had proven cases of chronic Q fever by the Dutch guideline, 46 (30.5%) would not have received a diagnosis by the alternative criteria designed by Raoult, and 14 (4.9%) would have been considered to have possible chronic Q fever. Six patients with proven chronic Q fever died of related causes. Until results from future studies are available, by which current guidelines can be modified, we believe that the Dutch literature-based consensus guideline is more sensitive and easier to use in clinical practice.

Embolization of a Large Rapidly Growing Aortic Pseudo-Aneurysm Not Amenable to Open or Endovascular Repair

BACKGROUND

To report the case of a rapidly growing aortic false aneurysm because of Q fever infection that was managed by embolization.

CASE REPORT

An 80-year-old man was admitted to our unit for an aortic false aneurysm from a chronic Q fever infection. During his stay, the aneurysm showed rapid progression necessitating urgent treatment. The patient was unfit for surgical repair; moreover, the location of the aneurysm at the level of the superior mesenteric artery prohibited the use of an endovascular graft. He was managed by coiling of the aneurysmal cavity with multiple detachable coils after positioning of a bare aortic stent to lock the coils and prevent their migration into the aortic lumen. The false aneurysm was successfully thrombosed with no complications. The patient was then put on doxycycline and hydroxychloroquine to target Coxiella burnetii.

CONCLUSIONS

Aortic false aneurysm coiling is feasible in cases where an endograft is not possible or an open repair is contraindicated. The use of a bare metal stent may help as a barrier to prevent the coils from migrating into the aneurysm and thus avoiding embolization into the systemic circulation.

Treatment and Prophylactic Strategy for Coxiella burnetii Infection of Aneurysms and Vascular Grafts: A Retrospective Cohort Study

Coxiella burnetii vascular infections continue to be very severe diseases and no guidelines exist about their prevention. In terms of treatment, the benefit of the surgical removal of infected tissues has been suggested by 1 retrospective study.We present a case of a C burnetii abdominal aortic graft infection for which we observed a dramatic clinical and biological recovery after surgery. We thus performed a retrospective cohort study to evaluate the impact of surgery on survival and serological outcome for patients with Q fever vascular infections diagnosed in our center.Between 1986 and February 2015, 100 patients were diagnosed with Q fever vascular infections. The incidence of these infections has significantly increased over the past 5 years, in comparison with the mean annual incidence over the preceding 22 years (8.83 cases per year versus 3.14 cases per year, P = 0.001). A two-and-a-half-year follow-up was available for 66 patients, of whom 18.2% died. We observed 6.5% of deaths in the group of patients who were operated upon at 2 and a half years, in comparison with 28.6% in the group which were not operated upon (P = 0.02). Surgery was the only factor that had a positive impact on survival at 2 and a half years using univariate analysis [hazard ratio: 0.17 [95% CI]: [0.039-0.79]; P = 0.024]. Surgery was also associated with a good serological outcome (74.1% vs 57.1% of patients, P = 0.03). In the group of patients with vascular graft infections (n = 47), surgery had a positive impact on serological outcome at 2 and a half years (85.7% vs 42.9%, P < 0.001) [hazard ratio: 0.40 [95% CI]: [0.17-098]; P = 0.046] and tended to be associated with lower although not statistically significant mortality (11.1% vs 27.6% of deaths, P = 0.19).Surgical treatment confers a benefit in terms of survival following C burnetii vascular infections. However, given the high mortality of these infections and their rising incidence, we propose a strategy that consists of screening for vascular graft and aneurysms in the context of primary Q fever, to decide when to start prophylactic treatment, similar to the strategy recommended for the prophylaxis of Q fever endocarditis.

Massive retroperitoneal aortoiliac aneurysm rupture revealing chronic Q fever

Chronic Coxiella burnetii vascular infection is rare and usually develops on a pre-existing vascular lesion, such as an aneurysm or vascular prosthesis. We report a case of proven C. burnetii aortic infection revealed by a massive retroperitoneal aortoiliac aneurysm rupture in a patient at apparent low risk for chronic Q fever. Emergency treatment consisted of resection of the infected aneurysm and replacement with an in situ graft angioplasty. Doxycycline and hydroxychloroquine therapy was started postoperatively. After 6 months of follow-up, the patient had no signs of infection, and C. burnetii serologic antibody titers had significantly decreased.

Vascular chronic Q fever: quality of life

The aim of this study was to evaluate the quality of life in patients with vascular chronic Q fever at time of diagnosis and during follow-up. Based upon the SF-36 questionnaire, the mean physical and mental health of each patient were assessed at 3-month intervals for up to 18 months. A total of 26 patients were included in the study. At time of diagnosis, the mean physical health and mental health score was 50·6 [95% confidence interval (CI) 46·7-54·4] and 44·6 (95% CI 41·6-47·5), respectively. During treatment, the mean physical health score declined significantly by 1·7 points each 3 months (P < 0·001) to 40·8 (95% CI 34·4-45·1). The mean mental health score significantly and steadily increased towards 51·2 (95% CI 46·9-54·3) during follow-up (P = 0·026). A total of 23% of patients were cured after 18 months of follow-up. In conclusion, quality of life at time of diagnosis for patients with vascular chronic Q fever is lower compared to a similar group of patients, matched for age and gender, with an aortic abdominal aneurysmal disease, and physical health decreases further after starting treatment. Considering the low percentage of cure, the current treatment of vascular chronic Q fever patients may require a separate strategy from that of endocarditis in order to increase survival.

Vascular complications and surgical interventions after world's largest Q fever outbreak

OBJECTIVE

Since chronic Q fever often develops insidiously, and symptoms are not always recognized at an early stage, complications are often present at the time of diagnosis. We describe complications associated with vascular chronic Q fever as found in the largest cohort of chronic Q fever patients so far.

METHODS

Patients with proven or probable chronic Q fever with a focus of infection in an aortic aneurysm or vascular graft were included in this study, using the Dutch national chronic Q fever database.

RESULTS

A total of 122 patients were diagnosed with vascular chronic Q fever between April 2008 and June 2012. The infection affected a vascular graft in 62 patients (50.8%) and an aneurysm in 53 patients (43.7%). Seven patients (5.7%) had a different vascular focus. Thirty-six patients (29.5%) presented with acute complications, and 35 of these patients (97.2%) underwent surgery. Following diagnosis and start of antibiotic treatment, 26 patients (21.3%) presented with a variety of complications requiring surgical treatment during a mean follow-up of 14.1 ± 9.1 months. The overall mortality rate was 23.7%. Among these patients, mortality was associated with chronic Q fever in 18 patients (62.1%).

CONCLUSIONS

The management of vascular infections with C. burnetii tends to be complicated. Diagnosis is often difficult due to asymptomatic presentation. Patients undergo challenging surgical corrections and long-term antibiotic treatment. Complication rates and mortality are high in this patient cohort.

Vasculitis related to viral and other microbial agents

Vasculitis due to infection may occur as a consequence of the inflammation of vessel walls due to direct or contiguous infection, type II or immune complex-mediated reaction, cell-mediated hypersensitivity, or inflammation due to immune dysregulation triggered by bacterial toxin and/or superantigen production. As immunosuppressive therapy administered in the absence of antimicrobial therapy may increase morbidity and fail to effect the resolution of infection-associated vascular inflammation, it is important to consider infectious entities as potential inciting factors in vasculitis syndromes. The causality between infection and vasculitis has been established in hepatitis B-associated polyarteritis nodosa (HBV-PAN) and hepatitis C-associated (cryoglobulinemic) vasculitis (HCV-CV). The review summarizes the recent literature on the pathophysiological mechanisms and the approaches to the management of HBV-PAN and HCV-CV. Roles of other viral and microbial infections, which either manifest as vasculitic syndromes or are implicated in the pathogenesis of primary vasculitides, are also discussed.

Persistent endoleak after endovascular aneurysm repair for acute Q-fever-infected aortocaval fistula

We present a case of an endovascular aneurysm repair for a Q-fever-infected acute abdominal aortic aneurysm with aortocaval fistula. Type 2 endoleak persisted after successful endovascular repair.

Coxiella burnetii infection in hemodialysis and other vascular grafts

Prosthetic arteriovenous (AV) graft infection is the principal cause of morbidity related to chronic hemodialysis AV graft fistula. Coxiella burnetii is a known pathogen that causes fever, pneumonia, and intravascular infections with the limitation of negative cultures. Herein, we report the first case of a patient who presented to the emergency department of our hospital with a prosthetic hemodialysis AV graft infection due to Coxiella burnetii. We also performed a literature search with PubMed to identify studies reporting cases of Coxiella burnetii vascular graft infection. Overall, we reviewed 15 cases of vascular graft infection, including ours. We found a high prevalence of male patients (87%); mean age ± standard deviation (SD) of the entire population was 60.4 ± 9.6 years. The dacron infrarenal aortic and the aortobifemoral bypass were the most common involved grafts. The early diagnosis of infection due to Coxiella burnetii was done by serology or with polymerase chain reaction (PCR), in 12 and 3 cases, respectively. All patients underwent partial or complete resection of the infected grafts; the most common antibiotic treatment for this entity was doxycycline and hydroxycloroquine.Although this is a relatively rare disease, Coxiella burnetii should be included in the differential diagnosis of all patients who present with infection of an endovascular graft of any nature with an inconclusive etiologic diagnosis.

Chronic Q fever in the Netherlands 5 years after the start of the Q fever epidemic: results from the Dutch chronic Q fever database

Coxiella burnetii causes Q fever, a zoonosis, which has acute and chronic manifestations. From 2007 to 2010, the Netherlands experienced a large Q fever outbreak, which has offered a unique opportunity to analyze chronic Q fever cases. In an observational cohort study, baseline characteristics and clinical characteristics, as well as mortality, of patients with proven, probable, or possible chronic Q fever in the Netherlands, were analyzed. In total, 284 chronic Q fever patients were identified, of which 151 (53.7%) had proven, 64 (22.5%) probable, and 69 (24.3%) possible chronic Q fever. Among proven and probable chronic Q fever patients, vascular infection focus (56.7%) was more prevalent than endocarditis (34.9%). An acute Q fever episode was recalled by 27.0% of the patients. The all-cause mortality rate was 19.1%, while the chronic Q fever-related mortality rate was 13.0%, with mortality rates of 9.3% among endocarditis patients and 18% among patients with a vascular focus of infection. Increasing age (P=0.004 and 0.010), proven chronic Q fever (P=0.020 and 0.002), vascular chronic Q fever (P=0.024 and 0.005), acute presentation with chronic Q fever (P=0.002 and P<0.001), and surgical treatment of chronic Q fever (P=0.025 and P<0.001) were significantly associated with all-cause mortality and chronic Q fever-related mortality, respectively.