Clinical Features and Complications of Coxiella burnetii Infections From the French National Reference Center for Q Fever

Acute Coxiella burnetii Infection: A 10-Year Clinical Experience at a Tertiary Care Center in the United States

Background

Identifying and treating patients with acute Q fever who are at an increased risk of progressing to persistent disease is crucial for preventing future complications. In this study, we share our decade-long clinical experience with acute Q fever, highlighting the challenges that clinicians encounter from making an initial diagnosis and performing risk stratification to determining the appropriate prophylaxis regimen and duration.

Methods

We retrieved records of adult Mayo Clinic patients (≥18 years) with positive Coxiella burnetii serology results between 1 January 2012 and 31 March 2022. Patients with Q fever anti-phase II immunoglobulin G ≥1:256 by indirect immunofluorescence were further analyzed.

Results

Thirty-one patients were included. Their median age was 58 years (IQR, 50-64), and the majority were men (84%). Acute hepatitis (29%), flu-like illness (25.8%), and pneumonia (16%) were the most common presentations. Thirteen patients (42%) received antibiotic prophylaxis to prevent disease progression, with significant variation in the indications and duration across physicians. The combination of doxycycline and hydroxychloroquine was the preferred regimen. Prophylaxis was administered for a median 333 days (IQR, 168-414). Four patients (13%) progressed to Q fever native valve infective endocarditis, with elevated anticardiolipin immunoglobulin G levels being the sole risk factor in 2 cases. The small sample size precluded drawing conclusions on the impact of prophylaxis in preventing disease progression.

Conclusions

Management of acute Q fever is complicated by the lack of comprehensive clinical guidelines leading to varied clinical practices. There is a critical need for randomized trials to establish robust evidence-based protocols for management.

Acute Q fever revealed by an anti-phospholipid syndrome: A case report

INTRODUCTION

Q fever is a zoonosis caused by Coxiella burnetii. Acute infection is mainly asymptomatic. In other cases it mainly causes a flu-like illness, a pneumonia, or an hepatitis. We present an atypical case of an acute Q fever revealed by a massive pleural effusion.

CASE REPORT

We report the case of a 43-year-old man referred to our hospital for an acute respiratory distress. Further analyses showed an exudative eosinophilic pleural effusion, associated with a pulmonary embolism and a deep femoral vein thrombosis. Aetiologic explorations revealed an acute Q fever (IgM and IgG against C. burnetii phase II antigens) associated with anti-phospholipids. The outcome was favorable with vitamin K antagonists, doxycycline, and hydroxychloroquine, till the negativation of the anti-phospholipid antibodies.

DISCUSSION AND CONCLUSION

During acute C. burnetii infections, anti-phospholipid antibodies are highly prevalent but thrombotic complications are rare. The 2023 ACR/EULAR APS criteria restricts the diagnosis of APS, as in our case of acute severe infection. In front of an atypical pneumonia and/or thrombotic events, screening of C. burnetii and anti-phospholipid antibodies could be useful. Given its low level of evidence, prolongated treatment by doxycycline, hydroxychloroquine ± anticoagulant for C. burnetii's associated anti-phospholipid syndrome is discussed, but succeeded in our case.

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.

[Non-viral infections of the liver]

Non-viral infections of the liver are rare to very rare compared to viral infections. They can be caused by various bacteria, helminths, protozoa, and fungi, often leading to liver involvement during dissemination. Some of these infections affect in particular immunocompromised individuals, while others need to be considered in the differential diagnostic work-up in patients returning from tropical countries. In cases where the infection occurs through oral ingestion of eggs, such as in cystic and alveolar echinococcosis, the liver is often the most commonly affected organ. Due to the diversity of non-viral liver infections and their varied clinical manifestations, a comprehensive discussion of all potential pathogens and their effects is not within the scope of this article. Therefore, only a few of these conditions will be discussed in more detail.

Lymphangiogenesis: A new strategy for heart disease treatment (Review)

Heart disease remains a global health challenge, contributing notably to morbidity and mortality. The lymphatic vasculature, an integral component of the cardiovascular system, plays a crucial role in regulating essential physiological processes, including fluid balance, transportation of extravasated proteins and immune cell trafficking, all of which are important for heart function. Through thorough scientometric analysis and extensive research, the present review identified lymphangiogenesis as a hotspot in cardiovascular disease research, and the mechanisms underlying impaired cardiac lymphangiogenesis and inadequate lymph drainage in various cardiovascular diseases are discussed. Furthermore, the way used to improve lymphangiogenesis to effectively regulate a variety of heart diseases and associated signaling pathways was investigated. Notably, the current review also highlights the impact of Traditional Chinese Medicine (TCM) on lymphangiogenesis, aiming to establish a clinical basis for the potential of TCM to improve cardiovascular diseases by promoting lymphangiogenesis.

Anticardiolipin Antibody Determination to Guide Q Fever Treatment

Query (Q) fever is a worldwide infectious disease with acute and chronic manifestations caused by Coxiella burnetii. The clinical manifestations are so variable that the disease is often only diagnosed if systematically considered as a differential diagnosis. Here, we present a case of a 39-year-old man who lived in a countryside house, with cattle and sheep in his field, with acute Q fever hepatitis with the typical granulomatous arrangement in the liver biopsy. The diagnosis was confirmed by polymerase chain reaction (PCR) assay in a serum sample and the presence of phase II antibodies. Anticardiolipin antibody (aCL) determination at diagnosis of acute Q fever and during follow-up was made to persecute early identification and to guide the treatment and prophylaxis of possible complications, such as endocarditis.

Chest CT findings in community-acquired pneumonia due to Coxiella burnetii (Q fever) compared to Streptococcus pneumoniae, a cross sectional study in French Guiana, 2013-2017

OBJECTIVES

Few and small studies previously examined chest CT-scan characteristics of Coxiella burnetii (Cb) community-acquired pneumonia (CAP). Larger studies are needed to guide physicians towards diagnosis of Q fever in case of pneumonia.

METHODS

We conducted a single-center retrospective observational study between 2013 and 2017. All patients with Cb or Streptococcus pneumoniae (Sp) CAP who had a chest CT-scan on admission at Cayenne Hospital (French Guiana) were included. Chest CT-scan were all analyzed by the same expert radiologist.

RESULTS

We included 75 patients with Cb CAP and 36 with Sp CAP. Fifty-nine percent of all patients were men (n = 66) and median age was 52 [IQR = 38-62]. Chest CT-scans of Cb CAP patients revealed 67 alveolar condensations (89 %), 52 ground-glass opacities (69 %), 30 cases of lymphadenopathy(ies) (40 %) and 25 pleural effusions (33 %). Parenchyma lesions caused by Cb were predominantly unilateral (67 %). We found high numbers of alveolar condensations in both Cb and Sp CAP (89 % and 75 %; respectively), but the presence of ground-glass opacities was significantly associated with Cb CAP (69 % versus 30 %; p < 0.01). Cb CAP were associated with more lymphadenopathies (40 % vs 17 %; p = 0.01) while Sp CAP showed more bronchial thickening (19 % versus 3 %; p < 0.01) and (micro)nodule(s) ≤1 cm (25 % vs 3 %, p < 0.01).

CONCLUSIONS

This large study shows that the most typical aspect of chest CT-scan in case of Cb CAP in French Guiana is a unilateral alveolar consolidation associated with ground glass opacities and lymphadenopathies. C. burnetti and S. pneumoniae both most often cause alveolar consolidations, but present some significantly different CT-scan patterns. This could help physicians through therapeutic choices.

Inpatient Q Fever Frequency Is on the Rise

Background

Q fever is a zoonotic bacterial infection caused by Coxiella burnetii that is reportable in the USA. This infection is often asymptomatic; acute infection usually manifests as a self-limited febrile illness, hepatitis, or pneumonia. Chronic infection (usually infective endocarditis) often affects patients with valvulopathy or immunosuppression. Herein, we study the inpatient frequency of Q fever in the United States.

Methods

We used a nationwide inpatient sample (NIS) for our retrospective cohort study to include hospitalizations with a diagnosis of Q fever between 2010 and 2019. Survey procedures were applied to accommodate for complex sampling design of NIS. Chi-square and least-square means were used for categorical and continuous variables, respectively. Jonckheere-Terpstra test was used to study the trends over the years. SAS 9.4 was used for data mining and analysis.

Results

A total of 2,685 hospitalizations with a diagnosis of Q fever were included, among which 451 (17%) cases had a concurrent diagnosis of infective endocarditis. The mean age of patients was 58 years, and less than a third was female. Our analysis demonstrated that infective endocarditis was the most common cardiac complication associated with Q fever and was associated with increased inpatient mortality (p value <0.001). There is a trend of an increase in cases of inpatient Q fever with or without endocarditis over the years (p value <0.05). Q fever cases were more common across the Pacific and the South Atlantic divisions.

Conclusion

Physicians should be aware of an increasing trend of hospitalized patients with Q fever and the significant association with infective endocarditis. Further studies are needed.

A Dual-Pathogen Mitral Valve Endocarditis Caused by Coxiella burnetii and Streptococcus gordonii-Which Came First?

Infective endocarditis (IE) is still a life-threatening disease with high morbidity and mortality. While usually caused by a single bacterium, poly-microbial infective endocarditis (IE) is rare. Here, we report a (blood-culture-negative) dual pathogen mitral valve IE caused by Coxiella burnetii and Streptococcus gordonii: A 53-year-old woman was presented to an internal medicine department with abdominal pain for further evaluation. Within the diagnostic work up, transthoracic echocardiography (TTE) revealed an irregularly shaped echogenic mass (5 × 13 mm) adherent to the edge of the posterior mitral valve leaflet and protruding into the left atrium. As infected endocarditis was suspected, blood cultures were initially obtained, but they remained negative. Chronic Q fever infection was diagnosed using serologic testing. After the occurrence of cerebral thromboembolic events, the patient was admitted for mitral valve surgery. Intraoperatively, a massively destructed mitral valve with adhering vegetations was noted. Examination of the mitral valve by broad-range bacterial polymerase chain reaction (PCR) and amplicon sequencing confirmed Coxiella burnetii infection and yielded Streptococcus gordonii as the second pathogen. Based on the detailed diagnosis, appropriate antibiotic therapy of both pathogens was initiated, and the patient could be discharged uneventfully on the 11th postoperative day after a successful minimal-invasive mitral valve replacement.

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.

Identification and Characterization of an HtrA Sheddase Produced by Coxiella burnetii

Having previously shown that soluble E-cadherin (sE-cad) is found in sera of Q fever patients and that infection of BeWo cells by C. burnetii leads to modulation of the E-cad/β-cat pathway, our purpose was to identify which sheddase(s) might catalyze the cleavage of E-cad. Here, we searched for a direct mechanism of cleavage initiated by the bacterium itself, assuming the possible synthesis of a sheddase encoded in the genome of C. burnetii or an indirect mechanism based on the activation of a human sheddase. Using a straightforward bioinformatics approach to scan the complete genomes of four laboratory strains of C. burnetii, we demonstrate that C. burnetii encodes a 451 amino acid sheddase (CbHtrA) belonging to the HtrA family that is differently expressed according to the bacterial virulence. An artificial CbHtrA gene (CoxbHtrA) was expressed, and the CoxbHtrA recombinant protein was found to have sheddase activity. We also found evidence that the C. burnetii infection triggers an over-induction of the human HuHtrA gene expression. Finally, we demonstrate that cleavage of E-cad by CoxbHtrA on macrophages-THP-1 cells leads to an M2 polarization of the target cells and the induction of their secretion of IL-10, which "disarms" the target cells and improves C. burnetii replication. Taken together, these results demonstrate that the genome of C. burnetii encodes a functional HtrA sheddase and establishes a link between the HtrA sheddase-induced cleavage of E-cad, the M2 polarization of the target cells and their secretion of IL-10, and the intracellular replication of C. burnetii.

Modulation of the E-cadherin in human cells infected in vitro with Coxiella burnetii

High concentration of soluble E-cadherin (E-cad) was previously found in sera from Q fever patients. Here, BeWo cells which express a high concentration of E-cad were used as an in vitro model to investigate the expression and function of E-cad in response to infection by Coxiella burnetii, the etiological agent of Q fever. Infection of BeWo cells with C. burnetii leads to a decrease in the number of BeWo cells expressing E-cad at their membrane. A shedding of soluble E-cad was associated with the post-infection decrease of membrane-bound E-cad. The modulation of E-cad expression requires bacterial viability and was not found with heat-inactivated C. burnetii. Moreover, the intracytoplasmic cell concentration of β-catenin (β-cat), a ligand of E-cad, was reduced after bacterial infection, suggesting that the bacterium induces modulation of the E-cad/β-cat signaling pathway and CDH1 and CTNNB1 genes transcription. Finally, several genes operating the canonical Wnt-Frizzled/β-cat pathway were overexpressed in cells infected with C. burnetii. This was particularly evident with the highly virulent strain of C. burnetii, Guiana. Our data demonstrate that infection of BeWo cells by live C. burnetii modulates the E-cad/β-cat signaling pathway.

Coxiella burnetii Pathogenesis: Emphasizing the Role of the Autophagic Pathway

Coxiella burnetii (C. burnetii), the etiological agent of the Q fever disease, ranks among the most sporadic and persistent global public health concerns. Ruminants are the principal source of human infections and diseases present in both acute and chronic forms. This bacterium is an intracellular pathogen that can survive and reproduce under acidic (pH 4 to 5) and harsh circumstances that contain Coxiella-containing vacuoles. By undermining the autophagy defense system of the host cell, C. burnetii is able to take advantage of the autophagy pathway, which allows it to improve the movement of nutrients and the membrane, thereby extending the vacuole of the reproducing bacteria. For this method to work, it requires the participation of many bacterial effector proteins. In addition, the precise and prompt identification of the causative agent of an acute disease has the potential to delay the onset of its chronic form. Moreover, to make accurate and rapid diagnoses, it is necessary to create diagnostic devices. This review summarizes the most recent research on the epidemiology, pathogenesis, and diagnosis approaches of C. burnetii. This study also explored the complicated relationships between C. burnetii and the autophagic pathway, which are essential for intracellular reproduction and survival in host cells for the infection to be effective.

Epidemiology of Zoonotic Coxiella burnetii in The Republic of Guinea

BACKGROUND

Q fever is a zoonotic infectious disease characterized by fever, malaise, chills, significant weakness, and muscle pain. In some cases, the disease can become chronic and affect the inner membranes of the heart, such as the valves, leading to endocarditis and a high risk of death. Coxiella burnetii (C. burnetii) is the primary causative agent of Q fever in humans. This study aims to monitor the presence of C. burnetii in ticks collected from small mammals and cattle in the Republic of Guinea (RG).

METHODS

Rodents were trapped in the Kindia region of RG during 2019-2020, and ticks were collected from cattle in six regions of RG. Total DNA was extracted using a commercial kit (RIBO-prep, InterLabService, Russia) following the manufacturer's instructions. Real-time PCR amplification was conducted using the kit (AmpliSens Coxiella burnetii-FL, InterLabService, Russia) to detect C. burnetii DNA.

RESULTS AND CONCLUSIONS

Bacterial DNA was detected in 11 out of 750 (1.4%) small mammals and 695 out of 9620 (7.2%) tick samples. The high number of infected ticks (7.2%) suggests that they are the main transmitters of C. burnetii in RG. The DNA was detected in the liver and spleen of a Guinea multimammate mouse, Mastomys erythroleucus. These findings demonstrate that C. burnetii is zoonotic in RG, and measures should be taken to monitor the bacteria's dynamics and tick prevalence in the rodent population.

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.

The First Report of Coxiella burnetii as a Potential Neglected Pathogen of Acute Hepatitis of Unknown Causes in Egypt

The World Health Organization (WHO) recently alerted the emergence of new pathogens causing acute hepatitis in children across several countries. This new situation directs us to the screening of neglected pathogens that cause acute hepatitis. Q-fever is a zoonotic disease, caused by Coxiella burnetii. Although a high seroprevalence of Coxiella burnetii was recorded in animals present in Egypt, Q-fever is still a neglected disease, and the diagnosis of Q-fever is not routinely performed in Egyptian hospitals. In this study, we performed a retrospective assessment for Coxiella burnetii in cases of hepatitis of unknown causes (HUC) enrolled in Assiut University hospitals, in Egypt. Out of 64 samples of HUC, 54 samples were negative for all hepatitis markers, labeled as acute hepatitis of unknown etiology (AHUE), and 10 samples tested positive for adenovirus and Hepatitis E virus (HEV). Q-fever was detected in 3 out of 54 (5.6%) of AHUE, and one sample was confirmed as coinfection of HEV/Q-fever. Jaundice was the most common clinical symptom developed in the patients. In conclusion, Coxiella burnetii was found to be a potential cause of acute hepatitis in HUC. The diagnosis of Q-fever should be considered in acute hepatitis cases in Egyptian hospitals.

Rare case of chronic Q fever myocarditis in end stage heart failure patient: A case report

BACKGROUND

Q fever myocarditis is a rare disease manifestation of Q fever infection caused by Coxiella burnetii. It is associated with significant morbidity and mortality if left untreated. Prior studies have reported myocarditis in patients with acute Q fever. We present the first case of chronic myocarditis in an end-stage heart failure patient with chronic Q fever infection.

CASE SUMMARY

A 69-year-old male was admitted with dyspnea on exertion, hypotension and bilateral lower extremity edema for a few months. He has a past medical history of ischemic cardiomyopathy with left ventricular ejection fraction of 25%, implantable cardioverter defibrillator in place, bioprosthetic aortic valve and mitral valve replacement. He continued to have shortness of breath despite diuresis along with low grade fevers. Initial infectious work up came back negative. On further questioning, the patient was found to have close contact with farm animals and the recurrent fevers prompted the work-up for Q fever. Q fever serologies and cardiac positron emission tomography confirmed the diagnosis of chronic Q fever myocarditis. He was then successfully treated with doxycycline and hydroxychloroquine for 18 mo.

CONCLUSION

Chronic Q fever myocarditis, if left untreated, carries a poor prognosis. It should be kept in differentials, especially in patients with recurrent fevers and contact with farm animals.

The epidemiological survey of Coxiella burnetii in small ruminants and their ticks in western Iran

Background

Q fever is one of the most important zoonotic diseases caused by Coxiella burnetii. Although Q fever is an endemic disease in Iran, epidemiological data on C. burnetii infection are not yet complete in reservoirs and vectors in some parts of Iran. This survey investigated C. burnetii infection in small ruminants (sheep and goat blood samples) and their ticks in western Iran (Kurdistan province) in 2020. The presence of C. burnetii DNA was identified in these samples by targeting the IS1111 gene using the quantitative PCR (qPCR) method.

Results

Out of 250 blood samples (232 sheep and 18 goats), C. burnetii was detected in two samples (0.8%) belonging to the sheep (0.9%). In addition, 34 of 244 collected ticks (13.9%) from infested animals (244) were positive for C. burnetii infection. The highest prevalence of infection was found in Dermacentor marginatus (18.3%) and Haemaphysalis concinna (12.5%).

Conclusions

The present study showed that ticks could have a possible role in the epidemiology of Q fever in Iran.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03396-0.

Targeted Screening for Chronic Q Fever, the Netherlands

Early detection of and treatment for chronic Q fever might prevent potentially life-threatening complications. We performed a chronic Q fever screening program in general practitioner practices in the Netherlands 10 years after a large Q fever outbreak. Thirteen general practitioner practices located in outbreak areas selected 3,419 patients who had specific underlying medical conditions, of whom 1,642 (48%) participated. Immunofluorescence assay of serum showed that 289 (18%) of 1,642 participants had a previous Coxiella burnetii infection (IgG II titer >1:64), and 9 patients were suspected of having chronic Q fever (IgG I y titer >1:512). After medical evaluation, 4 of those patients received a chronic Q fever diagnosis. The cost of screening was higher than estimated earlier, but the program was still cost-effective in certain high risk groups. Years after a large Q fever outbreak, targeted screening still detected patients with chronic Q fever and is estimated to be cost-effective.

High endemicity of Q fever in French Guiana: A cross sectional study (2007–2017)

Q fever (QF) is a zoonosis caused by Coxiella burnetii (Cb). French Guiana (FG) had a high incidence but no data have been published since 2006. The objective of this study was to update the incidence and epidemiological data on QF in FG. A retrospective study of all FG Q fever serodiagnosis between 2007 and 2017 was carried out. Among the 695 patients included, the M/F sex-ratio was 2.0 and the median age of 45.3 years (IQR 33.7–56.3). The annual QF incidence rate was 27.4 cases (95%CI: 7.1–47.7) per 100,000 inhabitants ranging from 5.2 in 2007 to 40.4 in 2010. Risk factors associated with Q fever compared to general population were male gender, being born in mainland France, an age between 30 to 59 years-old and a residence in Cayenne and surroundings. The incidence of QF in FG remains high and stable and the highest in the world.

We present here a study showing the exceptional nature of the incidence of Q fever in French Guiana. Indeed, this zoonosis due to the bacterium Coxiella burnetii, is a real public health problem in French Guiana, a French ultra-marine territory located in the North East of South America. The study found an endemic state with a stable incidence between 2010 and 2017 around 25–30 cases per 100,000 inhabitants per year. More than 90% of cases are concentrated in the territory’s capital, Cayenne, and its surroundings. The risk factors for Q fever are being male, being between 30 and 59 years old, which are risk factors found elsewhere, but also living in Cayenne and its surroundings and being born in mainland France or Europe.

Diagnosis of Coxiella burnetii infection via metagenomic next-generation sequencing: a case report

BACKGROUND

Coxiella burnetii, the etiologic agent of Q fever, is mainly responsible for endocardite. But there are only a few cases of Coxiella burnetii-caused wound infection have been published, because the pathogen is very difficult to isolate using conventional culture methods.

CASE PRESENTATIONS

A 76-year-old man, underwent endovascular repair of ruptured left iliac aneurysm plus abdominal aortic aneurysm under general anesthesia in 2018. Left iliac fossa mass resection was performed in 2020. After operation, the wound in the left iliac fossa was repeatedly ruptured and not healing. We used the wound tissue to perform the Metagenomics next-generation sequencing (mNGS), Coxiella burnetii was detected. Sanger sequencing and serologic verification of Coxiella burnetii all showed positive results.

CONCLUSIONS

This study proved that mNGS was an effective method to detect clinically unexplained infections, and showed the ability of pathogen identification with high sensitivity and accuracy.

Potential association between bacterial infections and ischemic stroke based on fifty case-control studies: a systematic review and meta-analysis

Background

Stroke is considered as one of the most important concerns in health care centers around the world. By definition there are two types of stroke including ischemic stroke and hemorrhagic stroke. Approximately three-quarters of stroke cases are ischemic strokes, which occur due to several risk factors such as hypertension, obesity, atherosclerosis, diabetes mellitus, osteoarthritis, and inflammatory responses. In recent years, infectious diseases have noticed as a new risk factor for ischemic stroke. Given the importance of the issue, some bacteria that cause chronic infections, especially Chlamydia pneumonia, Helicobacter pylori, Mycoplasma pneumonia, Mycobacterium tuberculosis, and Coxiella burnetii have been considered.

Methods

In the present meta-analysis, we reviewed 50 case-control studies and assessed the possible association of bacterial infections with the occurrence of ischemic stroke.

Results

We analyzed the information of 33,978 participants in several nested case-control studies, and ultimately showed that bacterial infections could increase the risk of ischemic stroke. Our results suggest that bacterial infections significantly increase in the risk of ischemic stroke (OR: 1.704; 1.57-1.84 with 95% CIs; p value = 0.01).

Conclusions

In this meta-analysis, a significant relationship was observed between infection by three bacteria such as C. pneumoniae, H. pylori, and M. tuberculosis with the occurrence of ischemic stroke. Furthermore, due to the similarity between TLRVYK domain in β2-glycoprotein-I and TLRVYK peptide in various of microorganisms, produced antibodies against pathogens interact with β2-glycoprotein-I, hence the cross-reaction phenomenon increases the positive relationship between infectious diseases and ischemic stroke.

Exposure of South African Abattoir Workers to Coxiella burnetii

Abattoir workers may contract Q fever by inhalation of Coxiella burnetii bacteria in aerosols generated by slaughtering livestock, or in contaminated dust. We estimated the seroprevalence of C. burnetii and examined the associated factors in a survey of South African abattoir workers. Coxiella burnetii seropositivity was determined by detection of IgG antibodies against C. burnetii phase II antigen. Logistic regression, adjusted for clustering and sampling fraction, was employed to analyze risk factors associated with C. burnetii seropositivity. Among 382 workers from 16 facilities, the overall seroprevalence was 33% (95% confidence interval (CI): 28–38%) and ranged from 8% to 62% at the facility level. Prolonged contact with carcasses or meat products (odds ratio (OR): 4.6, 95% CI: 1.51–14.41) and prior abattoir or butchery work experience (OR: 1.9, 95% CI: 1.13–3.17) were associated with C. burnetii seropositivity. In contrast, increasing age and livestock ownership were inversely associated. Precautions to protect abattoir personnel from Q fever are discussed.

Seroepidemiologic evidence of Q fever and associated factors among workers in veterinary service laboratory in South Korea

The incidence of Q fever has rapidly increased in South Korea since 2015. This study was undertaken to investigate the seroprevalence and seroreactivity of Q fever and the risk factors associated with its seroprevalence among workers in the veterinary service laboratory (VSL) in South Korea. This seroepidemiologic study was conducted in a total of 661 human subjects out of 1,328 subjects working in 50 VSL existing in South Korea between July 15 and July 29, 2019. Data were collected by administering survey questionnaires and by analyzing collected blood samples to determine the presence of antibodies against Coxiella burnetii. The seroprevalence and seroreactivity of C. burnetii infection were determined based on serum titers as (phase II IgG ≥1:256 and/or IgM ≥1:16) and (phase II IgG ≥1:16 and/or IgM ≥1:16) as determined by indirect immunofluorescent assay. Work, work environment, behavioral risk and protective factors associated with seroprevalence of Q fever were assessed by employing multivariable logistic regression analysis. Among the 661, the seroprevalence and seroreactivity of C. burnetii infection were 7.9% and 16.0%, respectively. Multivariate logistic regression analysis showed the risk factors significantly associated with seroprevalence were the antemortem inspection of cattle, goats, or sheep (APR (adjusted prevalence ratio), 2.52; 95% CI, 1.23–4.70)), animal blood splashed into or around eyes (APR, 2.24; 95% CI, 1.04–4.41), and contact with animals having Q fever (APR, 6.58; 95% CI, 3.39–10.85) during the previous year. This study suggests the need for precautions when contact with cattle, goats, or sheep is expected, especially during the antemortem inspection, when dealing with C. burnetii infected animals, or when there is a risk of ocular contact with animal derivatives. Therefore, we recommend the consistent use of appropriate personal protective equipment and other protective measures including PPE treatment and washing of body surfaces after work to prevent C. burnetii infections among VSL staff in South Korea.

Mimickers of Large Vessel Giant Cell Arteritis

Giant cell arteritis (GCA) is a large-vessel granulomatous vasculitis occurring in patients over 50-year-old. Diagnosis can be challenging because there is no specific biological test or other diagnoses to consider. Two main phenotypes of GCA are distinguished and can be associated. First, cranial GCA, whose diagnosis is usually confirmed by the evidence of a non-necrotizing granulomatous panarteritis on temporal artery biopsy. Second, large-vessel GCA, whose related symptoms are less specific (fever, asthenia, and weight loss) and for which other diagnoses must be implemented if there is neither cephalic GCA nor associated polymyalgia rheumatica (PMR) features chronic infection (tuberculosis, Coxiella burnetti), IgG4-related disease, Erdheim Chester disease, and other primary vasculitis (Behçet disease, relapsing polychondritis, or VEXAS syndrome). Herein, we propose a review of the main differential diagnoses to be considered regarding large vessel vasculitis.

In Silico Design of a New Multi-Epitope Peptide-Based Vaccine Candidate Against Q Fever

Novel types of the vaccines with high immunogenicity and low risks, including epitope-based vaccines, are sought. Among zoonotic disease, Q fever caused by Coxiella burnetii is an important target due to numerous outbreaks and the pandemic potential. Here we present a synthetic multi-epitope vaccine against Coxiella burnetii. This vaccine was developed using immunoinformatics approach. Antigenic proteins were studied, and five T cell epitopes were selected. Antigenicity, allergenicity, and toxicity of the selected epitopes were evaluated using the VaxiJen 2.0, AllerTOP, and ToxinPred servers, respectively. Selected epitopes were joined in a peptide sequence, with the cholera toxin B subunit (CTXB) as an adjuvant. The affinity of the proposed vaccine to MHC I and II molecules was measured in a molecular docking study. Resultant vaccine has high antigenicity, stability, and a half-life compatible with utilization in vaccination programs. In conclusion, the validated epitope sequences may be used as a potential vaccine to ensure protection against Q fever agent.

Impact of Sex Hormones on Macrophage Responses to Coxiella burnetii

Introduction

Q fever, a zoonosis caused by Coxiella burnetii, affects more males than females despite a similar level of exposure. A protective role of estradiol has been reported in mice, suggesting that sex hormones are involved in C. burnetii infection. We wondered whether the responses of monocytes and monocyte-derived macrophages (MDMs) to C. burnetii are influenced by sex hormones.

Materials and Methods

The bacterial intracellular fate in monocytes was studied using quantitative PCR, and monocyte cytokine production in response to C. burnetii was assessed using qRT-PCR and immunoassays. Before infection, MDMs from males and females were incubated with testosterone and estradiol, respectively.

Results

Bacterial uptake and persistence were similar in monocytes from males and females but were slightly increased in male MDMs. The expression of inflammatory genes, including those encoding TNF and CXCL10, was higher in MDMs from females than in MDMs from males infected by C. burnetii. Adding testosterone to male MDMs amplified their immunoregulatory properties, including increased expression of IL10 and TGFB genes and TGF-β production in response to C. burnetii. In contrast, adding estradiol to MDMs from females had no effect on their inflammatory profile.

Conclusion

The stronger inflammatory profile of macrophages from females may have a protective role, likely under estrogen control, while testosterone may affect disease progression by promoting an anti-inflammatory response. This finding may have consequences for personalized management of patients with Q fever.

Coxiella burnetti prosthetic joint infection in an immunocompromised woman: iterative surgeries, prolonged ofloxacin-rifampin treatment and complex reconstruction were needed for the cure

Background

Q fever is a zoonotic disease caused by the bacterium Coxiella burnetii, a strictly intracellular pathogen that can cause acute and chronic infection. Chronic Q fever can occur in immunocompetent as well as in immuno-compromised hosts, as a persistent localized infection. The main localizations are endocardial, vascular and, less frequently, osteoarticular. The most frequent osteoarticular form is spondyliscitis. Recommended treatment is combined doxycycline and hydroxychloroquine for 18 months, with cotrimoxazole as another option. Coxiella burnetti infection has been implicated in rare cases of prosthetic joint infection (PJI), and the medical and surgical management and outcome in such cases have been little reported.

Case presentation

We report an unusual case of chronic Q fever involving a hip arthroplasty in an immunocompromised woman treated with tumor necrosis factor (TNF)-α blockers for rheumatoid arthritis. Numerous surgical procedures (explantation, “second look”, femoral resection and revision by megaprosthesis), modification of the immunosuppressant therapy and switch from doxycycline-hydroxychloroquine to prolonged ofloxacin-rifampin combination therapy were needed to achieve reconstruction and treat the PJI, with a follow-up of 7 years.

Conclusions

Coxiella burnetti PJI is a complex infection that requires dedicated management in an experienced reference center. Combined use of ofloxacin-rifampin can be effective.

Metabolic Plasticity Aids Amphotropism of Coxiella burnetii

Coxiella burnetii, the causative agent of query (Q) fever in humans, is an obligate intracellular bacterium. C. burnetii can naturally infect a broad range of host organisms (e.g., mammals and arthropods) and cell types. This amphotropic nature of C. burnetii, in combination with its ability to utilize both glycolytic and gluconeogenic carbon sources, suggests that the pathogen relies on metabolic plasticity to replicate in nutritionally diverse intracellular environments. To test the significance of metabolic plasticity in C. burnetii host cell colonization, C. burnetii intracellular replication in seven distinct cell lines was compared between a metabolically competent parental strain and a mutant, CbΔpckA, unable to undergo gluconeogenesis. Both the parental strain and CbΔpckA mutant exhibited host cell-dependent infection phenotypes, which were influenced by alterations to host glycolytic or gluconeogenic substrate availability. Because the nutritional environment directly impacts host cell physiology, our analysis was extended to investigate the response of C. burnetii replication in mammalian host cells cultivated in a novel physiological medium based on the nutrient composition of mammalian interstitial fluid, interstitial fluid-modeled medium (IFmM). An infection model based on IFmM resulted in exacerbation of a replication defect exhibited by the CbΔpckA mutant in specific cell lines. The CbΔpckA mutant was also attenuated during infection of an animal host. Overall, the study underscores that gluconeogenic capacity aids C. burnetii amphotropism and that the amphotropic nature of C. burnetii should be considered when resolving virulence mechanisms in this pathogen.

Seroreactivity to Coxiella burnetii in an Agricultural Population and Prevalence of Coxiella burnetii Infection in Ticks of a Non-Endemic Region for Q Fever in South Korea

Coxiella burnetii infects humans and wild and domesticated animals. Although reported cases on Jeju Island, off the coast of South Korea, are rare, the region is considered to have a high potential for Q fever. We investigated the seroprevalence of antibodies to C. burnetii in 230 farmers living in ten rural areas on Jeju Island between January 2015 and December 2019. Blood samples were collected and examined for C. burnetii Phase I/II IgM and IgG antibodies. Trained researchers collected ticks from rural areas. Clone XCP-1 16S ribosomal RNA gene sequencing was performed to identify Coxiella species from the collected ticks. The overall seroprevalence of antibodies to C. burnetii in farmers was 35.7%. The seroprevalence was significantly higher in fruit farmers. Of the collected ticks, 5.4% (19/351) of the Haemaphysalis longicornis ticks harbored C. burnetti. A high seroprevalence of antibodies to C. burnetii was observed in this region of Jeju Island, confirming that C. burnetti is endemic. Physicians should thus consider Q fever in the differential diagnosis of patients that present with acute fever after participating in outdoor activities.

Screening for Q Fever in Patients Undergoing Transcatheter Aortic Valve Implantation, Israel, June 2018-May 2020

Q fever infective endocarditis frequently mimics degenerative valvular disease. We tested for Coxiella burnettii antibodies in 155 patients in Israel who underwent transcatheter aortic valve implantation. Q fever infective endocarditis was diagnosed and treated in 4 (2.6%) patients; follow-up at a median 12 months after valve implantation indicated preserved prosthetic valvular function.

Frenemies within: An Endocarditis Case in Behçet's Disease

A 57-year female patient diagnosed with Behçet's disease, on azathioprine, was noticed to have at a routine examination antinuclear and antiphospholipid antibodies. An overlapping lupus-like syndrome was diagnosed; hydroxychloroquine and aspirin were added. Three years later, the patient presented with dyspnea and sweating, with no fever. A cardiac bruit was noted; a giant vegetation was detected by echocardiography. Laboratory revealed severe thrombocytopenia, antiphospholipid antibodies and low complement. Blood cultures were positive for Abiotrophia defectiva serology and also revealed a chronic Coxiella burnetii infection. Antibiotic therapy, low-dose anticoagulation and control of the underlying disease mildly improved the platelet count, which fully recovered only after cardiac valve replacement. However, the Behçet's disease, initially quiescent, flared after the therapy of infections. We discuss potential links between Behçet's disease and the occurrence of antinuclear and antiphospholipid antibodies and Coxiella endocarditis in this setting. We also highlight the differences between the endocarditis in Behçet's disease, antiphospholipid syndrome, Coxiella burnetii and Abiotrophia defectiva infection, respectively. Intracellular infections may modify the presentation of autoimmune diseases. Confounding clinical features of Coxiella persistent infection and non-bacterial thrombotic endocarditis in Behçet's disease warrant further insight.

Sexual Dimorphism and Gender in Infectious Diseases

Epidemiological studies and clinical observations show evidence of sexual dimorphism in infectious diseases. Women are at less risk than men when it comes to developing most infectious diseases. However, understanding these observations requires a gender approach that takes into account an analysis of both biological and social factors. The host’s response to infection differs in males and females because sex differences have an impact on hormonal and chromosomal control of immunity. Estradiol appears to confer protective immunity, while progesterone and testosterone suppress anti-infectious responses. In addition, genetic factors, including those associated with sex chromosomes, also affect susceptibility to infections. Finally, differences in occupational activities, lifestyle, and comorbidities play major roles in exposure to pathogens and management of diseases. Hence, considering sexual dimorphism as a critical variable for infectious diseases should be one of the steps taken toward developing personalized therapeutic approaches.

The diagnostic challenge of acute Q fever endocarditis

A 79-year-old man was admitted to our ward with symptomatic heart failure 2 months after aortic valve replacement due to severe aortic stenosis. On the third day following admission, he became febrile (>38°C) while manifesting an increase in inflammatory markers. Endocarditis was suspected despite negative blood cultures. Echocardiogram (transthoracic and transesophageal) did not describe any vegetations. No hypermetabolic lesions were described on the Positron emission tomography scan. Empirical antibiotics were started but the fever persisted. Serologies revealed a Coxiella burnetii IgG phase II titre of 1:800, high erythrocyte sedimentation rate. Positive antinuclear antibodies, antibeta2 IgM and anticardiolipin supported a diagnosis of acute Q fever endocarditis. Doxycycline and hydroxychloroquine were started with total resolution of symptoms. This case illustrates the difficulty of diagnosing Q fever endocarditis during its acute phase, not only because vegetations can be minimal or absent, a challenge that is further compounded by a complex presentation of immunological markers.

Q Fever Endocarditis and a New Genotype of Coxiella burnetii, Greece

Underdiagnosis of Coxiella burnetii infections in Greece is possible because of lack of awareness by physicians, and most suspected cases are in patients with no bovine contact. We found serologic evidence of C. burnetii infection throughout Greece and identified a new C. burnetii genotype in the aortic valve of a patient with Q fever endocarditis.

Utility of positron emission tomography imaging in the diagnosis of chronic Q fever: A Systematic Review

Chronic Q fever is a diagnostic challenge. Diagnosis relies on serology and/or the detection of DNA from blood or tissue samples. PET-CT identifies tissues with increased glucose metabolism, thus identifying foci of inflammation. Our aim was to review the existing literature on the use of PET-CT to help diagnose chronic Q fever. A literature search was conducted in PubMed and Google Scholar to ascertain publications that included the terms 'Positron Emission Tomography' and 'PET CT' in combination with subheadings 'chronic Q fever' and 'Coxiella burnetii' within the search. To broaden our search retrieval, we used the terms 'chronic Q fever' and 'PET-CT'. Published literature up to 16^th April 2020 was included. 274 articles were initially identified. Post-exclusion criteria, 46 articles were included. Amongst case reports and series, the most frequent focus of infection was vascular, followed by musculoskeletal then cardiac. 79.5% of patients had a focus detected with 55.3% of these having proven infected prosthetic devices. Amongst the retrospective and prospective studies, a total of 394 positive sites of foci were identified with 186 negative cases. Some had follow-up scans (53), with 75.5% showing improvement or resolution. Average timeframe for documented radiological resolution post-initiating treatment was 8.86 months. PET-CT is a useful tool in the management of chronic Q fever. Knowledge of a precise focus enables for directed surgical management helping reduce microbial burden, preventing future complications. Radiological resolution of infection can give clinicians reassurance on whether antimicrobial therapy can be ceased earlier, potentially limiting side effects.

From Coxiella burnetii Infection to Pregnancy Complications: Key Role of the Immune Response of Placental Cells

The infection of pregnant animals and women by Coxiella burnetii, an intracellular bacterium, compromises both maternal health and foetal development. The placenta is targeted by C. burnetii, as demonstrated by bacteriological and histological evidence. It now appears that placental strains of C.&nbsp;burnetii are highly virulent compared to reference strains and that placental injury involves different types of placental cells. Trophoblasts, the major placental cells, are largely infected by C. burnetii and may represent a replicating niche for the bacteria. The placenta also contains numerous immune cells, including macrophages, dendritic cells, and mast cells. Placental macrophages are infected and activated by C. burnetii in an unusual way of M1 polarisation associated with bacterial elimination. Placental mast cells eliminate bacteria through a mechanism including the release of extracellular actin filaments and antimicrobial peptides. In contrast, C. burnetii impairs the maturation of decidual dendritic cells, favouring bacterial pathogenicity. Our aim is to review C. burnetii infections of human placentas, paying special attention to both the action and function of the different cell types, immune cells, and trophoblasts targeted by C. burnetii in relation to foetal injury.

Q fever presenting as myocarditis

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Coxiella burnetti should be evocated in patients with acute myocarditis in epidemic countries.

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The prognosis of myocarditis is uncertain Treatment with corticoid could be useful in myocarditis to avoid the evolution to dilated cardiomyopathy.

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Myocarditis in certainly under estimated in patients with Q fever.

We report the case of a 19-year-old healthy adolescent, living in an urban area, admitted because of acute chest pain and extensive anterior ST elevation. Coronary arteries were normal on coronary angiography; troponins were very high, echocardiography revealed a preserved global systolic function but an alteration of the longitudinal strain in the inferolateral wall. Cardiac MRI confirmed the diagnosis of acute myocarditis. As part of the etiological workup, Coxiella burnetii serology showed an acute infection. The diagnosis of Coxiella burnetii myocarditis was retained and the patient was treated with doxycycline and corticosteroid therapy. The myocardial localization of this germ is unusual but can be serious, hence the interest of a Coxiella serology in endemic countries face to any acute myocarditis.