Microbiological challenges in the diagnosis of chronic Q fever

Current Status of Q Fever and the Challenge of Outbreak Preparedness in Korea: One Health Approach to Zoonoses

Human Q fever, a zoonosis caused by Coxiella burnetii, presents with diverse clinical manifestations ranging from mild self-limited febrile illnesses to life-threatening complications such as endocarditis or vascular infection. Although acute Q fever is a benign illness with a low mortality rate, a large-scale outbreak of Q fever in the Netherlands led to concerns about the possibility of blood transfusion-related transmission or obstetric complications in pregnant women. Furthermore, a small minority (< 5%) of patients with asymptomatic or symptomatic infection progress to chronic Q fever. Chronic Q fever is fatal in 5-50% of patients if left untreated. In South Korea, Q fever in humans was designated as a notifiable infectious disease in 2006, and the number of Q fever cases has increased sharply since 2015. Nonetheless, it is still considered a neglected and under-recognized infectious disease. In this review, recent trends of human and animal Q fever in South Korea, and public health concerns regarding Q fever outbreaks are reviewed, and we consider how a One Health approach could be applied as a preventive measure to prepare for zoonotic Q fever outbreaks.

Diagnosis of Acute Q Fever in a Patient by Using Metagenomic Next-Generation Sequencing: A Case Report

Background

Q fever is a zoonotic disease caused by Coxiella burnetii infection, with domestic ruminants as the main source of infection and tick bites as one of the transmission vectors. The clinical manifestations of Q fever are varied and atypical. For the reason that C. burnetii is a strictly intracellular pathogen, it is difficult to be diagnosed by traditional culture methods. Additionally, serological and molecular diagnostic methods to assist in the diagnosis of Q fever are not routinely performed in most clinical laboratories. Therefore, early and rapid diagnosis of Q fever is a challenge.

Case Presentation

In the present study, a 34-year-old male patient presented with an acute onset and symptoms such as high fever, lethargy, pulmonary infection, and liver damage. In addition, he had a history of tick bites. Despite conducting relevant laboratory and radiological examinations, the etiology remained unknown. Subsequently, we detected the sequence reads of C. burnetii in a venous blood sample using metagenomic next-generation sequencing (mNGS), and the symptoms of patients were significantly improved after timely treatment with the special drug tetracycline. To our knowledge, this is the first report of Q fever associated with C. burnetii detected directly from venous blood sample in Wuhan, China.

Conclusion

Metagenomic next-generation sequencing is a new diagnostic technology that provides rapid and accurate detection of unexplained infections, including Q fever. Its application plays a crucial role in clinical diagnosis for identifying elusive pathogens.

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.

High incidence of asymptomatic phase I IgG seroconversion after acute Q fever episode: implications for chronic Q fever diagnosis

BACKGROUND

The aim of this study was to describe the natural history of acute Q fever, including its clinical and serological evolution and progression to chronic Q fever.

METHODS

Observational cohort study (January 2011-September 2020) performed at Valme University Hospital (Seville, Spain). Inclusion criteria: 1) Patients over the age of eighteen; 2) Acute Q fever diagnosis, defined as suggestive symptoms in the presence of phase II IgG titer > 1:256; 3) At least 6 months follow-up after the acute Q fever episode. The incidence of seroconversion to a chronic Q fever serological pattern, defined as phase I IgG titers ≥ 1:1024 six months after acute Q fever diagnosis, was assessed.

RESULTS

During the study period, 117 patients were included. Thirty-four (29%) patients showed phase I IgG titers ≥ 1:1024 six months after acute Q fever diagnosis. All patients with classic serologic criteria for chronic Q fever diagnosis remained asymptomatic despite no specific treatment, with a median (Q1-Q3) follow-up of 26.5 (14-44) months in this subgroup. No cases of Q fever endocarditis neither other persistent focalized infection forms were observed during the study period.

CONCLUSIONS

A significant proportion of acute Q fever patients develops classic serologic criteria for chronic Q fever diagnosis in the absence of additional data of chronic Q fever. Consequently, phase I IgG cutoff titer > 1:800 should not be used as a criterion to consider such a diagnosis. The incidence of persistent focalized infection forms after acute Q fever is extremely low and does not justify the use of prophylaxis strategies.

Polymicrobial Infections Among Patients with Vascular Q Fever, France, 2004-2020

We report 5 cases of vascular Q fever complicated by polymicrobial superinfection in patients who had no risk factors for acute Q fever. Q fever was diagnosed by serologic and molecular assays for Coxiella burnetii. We confirmed additional infections using conventional graft cultures.

The prognostic value of serological titres for clinical outcomes during treatment and follow-up of patients with chronic Q fever

OBJECTIVES

We assessed the prognostic value of phase I IgG titres during treatment and follow-up of chronic Q fever.

METHODS

We performed a retrospective cohort study to analyse the course of phase I IgG titres in chronic Q fever. We used a multivariable time-varying Cox regression to assess our primary (first disease-related event) and secondary (therapy failure) outcomes. In a second analysis, we evaluated serological characteristics after 1 year of therapy (fourfold decrease in phase I IgG titre, absence of phase II IgM and reaching phase I IgG titre of ≤1:1024) with multivariable Cox regression.

RESULTS

In total, 337 patients that were treated for proven (n = 284, 84.3%) or probable (n = 53, 15.7%) chronic Q fever were included. Complications occurred in 190 (56.4%), disease-related mortality in 71 (21.1%) and therapy failure in 142 (42.1%) patients. The course of phase I IgG titres was not associated with first disease-related event (HR 1.00, 95% CI 0.86-1.15) or therapy failure (HR 1.02, 95% CI 0.91-1.15). Similar results were found for the serological characteristics for the primary (HR 0.97, 95% CI 0.62-1.51; HR 1.12, 95% CI 0.66-1.90; HR 0.99, 95% CI 0.57-1.69, respectively) and secondary outcomes (HR 0.86, 95% CI 0.57-1.29; HR 1.37, 95% CI 0.86-2.18; HR 0.80, 95% CI 0.48-1.34, respectively).

DISCUSSION

Coxiella burnetii serology does not reliably predict disease-related events or therapy failure during treatment and follow-up of chronic Q fever. Alternative markers for disease management are needed, but, for now, management should be based on clinical factors, PCR results, and imaging results.

Surveillance for One Health and high consequence veterinary pathogens (Brucellosis, Coxiellosis and Foot and Mouth Disease) in Southeast Asia: Lao PDR and Cambodia in focus and the importance of international partnerships

Animal disease surveillance in limited-resource countries is challenging but critical in providing epidemiological information to inform disease prevention and control programmes. Despite multiple international agencies and partnerships supporting Lao PDR and Cambodia’s animal disease surveillance activities over many years, cost-effectiveness and sustainability remain significant constraints. Here we describe the development and implementation of national abattoir-based surveillance networks in Laos and central Cambodia consisting of an information exchange platform and sample collection and submission systems. The networks enhanced the national surveillance capacity and provided snapshot information of seroprevalence for selected One Health and high consequence veterinary pathogens, including Q fever, brucellosis, and Foot and Mouth Disease (FMD). Despite abattoir survey data revealing that the seroprevalence of Q fever and brucellosis was generally low, the true impact on public health for these diseases remains unclear due to low levels of awareness and diagnostic capacity. FMD antibodies derived from natural infection rather than vaccination were noted in greater than 40% of the animal sampled in both countries, which suggests significant underreporting of outbreak events. Such networks will continue to be refined to improve their cost-effectiveness and sustainability, including the introduction of a simple online application for reporting animal disease outbreaks as well as expanding to other relevant One Health pathogens and species.

Linking longitudinal and cross-sectional biomarker data to understand host-pathogen dynamics: Leptospira in California sea lions (Zalophus californianus) as a case study

Confronted with the challenge of understanding population-level processes, disease ecologists and epidemiologists often simplify quantitative data into distinct physiological states (e.g. susceptible, exposed, infected, recovered). However, data defining these states often fall along a spectrum rather than into clear categories. Hence, the host-pathogen relationship is more accurately defined using quantitative data, often integrating multiple diagnostic measures, just as clinicians do to assess their patients. We use quantitative data on a major neglected tropical disease (Leptospira interrogans) in California sea lions (Zalophus californianus) to improve individual-level and population-level understanding of this Leptospira reservoir system. We create a "host-pathogen space" by mapping multiple biomarkers of infection (e.g. serum antibodies, pathogen DNA) and disease state (e.g. serum chemistry values) from 13 longitudinally sampled, severely ill individuals to characterize changes in these values through time. Data from these individuals describe a clear, unidirectional trajectory of disease and recovery within this host-pathogen space. Remarkably, this trajectory also captures the broad patterns in larger cross-sectional datasets of 1456 wild sea lions in all states of health but sampled only once. Our framework enables us to determine an individual's location in their time-course since initial infection, and to visualize the full range of clinical states and antibody responses induced by pathogen exposure. We identify predictive relationships between biomarkers and outcomes such as survival and pathogen shedding, and use these to impute values for missing data, thus increasing the size of the useable dataset. Mapping the host-pathogen space using quantitative biomarker data enables more nuanced understanding of an individual's time course of infection, duration of immunity, and probability of being infectious. Such maps also make efficient use of limited data for rare or poorly understood diseases, by providing a means to rapidly assess the range and extent of potential clinical and immunological profiles. These approaches yield benefits for clinicians needing to triage patients, prevent transmission, and assess immunity, and for disease ecologists or epidemiologists working to develop appropriate risk management strategies to reduce transmission risk on a population scale (e.g. model parameterization using more accurate estimates of duration of immunity and infectiousness) and to assess health impacts on a population scale.

Role of Coxiella burnetii in the development of fever of unknown origin: А mini review

Q fever is a widespread zoonosis throughout the world in the form of numerous natural and agricul-tural outbreaks. C. burnetii infects various hosts, including humans, ruminants and pets and in rare cases, reptiles, birds, and ticks. This bacterium is excreted in urine, milk, faeces, and birth products. In humans Q fever occurs as acute or chronic disease with diverse clinical presentation, as isolated cases and epidemics. It affects various organs and systems, and in pregnant women can cause miscar-riage or premature birth. Untreated Q fever can become chronic with adverse effects on patients. Diversity in the clinical picture in the absence of specific pathological syndrome often hinders accurate diagnosis and proper etiological significance. Therefore, improvement of diagnostic methods and in particular the development and introduction of new molecular diagnostic methods is the basis of effective therapeutic and prophylactic approach. Тhe purpose of the review is to renew the interest to Q fever – on one hand, because of its serious impact on human health and agricultural systems, and on the other, the ability for development and introduction of new molecular diagnostic methods.

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.

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.

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.

Q Fever Chronic Osteomyelitis in Two Children

We report 2 cases of chronic Q fever osteomyelitis in 10- and 5-year-old girls who presented with distal right femoral and left parasternal granulomatous osteomyelitis, respectively. Both were treated with ciprofloxacin and rifampin with good response. Q fever osteomyelitis is a challenging diagnosis in children, and the choice of antimicrobial treatment is difficult because of limited available data.

Q fever in the Netherlands - 2007-2010: what we learned from the largest outbreak ever

Q fever is a zoonosis caused by Coxiella burnetii with a presentation ranging from asymptomatic seroconversion to possibly fatal chronic Q fever. The Netherlands faced an exceptionally large outbreak of Q fever from 2007 to 2010: 4026 human cases were notified, which makes it the largest Q fever outbreak ever reported. This outbreak, because of its size, allowed collecting a wide range of information on the natural history of Q fever, as well as on its transmission and clinical presentation. It also posed unprecedented public healthcare problems, especially for the concomitant management of the epizootic by veterinarian authorities and public health authorities, but also for the management of transmission risk related to blood donation. The need for cost efficient measures emerged rapidly because of the great number of infected individuals or at risk of infection, with a need for guidance on follow-up of acute Q fever patients, screening of pregnant women, or implementation of diagnostic algorithms. The acute outbreak was controlled by drastic veterinarian measures but chronic Q fever will remain a problem for the coming years.

Serological follow-up in patients with aorto-iliac disease and evidence of Q fever infection

The aim of this study was to provide data on the risk of developing chronic Q fever in patients with aorto-iliac disease and evidence of previous Q fever infection. Patients with an aortic and/or iliac aneurysm or aorto-iliac reconstruction (aorto-iliac disease) and evidence of previous Q fever infection were included. The presence of phase I and II Coxiella burnetii IgG antibodies was assessed periodically using immunofluorescence assay. A total of 111 patients with aorto-iliac disease were divided into three groups, based upon the serological profile [mean follow-up: 16 ± 9 months (mean ± standard deviation)]. Group 1 consisted of 30 patients with a serological trace of C. burnetii infection (negative IgG phase I, IgG phase II titer of 1:32). Of these, 36.7% converted to serological profile matching past resolved Q fever. Group 2 included 49 patients with negative IgG phase I titer and IgG phase II titer ≥1:64. No patients developed chronic Q fever, but 14.3% converted to a positive IgG phase I titer. Group 3 consisted of 32 patients with positive IgG phase I and positive IgG phase II titers, of which 9.4% developed chronic Q fever (significantly different from group 2, p = 0.039). The IgG phase I titer increased in 28.1% of patients (from 1:64 to 1:4,096). The risk of developing chronic Q fever in patients with aorto-iliac disease and previous Q fever infection with a positive IgG phase I titer was 9.4%. The IgG phase I titer increases or becomes positive in a substantial number of patients. A standardized serological follow-up is proposed.

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.

[Symptomatic acute Q fever: a series of 87 cases in an area of Mallorca]

INTRODUCTION

Q fever is a widespread zoonotic infection caused by Coxiella burnetii (C. burnetii). Acute infection varies from a self-limited flu-like illness to pneumonia or hepatitis.

METHODS

A retrospective case study from March 2003 to December 2011 was conducted in the Hospital Son Llàtzer in Palma de Mallorca. Acute Q-fever was diagnosed in a patient with clinical suspicion and IgM in phase ii positive (≥ 1/40), with a positive IgG (≥1/80), or when IgG seroconversion was observed during convalescence. A total of 87 cases of acute Q fever were diagnosed. The median age was 50 years (range 21-89), and 69 (79.3%) were male. Fever and headache were the most common symptoms. Pneumonia was diagnosed in 39 (44.8%) patients, febrile episode in 21 (24.1%), and acute hepatitis in 23 (25.6%). Increased serum transaminases were observed in 19 (21.8%). Doxycycline was prescribed in 29 cases (33.4%). There were 30 (34.5%) patients lost to follow up after hospital discharge. A favorable outcome was observed in all other cases. Only one new case progressed to chronic Q fever.

RESULTS

A total of 87 cases of acute Q fever were diagnosed. The median age was 50 years (range 21-89), and 69 (79.3%) were male. Fever and headache were the most common symptoms. Pneumonia was diagnosed in 39 (44.8%) patients, febrile episode in 21 (24.1%), and acute hepatitis in 23 (25.6%). Increased serum transaminases were observed in 19 (21.8%). Doxycycline was prescribed in 29 cases (33.4%). There were 30 (34.5%) patients lost to follow up after hospital discharge. A favorable outcome was observed in all other cases. Only one new case progressed to chronic Q fever.

CONCLUSION

Acute Q fever acute is common our environment. Pneumonia was the most common clinical presentation. Even although doxycycline was prescribed in a small number of patients, a favorable outcome was observed in all cases.