Chronic Q-Fever (Coxiella burnetii) Causing Abdominal Aortic Aneurysm and Lumbar Osteomyelitis: A Case Report

A case of tick-transmitted Q fever in Lishui, China diagnosed by next-generation sequencing

Q fever is a zoonotic disease caused by Coxiella burnetii. Most patients have non-specific symptoms at onset. In addition, routine diagnostic tests for C. burnetii are not sensitive, and the bacterium cannot grow in general culture medium. The diagnosis of Q fever therefore poses a challenge. This case study describes a man with a clear history of tick bite who had recurrent fever, pneumonia, and liver damage. Routine tests and bacterial cultures failed to clarify the pathogeny, but laboratory and imaging data suggested infection. After routine tests were exhausted, we detected the presence of C. burnetii in a whole blood sample using next-generation sequencing (NGS). To our knowledge, this is the first report of Q fever associated with Coxiella burnetii detected directly from blood samples in Lishui, China. NGS has revolutionized the diagnosis of infectious diseases, especially those caused by rare or newly discovered pathogens, and patient responses have finally proved its substantial benefits. NGS has important clinical significance for the early diagnosis of chronic Q fever. This proof-of-concept study is worthy of promotion in clinical practice.

Q fever vertebral osteomyelitis among adults: a case series and literature review

BACKGROUND

Q fever osteoarticular infections are a rare complication of the chronic form of Q fever. We aimed to characterize chronic Q fever vertebral osteomyelitis through our experience and a review of the literature.

METHODS

Four adult patients with Q fever vertebral osteomyelitis diagnosed in a tertiary hospital in northern Israel between 2016 to 2020 are described. In addition, a 30 years' literature review of Q fever vertebral osteomyelitis, characterizing predisposing factors, clinical presentation, course of disease, treatment and outcomes, was performed.

RESULTS

Thirty-four adult patients with Q fever vertebral osteomyelitis were identified. The vast majority were male (30/34, 88%) with a mean age of 67.2 ± 10 years. Involvement of the adjacent aorta, likely the origin of the infection, was observed in 23/34 (68%) of the patients, usually among patients with aortic graft or aneurysm. Clinical presentation was insidious and fever was frequently absent. Delayed diagnosis for months to years after symptoms onset was frequently reported. Vascular infections were managed with or without extraction of the infected aneurysm/aorta and graft placement. The outcome was variable with limited follow-up data in most cases. Patients were usually treated with prolonged antimicrobial therapy, most commonly doxycycline and hydroxychloroquine combination therapy.

CONCLUSION

Q fever should be included in the differential diagnosis of vertebral osteomyelitis in endemic settings, in particular when concomitant adjacent vascular infection exists.

A systematic review on the health outcomes associated with non-endocarditis manifestations of chronic Q fever

The aim of this study was to systematically review the non-endocarditis manifestations of chronic Q fever and understand the significance of non-specific symptoms like pain and fatigue in chronic endovascular, osteomyelitis and abscess due to chronic Q fever. We performed a systematic review using Pub Med (the National Library of Medicine (NLM)) and Scopus databases. All studies in English on chronic Q fever that listed clinical manifestations other than infective endocarditis (IE) and chronic fatigue syndrome (CFS). Meta-analysis was carried out to investigate the effects of patient's health outcomes (pain, fatigue, the need for surgery and mortality) on vascular infections, osteomyelitis and abscess. Among cases not presenting as IE or CFS, vascular infections and osteomyelitis were the most common chronic Q fever disease manifestations. There were distinct regional patterns of disease. Compared with infective endocarditis, these are significantly associated with increased risk of pain: osteomyelitis (relative risk (RR) = 4.13, 95% confidence interval (CI) 3.36-5.07), abscess (RR = 3.59, 95% CI 3.28-3.93) and vascular infection (RR = 2.46, 95% CI 1.99-3.03). The strongest significant association was observed between osteomyelitis and pain. There was no significant association between fatigue and these manifestations. Clinicians have to be aware of uncommon manifestations of chronic Q fever as they present with non-specific symptoms and are significantly associated with increased risk of morbidity and mortality. The findings emphasise the need to investigate patients with positive chronic Q fever serology presenting with acute or chronic pain for possible underlying complications.

Coxiella burnetii Multilevel Disk Space Infection, Epidural Abscess, and Vertebral Osteomyelitis Secondary to Contiguous Spread From Infected Abdominal Aortic Aneurysm or Graft: Report of 4 Cases Acquired in the US and Review of the Literature

Background

Chronic Coxiella burnetii infections such as vertebral osteomyelitis caused by contiguous spread from an infected abdominal aortic graft or aneurysm have been rarely reported and are associated with significant morbidity and mortality.

Methods

We present the first four reported US acquired cases of Coxiella burnetii vertebral osteomyelitis caused by contiguous spread from an infected abdominal aortic graft or aneurysm.

Results

Presenting symptoms included progressive back pain, malaise, and weight loss with recent or remote animal exposure. Typical imaging findings demonstrated a peri-aortic collection with extension to the paraspinal muscles and vertebrae. Antibiotic regimens included doxycycline with either hydroxychloroquine or a quinolone for at least 2 years or as chronic suppression.

Conclusions

C. burnetii vertebral osteomyelitis is rare and can occur by contiguous spread from an abdominal aneurysm or vascular graft infection. It should be suspected in patients where pre-antibiotic cultures are negative with animal/farming exposure.

A Case of Primary Aortoduodenal Fistula and Abdominal Aortic Aneurysm in a Patient with Chronic Q Fever

A 70-year-old man was successfully treated for an aortoduodenal fistula originating from a Q fever-related abdominal aortic aneurysm. He had no known history of contact with cattle or sheep. Although the combination of abdominal aortic aneurysm and aortoduodenal fistula is rare, one should be suspicious of Q fever infection as the causative agent, and additional medical treatment should be initiated.

Inhibitory effects of doxycycline on the onset and progression of abdominal aortic aneurysm and its related mechanisms

The objective of this study was to investigate whether doxycycline (DOX) given at different doses and via different administration routes had protective or therapeutic effects on abdominal aortic aneurysm (AAA) induced by elastase in mice. Moreover, the anti-AAA mechanism of DOX was studied in TNF-α-stimulated vascular smooth muscle cell (VSMC) in vitro. For in vivo study, either daily administration of 30mg/kg of DOX by gavage or intraperitoneal injection of 15mg/kg DOX every other day for 14 days significantly prevented the development of AAA at its early stage. Further study showed that intraperitoneal injection of 15mg/kg DOX every other day for 7 times in total could also cure the established AAA. In vitro study showed that treating VSMCs with TNF-α together with DOX remarkably inhibited the expressions and activities of MMPs (MMP-2 and MMP-9), significantly suppressed the activation of protein kinase B (AKT) signaling pathway and mitogen-activated protein kinases (MAPKs) signal proteins, including extracellular signal-regulated kinase (ERK), c-Jun amino-terminal kinases (JNK) and p38, and downregulated mRNA levels of interleukin-6 (IL-6) and monocyte chemotactic protein 1 (MCP-1), and significantly upregulated mRNA levels of transforming growth factor beta (TGF-β), heme oxygenase 1 (HO-1) and superoxide dismutase 1 (SOD-1), indicating that DOX inhibits activities of MMPs through reducing oxidative stress, suppressing MAPKs and AKT signaling pathways and ameliorating inflammation in VSMCs, and therefore, exerts preventive as well as therapeutic effects on AAA.

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.