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

Abstract 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 clinicians encounter from making an initial diagnosis and risk stratification to determining the appropriate prophylaxis regimen and duration. Methods We retrieved records of adult (≥ 18 years) Mayo Clinic patients with positive Coxiella burnetii serologies between January 1, 2012, and March 31, 2022. Patients with Q fever anti-phase II IgG ≥ 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 of 333 days (IQR 168-414). Four patients (13%) progressed to Q fever native valve infective endocarditis with elevated anticardiolipin (aCL) IgG levels being the sole risk factor in two cases. The small sample size precluded drawing conclusions on the impact of prophylaxis in preventing disease progression. Conclusion 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.