Acute Q Fever in an Elderly Traveler with Multiple Comorbidities Diagnosed by Blood mNGS and Resolved with Omadacycline.

This article reports a case of acute Q fever in a 61-year-old man. The patient mainly presented with high fever and cough. Extensive multi-system investigations failed to identify an etiology. On the fourth day of admission, the diagnosis of acute Q fever was confirmed by rapid detection of Coxiella burnetii nucleic acid sequence by blood metagenomic Next-Generation Sequencing (mNGS). With the treatment of intravenous omadacycline, the fever was controlled within 24 hours and the clinical symptoms significantly improved. Subsequent sequential therapy with oral doxycycline was administered, and the patient was discharged successfully. This case highlights the value of mNGS in the rapid diagnosis of rare or zoonotic pathogens in patients with fever of unknown origin, especially in patients with potential exposure to endemic areas. Furthermore, the novel tetracycline antibiotic omadacycline, demonstrating favorable efficacy and safety despite the patient's liver dysfunction, offers a valuable treatment option for rapid control of acute Q fever symptoms, especially in severe cases or those intolerant to doxycycline.