Coxiella burnetii Should Not Be Ignored: Two Cases of Q Fever Pneumonia Diagnosed by Metagenomic Next-Generation Sequencing

Jianchang Yao,1 Jingjing Zhang,1 Lin Zheng,1 Wanlan Fang,1 Yina Lang2 1Department of Respiratory and Critical Medicine, Deqing People’s Hospital (Deqing Campus, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University), Deqing, Zhejiang, 313200, People’s Republic of China; 2Department of Medical Oncology, Deqing People’s Hospital (Deqing Campus, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University), Deqing, Zhejiang, 313200, People’s Republic of ChinaCorrespondence: Yina Lang, Department of Medical Oncology, Deqing People’s Hospital (Deqing Campus, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University), No. 120 South Yingxi Road, Deqing, Zhejiang, 313200, People’s Republic of China, Email [email protected]: Q fever is a globally distributed zoonotic disease caused by Coxiella burnetii (C. burnetii). As an obligate intracellular bacterium, C. burnetii is primarily transmitted from domestic animals to humans, with ticks also serving as potential vectors. The clinical manifestations of Q fever are often nonspecific and highly variable, making its diagnosis particularly challenging.Case Presentation: Two male pneumonia patients were hospitalized in Deqing People’s Hospital, one was 73 years old, and the other one was 30 years old, both of them presented with hyperpyrexia without a clear epidemiological history. However, initial empirical treatment was ineffective and microbiological cultures were all negative, then bronchoscopy was conducted for them and bronchoalveolar lavage fluid (BALF) was sent for metagenomic next-generation sequencing (mNGS) test. Ultimately, two patients were diagnosed with Q fever pneumonia, and the symptoms of patients were significantly improved after timely treatment with the special drug doxycycline and moxifloxacin, and lung inflammation in both patients were effectively absorbed in the subsequent follow-up examination.Conclusion: Two cases of Q fever pneumonia were diagnosed through mNGS. As a new detection method, mNGS has advantages in the diagnosis of unknown infectious pathogens. As a zoonotic pathogen, C. burnetii should not be ignored. The One Health approach may be suitable for Q fever prevention and control.Keywords: Q fever, Coxiella burnetii, pneumonia, metagenomic next-generation sequencing, case report