Rickettsia burneti and Brucella melitensis co-infection: a case report and literature review

Abstract Background Rickettsia burneti is the causative agent of Q fever, Brucella melitensis is the causative agent of brucellosis, both of which are intracellular parasitic gram-negative bacteria. Rickettsia burneti and Brucella melitensis coinfection is fairly rarely reported in clinical. Early diagnosis and treatment are of great significance to the treatment and prognosis of brucellosis and Q fever. Case Presentation Here, we report a case of Rickettsia burneti and Brucella melitensis co-infection. The patient is a 49-year-old sheepherder, was hospitalized for left forearm trauma. Three days after admission, the patient’s fever up to 39.0°C with excessive sweating, weakness, loss of appetite and headache. Rickettsia burneti IgM was detected positive by indirect immunofluorescence assay (IFA). After 72 hours blood culture incubation, bacterial growth was detected in aerobic bottles, Gram-negative bacilli were found in culture medium smear, the colony was identified as Brucella melitensis by mass spectrometry. The patient accept therapy of doxycycline (100 mg bid, po) and rifampicin (600 mg qd, po) for a total duration of four weeks. After receiving treatment, the patient’s symptoms disappeared rapidly, there has been no relapse or signs of chronic infection.Conclusion For high-risk practitioners, Q fever and brucellosis may be present in one patient, we should routinely test for both pathogens through a variety of tests to prevent missed diagnosis.