ABSTRACT
Objective:To explore the clinical utility of metagenomic next-generation sequencing (mNGS) for patients with critically ill atypical rickettsial infections in the early diagnosis and therapy.Methods:From Jan 2020 to Aug 2022, clinical features, blood biochemical results, imaging data and mNGS results in patients with unexplained critical illnesses were collected and analyzed retrospectively. Fisher's exact test was used to compare the positive rate of mNGS and weil felix reaction.Results:All 15 patients with rickettsial disease had fever, 12 cases had headache, but only 3 had a typical rash or scab of diagnostic significance, 6 had septic shock and all had multi-organ dysfunction; blood mNGS tests were positive in 15 cases, of which 10 had Orientia tsutsugamushi detected in their blood and the remaining five had Rickettsia moschata detected in their blood. The positive rate of mNGS was significantly higher than that of the weil felix reaction (15/15 vs 0, P<0.001). All patients were given doxycycline and other treatments after diagnosis, of which 14 improved and were discharged, and one died 1 week after discharge due to critical condition and abandonment of treatment. Conclusion:mNGS can improve the detection rate of atypical rickettsiae in patients with negative routine test results, which can provide valuable reference basis for early diagnosis and early anti-infection treatment of patients with critical rickettsial disease.