Detection of aerobe–anaerobe mixed infection by metagenomic next-generation sequencing in an adult suffering from descending necrotizing mediastinitis

Abstract Background Descending necrotizing mediastinitis (DNM) is one of the most virulent forms of mediastinitis. The main causes of high mortality in DNM are believed to stem from difficulty and delay in the diagnosis. Fast and accurate identification of pathogens is important for the treatment of these patients. Metagenomics next-generation sequencing (mNGS) is a powerful tool to identify all kinds of pathogens, especially for rare and complex infections. Case presentation A 64-year-old male patient was admitted to the intensive care unit (ICU) with unconsciousness, dyspnea, and swelling in the mandible and neck. Computed tomography (CT) scan results combined with clinical laboratory examination indicated DNM. Vancomycin and imipenem were used, and vacuum sealing drainage was applied for debridement and drainage of the infected area. The positive mNGS results of drainage fluid confirmed the presence of mixed infection caused by Streptococcus anginosus , Prevotella oris, and several other anaerobes. The antibiotics were adjusted to piperacillin/tazobactam and tinidazole according to the mNGS results and antimicrobial susceptibility testing of cultured pathogens. After 11 days of antibiotic therapy, the infection symptoms of the neck and mediastinum improved, and the patient was transferred out of the ICU on the 26th day after negative result of drainage fluid culture. Conclusion This case suggested that mNGS is a promising technology for precise and fast pathogens identification with high sensitivity, which may guide the diagnosis of infectious diseases in the future trend.