Rothia mucilaginosa Pneumonia in an Immunocompromised Patient: Diagnosis With Plasma Microbial Cell-Free DNA Next-Generation Sequencing and Treatment With Eravacycline

Rothia mucilaginosa is a gram-positive coccus recognized as an opportunistic pathogen capable of causing pneumonia in immunocompromised patients (Antimicrob Agents Chemother. 1995;39:268-270). The organism is often resistant to fluoroquinolones and trimethoprim/sulfamethoxazole, agents routinely used as anti-infective prophylaxis in immunocompromised individuals (Inf Dis Clin Pract. 2020;28:361-365; Infect Dis Now. 2021;51:228-235). Plasma next-generation sequencing (NGS) is increasing in clinical use to aid in diagnosis of infections in immunocompromised patients (Infect Dis (Lond). 2015;47:125-1299). A patient with advanced multiple myeloma was admitted with pneumonia. Plasma NGS initially suggested R. mucilaginosa, which was confirmed by cultures of bronchoalveolar lavage (BAL) fluid. Treatment with eravacycline led to clinical and radiographic resolution of pneumonia.