First Case of Skin and Soft Tissue Infection Caused by Mycoplasma hominis in a Pediatric Immunocompromised Patient

Dear Editor, Mycoplasma hominis is a part of the urogenital commensal flora, with higher bacterial loads in women compared with men. Thus, infections of M. hominis are usually associated with endocervicitis and pelvic inflammatory diseases. Although rare, M. hominis can also cause various extra-urogenital infections, such as skin and soft tissue infections (SSTIs) [1, 2], central nervous system (CNS) infection, mediastinitis, and disseminated infection [3-6]. Because M. hominis lacks a cell wall and shows resistance to cell wall-acting antibiotics, including carbapenem and glycopeptides, it is important to accurately identify this bacterium and initiate appropriate treatment in the case of infection. Clindamycin shows the highest in vitro activity against M. hominis, followed by fluoroquinolones [4]. A 13-yr-old girl with aplastic anemia was admitted to the Seoul St. Mary’s Hospital, Korea, for allogeneic hematopoietic cell transplantation (HCT). On HCT day 6, the patient developed a fever, but all culture analyses, including blood, urine, and sputum, were negative. It was presumed that the fever was caused by acute graft-versus-host disease (GvHD), considering the presence of a skin rash and diarrhea that accompanied the symptoms. The intravenous antibiotic treatment (meropenem, teicoplanin) was continued because of her immune-compromised state. However, gastrointestinal (GI) symptoms were aggravated, and thus methylprednisolone, methotrexate, and cyclophosphamide were added to the treatment. Despite these treatment efforts, bloody diarrhea and fever persisted. On HCT day 28, a colonoscopy and random biopsies were performed to identify the cause of bloody diarrhea, and the biopsies showed findings consistent with acute GvHD and positive immunohistochemical (IHC) staining for cytomegalovirus (CMV). CMV was also detected in the blood by real-time quantitative PCR (RQ-PCR) (AccuPower CMV Quantitative PCR, Bioneer, Daejeon, Korea). After treatment (ganciclovir) for two months, the CMV disappeared, which was confirmed by biopsies and blood RQ-PCR. During the high-intensity immunosuppressive therapy, multifocal skin abrasions in the perianal area occurred because of persistent diarrhea. On HCT day 120, pressure sores developed on the buttocks. Vancomycin and amphotericin B were added to the regimen to treat these lesions. However, painful swelling in the left inguinal area and a high fever developed on HCT day 127; thus, antibiotic therapy was changed to tigecycline and arbekacin. A core needle biopsy was performed, and pus was aspirated. A Gram stain from this aspiration revealed no microor-