The Brief Case: Mycoplasma hominis Extragenital Abscess.

Abstract

A 55-year-old woman with an unexplored 1-month history of rectal bleeding presented to the emergency department with abdominal pain, chills, and fever. The patient had received rituximab, a monoclonal antibody targeting the CD20 antigen expressed on B cells, for rheumatoid arthritis. An abdominal computed tomography (CT) scan highlighted a right perirectal collection and focal sigmoiditis with few diverticula (Fig. 1). Owing to sepsis, the patient received piperacillin-tazobactam in association with gentamicin and underwent an early laparoscopy to drain the collection a few hours after the initiation of antimicrobial therapy. Gram staining of the perirectal collection revealed numerous polymorphonuclear leukocytes with no visible microorganisms. Surgical samples and blood cultures remained sterile even after 5 days of incubation. The patient presented no improvement in her clinical condition. Persistent fever and recurring chills along with high levels of inflammatory blood markers resulted in a treatment change to vancomycin, cefepime, and metronidazole. A CT scan on day 10 showed a stable rectal abscess. On day 14, the antibiotics were replaced by meropenem, amikacin, and fluconazole due to the persistent fever. Other sets of blood cultures remained negative. The fever persisted with no explanation other than the rectal abscess.