Mycoplasma hominis bloodstream infection and persistent pneumonia in a neurosurgery patient: a case report

Background Mycoplasma hominis is typically associated with a urogenital tract infection, while its association with bacteremia and pneumonia is rare and therefore easily overlooked. Here we report a M. hominis bloodstream infection and pneumonia in a surgical patient. Case presentation A 56-year-old male with symptoms of pneumonia underwent microsurgery and decompressive craniectomy after a left basal ganglia hemorrhage. The patient recovered well from surgery, but pulmonary symptoms progressively worsened, with antimicrobial therapies seemingly ineffective. Culturing of bilateral blood samples resulted in pin-point-sized colonies on blood agar plates, which were subsequently identified as M. hominis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Furthermore, sequencing of bronchoalveolar lavage samples also identified M. hominis as the main pathogen responsible for the pulmonary symptoms. The M. hominis strain was ciprofloxacin resistant, but susceptible to doxycycline and moxifloxacin. Doxycycline and moxifloxacin were subsequently used in a successful combination therapy that finally alleviated the patient's fever and resulted in absorption of pleural effusion. At 1-month follow-up, following complaints of dysuria, a prostate abscess containing M. hominis was detected as the likely primary source of infection. The abscess was successfully drained and treated with doxycycline. Conclusions Mycoplasma hominis should be considered as a source of bloodstream infections and pneumonia, particularly when the response to standard antimicrobial therapy is limited. In this case, effective antimicrobial therapy was only commenced after identification of M. hominis and antimicrobial susceptibility testing.