日本性感染症学会誌 Journal of Japanese Society for Sexually Transmitted Infections

Case 1: A 34-year-old woman visited our hospital with missed abortion. We performed the evacuation after weeks of observation. She complained of lower abdominal pain and fever on the third day post procedure. She was hospitalized and treated with ceftriaxone (CTRX) and metronidazole (MTZ) intravenously and orally, respectively. The symptoms improved on the following day the antibiotic treatments were started. However, the patient’s blood culture showed Mycoplasma hominis after ten days of culture submission. We switched to antibiotics that are sensitive to Mycoplasma species.

Case 2: A 42-year-old woman with right endometriotic cyst had fever and lower abdominal pain. She was diagnosed with ovarian abscess and was treated with CTRX and MTZ. The right adnexetomy was performed on the fifth day of admission because of continuous fever in spite of the antibiotic treatments. Based on the bacterial culture of the ovarian discharge, we suspected M. hominis infection due to the lack of gram-stain. The patient was then administered with minocycline.

Beta-lactam antibiotics are often used as perioperative antibiotic prophylaxis for gastrointestinal and gynecological surgeries. Mycoplasma species are characterized by a lack of cell wall around their cell membrane, which makes them resistant to antibiotics, like beta-lactams. Mycoplasma infections should be kept in mind when pelvic infectious disease resists the beta-lactam antibiotic treatment and when the cell body is difficult to identify in gram-staining method.