Mycoplasma hominis: an incidental but significant finding by routine bacteriological culture

Jan Berg Gertsen, Henrik Carl Schønheyder

Research output: Contribution to journalConference abstract in journalResearch


Objectives: M. hominis is part of the normal mucosal flora and is primarily associated with infections in the genitourinary tract. Most infections occur following delivery or genitourinary instrumentation, but are also seen in immunocompromised patients. We present 4 cases diagnosed by routine bacteriological culture during a 4-year period.
Methods: Dpt. of Clinical Microbiology, Aalborg Hospital serves a population of 0.5 mio. Aerobic bacteriologic cultures are routinely carried out on 5% horse blood agar and chocolate agar (SSI Diagnostika, DK) at 35 °C in 5% CO2. The finding of translucent, pinpoint colonies after 96-120 h of incubation raises the suspicion of M. hominis; support for the diagnosis is provided by Gram stain failing to reveal a distinctive micromorphology and growth of similar colonies on subculture. In the four cases a definitive identification was obtained by PCR performed at Statens Serum Institut, Copenhagen (by courtesy to Jørgen Skov).
Results: The four patients were immunocompetent women (23-56 years of age) without significant comorbidity (Table). In all patients M. hominis were obtained in pure culture. At the time of diagnosis three patients had abscesses in the genitourinary tract or endometritis. M. hominis infection was preceded by one instance of either caesarean section, vaginal hysterectomy, or a complicated vaginal delivery. The fourth patient was admitted at term with PROM and signs of chorioamnionitis and developed endometritis postpartum. The patients did not respond to surgical drainage of the abscesses (if present) and prolonged empirical intravenous therapy with a β-lactam antibiotic and metronidazole (median 9 days). The tentative diagnosis of M. hominis prompted a change of antibiotic therapy to either moxifloxacin or clindamycin which was followed by resolution of symptoms and normalisation of CRP (median 9 days).
Conclusion: M. hominis is a rare finding by prolonged incubation of conventional blood agar. A pathogenic role of M. hominis was supported by the lack of clinical response to surgical drainage and prolonged empirical antibiotic therapy. This experience raises the pertinent question whether M. hominis infections are overlooked particularly in obstetric and gynaecological patients subsequent to vaginal birth/caesarean section or genitourinary procedures.

123Acute caesarean section (PROM and chorioamnionitis)CervixPlacentaAmpicillin & metronidazole (6 days)Clindamycin: S Tetracycline: S
231Elective caesarean sectionIntraperitoneal abscess Surgical site infectionCefuroxime & metronidazole (8 days)MIC moxifloxacin: 0.047 μg/mL MIC ciprofloxacin: 0.094 μg/mLTetracycline: S Clindamycin: R
335Vaginal delivery (complicated by uterine perforation)Peritoneal fluidAmpicillin (8 d) → Cefuroxime (13 d) & metronidazole (21 d)Tetracycline: S
456Vaginal hysterectomy (metrorrhagia)Vaginal abscessRenal abscessAmpicillin & gentamicin & metronidazole (10 days)MIC moxifloxacin: 0.023 μg/mL MIC ciprofloxacin: 0.094 μg/mL Tetracycline: S Clindamycin: S
Original languageEnglish
JournalClinical Microbiology and Infection
Pages (from-to)s312-3
Number of pages2
Publication statusPublished - 2009
Externally publishedYes
Event19th European Congress of Clinical Microbiology and Infectious Diseases - Helsinki, Finland
Duration: 16 May 200919 May 2009


Conference19th European Congress of Clinical Microbiology and Infectious Diseases

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