Background: Mycoplasma hominis is increasingly recognized as a respiratory pathogen causing invasive disease in solid organ transplant (SOT) recipients. We reviewed the clinical characteristics, management approaches, and outcomes associated with this infection.

Methods: Adult SOT patients with microbiologically confirmed M.hominis infection diagnosed between 1 January 2010 and 30 April 2017 were identified at a large transplant centre. Clinical characteristics, treatment, and outcome variables were collected. M.hominis PCR was done retrospectively on donor bronchoalveolar lavage (BAL) where available.

Results: We identified 15 transplant recipients (all lung transplant) with M.hominis infection during a period in which 3657 transplantation surgeries (843 lung transplants) were performed. 67% of patients were male and the median age was 58 years [interquartile range (IQR): 35.5-63.5]. Diagnostic samples were acquired a median of 11 days post-transplant [IQR 8.0-17.5]. All patients received broad-spectrum antibiotics within one week prior to sample collection. The sites of infection were the respiratory tract [n=10 (67%); one with concurrent empyema], surgical wounds [n=4 (26%); one with sternal osteomyelitis], and pericardium with associated bacteremia [n=1 (7%)]. A matched Donor BAL sample was available in three cases, and two were positive for M.hominis by PCR. 9 patients (60%) were treated with a combination of fluoroquinolone plus doxycycline whereas 4 patients (26%) received monotherapy with either fluoroquinolone or doxycycline. Median duration of antibiotic therapy was 15d [IQR 12.5-28.5]. M.hominis infection was diagnosed after death in one patient. Another patient was not treated as symptoms had resolved prior to culture results. Five patients (33%) required definitive source-control procedures. There was one confirmed case of Hyperammonemia Syndrome. Mortality at discharge was 20%. The median length of stay (LOS) in hospital was 67d [IQR 42.5-95.0] with a median ICU LOS following transplantation of 27d [IQR 20.0-41.5].

Conclusions: Post-transplant M.hominis infections preferentially affected lung transplant recipients and led to significant morbidity and need for targeted antimicrobial therapy. We found evidence that at least some of these infections are donor derived which may indicate a potential role for screening of donors.

CITATION INFORMATION: Wright J., Law N., Murray M., Poutanen S., Husain S., Keshavjee S., Singer L., Humar A., Kumar D. Mycoplasma hominis Infection in Lung Transplant Recipients: A Retrospective Case Series Am J Transplant. 2017;17 (suppl 3).

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