Researchers at Mayo Clinic have identified a possible cause for a rare infection in heart and lung transplant recipients: the donor. The way in which heart and lung transplant recipients acquired a specific species of bacteria, Mycoplasma hominis, had been previously undefined, and the bacterium was difficult to test. Originally, this bacterium was considered to reside exclusively in, and be a potential pathogen of, the area of the reproductive and urinary organs – the genitourinary tract.