Mycoplasma hominis

M hominis infection should be considered as a possibility when transplant recipients are affected with pneumonia, and Gram stains and cultures from sputum are negative but with high neutrophil count. High peripheral leukocytosis in a patient who doesn't appear seriously ill can be a diagnostic clue. The manuscript describes the presentation of Mycoplasma hominis infection in three lung transplant recipients who develop pneumonia and/or arthritis soon after transplantation. The authors confirmed by molecular analysis that strains from one donor and one recipient were closely related. However, the other two reports were caused by different strains even though occurring closely in time. Interestingly, there were no other infections in the other organ recipients from the infected donor. Unfortunately, they could not study samples from the other two donors. Altogether raises suspicion that this cluster of Mycoplasma hominis could have been acquired in the setting of the ICU where all donor and recipients were cared for. Possible routes of transmission are person-to-person or environmental exposure, although fomite transmission of m hominis is not reported. As discussed in the Spiller and Moneke manuscripts, M hominis is likely an under-recognized pathogen, is not covered in typical antibiotic regimens for pneumonia (and is indeed resistant to many antibiotics), and is a fastidious organism with tiny colonies that take 48-72 hours to emerge, and because small the colonies are often overlooked even when present.