Pneumocystis jirovecii colonization among renal transplant recipients

Renal transplant recipients are at risk of developing Pneumocystis pneumonia (PcP), especially in the first 2 years after transplantation, with a mortality rate of up to 50%. No data are available on pulmonary colonization with Pneumocystis jirovecii in renal transplant recipients. The aim of this study was to determine the prevalence of pulmonary colonization with Pneumocystis jirovecii in renal transplant recipients and to find related risk factors.

We investigated the induced sputa of 70 renal transplant recipients for the presence of Pneumocystis jirovecii using nested polymerase chain reaction.

Thirteen of 70 patients (18.6%) were colonized with Pneumocystis jirovecii. There was no significant correlation between colonization and immunosuppressive medication or regimens. However, colonized subjects had undergone transplantation longer ago than non-colonized subjects. 30.8% of those whose transplantation had taken place more than 8 years previously were colonized, in contrast to 11.4% of those whose transplantation had taken place less than 8 years ago (P = 0.059; odds ratio = 3.467, 95% confidence interval = 0.99-12.09).

Most cases of Pneumocystis colonization were detected in those patients where renal transplantion had taken place more than 2 years previously. As most PcP cases occur within the first 2 years of transplantation, colonization does not seem to play a role in the development of acute PcP in this period. Though Pneumocystis pneumonia is likely to be a newly acquired infection in the first 2 years after transplantation, colonized patients remain a potential source of transmission of Pneumocystis jirovecii.