Post-transplant Pneumocystis jirovecii pneumonia--a re-emerged public health problem?

Pneumocystis jirovecii is a unicellular organism that in individuals with impaired immunity may cause pneumonia that can progress from minor illness to severe inflammatory pneumonia (PCP) with respiratory failure and death. Despite antimicrobial prophylaxis, which has reduced the incidence of PCP, clusters of late infections have been reported among kidney transplant recipients worldwide. A nosocomial PCP cluster was first recognized in 2010 at a Sydney hospital, but PCP clusters have since occurred in almost half of the renal transplant units on the eastern Australian seaboard, refocussing attention on optimal prophylaxis regimens and the likelihood of patient-to-patient transmission. A consensus meeting was conducted to derive the lessons from this experience for responding to PCP outbreaks. These included: (1) acting quickly--clusters of PCP in kidney transplant recipients with patient-to-patient transmission required transplant programs to act quickly to institute prophylactic and treatment measures; (2) instituting universal prophylaxis for all patients seen in the affected unit; (3) reducing patient-to-patient transmission via airborne droplets in the outpatient waiting areas; (4) examining the P. jirovecii genotypes. The meeting also considered recommendations for the duration of prophylaxis following de novo transplant and, for the individuals in whom long term prophylaxis is required, separating units with and without clusters of PCP.