title: Outbreak of pneumocystis pneumonia in renal and liver transplant patients caused by genotypically distinct strains of Pneumocystis jirovecii.
abstract: BACKGROUND
  An outbreak of 29 cases of Pneumocystis jirovecii pneumonia (PCP) occurred among renal and liver transplant recipients (RTR and LTR) in the largest Danish transplantation centre between 2007 and 2010, when routine PCP prophylaxis was not used.
  
  
  METHODS
  P. jirovecii isolates from 22 transplant cases, 2 colonized RTRs, and 19 Pneumocystis control samples were genotyped by restriction fragment length polymorphism and multilocus sequence typing analysis. Contact tracing was used to investigate transmission. Potential risk factors were compared between PCP cases and matched non-PCP transplant patients.
  
  
  RESULTS
  Three unique Pneumocystis genotypes were shared among 19 of the RTRs, LTRs, and a colonized RTR in three distinct clusters, two of which overlapped temporally. In contrast, Pneumocystis control samples harbored a wide range of genotypes. Evidence of possible nosocomial transmission was observed. Among several potential risk factors, only cytomegalovirus viremia was consistently associated with PCP (P=0.03; P=0.009). Mycophenolate mofetil was associated with PCP risk only in the RTR population (P=0.04).
  
  
  CONCLUSIONS
  We identified three large groups infected with unique strains of Pneumocystis and provide evidence of an outbreak profile and nosocomial transmission. LTRs may be infected in PCP outbreaks simultaneously with RTRs and by the same strains, most likely by interhuman transmission. Patients are at risk several years after transplantation, but the risk is highest during the first 6 months after transplantation. Because patients at risk cannot be identified clinically and outbreaks cannot be predicted, 6 months of PCP chemoprophylaxis should be considered for all RTRs and LTRs.
authors.affiliation: 1 Department of Infectious Diseases, Rigshospitalet-Copenhagen University Hospital, Copenhagen, Denmark. 2 Critical Care Medicine Department, National Institutes of Health Clinical Center, Bethesda, MD. 3 Centre for Medical Parasitology, Department of Clinical Microbiology, Rigshospitalet-Copenhagen University Hospital, and Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark. 4 Department of Nephrology, Rigshospitalet-Copenhagen University Hospital, Copenhagen, Denmark. 5 Department of Surgical Gastroenterology, Rigshospitalet-Copenhagen University Hospital, Copenhagen, Denmark. 6 Department of Laboratory Medicine, National Institutes of Health Clinical Center, Bethesda, MD. 7 Address correspondence to Jannik Helweg-Larsen, M.D., D.M.Sci., Department of Infectious Diseases, Rigshospitalet-Copenhagen University Hospital, Blegdamsvej 9, 2100 Copenhagen, Denmark.
authors.forename: Andreas A
authors.initials: AA
authors.lastname: Rostved
authors.forename: Monica
authors.initials: M
authors.lastname: Sassi
authors.forename: Jørgen A L
authors.initials: JA
authors.lastname: Kurtzhals
authors.forename: Søren Schwartz
authors.initials: SS
authors.lastname: Sørensen
authors.forename: Allan
authors.initials: A
authors.lastname: Rasmussen
authors.forename: Christian
authors.initials: C
authors.lastname: Ross
authors.forename: Emile
authors.initials: E
authors.lastname: Gogineni
authors.forename: Charles
authors.initials: C
authors.lastname: Huber
authors.forename: Geetha
authors.initials: G
authors.lastname: Kutty
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Kovacs
authors.forename: Jannik
authors.initials: J
authors.lastname: Helweg-Larsen
mesh_terms: D000935:Antifungal Agents / Q000008:administration & dosage; D016358:Contact Tracing; D003428:Cross Infection / Q000175:diagnosis / Q000382:microbiology* / Q000517:prevention & control / Q000635:transmission; D003718:Denmark; D004196:Disease Outbreaks / Q000517:prevention & control; D004334:Drug Administration Schedule; D005260:Female; D005838:Genotype; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects; D016030:Kidney Transplantation / Q000009:adverse effects*; D016031:Liver Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D045363:Pneumocystis carinii / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D011020:Pneumonia, Pneumocystis / Q000175:diagnosis / Q000382:microbiology* / Q000517:prevention & control / Q000635:transmission; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors
chemical_list: D000935:Antifungal Agents; D007166:Immunosuppressive Agents
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