title: Pneumocystis pneumonia outbreak among renal transplant recipients at a North American transplant center: Risk factors and implications for infection control.
abstract: BACKGROUND
  Pneumocystis pneumonia is a severe opportunistic fungal infection. Outbreaks among renal transplant recipients have been reported in Europe and Japan, but never in North America.
  
  
  METHODS
  We conducted a retrospective case-control study among adult renal transplant recipients at a Canadian center, using a 3:1 matching scheme. Ten cases and 30 controls were matched based on initial transplantation date, and all patients received prophylaxis with trimethoprim-sulfamethoxazole for 1 year posttransplantation.
  
  
  RESULTS
  The median time between transplantation and infection was 10.2 years, and all patients survived. Compared with controls, case patients had statistically lower estimated glomerular filtration rate (29.3 mL/min vs 66.3 mL/min; P = .028) and lymphopenia (0.51 × 10(9)/L vs 1.25 × 10(9)/L; P = .002). Transmission mapping revealed significant overlap in the clinic and laboratory visits among case vs control patients (P = .0002). One hundred percent of patients (4 out of 4) successfully genotyped had the same strain of Pneumocystis jirovecii.
  
  
  CONCLUSIONS
  Our study demonstrated an outbreak of pneumocystis more than 10 years following initial transplantation, despite using recommended initial prophylaxis. We identified low estimated glomerular filtration rate and lymphopenia as risk factors for infection. Overlapping ambulatory care visits were identified as important potential sources of infection transmission, suggesting that institutions should re-evaluate policy and infrastructure strategies to interrupt transmission of respiratory pathogens.
authors.affiliation: The Ottawa Hospital, Ottawa, Ontario, Canada; Division of Respirology, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada; Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada. Electronic address: smulpuru@toh.on.ca.
authors.forename: Sunita
authors.initials: S
authors.lastname: Mulpuru
authors.affiliation: The Ottawa Hospital, Ottawa, Ontario, Canada; Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; Division of Nephrology, Kidney Research Centre, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Greg
authors.initials: G
authors.lastname: Knoll
authors.affiliation: The Ottawa Hospital, Ottawa, Ontario, Canada.
authors.forename: Colleen
authors.initials: C
authors.lastname: Weir
authors.affiliation: The Ottawa Hospital, Ottawa, Ontario, Canada; Department of Pathology and Laboratory Medicine, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Marc
authors.initials: M
authors.lastname: Desjardins
authors.affiliation: The Ottawa Hospital, Ottawa, Ontario, Canada.
authors.forename: Daniel
authors.initials: D
authors.lastname: Johnson
authors.affiliation: The Ottawa Hospital, Ottawa, Ontario, Canada.
authors.forename: Ivan
authors.initials: I
authors.lastname: Gorn
authors.affiliation: The Ottawa Hospital, Ottawa, Ontario, Canada; Division of Nephrology, Kidney Research Centre, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Todd
authors.initials: T
authors.lastname: Fairhead
authors.affiliation: The Ottawa Hospital, Ottawa, Ontario, Canada.
authors.forename: Janice
authors.initials: J
authors.lastname: Bissonnette
authors.affiliation: The Ottawa Hospital, Ottawa, Ontario, Canada.
authors.forename: Natalie
authors.initials: N
authors.lastname: Bruce
authors.affiliation: The Ottawa Hospital, Ottawa, Ontario, Canada; Department of Pathology and Laboratory Medicine, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Baldwin
authors.initials: B
authors.lastname: Toye
authors.affiliation: The Ottawa Hospital, Ottawa, Ontario, Canada; Division of Infectious Diseases, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Suh
authors.affiliation: The Ottawa Hospital, Ottawa, Ontario, Canada; Division of Infectious Diseases, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Virginia
authors.initials: V
authors.lastname: Roth
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000553:Ambulatory Care / Q000379:methods; D002170:Canada / Q000453:epidemiology; D016022:Case-Control Studies; D004196:Disease Outbreaks; D018562:Disease Transmission, Infectious; D005260:Female; D005838:Genotype; D006801:Humans; D017053:Infection Control / Q000379:methods; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D045363:Pneumocystis carinii / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D011020:Pneumonia, Pneumocystis / Q000453:epidemiology* / Q000635:transmission*; D012189:Retrospective Studies; D012307:Risk Factors; D066027:Transplant Recipients; D055815:Young Adult
keywords: Fungal Pneumonia; Infection control; Solid Organ Transplant