title: Nosocomial Pneumocystis jirovecii pneumonia: lessons from a cluster in kidney transplant recipients.
abstract: BACKGROUND
  Pneumocystis jirovecii pneumonia (PJP) is an important infection-related complication, whose mode of transmission remains uncertain.
  
  
  METHODS
  We investigated a nosocomial cluster of 14 PJP cases (11 confirmed and 3 probable) in kidney transplant recipients using epidemiological and genotyping methods.
  
  
  RESULTS
  Poisson regression calculated an incidence density ratio of 42.8 (95% confidence interval [CI], 14.1-129.3) versus background 0.64 cases of 1000 patient-years (P<0.001). All patients presented with respiratory failure, 10 required ventilation, two died, and six transplants failed, costing $31,854 (±SD $26,048) per patient. Four-locus multilocus sequence typing analysis using DNA extracts from 11 confirmed cases identified two closely related genotypes, with 9 of 11 sharing an identical composite multilocus sequence typing genotype. Contact tracing found colocalization of cases within clinic waiting areas, suggesting person-to-person transmission. Minimal and maximal PJP incubation periods were 124±83 to 172±71 days, respectively. Oropharyngeal washes from outpatient staff and ambient air samples were negative for P. jirovecii DNA. Cohort analysis (14 cases vs. 324 unaffected clinic control patients) identified independent risk factors including previous cytomegalovirus infection (odds ratio [OR], 65.9; 95% CI, 7.9-550; P<0.001), underlying pulmonary disease (OR, 10.1; 95% CI, 2.3-45.0; P=0.002), and transplant dysfunction (OR=1.61 per 10 mL/min/1.73 m, 95% CI, 1.15-2.25, P=0.006). The outbreak was controlled by reintroduction of trimethoprim/sulfamethoxazole prophylaxis to all potentially exposed clinic patients and its extension to 12 months in recent recipients.
  
  
  CONCLUSIONS
  Nosocomial PJP clusters are likely due to interhuman transmission by airborne droplets to susceptible hosts. Prompt recognition and a strategy of early preemptive blanket PJP prophylaxis to all exposed transplant clinic recipients from the third confirmed case are recommended to limit outbreak escalation.
authors: Department of Renal Medicine, Westmead Hospital, Westmead, NSW, Sydney, Australia.
authors: Lisa M
authors: LM
authors: Phipps
authors: Sharon C-A
authors: SC
authors: Chen
authors: Kathy
authors: K
authors: Kable
authors: Catriona L
authors: CL
authors: Halliday
authors: Carolina
authors: C
authors: Firacative
authors: Wieland
authors: W
authors: Meyer
authors: Germaine
authors: G
authors: Wong
authors: Brian J
authors: BJ
authors: Nankivell
mesh_terms: D000328:Adult; D003586:Cytomegalovirus Infections / Q000150:complications; D004271:DNA, Fungal / Q000032:analysis; D005260:Female; D006801:Humans; D007165:Immunosuppression Therapy / Q000009:adverse effects; D016030:Kidney Transplantation / Q000009:adverse effects / Q000276:immunology; D008297:Male; D008875:Middle Aged; D045363:Pneumocystis carinii / Q000235:genetics / Q000302:isolation & purification; D011020:Pneumonia, Pneumocystis / Q000191:economics / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D012307:Risk Factors
chemical_list: D004271:DNA, Fungal