Respiratory Tract Colonization by species Portends Worse Outcomes in Immunocompromised Patients.

Background: The significance and clinical management of colonization of the respiratory tract are ill-defined. We now report the frequency of species from the lower respiratory tract in hematopoietic stem cell transplant recipients (HSCT) undergoing bronchoscopy with broncheoalveolar lavage (BAL) for pneumonitis post-HSCT.

Methods: The University of Michigan Clinical Microbiology Lab Database was queried for all respiratory cultures positive for species between 2000-2012. We concurrently performed a retrospective analysis of 515 HSCT recipients with pneumonitis at our institution between 2001-2012.

Results: During this twelve-year period, there were 2524 unique isolates (78% ). Of the 515 HSCT patients with suspected pneumonitis,127 (24.7%) HSCT subjects were culture positive for a fungal pathogen, with species identified in 27 cases (5.2%). When compared with other HSCT subjects, those cultures positive for had significantly increased mortality (p=0.04).

Conclusions: . are commonly cultured from the respiratory tract of HSCT recipients, with increased mortality in affected patients. While there is insufficient evidence for anti-fungal treatment of species colonization, the presence of the yeast may be useful as a surrogate marker of disease severity.