Molecular detection of Candida spp. and Aspergillus fumigatus in bronchoalveolar lavage fluid of patients with ventilator-associated pneumonia

Background: Ventilator-associated pneumonia (VAP) is a common nosocomial infection in critically ill patients with high morbidity and mortality rates. The etiology of VAP is usually bacterial. Opportunistic fungi such as Candida and Aspergillus species (spp.) are found frequently in the respiratory track secretions of immunocompetent critically ill patients known as colonization. Contribution of fungi colonization to severe bacterial VAP and poor prognosis of these patients has been documented in several studies. The aim of this study was to detect Candida spp. and Aspergillus fumigatus colonization in patients with a clinical diagnosis of VAP as a marker of high risk pneumonia.

Materials and methods: Bronchoscopic alveolar lavage (BAL) fluids from patients with VAP in central intensive care unit (ICU) of a tertiary university hospital in Isfahan were examined by real time polymerase chain reaction (PCR) to detect Candida spp. or A. fumigatus. Rate of fungi colonization and its association with clinical criteria of the patients was determined.

Results: BAL fluids from 38 patients were tested from which six samples (15.8%) were positive for Candida spp. and five (13.2%) for A. fumigatus. Fungi colonization was not associated with age, sex, or mortality rate of patients. Rate of A. fumigatus colonization was significantly more in traumatic patients (P = 0.036), and higher in patients ventilated more than 4 weeks (P = 0.022).

Conclusion: High rate of A. fumigatus colonization in our ICU patients indicates that underlying causes such as unfavorable ICU conditions and other patient related factors such as unnecessary antibiotic therapy should be further evaluated.