Pulmonary Aspergillosis in Patients with Suspected Ventilator-associated Pneumonia in UK ICUs

Abstract

<b>Rationale:</b><i>Aspergillus</i> infection in patients with suspected ventilator-associated pneumonia remains uncharacterized because of the absence of a disease definition and limited access to sensitive diagnostic tests.<b>Objectives:</b> To estimate the prevalence and outcomes of <i>Aspergillus</i> infection in adults with suspected ventilator-associated pneumonia.<b>Methods:</b> Two prospective UK studies recruited 360 critically ill adults with new or worsening alveolar shadowing on chest X-ray and clinical/hematological parameters supporting suspected ventilator-associated pneumonia. Stored serum and BAL fluid were available from 194 nonneutropenic patients and underwent mycological testing. Patients were categorized as having probable <i>Aspergillus</i> infection using a definition comprising clinical, radiological, and mycological criteria. Mycological criteria included positive histology or microscopy, positive BAL fluid culture, galactomannan optical index of 1 or more in BAL fluid or 0.5 or more in serum.<b>Measurements and Main Results:</b> Of 194 patients evaluated, 24 met the definition of probable <i>Aspergillus</i> infection, giving an estimated prevalence of 12.4% (95% confidence interval, 8.1-17.8). All 24 patients had positive galactomannan in serum (<i>n</i> = 4), BAL fluid (<i>n</i> = 16), or both (<i>n</i> = 4); three patients cultured <i>Aspergillus</i> sp. in BAL fluid. Patients with probable <i>Aspergillus</i> infection had a significantly longer median duration of critical care stay (25.5 vs. 15.5 d, <i>P</i> = 0.02). ICU mortality was numerically higher in this group, although this was not statistically significant (33.3% vs. 22.8%; <i>P</i> = 0.23).<b>Conclusions:</b> The estimated prevalence for probable <i>Aspergillus</i> infection in this geographically dispersed multicenter UK cohort indicates that this condition should be considered when investigating patients with suspected ventilator-associated pneumonia, including patient groups not previously recognized to be at high risk of aspergillosis.