A Bad Bug Takes on a New Role as a Cause of Ventilator-associated Pneumonia

Abstract

Despite use of preventive strategies and significant advances in supportive care and antimicrobial therapy, ventilator-associated pneumonia (VAP) remains an important cause of morbidity and mortality (1). Although bacteria cause most VAPs, invasive pulmonary aspergillosis (IPA) is extremely uncommon, except when classical risk factors for aspergillosis (hematologic cancer, neutropenia, transplantation) are present. In this issue of the Journal (pp. 27‐34), Meersseman and colleagues (2) report their findings using detection of Aspergillus galactomannan (GM) (cell wall constituent released during tissue invasion) in bronchoalveolar lavage (BAL) fluid (BAL-GM) for diagnosing VAP caused by Aspergillus spp. Upon diagnosis of pneumonia, 110 adults at risk for IPA underwent BAL for culture and GM detection, serum GM, and chest computed tomography (CT). Only 22% of patients were neutropenic and 67% had underlying diseases other than hematologic cancer, including cirrhosis and chronic obstructive pulmonary disease (COPD). Twenty-six patients (24%) developed histopathologically proven IPA. The diagnostic sensitivity and specificity of BAL-GM was 88 and 87%, respectively, compared with 42% sensitivity for serum GM. Serum GM and BAL culture remained negative in 11 patients (42%) in whom BAL-GM was positive. Chest CT was of limited diagnostic value. The findings of this prospective study, backed by an impressive 95% autopsy rate, underscore the increasingly important role that Aspergillus species play as a cause of VAP in apparently immunocompetent intensive care unit (ICU) patients