Diagnosis of Invasive Pulmonary Aspergillosis

Culturing strains from clinical samples is the main method to diagnose invasive pulmonary aspergillosis. Detecting the galactomannan antigen in serum samples is an auxiliary examination. The goal of this study was to determine the frequency with which Aspergillus fumigatus was cultured in clinical samples taken from patients hospitalized in the the Infant Jesus Teaching Hospital in Warsaw, Poland, in the period of 2013-2014. Specimens from the respiratory tract and blood were cultured for mycological and serological assessments. Strain isolation was performed in chloramphenicol Sabouraud agar. Species identification was based on morphological traits in macro-cultures and on microscopic examination. The galactomannan antigen was detected by ELISA method. Out of 2000 clinical samples with positive mycological results, 200 were obtained from the respiratory tract. A. fumigatus was cultured in 13 cases from the respiratory group. Ten cases were cultured out of tracheal aspirates and three from bronchoalveolar lavage fluid. The galactomannan antigen was detected in a serum sample from only one out of the 13 patients with cultures positive for A. fumigatus. It also was detected in serum samples of three other patients in whom A. fumigatus culture yielded a negative result. We conclude that culture-confirmed invasive pulmonary aspergillosis represents a scarce finding. A. fumigatus cultured from clinical samples may not always be confirmed by ELISA assay and vice versa a positive ELISA result does not attest the successful culture.