Relationship between spirometry results and colonisation of Aspergillus species in allergic asthma

Exposure to fungi in patients with asthma leads to the release of various fungal antigens, which can increase the severity of asthma. Regarding this, the present study was conducted to evaluate the relationship between the colonisation of Aspergillus species and spirometry results in allergic asthma.

Two hundred sixteen patients with mild to severe asthma and 30 healthy controls were included. All participants underwent pulmonary function tests. Furthermore, sputum samples were collected from each subject. Each sputum sample was subjected to direct microscopic examination and fungal culture. All cultured Aspergillus colonies were identified at species level by molecular methods. Finally, all available data from sputum culture and spirometry test were analysed.

Out of 216 sputum samples, 145 (67.1%) were positive for fungal growth. Furthermore, out of 264 grown fungal colonies, 137 (51.9%) were Aspergillus species. Among the Aspergillus isolates, A. flavus (29.2%) was the most prevalent species, followed by A. fumigatus (27.7%). The mean forced expiratory volume in one second (FEV1) in the mild, moderate and severe asthmatic patients with a positive sputum culture for fungi were obtained as 90.0 ± 11.1, 71.1 ± 15.9 and 54.9 ± 16.4, respectively. In general, Aspergillus species colonisation had no statistically significant effect on spirometry results of study patients.

Our results showed that there is no difference in the FEV1 and forced vital capacity between Aspergillus positive and negative patients in any asthma severity group.