Allergic bronchopulmonary aspergillosis: radiological and microbiological profile of patients presented in an outpatient pulmonary clinic in a developing country

There is limited data available about allergic bronchopulmonary aspergillosis (ABPA) in Pakistan. The aim of the study was to describe the radiological and microbiological profile of ABPA patients presenting to the outpatient pulmonary clinic of a tertiary care hospital in Karachi, Pakistan. A retrospective study was conducted on ABPA patients who presented to the pulmonary outpatient clinic at Aga Khan University Hospital, Karachi, Pakistan, from January 2017 to December 2019. Data was collected on microbiology and radiology features on a predesigned proforma. A total of 7759 asthmatic patients presented at the outpatient pulmonology clinic during the study period. Of the 245 patients labeled as ABPA, 167 fulfilled the inclusion criteria, and 91 (54.5%) were female (mean age 41.9±13.0 years). A high-resolution computed tomography scan of the chest was available for 126 patients. Of these, 104 (82.5%) patients had bronchiectasis. Central bronchiectasis was noted in 98 (94.2%) patients, mucus plugging in 71 (56.3%), and hyperinflation was seen in 30 (23.4%). Microbiological testing was available in 103/167 (61.7%) patients. The most common bacterial pathogen was Pseudomonas aeruginosa 32 (31.1%), followed by Hemophilus influenzae 16 (15.5%), and Moraxella catarrhalis 7 (9.7%). Aspergillus fumigatus 17 (23.6%) was the most common mold, followed by Aspergillus flavus 16 (22.2%) and Aspergillus niger 11 (15.3%). Co-infection (bacterial and fungal) was found in 18 (17.45%) patients. Bronchiectasis was frequently observed in our cohort of patients with ABPA. P. aeruginosa was found to be common among bacterial pathogens. Isolation of fungus is not uncommon in these patients.