Background:
Bronchoscopy with bronchoalveolar lavage (BAL) can be a useful tool in the early diagnosis and treatment of pulmonary infections in immunocompromised hosts (ICH). However, it is not without its risks, as these patients often have reduced physiologic reserves. Studies have suggested that pre-bronchoscopy exposure to antimicrobials may lower microbiological yield. As the administration of antimicrobials is common in immunocompromised patients prior to referral for bronchoscopy, it is uncertain if the impact on expected microbiological yields should be a factor to consider in the risk-benefit analysis of performing bronchoscopy.

Aim:
We aim to evaluate if pre-bronchoscopy exposure to antimicrobials has an effect on BAL microbiological yields in our ICH.

Methods:
A prospective registry of ICH undergoing bronchoscopy was established in a tertiary university-affiliated hospital. Data on pre-bronchoscopy antimicrobial exposure and microbiological results from BAL fluid were examined.

Results:
67 patients underwent 75 bronchoscopies from 1st May 2021 to 31st October 2022. Pre-bronchoscopy antifungal use was associated with BAL fungal culture negativity (OR 0.114, p-value <0.05). No association was found for positive BAL galactomannan (defined as a value above 0.5 (units)). Yield for bacterial and viral organisms from BAL was not affected by pre-bronchoscopy antibiotic or antiviral use.

Conclusion:
Antifungals may reduce BAL fungal culture positivity but BAL galactomannan remains unaffected. As such, even in patients who have received antifungals, bronchoscopy and BAL retains usefulness to detect invasive fungal infections.