Systematic screening for COVID‐19 associated invasive aspergillosis in ICU patients by culture and PCR on tracheal aspirate

Abstract

Background

A high prevalence of COVID‐19 associated pulmonary aspergillosis (CAPA) has been reported, though histopathological evidence is frequently lacking. To assess the clinical significance of Aspergillus species in respiratory samples of mechanically ventilated COVID‐19 patients, we implemented routine screening for Aspergillus in tracheal aspirate (TA).

Patients/methods

From all adult COVID‐19 patients admitted to the intensive care unit (ICU), TA samples were collected twice a week for Aspergillus screening by PCR and or culture. Bronchoalveolar lavage (BAL) sampling was performed in patients with a positive screening result if possible. Clinical information was obtained from the electronic patient record and patients were categorised according to the recently published consensus case definition for CAPA.

Results

Our study population consisted of 63 predominantly (73%) male patients, with a median age of 62 years and total median ICU stay of 18 days. Aspergillus species were present in TA screening samples from 15 patients (24%), and probable CAPA was diagnosed in 11 (17%) patients. Triazole resistance was detected in one patient (14%). Concordance between TA and BAL was 86%, and all TA culture positives were confirmed in BAL. We were able to withhold treatment in three of fifteen patients with positive screening (20%) but negative BAL results.

Conclusions

Positive culture, molecular detection and or antigen detection of Aspergillus species do not equal infection. Until we understand the clinical relevance of Aspergillus species detected in respiratory samples of COVID‐19 patients, minimal‐invasive screening by TA is a feasible method to monitor patients. Positive screening results should be an indication to perform a BAL to rule out upper airway colonisation.