Routine comprehensive Aspergillus screening of bronchoalveolar lavage samples in lung transplant recipients

Background: Invasive aspergillosis is a significant cause of morbidity and mortality in lung transplant recipients (LTRs). Early diagnosis may improve outcome, yet is challenging. We assessed the diagnostic yield of a routine, comprehensive, prospectively employed Aspergillus screening strategy in LTRs.

Methods: During a 6-month period, all bronchoalveolar lavage (BAL) samples (including post-transplant surveillance) obtained from LTRs at our center were routinely tested for Aspergillus PCR, galactomannan (GM), and fungal culture. Invasive aspergillosis (IA) was defined using EORTC/MSG and ISHLT criteria for proven and probable aspergillosis.

Results: Ninety-five consecutive BAL samples were tested. PCR, GM, and fungal culture were positive in 28.4%, 30.6%, and 7.4%, respectively. Five cases of IA (two proven, three probable) were identified. Fungal culture failed to detect 40% of IA cases, which were detected by a positive PCR and/or GM. However, the majority of positive PCR samples represented colonization (59.3%). Sensitivity of PCR, GM, and culture for IA was 80%, 60%, and 60%, respectively, and specificity was 74%, 71%, and 96%.

Conclusions: In LTRs, a routine prospectively employed screening strategy in which all BAL samples were screened for Aspergillus PCR and GM, detected aspergillosis cases that were otherwise missed by a false-negative fungal culture, but resulted in more cases of colonization being detected. Clinical judgment is thus warranted to avoid unnecessary treatment of colonization.