Differences in nosocomial infections in patients on VV-ECMO for COVID-19 and influenza

ABSTRACT

Objectives: In COVID-19 associated acute respiratory distress syndrome (ARDS) requiring VV-ECMO, ventilator-associated-pneumonia (VAP), pulmonary aspergillosis and viral reactivations are observed frequently, but there is only little knowledge on incidence, onset and causative pathogens. This study analyzes frequency of VAP, pulmonary aspergillus infections, and viral reactivations in a large cohort of patients with ARDS treated with VV-ECMO due to either COVID-19 or Influenza. Method(s) Retrospective analysis of all consecutively patients at the University Hospital Regensburg requiring VVECMO due to COVID-19 (March 2020 and May 2022) or Influenza (May 2012 and December 2022). VAP was diagnosed according to current guidelines. Pulmonary Aspergillosis met criteria of probable COVID-associated Aspergillosis according to current guidelines. Result(s) 147 patients (age (median [IQR]) 55.3 [48.7 - 61.7], SOFA at VV-ECMO initiation 9 [8 - 12], 23 [14 - 38] days on VV-ECMO) suffering from COVID-19 and 72 influenza patients (age 55.3 [46 - 61.3], SOFA at VV-ECMO initiation 13 [10 - 15], 16 [10 - 23] days on VV-ECMO) were included in the analysis. Pulmonary superinfections were more frequent in COVID-19 than in influenza (VAP 61% vs. 39%, pulmonary Aspergillosis 33% vs. 22%, CMV reactivation 19% vs. 4%, HSV reactivation 49% vs. 26%.) The first episode of VAP in COVID-19 and Influenza was detected 2 days [1 - 15] after and 1 day (-3 - 22) before ECMO initiation, respectively. First VAP-episode in COVID-19 were mainly caused by Klebsiella spp. (29%,), Staphylococcus aureus (27%) and E. coli (11%). Further VAP-episodes (30% in COVID-19) and relapses of VAP were mainly caused by Klebsiella spp. (53%, 64%, respectively). In Influenza, VAP was mainly caused by Staphylococcus aureus (28%) and Streptococcus pneumoniae(28%), further VAP episodes were not observed. Conclusion(s) Superinfections were common in patients treated with VV-ECMO and occur more frequently in COVID-19 ARDS compared to Influenza. VAP occurs early and may significantly contribute to the need of VV-ECMO. Therefore, a meticulous routine microbiologic workup is advisable. The observed differences in the spectrum of secondary infectious agents in COVID19 compared to Influenza are not understood yet.