Antimicrobial stewardship in the ICU in COVID times: the known unknowns

Schouten, Jeroen; De Waele, Jan; Lanckohr, Christian; Koulenti, Despoina; Haddad, Nisrine; Rizk, Nesrine; Sjövall, Fredrik; Kanj, Souha S.

Since the start of the COVID-19 pandemic, there has been concern about the concomitant rise of antimicrobial resistance (AMR). While bacterial co-infections seem rare in COVID-19 patients admitted to hospital wards and ICUs, an increase in empirical antibiotic use has been described. In the ICU setting, where antibiotics are already abundantly -and often inappropriately- prescribed, the need for an ICU specific Antimicrobial Stewardship Program (ASP) is widely advocated. Apart from essentially warning against the use of antibacterial drugs for the treatment of a viral infection, other aspects of ICU antimicrobial stewardship need to be considered in view of the clinical course and characteristics of COVID-19. First, the distinction between infectious and non-infectious (inflammatory) causes of respiratory deterioration during ICU stay is difficult and the much-debated relevance of fungal and viral co-infections adds to the complexity of empirical antimicrobial prescribin. Biomarkers such as PCT for the decision to start antibacterial therapy for ICU nosocomial infections seem to be more promising in COVID-19 than in non-COVID-19 patients. In COVID-19 patients CMV reactivation is an important factor to consider when assessing patients infected with SARS-CoV-2 as it may have a role in modulating patient immune response. The diagnosis of COVID-19 associated Invasive Aspergillosis (CAPA) is challenging because of the lack of sensitivity and specificity of the available tests. Further, altered PK/PD properties need to be taken into account when prescribing antimicrobial therapy. Future research should now further explore the “known unknowns”, ideally with robust prospective study designs.