Bacterial and fungal superinfections in critically ill patients with COVID-19

Abstract

Are critically ill patients with coronavirus disease 2019 (COVID-19) at high risk of bacterial and fungal superinfections developing on the top of the viral infection in the lung or in other body sites? And from which organisms? Answering these apparently simple questions could be far more difficult than expected, for at least three important reasons. The first one is that the timing of development of superinfection (early or late) with respect to the intensive care unit (ICU) admission may have relevant clinical implications. Indeed, borrowing from experiences in other ICU populations it cannot be excluded a priori that early and late superinfections may be profoundly different in terms of risk [1, 2]. However, early and late superinfections have been frequently lumped together in the currently available literature on COVID-19 patients, making it difficult to firmly grasp their separate risks [3, 4]. The second reason is that the high case fatality of the viral disease per se may be an important competing risk for the development of late superinfection, which may lead to an unintended underestimation of the risk of superinfection at the bedside of alive patients. The third reason specifically involves invasive aspergillosis, for which the current absence of a standardized definition for non-proven disease in non-neutropenic critically ill patients may preclude a reliable risk assessment also in COVID-19 patients [5]. In the next few paragraphs, we briefly discuss each of these three intertwined, important issues.

Ventilator-associated pneumonia in critically ill patients with COVID-19

“…Although debate continues regarding the differences and similarities between influenza and COVID-associated aspergillosis [10], in keeping with our findings in bacterial VAP it appears that IPA is more common in COVID-19 patients than in ICU patients without COVID-19. It has been suggested that CAPA may relate to the use of immunosuppressive medications [10]. As can be seen from Table 1, steroids were relatively rarely used in this cohort of COVID-19 patients who were largely admitted before the results of the RECOVERY trial had been announced [24] and indeed none of the 3 CAPA patients we identified had received steroids prior to their diagnosis or had underlying immunosuppressive conditions.…”

“…There is increasing recognition of fungal infections amongst patients with viral pneumonitides and VAP [ 11 , 21 , 22 ]. Although debate continues regarding the differences and similarities between influenza and COVID-associated aspergillosis [ 10 ], in keeping with our findings in bacterial VAP it appears that IPA is more common in COVID-19 patients than in ICU patients without COVID-19. It has been suggested that CAPA may relate to the use of immunosuppressive medications [ 10 ].…”

“…More recent reports, including a large survey from a single hospital [ 8 ] and a synthesis of the literature [ 9 ] suggested that rates of secondary infections were low, although neither study focussed specifically on critical care. There remains considerable uncertainty around the incidence of nosocomial infections in severe COVID-19, which has led to recent calls for more analysis on the frequency, timing, and causative organisms of these important adverse events [ 10 ].…”

High rate of infections during ICU admission of patients with severe SARS-CoV-2 pneumonia: A matter of time?

“…Even though the AspICU algorithm to diagnose invasive pulmonary aspergillosis in critically ill patients requires a positive respiratory culture to identify Aspergillus , the real prevalence remains elusive because of the current absence of a standardized definition for non-proven disease in non-neutropenic critically ill patients. 8 , 9 Nine multidrug-resistant strains were isolated, which represented 6% of microbial isolates: extended-spectrum beta-lactamase E. coli (4); multi-resistant P. aeruginosa (2), and methicillin-resistant S. aureus (3).…”

Invasive Aspergillosis associated with Covid-19: A word of caution

“…Furthermore, multiple criteria for IPA diagnostic are available, and the most reliable for COVID-19 patient are presently being determined, as was recently the case for IAPA [7] . Whereas, as recently noted by experts [13] , there exists no perfect definition, we strongly believe the most realistic one should focus on specificity, as Asp-ICU, focuses on specificity. Depending on the criteria used, the number of cases might support major variations, thereby underlining the importance of carefully choosing which definition to use.…”