The Acquisition of Multidrug-Resistant Bacteria in Patients Admitted to COVID-19 Intensive Care Units: A Monocentric Retrospective Case Control Study

Abstract

Whether the risk of multidrug-resistant bacteria (MDRB) acquisition in the intensive care unit (ICU) is modified by the COVID-19 crisis is unknown. In this single center case control study, we measured the rate of MDRB acquisition in patients admitted in COVID-19 ICU and compared it with patients admitted in the same ICU for subarachnoid hemorrhage (controls) matched 1:1 on length of ICU stay and mechanical ventilation. All patients were systematically and repeatedly screened for MDRB carriage. We compared the rate of MDRB acquisition in COVID-19 patients and in control using a competing risk analysis. Of note, although we tried to match COVID-19 patients with septic shock patients, we were unable due to the longer stay of COVID-19 patients. Among 72 patients admitted to the COVID-19 ICUs, 33% acquired 31 MDRB during ICU stay. The incidence density of MDRB acquisition was 30/1000 patient days. Antimicrobial therapy and exposure time were associated with higher rate of MDRB acquisition. Among the 72 SAH patients, 21% acquired MDRB, with an incidence density was 18/1000 patient days. The septic patients had more comorbidities and a greater number of previous hospitalizations than the COVID-19 patients. The incidence density of MDRB acquisition was 30/1000 patient days. The association between COVID-19 and MDRB acquisition (compared to control) risk did not reach statistical significance in the multivariable competing risk analysis (sHR 1.71 (CI 95% 0.93-3.21)). Thus, we conclude that, despite strong physical isolation, acquisition rate of MDRB in ICU patients was at least similar during the COVID-19 first wave compared to previous period.

Keywords: Enterobacteriaceae; SARS-CoV-2; antimicrobial resistance; critically illness; infection control; subarachnoid hemorrhage; viral pandemic.

Figure 1

Distribution of MDRB bacteria acquired during COVID-19 ICU stay according to mechanism of resistance. AmpC β lactamase (AmpC) Enterobacteriaceae (N = 12): Enterobacter aerogenes (N = 6); E. cloacae (N = 5); Escherichia coli (N = 1). Extended spectrum β-lactamase (ESBL) Enterobacteriaceae (N = 9): Klebsiella pneumoniae (N = 6); E. coli (N = 2); E. aerogenes (N = 1). Carbapenem-resistant Enterobacteriaceae (CRE) (N = 3): K. pneumoniae (N = 2); E. aerogenes (N = 1). Vancomycin-resistant enterococci (VRE) (N = 3): Enterococcus faecium (N = 3); Multidrug-resistant Pseudomonas aeruginosa (N = 4).

Figure 2

Cumulative incidence of MDRB over time during ICU admission into two types of units (Medical–surgical and COVID-19 units). Comparison of Hazard ratios was calculated using the Fine and Gray method. p = 0.14 between groups.