The effect of the COVID-19 pandemic on the epidemiology of positive blood cultures in Swiss intensive care units: a nationwide surveillance study.
Lauro Damonti, Andreas Kronenberg, Jonas Marschall, Philipp Jent, Rami Sommerstein, Marlieke E A De Kraker, Stephan Harbarth, Michael Gasser, Niccolò Buetti
Author Information
Lauro Damonti: Department of Infectious Diseases, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland. lauro.damonti@insel.ch. ORCID
Andreas Kronenberg: Swiss Centre for Antibiotic Resistance, Institute for Infectious Diseases, University Bern, Bern, Switzerland.
Jonas Marschall: Department of Infectious Diseases, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
Philipp Jent: Department of Infectious Diseases, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
Rami Sommerstein: Department of Infectious Diseases, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
Marlieke E A De Kraker: Infection Control Program and WHO Collaborating Centre on Patient Safety, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland.
Stephan Harbarth: Infection Control Programme, University of Geneva Hospitals and Faculty of Medicine, WHO Collaborating Center, Geneva, Switzerland.
Michael Gasser: Swiss Centre for Antibiotic Resistance, Institute for Infectious Diseases, University Bern, Bern, Switzerland.
Niccolò Buetti: Infection Control Programme, University of Geneva Hospitals and Faculty of Medicine, WHO Collaborating Center, Geneva, Switzerland.
BACKGROUND: Evidence about the impact of the pandemic of COVID-19 on the incidence rates of blood cultures contaminations and bloodstream infections in intensive care units (ICUs) remains scant. The objective of this study was to investigate the nationwide epidemiology of positive blood cultures drawn in ICUs during the first two pandemic waves of COVID-19 in Switzerland. METHODS: We analyzed data on positive blood cultures among ICU patients, prospectively collected through a nationwide surveillance system (ANRESIS), from March 30, 2020, to May 31, 2021, a 14-month timeframe that included a first wave of COVID-19, which affected the French and Italian-speaking regions, an interim period (summer 2020) and a second wave that affected the entire country. We used the number of ICU patient-days provided by the Swiss Federal Office of Public Health as denominator to calculate incidence rates of blood culture contaminations and bloodstream infections (ICU-BSI). Incidence rate ratios comparing the interim period with the second wave were determined by segmented Poisson regression models. RESULTS: A total of 1099 blood culture contaminations and 1616 ICU-BSIs were identified in 52 ICUs during the study. Overall, more episodes of blood culture contaminations and ICU-BSI were observed during the pandemic waves, compared to the interim period. The proportions of blood culture contaminations and ICU-BSI were positively associated with the ICU occupancy rate, which was higher during the COVID-19 waves. During the more representative second wave (versus interim period), we observed an increased incidence of blood culture contaminations (IRR 1.57, 95% CI 1.16-2.12) and ICU-BSI (IRR 1.20, 95% CI 1.03-1.39). CONCLUSIONS: An increase in blood culture contaminations and ICU-BSIs was observed during the second COVID-19 pandemic wave, especially in months when the ICU burden of COVID-19 patients was high.
