Healthcare-Associated Bloodstream Infections Due to Multidrug-Resistant Acinetobacter baumannii in COVID-19 Intensive Care Unit: A Single-Center Retrospective Study

Abstract

Healthcare-associated infections are an emerging cause of morbidity and mortality in COVID-19 intensive care units (ICUs) worldwide, especially those caused by multidrug-resistant (MDR) pathogens. The objectives of this study were to assess the incidence of bloodstream infections (BSIs) among critically ill COVID-19 patients and to analyze the characteristics of healthcare-associated BSIs due to MDR Acinetobacter baumannii in an COVID-19 ICU. A single-center retrospective study was conducted at a tertiary hospital during a 5-month period. The detection of carbapenemase genes was performed by PCR and genetic relatedness by pulsed-field gel electrophoresis (PFGE) and multilocus-sequence typing. A total of 193 episodes were registered in 176 COVID-19 ICU patients, with an incidence of 25/1000 patient-days at risk. A. baumannii was the most common etiological agent (40.3%), with a resistance to carbapenems of 100%. The bla_OXA-23 gene was detected in ST2 isolates while the bla_OXA-24 was ST636-specific. PFGE revealed a homogeneous genetic background of the isolates. The clonal spread of OXA-23-positive A. baumannii is responsible for the high prevalence of MDR A. baumannii BSIs in our COVID-19 ICU. Further surveillance of resistance trends and mechanisms is needed along with changes in behavior to improve the implementation of infection control and the rational use of antibiotics.

Keywords: Acinetobacter baumannii; COVID-19; blaOXA-23; bloodstream infection; carbapenem resistance; carbapenemase genes; healthcare-associated infections; intensive care units; multidrug resistance.

Figure 1

The most common etiological agents of healthcare-associated bloodstream infections in the COVID-19 intensive care unit at the Dubrava University Hospital during the second wave of the COVID-19 pandemic (1 October 2020–28 February 2021) (N = 278). Legend: CoNS—coagulase-negative staphylococci; ESBL—extended-spectrum beta-lactamase; MRSA—methicillin-resistant Staphylococcus aureus; OXA-48—oxacillinase (OXA)–48; VRE—vancomycin-resistant enterococci.