Clinical and microbiological characteristics of bloodstream infections caused by carbapenem- and polymyxin-resistant Klebsiella pneumoniae among patients with and without COVID-19 in a tertiary hospital in Brazil

The COVID-19 pandemic has been associated with increased antimicrobial use and disruption of infection control practices, potentially contributing to the emergence and dissemination of multidrug-resistant pathogens. Data on bloodstream infections caused by carbapenem- and polymyxin-resistant Klebsiella pneumoniae (CR/PR-Kp), particularly in Latin American settings, remain limited. A retrospective cross-sectional study was conducted including 173 patients with positive blood cultures for K. pneumoniae between January 2020 and May 2023 in a tertiary hospital. Antimicrobial susceptibility testing was performed using standard methods, with polymyxin resistance confirmed by broth microdilution and the polymyxin B drop test. Molecular detection of resistance genes, including bla KPC, was performed by polymerase chain reaction. Clinical, demographic, and laboratory data were extracted from medical records and compared between COVID-19 and non-COVID-19 patients. Multivariable logistic regression was used to identify factors independently associated with COVID-19 status. Resistance to both carbapenems and polymyxins was significantly higher among COVID-19 patients (80.8%) compared with non-COVID-19 patients (64.2%) ( p = 0.010). The bla KPC gene was more frequently detected among COVID-19 patients. In addition, COVID-19 patients presented greater clinical severity, including higher rates of acute kidney injury and need for intensive care support. Bloodstream infections caused by carbapenem- and polymyxin-resistant K. pneumoniae were highly prevalent among patients with COVID-19 in this tertiary care hospital. This finding likely reflects the interaction between disease severity, increased antimicrobial exposure, and prolonged ICU stay rather than a direct effect of COVID-19. Continuous microbiological surveillance and strengthened antimicrobial stewardship strategies are essential to control the spread of multidrug-resistant pathogens in hospital settings.