Bacteriuria and antibiotic use during the third wave of COVID-19 intensive care in Sweden

Background Urinary tract infections (UTIs) are prevalent among patients carrying indwelling catheters in the intensive care unit (ICU). This study investigates antibiotic use and bacterial colonisation among ICU patients during the third wave of the COVID-19 pandemic, building on our prior discovery of increased Enterococcus colonisation associated with increased cephalosporin use in early COVID-19. Methods Longitudinal urine samples from COVID-19 patients (n = 109) with transurethral catheterisation were analysed for bacterial prevalence, further identified via MALDI-TOF. Microbiological results were combined with clinical data obtained daily, assessed and compared with COVID-19 waves 1 and 2. Results Patients in wave 3 exhibited improved outcomes compared to those in waves 1 and 2, alongside a decrease in antibiotic use. Staphylococcus emerged as the primary bacterium and early colonizer of the urinary tract, potentially due to the absence of antibiotic treatment. Our results imply that length of stay (LOS) correlates solely with enteric pathogens and that antibiotic treatment correlates with colonisation by certain uropathogens, whereas the absence of antimicrobial therapy is associated with rapid colonisation of skin flora. Polymicrobial colonisation was common, predominantly involving Gram-positive bacteria. Conclusion Our findings underscore the complexity of bacteriuria in ICU patients, advocating for targeted surveillance and tailored antibiotic approaches to mitigate UTI risk. Insights into antibiotic use and bacterial colonisation are vital for optimising stewardship practices, combating antimicrobial resistance, and enhancing ICU patient outcomes.