Sepsis has been increasing by an average of 9% annually. Notably, over 60% of patients with severe sepsis are aged 65 or older, and older adults have twice the mortality risk from sepsis compared to younger adults. Urosepsis is a form of sepsis in which the urinary tract is the confirmed or highly suspected source of infection. This study investigates the microbiological characteristics of patients diagnosed with urosepsis among those with febrile urinary tract infections (UTIs) who visited a university hospital in South Korea.

This study included patients aged 65 years or older who visited a university hospital with febrile UTIs between January 2018 and December 2022. A retrospective review of medical records was conducted to identify causative pathogens, antibiotic resistance, sepsis occurrence, mortality, and other complications. Based on the patients’ place of residence before hospitalization, infections were categorized as community-acquired, hospital-acquired, or healthcare-associated.

Among a total of 1,108 patients, 281 (25.4%) developed sepsis. The mean age of patients with sepsis was 79.8 years, which was not significantly different from those without sepsis (p > 0.05). The proportion of male patients was higher in the sepsis group (37.0% vs. 28.9%, p = 0.011), and sepsis was associated with significantly higher mortality (20.3% vs. 1.7%, p = 0.000) and longer hospital stays (22.4 days vs. 13.4 days, p = 0.000). Escherichia coli was the most common pathogen in both groups, accounting for 63.7% of cases in the sepsis group and 71.2% in the non-sepsis group. While the prevalence of extended-spectrum beta-lactamase (ESBL)-producing strains was similar between the groups, the proportion of multidrug-resistant organisms was higher in the sepsis group (64.8% vs. 56.1%). Additionally, patients with sepsis were more likely to have an indwelling urinary catheter before the febrile event (33.5% vs. 15.5%, p = 0.000). The distribution of pre-hospital residence differed between the sepsis and non-sepsis groups.

Sepsis occurs frequently following febrile UTIs in older adults and is associated with high mortality. The incidence of sepsis varied based on the infection acquisition setting, and patients suspected of having healthcare-associated infections require intensive management.