Urinary tract infections (UTIs) are among the most common healthcare-associated infections. The increasing microbial resistance, varying by region, observed in pathogens such as Klebsiella pneumoniae and Escherichia coli (E. coli) compromises the effectiveness of empirical treatment regimens and represents a major public health challenge. This study aimed to analyze the microbiological profiles and resistance patterns of microorganisms causing UTIs in the state of Santa Catarina, Brazil, in 2024.

This was an ecological study using secondary data made publicly available by the Brazilian Health Regulatory Agency (ANVISA) through its 2024 statistical bulletins on healthcare-associated infections and antimicrobial resistance. The analysis included Gram-negative and Gram-positive pathogens responsible for UTIs in adult intensive care units (ICUs) in Santa Catarina.

The main microorganism identified was Klebsiella pneumoniae (n = 143), followed by E. coli (n = 123), Pseudomonas aeruginosa (n = 54), Enterococcus spp. (n = 21), Enterococcus faecalis (n = 19), Proteus spp. (n = 18), Enterobacter spp. (n = 17), Acinetobacter (n = 9), Serratia spp. (n = 6), and Enterococcus faecium (n = 1). In the analysis of antimicrobial resistance rates, K. pneumoniae showed a rate of 59.4%, Enterobacter spp. 45.2%, P. aeruginosa 32.8%, and E. coli 32.5%. Notably high resistance rates were observed for E. faecium (100%) and Acinetobacter spp. (90%), despite their lower prevalence compared with other pathogens. Data on antimicrobial resistance revealed that cephalosporins exhibited the highest resistance rates for K. pneumoniae (87.8%), Enterobacter spp. (68.8%), E. coli (58.5%), and Proteus spp. (41.2%). These agents also showed resistance to carbapenems, with K. pneumoniae displaying the highest rate (46.8%) and Proteus spp. the lowest (5.9%).

The findings revealed Klebsiella pneumoniae as the predominant pathogen in adult ICU UTIs in Santa Catarina in 2024, contrasting with most national studies that identify E. coli as the most frequent. The predominance of resistant Gram-negative bacteria underscores the current therapeutic challenge. Understanding local resistance profiles and promoting awareness among healthcare professionals are essential strategies to prevent severe infectious outcomes.