Health care–associated infections (HAIs) are a challenge in ICUs, where patient severity and invasive device use increase risk. Primary bloodstream infections (PBSIs), often caused by multidrug-resistant microorganisms, compromise treatment and increase mortality and costs. Inappropriate antimicrobial use worsens this scenario, reinforcing the importance of monitoring. This study analyzed the relationship between microbial resistance (MR), antimicrobial consumption, and PBSIs in adult ICUs in Ceará between 2021 and 2023.

A cross-sectional, quantitative, retrospective study using HAI, MR, and antimicrobial consumption data from adult ICUs in Ceará (2021–2023), obtained from ANVISA forms completed by 67 services. Laboratory-confirmed PBSIs (LC-PBSI), MR, and median antimicrobial consumption were evaluated. Analysis was descriptive, performed in Excel, using public data, dispensing with ethical approval.

LC-PBSI incidence varied: 9.5/1,000 patient-days (2021), 3.45 (2022), and 10.51 (2023). This fluctuation may be associated with changes in protocols, catheter management, length of stay, and clinical severity. In MR analysis among Gram-negative bacteria, Klebsiella pneumoniae stood out, with persistently high resistance to cephalosporins and carbapenems, and a marked increase in resistance to ceftazidime/avibactam, reaching 58.82% in 2023; and Enterobacter spp., with increasing carbapenem and cephalosporin resistance from 2021 to 2023 and 40% resistance to ceftazidime/avibactam in 2023. Among Gram-positive bacteria, Enterococcus spp. showed increased vancomycin resistance (62.5% in 2023), and Staphylococcus spp. showed reduced oxacillin resistance from 54.3% (2022) to 40.9% (2023), possibly related to reduced testing. Antimicrobial consumption increased for vancomycin, piperacillin/tazobactam, and amikacin, and decreased for polymyxins and fluconazole, indicating therapeutic adjustments. The correlation between consumption and resistance was multifactorial and non-linear.

The analysis showed a critical MR scenario, especially among Gram-negative bacteria, particularly Klebsiella pneumoniae, with high resistance to carbapenems and ceftazidime/avibactam. The increase in LC-PBSI in 2023 reinforces the severity of the problem. In this context, it is essential to intensify surveillance and optimize antimicrobial use.