Hospital Infection Control Committees (HICC) monitor pathogens responsible for healthcare-associated infections (HAIs) and issue antimicrobial susceptibility profiles to identify the institution’s pathogens, assisting in the empirical treatment of HAIs, as well as isolating or cohorting patients when indicated.

To identify the pathogens associated with HAIs and their susceptibility profiles in a university hospital during the pre, during, and post-COVID-19 pandemic periods.

A retrospective study was conducted at a tertiary, high-complexity university hospital with 80–100 ICU beds, which fluctuated during the pandemic. Data were collected from the hospital’s electronic system (Medview, HICC module), including all positive cultures with antibiograms from patients hospitalized for more than 3 days, from all infection sites (excluding swabs and colonizations). The analyzed periods were: 2018–2019 (I – pre-pandemic), 2021–2022 (II – pandemic), and 2023–2024 (III – post-pandemic).

The most prevalent Gram-negative pathogens in the three periods were Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa. The evolution of resistance in the three periods was: Klebsiella pneumoniae/carbapenems: 53% - 70% - 68.5%; Klebsiella pneumoniae/polymyxin: 58% - 49% - 31.5%; Acinetobacter baumannii/carbapenems: 95% - 96% - 95%; Acinetobacter/polymyxin: 4% - 21% - 8.5%; Pseudomonas aeruginosa/carbapenems: 46% - 43% - 41%. There was no resistance of P. aeruginosa to polymyxins. Regarding Gram-positive bacteria, Enterococcus faecalis maintained sensitivity to ampicillin, but resistance to vancomycin (VRE) was 9% - 31.5% - 20.5%; Enterococcus faecium/ampicillin: 82% - 94% - 93.5% and Enterococcus faecium/vancomycin: 24% - 57% - 61.5%.

The University Hospital presents a sensitivity profile with a high prevalence of Acinetobacter spp., Klebsiella pneumoniae and Pseudomonas aeruginosa resistant to carbapenems, worsened during the pandemic period, especially K. pneumoniae resistant to carbapenems and A. baumannii to polymyxins. Regarding Gram-positive bacteria, we observed an increase in the resistance of E. faecalis and E. faecium to vancomycin (VRE). Worsening resistance data have been addressed in several publications, especially the increase in VRE infections. Preventive measures such as hand hygiene, environmental hygiene, isolation, and precautions are fundamental in controlling multidrug-resistant pathogens