Variation in the Microbiological Profile and Mortality in a Public Hospital in the Southern Zone of the City of São Paulo: During and After Covid-19

The COVID-19 pandemic directly impacted the organization of health services, leading several hospitals to operate exclusively in the care of patients with SARS-CoV-2. This scenario implied intensified precautions, expanded antimicrobial use, and care overload, contributing to increased multidrug-resistant microorganisms (MDROs). With the reduction of severe cases and the resumption of activities as general hospitals, the hypothesis arose that the epidemiological profile of MDROs also changed, requiring comparative analysis between the two periods. The objective is to analyze the profile of MDROs isolated in a municipal hospital in the southern zone of São Paulo during the COVID-19 pandemic and after its transition to a general hospital. A retrospective, descriptive, quantitative study divided into two periods: “pandemic phase” (May 2020 to December 2021) and “general hospital phase” (January 2022 to May 2025). Laboratory data from clinical and surveillance cultures were analyzed, as well as electronic medical record data. In the “pandemic phase,” 265 medical records were evaluated, with mortality of 73.2%. The main MDROs were: Klebsiella pneumoniae – KPC (55.5%), Acinetobacter baumanii (34%), and Pseudomonas aeruginosa (3.8%) resistant to carbapenems. In the “general hospital phase,” 644 medical records were analyzed, with mortality of 44.9%. The main MDROs were: A. baumanii carbapenem-resistant (38%), K. pneumoniae – KPC (29.2%), and P. aeruginosa carbapenem-resistant (6.7%). Comparison between periods revealed reversals in the institutional microbiological profile, with a proportional reduction in Klebsiella pneumoniae – KPC and an increase in carbapenem-resistant A. baumanii . The post-pandemic scenario was accompanied by a marked decrease in mortality due to lower clinical severity, involvement of new specialties in the institution, reorganization of patient flows, and structuring of care teams. These changes require constant reevaluation of infection prevention protocols, active surveillance for MDRO colonization, periodic review of the institutional microbiota, adjustment of antimicrobials, and intensification of continuing education. The post-COVID care transition reinforces the importance of dynamic strategies supported by local data to contain the spread of resistance, improve clinical outcomes, and enhance quality of care.