Multidrug resistant infections in COVID-19 patients drive the transition toward a post antibiotic era

Introduction: The pandemic caused by coronavirus disease 2019 led to an unprecedented increase in antimicrobial consumption within Intensive Care Units. Prolonged hospitalizations and frequent invasive procedures created a high-pressure environment for the selection of multidrug-resistant organisms, signaling a critical transition toward a post-antibiotic era. Objectives: This study aimed to characterize the microbiological profile and antimicrobial susceptibility of healthcare-associated infections in patients with coronavirus disease 2019 and identify independent predictors of mortality. Methods: A retrospective study was conducted in an Intensive Care Unit dedicated exclusively to coronavirus disease 2019 in Brazil. We analyzed clinical data, infection sites, etiological agents, and resistance profiles. Multivariate logistic regression identified independent risk factors for mortality. Results: Among 130 isolated agents, Gram-negative bacteria predominated (74.6%). Acinetobacter baumannii was the most frequent pathogen, with a 90.6% carbapenem resistance rate. Klebsiella pneumoniae showed 52.4% carbapenem resistance and 42.9% extended-spectrum beta-lactamase production. Notably, Polymyxin B resistance escalated from 4.1% in 2020 to 22.2% in 2022, signaling emerging resistance in Acinetobacter baumannii and Klebsiella pneumoniae . Ventilator-associated pneumonia and bloodstream infections were the most common infections. Mortality was significantly associated with invasive mechanical ventilation (adjusted odds ratio 4.56; 95% confidence interval: 2.10–9.88; p < 0.001) and antimicrobial escalation (adjusted odds ratio 2.15; 95% confidence interval: 1.45–3.20; p < 0.001). Conclusion: The high prevalence of carbapenem-resistant Gram-negative bacteria and the rapid rise in polymyxin resistance are alarming. The strong association between mechanical ventilation, antimicrobial escalation and mortality underscores the urgent need for robust antimicrobial stewardship during respiratory pandemics.