Antimicrobial resistance (AMR) in hospital-acquired Gram-negative bacterial infections represents one of the most urgent threats to global health security, with carbapenem-resistant Enterobacteriaceae (CRE), extended-spectrum beta-lactamase-producing organisms (ESBL), and multidrug-resistant Pseudomonas aeruginosa collectively accounting for an estimated 700,000 deaths annually from AMR-attributable infections. Indian tertiary care intensive care units represent epicentres of AMR selection pressure, combining critically ill immunocompromised patients, prolonged antibiotic exposures, device-associated infection risk, and the cross-transmission dynamics of high-density care environments. This study presents a four-year retrospective surveillance analysis (2020-2024) of antimicrobial resistance rates in Gram-negative hospital-acquired infections across twenty-two ICUs in eight major Indian cities, examining temporal trends in resistance to first-line, second-line, and last-resort antimicrobial agents. Microbiological data from 18,742 clinical isolates of Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa were extracted from participating institutions' laboratory information systems and linked to clinical outcome data including ICU length of stay, 30-day mortality, and antimicrobial treatment duration. Resistance rates across fourteen antimicrobial classes were calculated annually per organism. Results demonstrate a consistent temporal escalation in resistance across all three organisms and nearly all antimicrobial classes, with the most alarming trajectory observed for carbapenem resistance in K. pneumoniae (8.7% in 2020 to 18.3% in 2024) and meropenem resistance in E. coli (4.2% to 9.8%). Multivariable Cox regression identified carbapenem resistance as the strongest predictor of 30-day mortality (HR 3.42, 95% CI 2.87-4.07), confirming the clinical severity of the resistance escalation trend.
Suresh Kumar Sharma, Anita Patel, Rajiv Mohan (Tue,) studied this question.