PREVALENCE, DETERMINANTS, AND CLINICAL OUTCOMES OF ANTIMICROBIAL RESISTANCE IN TERTIARY CARE HOSPITALS OF PAKISTAN: A MULTICENTER PHARMACOVIGILANCE AND MOLECULAR SURVEILLANCE STUDY

Abstract

Antimicrobial resistance (AMR) is a major global health threat, particularly in tertiary care hospitals where high-risk patients are exposed to invasive procedures and broad-spectrum antibiotics. This multicenter study aimed to evaluate the prevalence, determinants, molecular mechanisms, and clinical outcomes of AMR in Pakistani tertiary hospitals. A total of 385 hospitalized patients were enrolled, and bacterial isolates were analyzed for phenotypic resistance, molecular markers, and clinical outcomes. Results revealed a high prevalence of multidrug-resistant Gram-negative bacteria, including Klebsiella pneumoniae (68%), Acinetobacter baumannii (72%), and Escherichia coli (62%), as well as methicillin-resistant Staphylococcus aureus (48%). Logistic regression identified prior antibiotic use, ICU admission, invasive devices, prolonged hospitalization, and non-adherence to stewardship guidelines as significant determinants of AMR (p < 0.05). Molecular analysis detected blaNDM-1, blaOXA-23, mcr-1, mecA, and vanA/B, correlating strongly with phenotypic resistance. Patients with resistant infections experienced higher treatment failure, longer hospital stays, and increased mortality compared to those with susceptible infections (p < 0.01). These findings emphasize the need for robust antimicrobial stewardship, pharmacovigilance, and molecular surveillance to guide empiric therapy and reduce AMR burden in high-risk hospital settings.