Whole-Genome Analysis of Multidrug-Resistant Escherichia coli from Bloodstream Infections in Iraqi Cancer Patients

A multicenter study in three oncology hospitals in Baghdad, Iraq, examined bloodstream infections caused by Escherichia coli in cancer patients, a group particularly vulnerable to antimicrobial resistance (AMR). Among 55 isolates, about two-thirds were multidrug-resistant (MDR). Whole-genome sequencing revealed 36 different resistance genes, with MDR strains showing a complex resistome dominated by efflux pump systems and supplemented by β-lactamase and other resistance genes affecting macrolides, tetracyclines, and aminoglycosides. In contrast, antibiotic-sensitive isolates contained only a smaller core set of genes that alone did not produce resistance. The findings highlight the growing challenge of treating bloodstream infections in oncology patients and underscore the importance of genomic surveillance and targeted antimicrobial stewardship in cancer care settings, particularly in regions with limited diagnostic and treatment resources.