Fluoroquinolone-Resistant Escherichia coli

Fluoroquinolone-Resistant Escherichia coli

The most common outpatient pathogen rapidly gaining resistance to the most prescribed antibiotic class

Background

Escherichia coli, a member of the Enterobacteriaceae family of bacteria, is the leading cause of community- and hospital-acquired urinary tract infections (UTIs). Although E. coli is found naturally in the human gut, certain food-borne strains can cause serious gastrointestinal infections.

Fluoroquinolones are the most frequently prescribed drug class in the United States, including drugs like ciprofloxacin and levofloxacin that are recommended as first-line drugs for uncomplicated UTIs when local trimethophrim-sulfa resistance is known to be high. Rising fluoroquinolone resistance is worriesome because it has been linked to the emergence of plasmid-mediated quinolone resistance (PMQR), a mechanism by which genes that encode for resistance are transmitted horizontally (from one organism to another) rather than vertically (from parent organism to offspring), thus accelerating the rate at which similar species such as K. pneumoniae develop resistance.