Comparison of the microbiological characteristics and virulence factors of ST131 and non-ST131 clones among extended-spectrum β-lactamase-producing Escherichia coli causing bacteremia.

Abstract

We evaluated the molecular epidemiology and microbiological characteristics of extended-spectrum β- lactamase–producing Escherichia coli (ESBL-EC) isolates that cause bacteremia in Korean hospitals, focusing especially on ST131. Our data suggest that ST131 isolates possessedmore virulence traits and showedmoremultidrug resistance patterns than non-ST131 isolates.Among CTX-M-15 producers, the frequency of serumresistancewas significantly higher in ST131 than in non-ST131. As in other parts of the world, the ESBL-EC ST131 clone has emerged and disseminated in both community and hospital settings in Korea, including in blood isolates in patients with bacteremia.