Changes in the characteristics of community-onset fluoroquinolone-resistant Escherichia coli isolates causing communityacquired acute pyelonephritis in South Korea

Abstract

Abstract Purpose: This study aimed to examine the changes in the characteristics of community-onset fluoroquinolone-resistant (FQ-R) Escherichia coli isolates causing community-acquired acute pyelonephritis (APN) in South Korea. Methods: Blood or urine samples were prospectively collected from patients aged 15 years with community-acquired APN who were admitted to one of the eight Korean hospitals included in this study between September 2017 and August 2018. Phylogenetic typing, multilocus sequence typing, and molecular characterization of b-lactamase resistance and plasmid-mediated quinolone resistance (PMQR) determinants were performed. The data were compared with those from a previous study with the same design conducted in 2010e2011. Results: A total of 300 and 346 isolates were identified in 2010e2011 and 2017e2018, respectively. Among them, 76 (22.0%) and 77 (25.7%) FQ-R isolates were identified in 2010e2011 and 2017e2018, respectively. A significantly higher antimicrobial resistance against third-to fourthgeneration cephalosporins, including cefotaxime (23.9% vs. 77.9%, P < 0.001), were observed among FQ-R isolates in 2017e2018 than among those in 2010e2011. A higher proportion of ST131 isolates (27.6% vs. 66.2%, P < 0.001), as well as isolates that had extended-spectrum b-lactamase (ESBL)/plasmid-mediated AmpC b-lactamase (PABL) (23.7% vs. 79.2%, P < 0.001), was observed in 2017e2018 than in 2010e2011. Further, more PMQR determinants (11.8% vs. 40.8%, P < 0.001) were observed in 2017e2018 than in 2010e2011. Conclusions: Among uropathogenic FQ-R E. coli isolates in South Korea, the prevalence of ST131 and the proportion of isolates containing ESBL and/or PMQR determinants have increased