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

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 β-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 2010–2011. Results: A total of 300 and 346 isolates were identified in 2010–2011 and 2017–2018, respectively. Among them, 76 (22.0%) and 77 (25.7%) FQ-R isolates were identified in 2010–2011 and 2017–2018, respectively. A significantly higher antimicrobial resistance against third-to fourth-generation cephalosporins, including cefotaxime (23.9% vs. 77.9%, P < 0.001), were observed among FQ-R isolates in 2017–2018 than among those in 2010–2011. A higher proportion of ST131 isolates (27.6% vs. 66.2%, P < 0.001), as well as isolates that had extended-spectrum β-lactamase (ESBL)/plasmid-mediated AmpC β-lactamase (PABL) (23.7% vs. 79.2%, P < 0.001), was observed in 2017–2018 than in 2010–2011. Further, more PMQR determinants (11.8% vs. 40.8%, P < 0.001) were observed in 2017–2018 than in 2010–2011. 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.