Original Article

Ann Lab Med 2022; 42(2): 203-212

Published online March 1, 2022

Copyright © Korean Society for Laboratory Medicine.

Virulence Factors Associated With Escherichia coli Bacteremia and Urinary Tract Infection

Bongyoung Kim, M.D., Ph.D.1 , Jin-Hong Kim, M.D.2 , and Yangsoon Lee, M.D., Ph.D.2

Departments of 1Internal Medicine and 2Laboratory Medicine, Hanyang University College of Medicine, Seoul, Korea

Correspondence to: Yangsoon Lee, M.D., Ph.D.
Department of Laboratory Medicine, Hanyang University Seoul Hospital, Hanyang University College of Medicine, 222-1 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea
Tel: +82-2-2290-8973
Fax: +82-2-2290-9193

Received: February 23, 2021; Revised: April 5, 2021; Accepted: September 13, 2021

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background: Extraintestinal pathogenic Escherichia coli (ExPEC) causes various infections, including urinary tract infection (UTI), sepsis, and neonatal meningitis. ExPEC strains have virulence factors (VFs) that facilitate infection by allowing bacterial cells to migrate into and multiply within the host. We compared the microbiological characteristics of ExPEC isolates from blood and urine specimens from UTI patients.
Methods: We conducted a single-center, prospective study in an 855-bed tertiary-care hospital in Korea. We consecutively recruited 80 hospitalized UTI patients with E. coli isolates, which were isolated from blood and/or urine, and urine alone between March 2019 and May 2020. We evaluated the 80 E. coli isolates for the presence of bacterial genes encoding the sequence types (STs), antimicrobial resistance, and VFs using whole-genome sequencing (WGS).
Results: We found no significant differences in STs, antimicrobial resistance patterns, or VFs between isolates from blood and urine specimens. ST131, a pandemic multidrug-resistant clone present in both blood and urine, was the most frequent ST (N=19/80, 24%), and ST131 isolates carried more virulence genes, especially, tsh and espC, than non-ST131 isolates. The virulence scores of the ST131 group and the ST69, ST95, and ST1193 groups differed significantly (P<0.05).
Conclusions: We found no STs and VFs associated with bacteremia in WGS data of E. coli isolates from UTI patients. ST131 was the most frequent ST among UTI causing isolates and carried more VF genes than non-ST131 isolates.

Keywords: Escherichia coli, ST131, Urinary tract infection, Whole-genome sequencing, tsh, Virulence factors