Characterization of auto-agglutinating and non-typeable uropathogenic Escherichia coli strains.

Ulises Hernández-Chiñas,Armando Navarro-Ocaña,María E Chávez-Berrocal,Alejandro Pérez-Ramos,Laura Belmont-Monroy,Carlos A Eslava,Edgar González-Villalobos,Jose Molina-Lopez

doi:10.3855/jidc.11098

Abstract

Uropathogenic Escherichia coli (UPEC) are the main etiological agent of urinary tract infections (UTIs). Association between different serotypes and UTIs is known, however, some strains are incapable to be serotyped. The aim of this work was to study bthe phenotypical and genotypical characteristics of 113 non-typeable (NT) and auto-agglutinating (AA) E. coli strains, isolated from UTIs in children and adults. The 113 UPEC strains were analyzed by PCR assays using specific primers to determine their serogroups, fimH, papC, iutA, sat, hlyCA and cnf1, virulence associated genes, and chuA, yjaA and TSPE4.C2 for phylogroup determination. Additionally, the diffusion disk method was performed to evaluate the antimicrobial resistance to 18 antimicrobial agents. Using the PCR assay, 63% (71) of the strains were genotyped showing O25 and O75 as the most common serogroups. The virulence genes fimH (86%) and iutA (74%) were the most prevalent, in relation to the phylogroups the commensal (A and B1) and virulent (B2 and D) showed similar frequencies (P > 0.05). The antimicrobial susceptibility test showed a high percentage (73%) of multidrug-resistant strains. The genotyping allowed identifying the serogroup in many of the strains that could not be typed by traditional serology. The strains carried virulence genes and were multidrug-resistant in both, commensal and virulent phylogroups. Our findings revealed that, in addition to the classical UPEC serogroups, there are pathogenic serogroups not reported yet.

Highlights

Uropathogenic Escherichia coli (UPEC) are the main etiological agent of urinary tract infections (UTIs)
In order to define that an Escherichia coli (E. coli) strain corresponds to the uropathogenic group (UPEC), the bacteria should be isolated from a patient with symptoms of urinary tract infections (UTIs), be included in the classic UPEC serogroups with phylogenetic background and have specific virulence factors and antimicrobial resistance [1]
We evaluated if the isolates carried genes that code for virulence properties of UPEC strains and their behavior against antimicrobials used in UTIs treatment

Summary

Introduction

Uropathogenic Escherichia coli (UPEC) are the main etiological agent of urinary tract infections (UTIs). In order to define that an Escherichia coli (E. coli) strain corresponds to the uropathogenic group (UPEC), the bacteria should be isolated from a patient with symptoms of urinary tract infections (UTIs), be included in the classic UPEC serogroups with phylogenetic background and have specific virulence factors and antimicrobial resistance [1]. These UPEC strains are the main etiologic agent of UTIs within the community (60-90%) as well as in hospitals (50-70%) [2,3]. A multiplex PCR was developed by Li. et al [7] to identify those serogroups commonly occurring in UPEC by using the wzx (flippase), wzy (polymerase) and orf486 target genes, as they are linked to the Hernández-Chiñas et al – Typing of non-serotypeable UPEC strains

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