Determination of the frequency of β-lactamase genes (bla SHV, bla TEM, bla CTX-M) and phylogenetic groups among ESBL-producing uropathogenic Escherichia coli isolated from outpatients

Shiva Mirkalantari,Emmanuel Edwar Siddig,Azam Fattahi,Gholamreza Irajian,Faramarz Masjedian

doi:10.1515/labmed-2018-0136

Shiva Mirkalantari, Emmanuel Edwar Siddig + Show 3 more

Open Access

https://doi.org/10.1515/labmed-2018-0136

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Abstract

Abstract Background Escherichia coli accounts for 70–95% of community-acquired urinary tract infections (UTIs). Recently, there has been an increase in the prevalence of extended-spectrum β-lactamase (ESBL) in the community which required an accurate identification for better management. Therefore, the current study was performed to determine the antimicrobial resistance pattern, investigate ESBL phenotypes and genotypes (blaCTX-M, bla TEM and bla SHV genes) and determine the phylogenetic groups among ESBL-positive isolates from outpatients. Methods One hundred and eighty-three positive urine samples were collected from 4450 outpatient clinic attendees. Antibiotic susceptibility was determined and ESBL phenotype screening was carried out using disk diffusion agar and combination disk techniques, respectively. The assessment of the presence of the blaCTX-M, bla TEM and blaSHV genes and phylogenetic grouping were performed using the polymerase chain reaction (PCR) method. Results Out of 183 E. coli isolates, 59 (32.2%) showed a positive ESBL phenotype. The prevalence of ESBL-producing E. coli was higher in males (57.4%). Fifty-seven of the ESBL-producing strains carried at least one of the β-lactamase genes (bla CTX-M, bla TEM, bla SHV). Phylotyping of multi-drug resistant isolates indicated that the isolates belonged to B2, A and D phylogroups. Analysis of resistance patterns among these phylogroups revealed that 74.4%, 55.3% and 29.7% of the isolates in the B2 group were resistant to trimethoprim-sulfamethoxazole, ciprofloxacin and gentamicin, respectively. Most of the strains in the phylogroup B2 carried the bla CTX-M gene. Conclusions All the ESBL-producing isolates were placed in one of the four phylogenetic groups. The presence of CTX-M and resistance to quinolones were more frequent in B2 strains than in non-B2 strains.

Highlights

Urinary tract infections (UTIs) are considered to be one of the most important and frequent infectious diseases, especially among adults
urinary tract infections (UTIs) is the second most prevalent bacterial infection in the community, and uropathogenic E. coli accounts for 70–95% of community-acquired UTI cases [4,5,6]. β-Lactam antibiotics due to their broad antibacterial spectrum and minimal side effects are widely used in the treatment of various infections such as UTI [7]
Several antibiotics can be used for the treatment of bacterial infections; most general practitioners prescribe β-lactam antibiotics to be used as the first line of UTI treatment

Summary

Introduction

Urinary tract infections (UTIs) are considered to be one of the most important and frequent infectious diseases, especially among adults. Escherichia coli, from the Enterobacteriaceae family, is the most frequent bacterial agent in both nosocomial and community-acquired UTIs. About 70–80% of all uropathogens is E. coli [1,2,3]. UTI is the second most prevalent bacterial infection in the community, and uropathogenic E. coli accounts for 70–95% of community-acquired UTI cases [4,5,6]. The resistance of community-acquired E. coli to extended spectrum β-lactamases (ESBLs) is a particular concern for clinicians. Escherichia coli accounts for 70–95% of community-acquired urinary tract infections (UTIs). The current study was performed to determine the antimicrobial resistance pattern, investigate ESBL phenotypes and genotypes (blaCTX-M, bla TEM and bla SHV genes) and determine the phylogenetic groups among ESBL-positive isolates from outpatients.

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