Virulence gene profiles and molecular genetic characteristics of diarrheagenic Escherichia coli from a hospital in western China

Abstract

BackgroundDiarrheagenic Escherichia coli (DEC) is one of the most important etiological agents of diarrheal diseases. In this study we investigated the prevalence, virulence gene profiles, antimicrobial resistance, and molecular genetic characteristics of DEC at a hospital in western China.MethodsA total of 110 Escherichia coli clinical isolates were collected from the First Affiliated Hospital of Chengdu Medical College from 2015 to 2016. Microbiological methods, PCR, antimicrobial susceptibility test, pulsed-field gel electrophoresis and multilocus sequence typing were used in this study.ResultsMolecular analysis of six DEC pathotype marker genes showed that 13 of the 110 E. coli isolates (11.82%) were DEC including nine (8.18%) diffusely adherent Escherichia coli (DAEC) and four (3.64%) enteroaggregative Escherichia coli (EAEC). The adherence genes fimC and fimH were present in all DAEC and EAEC isolates. All nine DAEC isolates harbored the virulence genes fyuA and irp2 and four (44.44%) also carried the hlyA and sat genes. The virulence genes fyuA, irp2, cnf1, hlyA, and sat were found in 100%, 100%, 75%, 50%, and 50% of EAEC isolates, respectively. In addition, all DEC isolates were multidrug resistant and had high frequencies of antimicrobial resistance. Molecular genetic characterization showed that the 13 DEC isolates were divided into 11 pulsed-field gel electrophoresis patterns and 10 sequence types.ConclusionsTo the best of our knowledge, this study provides the first report of DEC, including DAEC and EAEC, in western China. Our analyses identified the virulence genes present in E. coli from a hospital indicating their role in the isolated DEC strains’ pathogenesis. At the same time, the analyses revealed, the antimicrobial resistance pattern of the DEC isolates. Thus, DAEC and EAEC among the DEC strains should be considered a significant risk to humans in western China due to their evolved pathogenicity and antimicrobial resistance pattern.

<p>Diversity of Virulence Genes in Multidrug Resistant <em>Escherichia coli</em> from a Hospital in Western China</p>

“…The 24 most commonly used antimicrobials in Chinese practice clinical were used in this study to test the antibiotic resistance of the 97 E. coli isolates,14,18–20 including penicillin (ampicillin, ticarcillin, piperacillin), cephems (cefoxitin, cefoperazone, cefotaxime, ceftazidime), monobactams (aztreonam), carbapenems (meropenem, imipenem, ertapenem), aminoglycosides (tobramycin, kanamycin, gentamicin, amikacin, chloramphenicol), tetracyclines (deoxycycline, minocycline, tetracycline), quinolones (levofloxacin, ofloxacin, nalidixic acid, ciprofloxacin) 16. The resistance profiles of the E. coli isolates against these 24 antibiotics are detailed in Table 3.…”

“…E. coli strains have been well documented in healthcare settings in western China; however, their characterization has often been limited to phenotypic tests and the identification of resistance genes,9–13 with limited information regarding their virulence factors. Previously, we examined the virulence gene profiles of 13 diarrheagenic E. coli (DEC) strains isolated from a hospital in western China, as well as the molecular characteristics of their genes 14. Here, we characterized E. coli strains from a hospital in western China and determined their virulence and antimicrobial resistance potential, to better understand the prevalence of virulence genes and antimicrobial resistance in clinical E.coli isolates.…”

Advanced molecular characterization of enteropathogenic Escherichia coli isolated from diarrheic camel neonates in Egypt

“…Moreover, adherence of E. coli to host receptors confers resistance to mechanical elimination and increases persistence. fimH is a major determinant encoding adhesins that target epithelial receptors; thus, the gene is crucial for E. coli colonization [11]. Results obtained from diplex PCR (Figure-2) recognized traT and fimH genes in 8 and 10 isolates (75%, 83.3%), respectively.…”

“…An essential step for initiation and development of enteritis is bacterial attachment to intestinal epithelial cells. E. coli attachment is mediated by fimbriae (adhesins) that bind to host cell receptors; the FimH gene is representative [11].…”

Virulence Profiles of Diarrheagenic <i>Escherichia coli</i> Isolated from the Western Region of Ghana

“…Other virulence factors including those involved in adherence were determined as described previously (23,24). ETEC-specific adherence genes, such as those encoding CFA/I, CS1, CS2, CS3, CS4, CS5, and CS6, as well as other adherence and non-adherence genes, such as lpfA, pap, pic, and cnf1, were also screened.…”