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Characterization of multidrug resistant ESBL-producing Escherichia coli isolates from hospitals in Malaysia

King-Ting Lim1, Rohani Yasin, Chew-Chieng Yeo

  • 1Microbiology Division, Institute of Biological Science, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.

Journal of Biomedicine & Biotechnology
|August 13, 2009
PubMed

Insights

Multidrug-resistant Escherichia coli producing extended-spectrum beta-lactamases (ESBLs) are a growing concern. This study identified ESBL and resistance genes in Malaysian E. coli, finding them diverse and often plasmid-borne.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Infectious Diseases

Background:

  • Emergence of multidrug-resistant (MDR) Escherichia coli strains, particularly those producing extended-spectrum beta-lactamases (ESBLs), presents significant challenges in antibiotic management.
  • ESBL-producing E. coli are a major cause of hospital-acquired infections globally, necessitating a thorough understanding of their genetic basis and epidemiology.

Purpose of the Study:

  • To investigate the genetic characteristics of ESBL- and MDR-producing E. coli isolates from Malaysian hospitals.
  • To identify specific antibiotic resistance genes and their genetic elements, such as integrons and plasmids.
  • To evaluate the discriminatory power of different molecular subtyping methods for these E. coli isolates.

Main Methods:

  • Phenotypic characterization of antibiotic resistance profiles for 47 E. coli isolates.
  • Polymerase Chain Reaction (PCR) for detecting ESBL genes (blaTEM, blaOXA, blaSHV, blaCTX-M) and integron-encoded integrases (intI1).
  • Sequence analysis of integron 5'CS regions, conjugation and transformation experiments, and molecular subtyping using Pulsed-Field Gel Electrophoresis (PFGE), RAPD, REP-PCR, and ERIC.

Main Results:

  • All 47 isolates were susceptible to imipenem; 36 isolates exhibited multidrug resistance.
  • The blaTEM gene was present in 87.5% of ESBL-producing isolates, with blaOXA, blaSHV, and blaCTX-M also detected.
  • Integron-encoded integrases, predominantly class 1 (intI1), were found in 55.3% of isolates, harboring various antibiotic resistance gene cassettes.
  • Conjugation and transformation studies suggested plasmid-mediated transmission of some resistance genes.
  • Molecular subtyping revealed high diversity among isolates, with PFGE, ERIC, and REP-PCR demonstrating greater discriminatory power than RAPD.

Conclusions:

  • Malaysian E. coli isolates harbor diverse ESBL and MDR genes, often associated with integrons and transmissible plasmids.
  • Understanding the genetic elements and transmission routes of these resistant strains is crucial for effective antibiotic stewardship.
  • PFGE, ERIC, and REP-PCR are recommended for robust epidemiological surveillance and subtyping of E. coli outbreaks.

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