Differentiation of Escherichia coli strains using randomly amplified polymorphic DNA analysis

Area of Science:

• Microbiology
• Molecular Biology
• Epidemiology

Background:

• Escherichia coli (E. coli) strains vary in virulence and genetic makeup.
• Molecular epidemiology requires reliable methods for strain differentiation.
• Previous studies utilized ribotyping for E. coli strain characterization.

Purpose of the Study:

• To evaluate the utility of randomly amplified polymorphic DNA (RAPD) analysis for E. coli molecular epidemiology.
• To compare RAPD genotyping with existing ribotyping methods.
• To identify potential genetic markers associated with E. coli virulence.

Main Methods:

• Sixty E. coli strains, including a reference strain, were analyzed using RAPD with a 10-mer oligonucleotide primer.
• RAPD patterns were compared with existing ribotype data obtained from EcoRI and HindIII digests.
• Reproducibility and stability of RAPD patterns were assessed under in vitro and in vivo conditions.

Main Results:

• RAPD analysis distinguished 28 different fingerprints among the 60 E. coli strains, complementing the 36 previously identified ribotypes.
• Some strains with identical ribotypes showed distinct RAPD patterns, highlighting the benefit of combined markers.
• Specific RAPD bands were uniquely identified in highly virulent carboxylesterase type B2 strains, suggesting potential virulence-associated markers.

Conclusions:

• RAPD analysis is a reproducible, rapid, and valuable tool for E. coli molecular epidemiology.
• Combining RAPD with ribotyping enhances the assessment of E. coli strain relationships.
• RAPD can potentially identify genetic markers linked to E. coli virulence, particularly in homogeneous virulent strains.