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Updated: Jun 16, 2026
Demonstrating a Multi-drug Resistant Mycobacterium tuberculosis Amplification Microarray
Published on: April 25, 2014
An oligonucleotide microarray to characterize multidrug resistant plasmids
Rebecca L Lindsey1, Jonathan G Frye, Paula J Fedorka-Cray
1U.S. Department of Agriculture, Agricultural Research Service, Bacterial Epidemiology and Antimicrobial Resistance Research Unit, Richard B. Russell Agricultural Research Center, 950 College Station Road, Athens, GA 30604-2720, United States.
Abstract:
Many of the Enterobacteriaceae carry multiple drug resistance (MDR) genes on large plasmids of replicon type Inc A/C and Inc H1. It is important to understand the transmission of these MDR plasmids because the genes they carry can affect the outcome of antimicrobial therapy. The aim of this study was to design a microarray with oligonucleotide probes for every gene in the six Inc A/C and one Inc H1 plasmids of interest while representing all redundant sequences only once. The microarray is printed in triplicate with 493 unique oligonucleotide probes 70 nucleotides in length. Salmonella enterica and Escherichia coli control strains and test plasmids (in the parent strain and transformed into a known E. coli background strain) were hybridized to the plasmid microarray. This hybridization arrays presents a rapid and cost effective method for high-density screening of isolates to evaluate the gene content of Inc A/C and H1 plasmids and will show how plasmids can change content with transmission.
Insights
This study developed a novel microarray to rapidly screen for multiple drug resistance (MDR) genes on Inc A/C and Inc H1 plasmids. This method aids in understanding MDR plasmid transmission and its impact on antimicrobial therapy outcomes.
Area of Science:
- Microbiology
- Genetics
- Molecular Biology
Background:
- Enterobacteriaceae frequently harbor multiple drug resistance (MDR) genes on Inc A/C and Inc H1 plasmids.
- Understanding the transmission of these MDR plasmids is crucial for effective antimicrobial therapy.
- Plasmids carrying MDR genes significantly influence treatment outcomes.
Purpose of the Study:
- To design and validate a microarray for comprehensive gene content analysis of Inc A/C and Inc H1 plasmids.
- To create a cost-effective and rapid screening method for MDR plasmid-associated genes.
- To investigate the dynamic changes in plasmid gene content during transmission.
Main Methods:
- Designed a microarray with 493 unique oligonucleotide probes (70 nucleotides in length) targeting all genes in six Inc A/C and one Inc H1 plasmid types.
- Represented all redundant sequences only once to ensure specificity.
- Hybridized control strains (Salmonella enterica, Escherichia coli) and test plasmids to the microarray.
Main Results:
- The developed plasmid microarray enables high-density screening of bacterial isolates.
- Demonstrated a rapid and cost-effective method for evaluating the gene content of Inc A/C and H1 plasmids.
- Provided insights into how plasmid content evolves with transmission.
Conclusions:
- The designed microarray is a valuable tool for studying MDR plasmid epidemiology.
- Facilitates rapid identification of resistance genes and tracking of plasmid dissemination.
- Supports better understanding of antimicrobial resistance mechanisms and transmission dynamics.
