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Isolation and characterization of integron-containing bacteria without antibiotic selection
Robert S Barlow1, John M Pemberton, Patricia M Desmarchelier
1Food Science Australia, Tingalpa DC, Queensland 4173, Australia.
Antimicrobial Agents and Chemotherapy
|February 26, 2004
Summary
Researchers identified antibiotic resistance genes in bovine fecal bacteria using a novel method that avoids antibiotic selection. This approach helps understand the spread of resistance in food animals.
Area of Science:
- Microbiology
- Genetics
- Public Health
Background:
- Antibiotic resistance in bacteria is a growing global health concern.
- Widespread antibiotic use contributes to the development of resistant microorganisms.
- Integrons are genetic elements that facilitate the acquisition of antibiotic resistance genes.
Purpose of the Study:
- To develop and validate a method for identifying and isolating integron-carrying bacteria from bovine feces without using antibiotic-selective media.
- To detect integron-associated antibiotic resistance genes in various bacterial species from cattle.
- To understand the prevalence and types of antibiotic resistance associated with integrons in a food animal reservoir.
Main Methods:
- Bacterial cultures from bovine feces were enriched using buffered peptone water (BPW).
- Class 1 and 2 integrase genes (intI1 and intI2) were detected using integrase-specific PCR.
- Integrase-positive colonies were isolated using hydrophobic grid membrane filters and gene probes.
- Isolated bacterial clones were confirmed for integrons via PCR and DNA sequencing.
Main Results:
- Integron-associated antibiotic resistance genes were identified in various bacteria, including Escherichia coli, Aeromonas spp., Proteus spp., Morganella morganii, Shewanella spp., and urea-positive Providencia stuartii.
- Streptomycin and trimethoprim resistance were frequently linked to integrons.
- The method successfully detected resistance genes without antibiotic selection, avoiding culture biases.
- The protocol enabled rapid and efficient identification, isolation, and characterization of antibiotic resistance-associated integrons.
Conclusions:
- The developed methodology allows for simultaneous culturing of diverse integron-containing bacteria.
- This approach provides a valuable tool for studying antibiotic resistance integrons in food animals.
- Understanding integron-associated resistance in cattle can inform strategies to mitigate its spread in food production systems.