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Unusual expression of new low-level-trimethoprim-resistance plasmids
Abstract:
In a survey, 42% of trimethoprim-resistant clinical members of the family Enterobacteriaceae were able to transfer trimethoprim resistance to standard Escherichia coli strains when selection was made on complex bacteriological media. When transfer experiments were performed with minimal medium, another 16% of the clinical strains were shown to have transferred trimethoprim resistance. Twelve transconjugants produced negligible trimethoprim resistance in complex media but were resistant in minimal medium. The methionine, glycine, and purine components of complex media appeared to be responsible for the reduced expression of trimethoprim resistance in these strains.
Insights
Trimethoprim resistance transfer in Enterobacteriaceae is higher than previously thought. Complex media components like methionine, glycine, and purines can mask this resistance transfer.
Area of Science:
- Microbiology
- Genetics
- Antimicrobial Resistance
Background:
- Trimethoprim resistance is a growing concern in clinical Enterobacteriaceae.
- Understanding resistance transfer mechanisms is crucial for effective treatment strategies.
Purpose of the Study:
- To quantify trimethoprim resistance transfer in clinical Enterobacteriaceae.
- To investigate the influence of media composition on resistance expression.
Main Methods:
- Clinical Enterobacteriaceae isolates were tested for trimethoprim resistance transfer to Escherichia coli.
- Transfer experiments were conducted using both complex and minimal bacteriological media.
Main Results:
- 42% of resistant Enterobacteriaceae transferred resistance on complex media.
- An additional 16% transferred resistance on minimal media.
- Specific media components (methionine, glycine, purines) reduced resistance expression.
Conclusions:
- The prevalence of trimethoprim resistance transfer in Enterobacteriaceae is significant.
- Media composition critically affects the detection and expression of trimethoprim resistance.