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A multidrug efflux phenotype mutant of Streptococcus pyogenes
H E Jones1, N P Brenwald, K A Owen
1Division of Immunity & Infection, Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
The Journal of Antimicrobial Chemotherapy
|March 5, 2003
Summary
Researchers identified a Streptococcus pyogenes mutant exhibiting multidrug efflux. This mutant showed increased resistance to norfloxacin, ethidium bromide, and acriflavine, suggesting a novel efflux mechanism in this bacterium.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Streptococcus pyogenes is a significant human pathogen.
- Multidrug resistance (MDR) is a growing public health concern.
- Efflux pumps play a crucial role in bacterial MDR.
Purpose of the Study:
- To characterize a multidrug efflux phenotype in Streptococcus pyogenes.
- To investigate the specific resistance profile and potential mechanisms involved.
Main Methods:
- Selection of a mutant strain using ethidium bromide.
- Determination of Minimum Inhibitory Concentrations (MICs) for various antimicrobial agents.
- Assessment of ethidium bromide accumulation in parent and mutant strains.
- Testing the effect of efflux pump inhibitors.
Main Results:
- The mutant strain displayed significantly increased MICs for norfloxacin, ethidium bromide, and acriflavine compared to the parent strain.
- Efflux pump inhibitors (reserpine, rescinnamine, verapamil) did not affect the mutant's MICs.
- Norfloxacin partially reversed the ethidium bromide resistance in the mutant.
- Ethidium bromide accumulation was substantially reduced in the mutant strain.
Conclusions:
- A novel multidrug efflux mechanism is present in this Streptococcus pyogenes mutant.
- The identified efflux system contributes to resistance against multiple antimicrobial agents.
- Further investigation is warranted to elucidate the specific genes and proteins involved in this efflux phenotype.