Functionally cloned pdrM from Streptococcus pneumoniae encodes a Na(+) coupled multidrug efflux pump
Kohei Hashimoto1, Wakano Ogawa, Toshihiro Nishioka
1Department of Molecular Microbiology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Tsushima, Okayama, Japan.
Plos One
|April 5, 2013
Summary
Streptococcus pneumoniae possesses a multidrug efflux pump, PdrM, which confers resistance to antibacterial agents by acting as a sodium-dependent drug antiporter. Other MATE-type genes in S. pneumoniae may have different physiological roles.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Multidrug efflux pumps are crucial bacterial self-defense mechanisms.
- These pumps are categorized into five families: RND, SMR, MF, ABC, and MATE.
- Understanding MATE-type pumps is vital for combating bacterial drug resistance.
Purpose of the Study:
- To clone and characterize a MATE-type multidrug efflux pump from Streptococcus pneumoniae R6.
- To investigate the substrate specificity and transport mechanism of the identified pump.
- To explore other potential MATE-type genes in S. pneumoniae.
Main Methods:
- Gene cloning and heterologous expression in E. coli KAM32.
- Determination of minimum inhibitory concentrations (MICs) for various antibacterial agents.
- Analysis of ion dependency (Na+, Li+) for substrate efflux.
- Detection of mRNA expression using laboratory growth conditions.
Main Results:
- Cloned MATE-type pump, designated PdrM, conferred resistance to norfloxacin, acriflavine, and DAPI.
- PdrM functions as a Na+/drug antiporter, exhibiting Na+- or Li+-dependent efflux of acriflavine and DAPI.
- Two additional MATE-type genes (spr1756, spr1877) were identified in S. pneumoniae but did not confer drug resistance.
- mRNA expression of pdrM, spr1756, and spr1877 was detected in S. pneumoniae R6.
Conclusions:
- PdrM is a novel Na+/drug antiporter in Streptococcus pneumoniae.
- While spr1756 and spr1877 are expressed, they likely serve physiological roles unrelated to the tested drug resistance.
- This study enhances the understanding of MATE-type efflux pumps and their diverse functions in bacteria.
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