AAC
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Masuda, N.
Right arrow Articles by Nishino, T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Masuda, N.
Right arrow Articles by Nishino, T.

 Previous Article  |  Next Article 

Antimicrobial Agents and Chemotherapy, September 2000, p. 2242-2246, Vol. 44, No. 9
0066-4804/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.

Contribution of the MexX-MexY-OprM Efflux System to Intrinsic Resistance in Pseudomonas aeruginosa

Nobuhisa Masuda,1,* Eiko Sakagawa,1 Satoshi Ohya,1 Naomasa Gotoh,2 Hideto Tsujimoto,2 and Takeshi Nishino2

Biological Research Laboratories, Sankyo Co., Ltd., Shinagawa-ku, Tokyo 140-8710,1 and Department of Microbiology, Kyoto Pharmaceutical University, Yamashina, Kyoto 607-8414,2 Japan

Received 18 October 1999/Returned for modification 20 February 2000/Accepted 26 May 2000

To test the possibility that MexX-MexY, a new set of efflux system components, is associated with OprM and contributes to intrinsic resistance in Pseudomonas aeruginosa, we constructed a series of isogenic mutants lacking mexXY and/or mexAB and/or oprM from a laboratory strain PAO1, and examined their susceptibilities to ofloxacin, tetracycline, erythromycin, gentamicin, and streptomycin. Loss of either MexXY or OprM from the MexAB-deficient mutant increased susceptibility to all agents tested, whereas loss of MexXY from the MexAB-OprM-deficient mutant caused no change in susceptibility. Introduction of an OprM expression plasmid decreased the susceptibility of the mexAB-oprM-deficient-/mexXY-maintaining mutant, yet caused no change in the susceptibility of a mexAB-oprM- and mexXY-deficient double mutant. Immunoblot analysis using anti-MexX polyclonal rabbit serum generated against synthetic oligopeptides detected expression of MexX in the PAO1 cells grown in medium containing tetracycline, erythromycin, or gentamicin, although expression of MexX was undetectable in the cells incubated in medium without any agent. These results suggest that MexXY induced by these agents is functionally associated with spontaneously expressed OprM and contributes to the intrinsic resistance to these agents.

* Corresponding author. Mailing address: Biological Research Laboratories, Sankyo Co., Ltd., 2-58 Hiromachi 1-chrome, Shinagawa-ku, Tokyo 140-8710, Japan. Phone: 81-3-3492-3131. Fax: 81-3-5436-8566. E-mail: nmasud{at}shina.sankyo.co.jp.

Antimicrobial Agents and Chemotherapy, September 2000, p. 2242-2246, Vol. 44, No. 9
0066-4804/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Clin. Vaccine Immunol. Clin. Microbiol. Rev.
J. Clin. Microbiol. ALL ASM JOURNALS

Copyright © 2000 by the American Society for Microbiology. All rights reserved.