AAC
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
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 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 Cui, L.
Right arrow Articles by Hiramatsu, K.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Cui, L.
Right arrow Articles by Hiramatsu, K.
Antimicrobial Agents and Chemotherapy, August 2005, p. 3404-3413, Vol. 49, No. 8
0066-4804/05/$08.00+0     doi:10.1128/AAC.49.8.3404-3413.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

DNA Microarray-Based Identification of Genes Associated with Glycopeptide Resistance in Staphylococcus aureus{dagger}

Longzhu Cui,* Jian-Qi Lian,{ddagger} Hui-min Neoh, Ethel Reyes, and Keiichi Hiramatsu

Department of Bacteriology, Juntendo University, 2-1-1 Bunkyo-Ku, Tokyo, Japan 113-8421

Received 21 December 2004/ Returned for modification 10 February 2005/ Accepted 9 May 2005

Six pairs of transcription profiles between glycopeptide-intermediate S. aureus (GISA [or vancomycin-intermediate S. aureus; VISA]) and glycopeptide-susceptible S. aureus (vancomycin-susceptible S. aureus [VSSA], including glycopeptide-susceptible isogenic mutants from VISA) strains were compared using a microarray. Ninety-two open reading frames which were or tended to be increased in transcription in VISA in at least five out of six array combination pairs were evaluated for their effects on glycopeptide susceptibility by introducing these genes one by one into VSSA strain N315 to construct an overexpression library. By screening the library, 17 genes including 8 novel genes were identified as associated with glycopeptide resistance since their experimental overexpression reduced vancomycin and/or teicoplanin susceptibility of N315. The raised MICs of vancomycin and teicoplanin were 1.25 to 3.0 and 1.5 to 6.0 mg/liter, respectively, as compared to 1.0 mg/liter of N315. Three of these genes, namely graF, msrA2, and mgrA, also raised the oxacillin MIC from 8.0 mg/liter for N315 to 64 to ~128 mg/liter when they were overexpressed in N315. Their contribution to vancomycin and beta-lactam resistance was further supported by gene knockout and trans-complementation assay. By using a plasmid-based promoter-green fluorescent protein gene (gfp) transcriptional fusion system, graF promoter-activated cells were purified, and subsequent susceptibility tests and Northern blot analysis demonstrated that the cells with up-regulated activity of graF promoter showed reduced susceptibility to vancomycin, teicoplanin, and oxacillin. In addition, cell morphology studies showed that graF and msrA2 overexpression increased cell wall thickness of N315 by factors of 23.91 and 22.27%, respectively, accompanied by glycopeptide MIC increments of 3- to 6-fold, when they were overexpressed in N315. Moreover, extended experiments and analyses indicate that many of the genes identified above are related to the cell wall biosynthetic pathway, including active nutrient transport systems. We propose that the genes which raise glycopeptide resistance in S. aureus function toward altering the cell wall metabolic pathway.

* Corresponding author. Mailing address: Department of Bacteriology, Faculty of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-Ku, Tokyo 113-8421, Japan. Phone: 81-3-5802-1041. Fax: 81-3-5684-7830. E-mail: longzhu{at}med.juntendo.ac.jp.

{dagger} Supplemental material for this article may be found at http://aac.asm.org/.

{ddagger} Present address: Department of Infectious Diseases, Tangdu Hospital, Fourth Military Medical University, Xinshilu-1, Baqiaoqu, Xi'an 710038, China.

Antimicrobial Agents and Chemotherapy, August 2005, p. 3404-3413, Vol. 49, No. 8
0066-4804/05/$08.00+0     doi:10.1128/AAC.49.8.3404-3413.2005
Copyright © 2005, 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 © 2005 by the American Society for Microbiology. All rights reserved.