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
Google Scholar
Right arrow Articles by Yang, T.-C.
Right arrow Articles by Lin, Y.-T.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Yang, T.-C.
Right arrow Articles by Lin, Y.-T.

 Previous Article  |  Next Article 

Antimicrobial Agents and Chemotherapy, July 2009, p. 2902-2907, Vol. 53, No. 7
0066-4804/09/$08.00+0     doi:10.1128/AAC.01513-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

AmpDI Is Involved in Expression of the Chromosomal L1 and L2 β-Lactamases of Stenotrophomonas maltophilia{triangledown}

Tsuey-Ching Yang,1* Yi-Wei Huang,1 Rouh-Mei Hu,2 Shao-Cheng Huang,1 and Yu-Tzu Lin1

Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung 404, Taiwan,1 Department of Biotechnology, Asia University, Taichung 413, Taiwan2

Received 12 November 2008/ Returned for modification 6 January 2009/ Accepted 25 April 2009

Two ampD homologues, ampDI and ampDII, of Stenotrophomonas maltophilia have been cloned and analyzed. Comparative genomic analysis revealed that the genomic context of the ampDII genes is quite different, whereas that of the ampDI genes is more conserved in S. maltophilia strains. The ampD system of S. maltophilia is distinct from that of the Enterobacteriaceae and Pseudomonas aeruginosa in three respects. (i) AmpDI of S. maltophilia is not encoded in an ampDE operon, in contrast to what happens in the Enterobacteriaceae and P. aeruginosa. (ii) The AmpD systems of the Enterobacteriaceae and P. aeruginosa are generally involved in the regulation of ampR-linked ampC gene expression, while AmpDI of S. maltophilia is responsible for the regulation of two intrinsic β-lactamase genes, of which the L2 gene, but not the L1 gene, is linked to ampR. (iii) S. maltophilia exhibits a one-step L1 and L2 gene derepression model involving ampDI, distinct from the two- or three-step derepression of the Enterobacteriaceae and P. aeruginosa. Moreover, the ampDI and ampDII genes are constitutively expressed and not regulated by the inducer and AmpR protein, and the expression of ampDII is weaker than that of ampDI. Finally, AmpDII is not associated with the derepression of β-lactamases, and its role in S. maltophilia remains unclear.

* Corresponding author. Mailing address: 91 Hsueh-Shih Rd., Taichung, Taiwan, 40402, Republic of China. Phone: 886-4-2205-3366, ext. 7203. Fax: 886-4-2205-7414. E-mail: tcyang{at}mail.cmu.edu.tw

{triangledown} Published ahead of print on 4 May 2009.

Antimicrobial Agents and Chemotherapy, July 2009, p. 2902-2907, Vol. 53, No. 7
0066-4804/09/$08.00+0     doi:10.1128/AAC.01513-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»