当前位置： SCI文献检索 > PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA期刊下所有文献 > DNA topoisomerase targets of the fluoroquinolones: a strategy for avoiding bacterial resistance.

DNA topoisomerase targets of the fluoroquinolones: a strategy for avoiding bacterial resistance.

Abstract：

:Fluoroquinolones are antibacterial agents that attack DNA gyrase and topoisomerase IV on chromosomal DNA. The existence of two fluoroquinolone targets and stepwise accumulation of resistance suggested that new quinolones could be found that would require cells to obtain two topoisomerase mutations to display resistance. For wild-type cells to become resistant, the two mutations must be acquired concomitantly. That is expected to occur infrequently. To identify such compounds, fluoroquinolones were tested for the ability to kill a moderately resistant gyrase mutant. Compounds containing a C8-methoxyl group were particularly lethal, and incubation of wild-type cultures on agar containing C8-methoxyl fluoroquinolones produced no resistant mutant, whereas thousands arose during comparable treatment with control compounds lacking the C8 substituent. When the test strain contained a preexisting topoisomerase IV mutation, which by itself conferred no resistance, equally high numbers of resistant mutants were obtained for C8-methoxyl and control compounds. Thus C8-methoxyl fluoroquinolones required two mutations for expression of resistance. Although highly lethal, C8-methoxyl fluoroquinolones were not more effective than C8-H controls at blocking bacterial growth. Consequently, quinolone action involves two events, which we envision as formation of drug-enzyme-DNA complexes followed by release of lethal double-strand DNA breaks. Release of DNA breaks, which must occur less frequently than complex formation, is probably the process stimulated by the C8-methoxyl group. Understanding this stimulation should provide insight into intracellular quinolone action and contribute to development of fluoroquinolones that prevent selection of resistant bacteria.

journal_name

Proc Natl Acad Sci U S A

journal_title

Proceedings of the National Academy of Sciences of the United States of America

authors

Zhao X,Xu C,Domagala J,Drlica K

doi

10.1073/pnas.94.25.13991

subject

Has Abstract

pub_date

1997-12-09 00:00:00

pages

13991-6

issue

eissn

0027-8424

issn

1091-6490

journal_volume

pub_type

杂志文章

在线工具

DNA topoisomerase targets of the fluoroquinolones: a strategy for avoiding bacterial resistance.