Abstract
The combined effects of trimethoprim and sulfamethoxazole on the viability of Escherichia coli K-12 and resistant strains possessing resistance plasmids were examined in minimal medium. When methionine, glycine, and adenine were present, sulfamethoxazole could enhance trimethoprim activity against E. coli K-12 so that the combination was bactericidal. However, this enhancement occurred over a narrow range of trimethoprim concentrations (0.04 to 0.2 mg liter-1) and only when the sulfamethoxazole concentration was more than 10 times that of trimethoprim. Under certain conditions, sulfamethoxazole enhanced trimethoprim bactericidal activity against E. coli K-12 carrying plasmid R1 at concentrations of sulfamethoxazole far below those required to inhibit the organism, but there was no such enhancement with the same host containing the SSu plasmid. Similar differences were found with strains possessing trimethoprim resistance plasmids R483 and R751. Sulfamethoxazole can promote a bactericidal response with trimethoprim in E. coli K-12 and some of its resistant derivatives, but only under a narrow range of concentrations.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Pharmacology (medical),Pharmacology
Reference31 articles.
1. Synergistic activity of trimethoprim-sulfamethoxazole on Gram-negative bacilli: observations in vitro and in vivo;Acar J. F.;J. Infect. Dis.,1973
2. Co-trimoxazole sensitivity tests improved with separate trimethoprim and sulfamethoxazole disks;Amyes S. G. B.;J. Clin. Microbiol.,1981
3. Amyea S. G. B. C. J. McMlilan and J. L. Drysdale. 1981. Transferable trimethoprim resistance amongst hospital isolates p. 325-327. In G. G. Grassi and L. D. Sabath (ed.) New trends in antibiotics: research and therapy. Elsevier/North Holland Biomedical Press Amsterdam.
4. Trimethoprim action and its analogy with thymine starvation;Amyes S. G. B.;Antimicrob. Agents Chemother.,1974
5. R-factor mediated dihydrofolate reductases which confer trimethoprim resistance;Amyes S. G. B.;J. Gen. Microbiol.,1978
Cited by
13 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献