In vitro activity of N-formimidoyl thienamycin, moxalactam, and other new beta-lactam agents against Bacteroides fragilis: contribution of beta-lactamase to resistance.
Abstract
In vitro activity of N-formimidoyl thienamycin, moxalactam, and other new beta-lactam agents against Bacteroides fragilis: contribution of beta-lactamase to resistance. J E Brown , V E Del Bene and C D Collins ABSTRACT N-Formimidoyl thienamycin (N-F-thienamycin) and moxalactam were compared with other currently available and investigational antibiotics against 100 clinical isolates of Bacteroides fragilis by an agar dilution method. N-F-thienamycin was the most active among the beta-lactam agents tested, with a minimal inhibitory concentration for 90% of isolates (MIC90) of 0.25 micrograms/ml. Moxalactam was next in activity, with an MIC90 of 4 micrograms/ml. N-F-thienamycin was somewhat more active, and moxalactam was slightly less active, than metronidazole and clindamycin. An increase in inoculum size caused an increase in the MIC of N-F-thienamycin, cefoperazone, and cefotaxime. This inoculum effect could influence the usefulness of these drugs in certain clinical conditions. The minimal bactericidal concentration was less than two times the MIC for most agents and less than four times the MIC for all beta-lactam agents at each inoculum size tested. Investigation of the mechanism of resistance to beta-lactam agents demonstrated a correlation between the level of resistance and beta-lactamase activity in each strain tested. N-F-thienamycin and cefoxitin were not hydrolyzed, and moxalactam was less susceptible to hydrolysis than the other beta-lactam antibiotics. Moxalactam and N-F-thienamycin may prove to be useful against infections with B. fragilis. CiteULike Connotea Delicious Digg Facebook Google+ Mendeley Reddit StumbleUpon Twitter What's this? « Previous | Next Article » Table of Contents This Article doi: 10.1128/AAC.19.2.248 Antimicrob. Agents Chemother. February 1981 vol. 19 no. 2 248-252 » Abstract PDF Classifications Research Article Services Email this article to a colleague Similar articles in ASM journals Alert me when this article is cited Alert me if a correction is posted Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of AAC Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Load citing article information Citing articles via Web of Science Citing articles via Google Scholar Google Scholar Articles by Brown, J. E. Articles by Collins, C. D. Search for related content PubMed PubMed citation Articles by Brown, J. E. Articles by Collins, C. D. Related Content Load related web page information Social Bookmarking CiteULike Connotea Delicious Digg Facebook Google+ Mendeley Reddit StumbleUpon Twitter What's this? current issue December 2011, volume 55, issue 12 Alert me to new issues of AAC About AAC Subscribers Authors Reviewers Advertisers Inquiries from the Press Permissions & Commercial Reprints ASM Journals Public Access Policy AAC RSS Feeds 1752 N Street N.W. • Washington DC 20036 202.737.3600 • 202.942.9355 fax • journals@asmusa.org Print ISSN: 0066-4804 Online ISSN: 1098-6596 Copyright © 2011 by the American Society for Microbiology. For an alternate route to AAC .asm.org, visit: http://intl- AAC .asm.org | More Info» var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); var pageTracker = _gat._getTracker("UA-5821458-3"); pageTracker._trackPageview();