Abstract
When disks containing cefuroxime (CXM) or HR 756 (756) were placed next to cefoxitin (FOX) on plates inoculated with Enterobacter resistant to FOX, there was marked flattening of the zones of inhibition produced by CXM or 756, but colonies growing near the CXM or 756 disks were found to be fully susceptible to these drugs on retesting. In contrast, when a checkerboard titration with CXM or 756 and FOX was done in broth, organisms growing in the presence of high concentrations of either of the former plus FOX were found to be resistant on retesting. Broth cultures of Enterobacter were found to contain small numbers of mutants which were resistant to and inactivated CXM and 756. Evidence is presented suggesting that the addition of FOX induces similar properties in the whole culture, which then becomes resistant to all of the nine cephalosporins tested and to four of six penicillins tested. Such cultures rapidly reverted to susceptible when FOX was removed or inactivated, and an explanation is offered as to why this did not happen in fluid media.
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- Birnbaum J., Stapley E. O., Miller A. K., Wallick H., Hendlin D., Woodruff H. B. Cefoxitin, a semi-synthetic cephamycin: a microbiological overview. J Antimicrob Chemother. 1978 Jul;4(B):15–32. doi: 10.1093/jac/4.suppl_b.15. [DOI] [PubMed] [Google Scholar]
- Findell C. M., Sherris J. C. Susceptibility of Enterobacter to cefamandole: evidence for a high mutation rate to resistance. Antimicrob Agents Chemother. 1976 Jun;9(6):970–974. doi: 10.1128/aac.9.6.970. [DOI] [PMC free article] [PubMed] [Google Scholar]
- GARROD L. P. The erythromycin group of antibiotics. Br Med J. 1957 Jul 13;2(5036):57–63. doi: 10.1136/bmj.2.5036.57. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Onishi H. R., Daoust D. R., Zimmerman S. B., Hendlin D., Stapley E. O. Cefoxitin, a semisynthetic cephamycin antibiotic: resistance to beta-lactamase inactivation. Antimicrob Agents Chemother. 1974 Jan;5(1):38–48. doi: 10.1128/aac.5.1.38. [DOI] [PMC free article] [PubMed] [Google Scholar]
- WEAVER J. R., PATTEE P. A. INDUCIBLE RESISTANCE TO ERYTHROMYCIN IN STAPHYLOCOCCUS AUREUS. J Bacteriol. 1964 Sep;88:574–580. doi: 10.1128/jb.88.3.574-580.1964. [DOI] [PMC free article] [PubMed] [Google Scholar]