Skip to main content
NCBI home page
Antimicrobial Agents and Chemotherapy logoLink to Antimicrobial Agents and Chemotherapy
. 1978 Mar;13(3):383–388. doi: 10.1128/aac.13.3.383

Modified agar dilution method for rapid antibiotic susceptibility testing of anaerobic bacteria.

C W Hanson, W J Martin
PMCID: PMC352249  PMID: 400819

Abstract

A simplified method has been developed for agar dilution antimicrobial susceptibility testing of anaerobic bacteria, designed to economize on time and money when only a few isolates need to be tested. The procedure is based on the principle of using filter paper disks as carriers of the antibiotic and 35- by 10-mm petri dishes which, when inoculated with the Steers replicator, can test up to four organisms per plate. The procedure was run in parallel with conventional agar dilution techniques and showed 95% agreement to within one dilution for all minimal inhibitory concentrations recorded on fresh anaerobic isolates from clinical specimens. The technique was further simplified by using commercially available antibiotic-containing disks, thereby alleviating the tedious and time-consuming procedure of preparing the disks. The data indicated that 48- to 72-h diffusion periods were sufficient to achieve a uniform concentration of the antibiotic in the petri plate and that the antibiotics were stable at room temperature for that period of time. In terms of applicability and relevance to the needs of the clinical microbiology laboratory, the modified agar dilution method for rapid antimicrobial susceptibility testing of individual anaerobic isolates was found to be superior to the broth dilution method since it was easier to read and required considerably less set up time.

Full text

PDF
383

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Fass R. J., Prior R. B., Rotilie C. A. Simplified method for antimicrobial susceptibility testing of anaerobic bacteria. Antimicrob Agents Chemother. 1975 Oct;8(4):444–452. doi: 10.1128/aac.8.4.444. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Hanson C. W., Martin W. J. Evaluation of enrichment, storage, and age of blood agar medium in relation to its ability to support growth of anaerobic bacteria. J Clin Microbiol. 1976 Nov;4(5):394–399. doi: 10.1128/jcm.4.5.394-399.1976. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Hauser K. J., Johnston J. A., Zabransky R. J. Economical agar dilution technique for susceptibility testing of anaerobes. Antimicrob Agents Chemother. 1975 May;7(5):712–714. doi: 10.1128/aac.7.5.712. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Martin W. J. Isolation and indentification of anaerobic bacteria in the clinical laboratory. A 2-year experience. Mayo Clin Proc. 1974 May;49(5):300–308. [PubMed] [Google Scholar]
  5. Martin W. J. Practical method for isolation of anerobic bacteria in the clinical laboratory. Appl Microbiol. 1971 Dec;22(6):1168–1171. doi: 10.1128/am.22.6.1168-1171.1971. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Rolinson G. N., Russell E. J. A new method for antibiotic sensitivity testing. Lancet. 1971 Oct 2;2(7727):745–746. doi: 10.1016/s0140-6736(71)92110-6. [DOI] [PubMed] [Google Scholar]
  7. Rotilie C. A., Fass R. J., Prior R. B., Perkins R. L. Microdilution technique for antimicrobial susceptibility testing of anaerobic bacteria. Antimicrob Agents Chemother. 1975 Mar;7(3):311–315. doi: 10.1128/aac.7.3.311. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Sapico F. L., Kwok Y. Y., Sutter V. L., Finegold S. M. Standardized antimicrobial disc susceptibility testing of anaerobic bacteria: in vitro susceptibility of Clostridium perfringens to nine antibiotics. Antimicrob Agents Chemother. 1972 Oct;2(4):320–325. doi: 10.1128/aac.2.4.320. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Shafi M. S. Determination of antimicrobial MIC by paper diffusion method. J Clin Pathol. 1975 Dec;28(12):989–992. doi: 10.1136/jcp.28.12.989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Sutter V. L., Kwok Y. Y., Finegold S. M. Standardized antimicrobial disc susceptibility testing of anaerobic bacteria. I. Susceptibility of Bacteroides fragilis to tetracycline. Appl Microbiol. 1972 Feb;23(2):268–275. doi: 10.1128/am.23.2.268-275.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Wayne L. G., Krasnow I. Preparation of tuberculosis susceptibility testing mediums by means of impregnated disks. Am J Clin Pathol. 1966 Jun;45(6):769–771. doi: 10.1093/ajcp/45.6_ts.769. [DOI] [PubMed] [Google Scholar]
  12. Wikins T. D., Holdeman L. V., Abramson I. J., Moore W. E. Standardized single-disc method for antibiotic susceptibility testing of anaerobic bacteria. Antimicrob Agents Chemother. 1972 Jun;1(6):451–459. doi: 10.1128/aac.1.6.451. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Wilkins T. D., Chalgren S. Medium for use in antibiotic susceptibility testing of anaerobic bacteria. Antimicrob Agents Chemother. 1976 Dec;10(6):926–928. doi: 10.1128/aac.10.6.926. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Wilkins T. D., Thiel T. Modified broth-disk method for testing the antibiotic susceptibility of anaerobic bacteria. Antimicrob Agents Chemother. 1973 Mar;3(3):350–356. doi: 10.1128/aac.3.3.350. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Antimicrobial Agents and Chemotherapy are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES