Abstract
A semiautomated microdilution susceptibility test is described. The effect of certain parameters such as inoculum size, growth media, incubation conditions, and inoculum dispensing systems was studied. Both medium type and inoculum size caused significant variations in the minimum inhibitory concentrations (MIC) of certain antibiotic-organism combinations. No effect on MIC was observed as a function of incubator type. Efforts to read a reproducible MIC value in less than 12 h failed. A commercially available wire pronged inoculator was determined to be inaccurate and unsafe. Disposable dropper pipettes proved to be economical, accurate, and precise. Although a standard method for microdilution antibiotic susceptibility testing is not proposed, data are presented which show that future attempts at standardized procedures are mandatory if inter- and intralaboratory reliability is desired.
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Selected References
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- Bauer A. W., Kirby W. M., Sherris J. C., Turck M. Antibiotic susceptibility testing by a standardized single disk method. Am J Clin Pathol. 1966 Apr;45(4):493–496. [PubMed] [Google Scholar]
- Cooper H. A., Bowie E. J., Owen C. A., Jr Pitfalls of the microtiter system for serial dilutions and standardization using radioiodinated albumin. Am J Clin Pathol. 1972 Mar;57(3):332–335. doi: 10.1093/ajcp/57.3.332. [DOI] [PubMed] [Google Scholar]
- Ericsson H. M., Sherris J. C. Antibiotic sensitivity testing. Report of an international collaborative study. Acta Pathol Microbiol Scand B Microbiol Immunol. 1971;217(Suppl):1+–1+. [PubMed] [Google Scholar]
- Gavan T. L., Town M. A. A microdilution method for antibiotic susceptibility testing: an evaluation. Am J Clin Pathol. 1970 Jun;53(6):880–885. doi: 10.1093/ajcp/53.6.880. [DOI] [PubMed] [Google Scholar]
- Harwick H. J., Weiss P., Fekety F. R., Jr Application of microtitration techniques to bacteriostatic and bactericidal antibiotic susceptibility testing. J Lab Clin Med. 1968 Sep;72(3):511–516. [PubMed] [Google Scholar]
- MacLowry J. D., Marsh H. H. Semiautomatic microtechnique for serial dilution-antibiotic sensitivity testing in the clinical laboratory. J Lab Clin Med. 1968 Oct;72(4):685–687. [PubMed] [Google Scholar]
- Marymont J. H., Jr, Wentz R. M. Serial dilution antibiotic sensitivity testing with the microtitrator system. Am J Clin Pathol. 1966 May;45(5):548–551. doi: 10.1093/ajcp/45.5.548. [DOI] [PubMed] [Google Scholar]
- TAKATSY G. The use of spiral loops in serological and virological micro-methods. Acta Microbiol Acad Sci Hung. 1955;3(1-2):191–202. [PubMed] [Google Scholar]