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August 1959

Single-Disk Antibiotic-Sensitivity Testing of Staphylococci: An Analysis of Technique and Results

Author Affiliations


Department of Medicine, University of Washington School of Medicine, and the King County Hospital.

AMA Arch Intern Med. 1959;104(2):208-216. doi:10.1001/archinte.1959.00270080034004

With the increasing number of antibiotics available and useful for the treatment of infectious diseases, the development of accurate and simple methods to determine the antibiotic susceptibility of micro-organisms is of increasing importance. The most widely used method at present is the paper-disk sensitivity test. The more cumbersome tube-dilution technique is valuable in special instances in which bactericidal as well as bacteriostatic end-points are needed. Other procedures, such as the plate-dilution, agarwell-diffusion, or ditch-diffusion technique, are more difficult, offer no advantages for routine use, and have been more or less abandoned.

In spite of its widespread use there exists considerable variability in the performance of the disk technique, leading to a large number of confusing reports in the literature. There are two methods of performing and interpreting the test. In the first, two or three disks containing different concentrations are used for each antibiotic. The presence or absence of a

Microbial Sensitivity Testing (No. 146), Detroit, Difco Laboratories, (Feb.) 1958.
BBL Products for the Microbiological Laboratory, Baltimore, Baltimore Biological Laboratory, Inc., 1958.
Tunevall, G., and Ericsson, H.:  Sensitivity Tests by the Disc Method as a Guide for Chemotherapy ,  Antibiotics & Chemother. 4:886, 1954.
Fairbrother, R. W., and Jennings, R. C.:  The Dried Disc Technique with Bacitracin, Carbomycin, Erythromycin, Polymyxin B, and Tetracycline ,  J. Clin. Path. 8:117, 1955.
Hoette, I., and Struyk, A. P.:  A Modified Method for Evaluation of Clinical Usefulness of Antibiotics ,  J. Lab. & Clin. Med. 51:638, 1958.
Tung, S. L.:  Studies on a Direct Method for Estimation of Bacterial Resistance to Antibiotics ,  Acta path. et microbiol. scandinav. 29:182, 1951.
Mørch-Lund, E.; Funder-Schmidt, B.; Christensen, H., and Dupont, A.:  Sensitivity Testing with the Tablet Method ,  Acta path. et microbiol. scandinav. 29:221, 1951.
Kirby, W. M. M.; Yoshihara, G. M.; Sundsted, K. S., and Warren, J. H.:  Clinical Usefulness of a Single Disc Method for Antibiotic Sensitivity Testing ,  Antibiotics Ann. , p. 892, 1956-1957.
Patrick, W. C.; Craig, G. H., and Bachman, M. C.:  Diameter of Inhibition Zones Correlated with Tube Sensitivities Using 6 Antibiotics ,  Antibiotics & Chemother. 1:133, 1951.
Kirschbaum, A.; Kramer, J., and Arret, B.: The Assay and Control of Antibiotic Sensitivity Discs, to be published.
Erlanson, P.:  Determination of the Sensitivity in Vitro of Bacteria to Chemotherapeutic Agents ,  Acta path. et microbiol. scandinav. (Supp. 85) , p. 1, 1951.
Greer, J. E., and Menard, R. R.:  Neomycin Susceptibility for Differentiating Coagulase-Positive from Coagulase-Negative Staphylococci ,  Antibiotics Ann. , p. 149, 1957-1958.
Hospital-Acquired Staphylococcal Disease, in Proceedings of the National Conference, Sept. 1958, USPHS Communicable Disease Center, Appendix, p. XVIII.
Sensitivity Testing: Bacto-Sensitivity Discs and Bacto-Unidiscs (Leaflet No. 119), Detroit, Difco Laboratories.
Royer, A.:  Changes in Resistance to Various Antibiotics of Staphylococci ,  Antibiotics Ann. , p. 783, 1957-1958.
Branch, A.; Starkey, D. H., and Power, E. E.:  Control of Antibiotic Sensitivity Discs ,  Antibiotics Ann. , p. 107, 1957-1958.