Open AccessSimple Technique for the Assay of Antibiotic Synergism Against Enterococci
Author(s) -
Wie-Shing Lee,
Louis Komarmy
Publication year - 1975
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.7.1.82
Subject(s) - antibiotics , streptomycin , incubation , microbiology and biotechnology , incubation period , minimum inhibitory concentration , biology , chemistry , biochemistry
A simple technique with antibiotic-impregnated disks has been developed to demonstrate the antibiotic synergism of penicillins and aminoglycosides against enterococci. The two antibiotic disks are placed on inoculated plates so that the distance between their centers is less than the sum of the two radii of their previously determined inhibitory zones. After 5 h of incubation, β-lactamase powder is dusted onto the susceptibility plate with a sterile cotton swab. After overnight incubation, the synergistic effect of the antibiotics is demonstrated by a clear area of no growth in between the two disks. There is good correlation between the synergism determined by this procedure and the susceptibility of the organisms to 2 mg of streptomycin per ml. This technique is simple and can be employed by any laboratory which performs Kirby-Bauer susceptibility procedures.