Antibiotic Sensitivity Tests

Light-scattering methods for antibiotic sensitivity tests.

The total intensity of light scattered in the angular range 30 degrees-130 degrees by a suspension of bacteria can be used as the basis of a method of antibiotic sensitivity testing. A procedure is given in which the bacteria are incubated in the presence of antibiotic, as a test, and in its absence, as a control, for 60 minutes. An incubation time of 90 minutes gives slightly more reliable res...

Antibiotic and Sulfonamide Disc Sensitivity Tests

Avian strains of Escherichia coli (213) were subjected to in vitro antibiotic sensitivity tests with twenty-four different chemotherapeutic agents. Chlorhexidine, polymyxin B, colistin, and nitrofurazone exhibited the greatest inhibitory activities against these strains. Various potencies of antibiotics were compared. The activity of sulfachloropyridazine on various types of media failed to sho...

Colouring agents for use in disc-antibiotic sensitivity tests.

Antibiotic Sensitivity Discs

KRAMER, JULIAN (Food and Drug Administration, Washington, D. C.), AND AMIEL KIRSHBAUM. Effect of paper on the performance assay in the control of antibiotic sensitivity discs. Appl. Microbiol. 9:334-336. 1961.-Antibiotic discs were prepared, using several several batches of papers meeting Food and Drug Administration specifications. The analysis of 1,152 zones of inhibition produced showed no p...

Stable antibiotic sensitivity disks.

Two methods of preparing sensitivity disks were compared for their effect on disk stability at 25 and 37 C. One method consisted of applying a solution of the antibiotic to blank disks by the conventional procedure; the second method consisted of applying the antibiotic to the disks as a suspension of crystals. Of the four beta-lactam antibiotics that were studied, disks made with suspended cry...