Abstract
Antimicrobial agents are generally used by physicians In one of three ways: to treat specific infections, to treat fever, and to treat clinical entities as colds, pneumonia, diarrhea and meningitis without regard for the specific cause. | Sensitivity testing In vitro, is used as a guide to treat specific infections by indicating inhibition of growth of the causative organisms while in the presence of one or more antimicrobial agents. These tests usually require the testing of several antimicrobial agents to establish their relative effectiveness against such organisms. This offers the clinician a choice of antimicrobial agents to use since factors as expense, availability and tolerance enter into the over-all picture of therapy. Also, the simultaneous testing of several antimicrobial agents at once reduces the time required to obtain the information of sensitivity in contrast to testing each one individually. The differing spectrums of the various antimicrobial agents and the variety of pure and mixed cultures obtained from infectious material, combined with the apparent adapt ability of bacterial cells to resist the effects of these antimicrobial agents has prompted the use of sensitivity testing for effective treatment of individual cases. Several in vitro methods are in common use and the sensitivity results obtained with any one strain of organism by these various methods may show discrepancies, however, the limits of susceptibility seem broad enough to make them sufficiently accurate for this purpose.