LABORATORY AIDS IN THE SELECTION OF ANTIMICROBIAL THERAPY
The antimicrobial drug used initially in the treatment of an infection is chosen on the basis of clinical impression after the physician is convinced that an infection exists and has made a tentative etiologic diagnosis on clinical grounds. On the basis of this "best guess," a probable drug of choice can be selected . Before this drug is administered, specimens are obtained for laboratory isolation of the causative agent. The results of these examinations may necessitate selection of a different drug. The identification of certain microorganisms that are uniformly drug-susceptible eliminates the necessity for further testing and permits the selection of optimally effective drugs solely on the basis of experience.
The commonly performed disk diffusion susceptibility test must be used judiciously and interpreted with
restraint. In general, only one member of each…