Computerized interpretation of minimum inhibitory concentration antimicrobic susceptibility testing

Quantitative antimicrobic susceptibility tests by determining the minimum inhibitory concentration (MIC) are becoming more and more prevalent in United States laboratories. Interpretation of MIC values is complex and should be considered as part of the laboratory service. This communication provides a simple computerized scheme for MIC interpretation that has been used for more than three years in the authors' laboratories. This computer algorithm provides a semigraphic output documenting relative susceptibility for a matrix of various dosages and sites of the body. Additional features, such as consideration of beta-lactamase production for Staphylococcus aureus and toxic levels for aminoglycosides, are considered in this algorithm. In addition, the authors present a compendium of achievable levels for a comprehensive list of antimicrobics, together with literature reference documentation.