Correlation of Minimum Inhibitory Concentration Results between the Vitek System and the Biomic System
This study compared the BIOMIC system to the Vitek system to determine the percentage of agreement between the minimum inhibitory concentrations. The BIOMIC semi-automated system employs disk diffusion test zone diameters to determine minimum inhibitory concentrations. Results were in agreement when the BIOMIC minimum inhibitory concentration was within ± 1 doubling dilution of the Vitek result. A total of 137 clinical isolates, including Enterobacteriaceae, non-fermenters, staphylococci, and enterococci were tested. The overall agreement for 1335 organism/drug combinations was 85%, with 10% minor and 5% major discrepancies. The agreement by organism group was 87% for Enterobacteriaceae, 87% for nonfermenters, and 79% for enterococci and staphylococci. Antimicrobic combinations that exhibited a high discrepancy rate included tetracycline vs. Enterobacteriaceae (39%) and amikacin vs. nonfermenters (30%). An agreement of 100% was found for ciprofloxacin and imipenem vs. nonfermenters, as well as for clindamycin and oxacillin vs. staphylococci. This study showed the BIOMIC system to be an acceptable, cost-effective alternative for determining minimum inhibitory concentrations.
KeywordsMajor Discrepancy Clavulanic Acid Acinetobacter Calcoaceticus Disk Diffusion Test BIOMIC System
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