University of Pennsylvania Medical Center Guidelines for Antibiotic Use




Pictured above is a graph which shows the relationship between the MIC and the size of the zone of inhibition in the Bauer-Kirby test for the drug-A using the bacteria-Q. "R" represents the cutoff for the interpretation of "resistant", and "S" represents the cutoff for the interpretation of "susceptible"

The portion of the curve which is green represents the region where it would be reported that bacteria-Q is susceptible to drug-A. Refection of the curve onto the X-axis (dotted green lines) show that a zone diameter greater than 23 mm (green arrow) is required for "susceptible" to be reported out for this bug/drug pair. This correlates approximately with an MIC of < 8 micrograms.

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