CORRELATION OF IN-VITRO SUSCEPTIBILITY TEST-RESULTS WITH CLINICAL-RESPONSE - A STUDY OF AZOLE THERAPY IN AIDS PATIENTS

The in-vitro susceptibilities of 40 clinical isolates of Candida albic ans to ketoconazole and fluconazole were determined and an attempt was made to correlate these data with the clinical responses of the patie nts from whom the strains were originally isolated to treatment with t hese agents. Of 40 patients with the acquired immunodeficiency syndrom e (AIDS) with oropharyngeal and/or oesophageal candidosis, 21 received ketoconazole and 19 fluconazole. Susceptiblity testing was performed by a microbroth dilution method with RPMI-2% glucose medium according to the recommendations of the National Committee for Clinical Laborato ry Standards; growth inhibition was estimated spectrophotometrically a nd the MIC endpoint was defined in terms of the IC. The MICs of 236 ad ditional strains of C. albicans, which were also isolated from AIDS pa tients, were used to establish a susceptibility profile for this speci es. On the basis of the susceptibility test results and the clinical r esponses of the 40 patients, the following tentative breakpoints for k etoconazole and fluconazole are proposed: patients with infections cau sed by C. albicans strains with MICs of ketoconazole and fluconazole o r less than or equal to 0.001 and less than or equal to 0.25 mg/L resp ectively would be expected to respond to treatment with these agents a nd isolates with MICs which meet these criteria are therefore classifi ed as susceptible; patients with infections caused by strains with MIC s of ketoconazole and fluconazole of greater than or equal to 0.06 and greater than or equal to 16.0 mg/L respectively would not be expected to respond to treatment with these agents and isolates with MICs whic h meet these criteria are therefore classified as resistant; the respo nse of patients with infections caused by strains with MICs of ketocon azole and fluconazole of 0.003-0.03 and 0.5-8.0 mg/L respectively cann ot be reliably predicted and isolates with MICs which fall within thes e ranges are therefore classified as being of indeterminate susceptibi lity. The present study demonstrates that the results of in-vitro susc eptibility testing with RPMI-2% glucose broth correlate with the clini cal response to therapy and can be used to facilitate optimal treatmen t in AIDS patients with oropharyngeal and/or oesophageal candidosis.