DO IN-VITRO SUSCEPTIBILITY DATA PREDICT THE MICROBIOLOGIC RESPONSE TOAMPHOTERICIN-B - RESULTS OF A PROSPECTIVE-STUDY OF PATIENTS WITH CANDIDA-FUNGEMIA

Outcome for 105 patients with candidemia treated with amphotericin B w as correlated with amphotericin B in vitro susceptibility results, Thi rty-three patients had microbiologic failure, which was defined as per sistence of Candida in the bloodstream despite greater than or equal t o 3 days of amphotericin B. Amphotericin B minimum inhibitory concentr ations (MICs) were determined by the National Committee for Clinical L aboratory Standards methodology, After determination of MICs, the mini mal lethal concentrations (MLCs) were determined. The isolates tested yielded a narrow range of amphotericin B MICs (0.06-2 mu g/mL); only 5 % (5/105) exhibited MICs greater than or equal to 1 mu g/mL. The MLC r ange, on the other hand, was significantly broader (0.125 to >16 mu g/ mL); 24% (25/105) exhibited MLCs greater than or equal to 1 mu g/mL. T he strongest predictor for microbiologic failure was 48-h MLC (P < .00 1), followed by 24-h MLC (P = .03) and 48-h MIC (P = .11). A resistant break point for amphotericin B of >1 mu g/mL for MLC and greater than or equal to 1 mu g/mL for MIC could be inferred from this study.