Correlation of Proteinase Production with Amphotericin B Resistance in Fungi from Mycotic Keratitis

Two hundred fungal isolates (Aspergillus and Fusarium species) from mycotic keratitis were tested for in vitro susceptibilities to amphotericin B and proteinase production. Geometric mean MICs for all fungal species increased fourfold with thousandfold increase in the inoculum. The MIC50 and MIC90 values ranged between 3.12–6.25 and 3.12–12.5 µg/ml, respectively. Proteinase production was noted in 113 (56.5%) isolates. Ninety-eight (49%) showed MICs of ≧1.56 µg/ml that was above the criteria of ≧1 µg/ml for amphotericin B resistance (CLSI). Seventy-three (74.5%) of these 98 isolates were proteinase producers, whereas only 40 (39.2%) of the remaining 102 with low MICs (