Effects of two different growth media on the postantifungal effect induced by polyenes on Candida species.

There are no data on the effects of different growth media on polyene-induced postantifungal effect (PAFE) in Candida species. Hence, the nystatin- and amphotericin B-induced PAFEs in six Candida species (26 isolates) grown in Sabouraud's dextrose broth (SAB) and RPMI broth were evaluated, following limited exposure to the MICs of the two polyenes, using an automated turbidometric method. For nystatin, PAFE varied between 1.88 and 4.87 h in SAB and 0.66 and 6.89 h in RPMI, and for amphotericin B, the equivalent values were 3.13 to 10.98 h in SAB and 0.97 to 7.01 h in RPMI. These highly significant (P < 0.001) variations in the PAFE with both drugs, noted with most Candida strains grown in different media, call for standardization of intralaboratory methodology in measuring this parameter in order to obtain universally comparable data.