Mutants resistant to nystatin have been selected from cultures of a strain of isolated from a patient after it had been treated with N-methyl-N'-nitro-N-nitrosoguanidine. The resistance of the mutants to nystatin, amphotericin and filipin was respectively 12- to 16-fold, 30- to 40-fold and 3- to 7-fold, more than that of the parent strain. Sensitivity to three non-polyene compounds, clotrimazole, 5-fluorocytosine and pyrrolnitrin, was not altered. The mutants were identifiable as by standard laboratory tests; two of them seemed to have a decreased ability to form mycelium. There was some loss of acquired resistance after 46 passages . The mutants had more homogeneous patterns of resistance than did a resistant isolate of the same parent strain which had been serially subcultured in the presence of increasing concentrations of nystatin. Mutant cells were found to be of greater eccentricity, and of greater total volume and mass, than those of the parent strain. In shaken culture at 37°C the mutants grew more slowly than the parent; decreased growth rates and prolonged lag phases were also noted for the mutants when grown on solid media at four temperatures. The resistant isolates were agglutinated by similar dilutions of an antiserum to , and the agglutinins were removed by absorption of the antiserum with the parent strain. Possible taxonomic differences arising from loss of mycelium-forming ability of strains are discussed.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error