A study of 666 strains of Candida albicans: correlation between serotype and susceptibility to 5-fluorocytosine.

The minimal inhibitory concentrations (MICs) of 5-fluorocytosine (5-FC) and the serotypes were determined for 666 strains of Candida albicans isolated from white patients in Canada. Of these strains, 495 (74.3%) were serotype A and 71 (25.7%) were serotype B. Resistance to 5-FC (MIC, greater than or equal to 25 microgram/ml) was observed in 11.3% of the serotype A strains and in 49.7% of the strains of serotype B. Most specimens were from the urogenital and respiratory tracts. The results showed the difference between the distribution of the two serotypes of C. albicans in North America and that in Europe. Serotyping of C. albicans strains by indirect immunofluorescence is a rapid means of predicting the de novo sensitivity of this year to 5-FC. The specificity of this technique for the isolated strains was approximately 79%.