[Methodologic problems in the biotyping of Candida albicans]

Area of Science:

• Medical Mycology
• Microbial Genetics
• Epidemiology

Background:

• Candida albicans is an opportunistic fungal pathogen.
• Accurate biotyping is crucial for epidemiological studies of C. albicans.
• Existing biotyping methods require evaluation for reliability and potential improvements.

Purpose of the Study:

• To assess the reliability of a three-test biotyping system for C. albicans.
• To analyze the independence of biotyping markers and the symmetry of 5-fluorocytosine sensitivity testing.
• To investigate the stability of C. albicans biotypes during prolonged storage.

Main Methods:

• Biotyping of 284 C. albicans strains using a three-test system (Odds and Abbott).
• Analysis of test independence and 5-fluorocytosine sensitivity.
• Evaluation of strain characteristics after prolonged storage and subculturing.

Main Results:

• The independence of C. albicans biotyping signs was confirmed.
• The 5-fluorocytosine sensitivity test was found to be asymmetrical; a more symmetrical test is proposed.
• Prolonged storage decreased the proportion of C. albicans strains resistant to low pH and with proteolytic activity.
• Biotype distribution was similar in strains from candidiasis patients and carriers.

Conclusions:

• The established biotyping system's reliability for epidemiological conclusions is supported, with suggested improvements.
• Strain characteristics, such as low pH resistance and proteolytic activity, can change with storage.
• The distribution of C. albicans biotypes does not differ significantly between clinical and carrier isolates.