Molecular epidemiology of Candida albicans isolates from AIDS and cancer patients using a novel standardized CARE-2 DNA fingerprinting technique.

A total of 277 Candida isolates from various body sites of 149 AIDS and cancer patients treated in four different university clinics in Würzburg, Germany were collected over a period of 27 months and phenotypically and genotypically characterized. The fingerprinting patterns of 194 Candida albicans isolates obtained with the moderately repetitive, C. albicans-specific DNA fragment CARE-2 were digitized and retrospectively compared with a highly accurate computer-assisted standardization method. A total of 168 different genotypic patterns (< 100% identity) could be differentiated using this technique. Although comparative analysis of C. albicans subsets revealed a pronounced tendency of C. albicans isolates from HIV patients to form clusters, the mean genetic variability in HIV and cancer patient isolates was virtually identical. Patients with a specific disease condition or in a certain age group were not found to harbour C. albicans isolates displaying a characteristic "signature genotype". Micro-evolutionary changes were detected by CARE-2 fingerprinting in temporal successive isolates of one patient, but nosocomial transmission of identical isolates between unrelated patients was never seen. Genotyping showed that patient isolates can replace one another; occasionally also species switches were observed. Secreted aspartic protease (SAP) production was not correlated with a specific C. albicans banding pattern; isolates obtained from HIV patients and from an internal control group secreted comparable amounts of SAP. Candida dubliniensis isolates in this study showed an elevated level of SAP production. When used under standardized conditions, CARE-2 fingerprinting is an efficient, reproducible and sensitive technique to characterize C. albicans isolates.