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Molecular epidemiology and antifungal susceptibility of Cryptococcus neoformans isolates from Ugandan AIDS patients
1Department of Pathology, University of Iowa College of Medicine, Iowa City 52242, USA.
Abstract:
Little is known of the antifungal susceptibility patterns and molecular epidemiology of Cryptococcus neoformans from tropical regions. We studied 164 clinical isolates of C. neofomans from 120 Ugandan AIDS patients with cryptococcal meningitis by analyzing their electrophoretic karyotypes and antifungal susceptibility profiles. Computer-assisted analysis of karyotype patterns was performed to generate dendrograms. MICs of fluconazole and flucytosine were determined by reference methods. A total of 43 distinguishable DNA types were identified among the 164 isolates. Only 30 patients (25%) were infected with their own unique strain of c. neoformans, whereas 75% of the patients shared their infecting strain with at least one other patient. Among 17 patients with more than one CSF isolate of C. neoformans, sequential isolates were identical or highly related in 12 (71%) and were different in five patients (29%). The isolates were susceptible to both fluconazole and flucytosine and there were no instances in which a stepwise increase in either fluconazole or flucytosine MICs was observed among serial isolates. These findings suggest that the epidemiology of cryptococcal disease in AIDS patients from tropical regions may be somewhat different from that observed in more temperate climates.
Insights
Cryptococcus neoformans strains in Ugandan AIDS patients showed shared infections and susceptibility to antifungals. Molecular epidemiology revealed distinct patterns compared to temperate regions.
Area of Science:
- Mycology
- Infectious Diseases
- Epidemiology
Background:
- Limited data exists on Cryptococcus neoformans antifungal susceptibility and molecular epidemiology in tropical regions.
- Cryptococcal meningitis is a significant opportunistic infection in Human Immunodeficiency Virus (HIV)-infected individuals.
Purpose of the Study:
- To investigate the antifungal susceptibility patterns and molecular epidemiology of Cryptococcus neoformans in Ugandan AIDS patients.
- To compare findings from a tropical region with those from temperate climates.
Main Methods:
- Analysis of electrophoretic karyotypes and antifungal susceptibility profiles of 164 clinical isolates from 120 Ugandan AIDS patients.
- Computer-assisted analysis of karyotype patterns to generate dendrograms.
- Determination of Minimum Inhibitory Concentrations (MICs) of fluconazole and flucytosine using reference methods.
Main Results:
- 43 distinguishable DNA types were identified among the isolates.
- 75% of patients shared their infecting Cryptococcus neoformans strain with at least one other patient.
- All isolates were susceptible to fluconazole and flucytosine, with no observed increase in MICs among serial isolates.
Conclusions:
- The molecular epidemiology of cryptococcal disease in Ugandan AIDS patients may differ from that in temperate regions, characterized by strain sharing.
- Susceptibility to fluconazole and flucytosine was consistent, suggesting these drugs remain viable treatment options.
- Further research is needed to understand the implications of these findings for cryptococcal meningitis management in tropical settings.