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Persistence of the same Candida albicans strain despite fluconazole therapy. Documentation by pulsed-field gel
H M Blumberg1, E F Hendershot, T J Lott
1Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia 30303.
Abstract:
Candida albicans and other Candida species have emerged as major nosocomial pathogens associated with a high mortality. Therapeutic options for fungal infections are limited. Amphotericin B has been the mainstay of treatment for serious systemic candidal infections, but it is relatively toxic and associated with a variety of side effects. Fluconazole has been proposed as alternative therapy for the treatment of systemic candidiasis including candidemia. We report the case of a patient with fungemia in whom fluconazole failed to eradicate C. albicans and C. tropicalis. These pathogens were recovered from sputum and urine cultures, respectively, on day 12 of intravenous fluconazole therapy. Molecular epidemiologic techniques employing pulsed-field gel electrophoresis confirmed the persistence of the same C. albicans strain. Susceptibility studies showed a marked change in MICs of fluconazole between 24 and 48 hr, with an increase from less than or equal to 1.25 to greater than 80 micrograms/ml. Controlled trials will be needed to delineate the role of fluconazole in the treatment of disseminated candidiasis and its efficacy in comparison with amphotericin B. Amphotericin B should remain the drug of choice for such infections until data from controlled trials are available.
Insights
Fluconazole therapy failed to eradicate Candida species in a patient with fungemia, indicating potential resistance. Amphotericin B remains the preferred treatment for serious fungal infections pending further clinical trials.
Area of Science:
- Medical Mycology
- Infectious Diseases
- Clinical Microbiology
Background:
- Candida species are significant nosocomial pathogens causing high mortality.
- Limited therapeutic options exist for invasive fungal infections.
- Amphotericin B is a primary treatment but has toxicity concerns.
Observation:
- A case of fungemia is presented where fluconazole failed to eradicate Candida albicans and Candida tropicalis.
- Pathogens persisted despite intravenous fluconazole therapy, confirmed by molecular typing.
- Susceptibility testing revealed a significant increase in fluconazole minimum inhibitory concentrations (MICs).
Findings:
- Fluconazole resistance emerged during treatment in a patient with candidemia.
- Molecular epidemiology confirmed the persistence of the same Candida albicans strain.
- Rapid development of high-level fluconazole resistance was observed.
Implications:
- The findings highlight the potential for fluconazole treatment failure in invasive candidiasis.
- Further controlled trials are necessary to establish fluconazole's role versus amphotericin B.
- Amphotericin B is recommended as the drug of choice for severe candidal infections until more data are available.