It is apparent that both nosocomial and community-acquired fungal infections are becoming more prominent. This is largely due to an increase in the number of individuals at risk for acquiring fungal infection. As a result, infections due to both common and previously obscure or unusual fungi are being seen more frequently in both the hospital environment and the community. The increase in the frequency and spectrum of fungal infections has coincided with an increase in the number of antifungal agents available for the treatment of infection. In addition to the licensed systemic agents (amphotericin B, fluconazole, itraconazole, ketoconazole and 5-FC), new triazoles with extended spectrums of activity (posaconazole, ravuconazole and voriconazole), novel echinocandin agents (caspofungin, anidulafungin, and micafungin), as well as novel formulations and delivery systems (lipid formulations of amphotericin B and nystatin; intravenous itraconazole) are available or under investigation. Due to the severe and prolonged immunosuppression associated with HIV infection and organ transplantation, it is often necessary to provide long term suppressive therapy to adequately treat fungal infection in these individuals. This situation presents the potential for development of resistance in formerly susceptible strains. It is now apparent that resistance to antifungal agents is an issue of both clinical and epidemiologic importance. All of these factors have combined to increase the need for reproducible, clinically relevant antifungal susceptibility testing for both yeasts and moulds. Antifungal susceptibility (resistance) testing has been standardized and now plays an increasingly important role in guiding therapeutic decision making, as an aid in drug development studies, and as a means of tracking the development of antifungal resistance. In addition to in vitro resistance detection, one of the major strategies to control the spread of infectious diseases and reduce antimicrobial use, and thus resistance, is to develop improved diagnostic strategies. Unfortunately, existing microbiologic methods are slow, insensitive, and are imprecise markers for complete eradication of infection. Although culture independent diagnostic tests for invasive fungal infection are limited, they include detection of antigens and metabolites and the use of nucleic acid-based methods. All of these approaches offer the potential for rapid detection of fungal pathogens, but currently are limited in availability and usage. Further development of both antifungal susceptibility testing and rapid diagnostic technologies will be important and will require careful clinical and epidemiologic studies for validation. If rapid and sensitive methods for diagnosis, identification and resistance detection can be developed at competitive prices, they will improve diagnosis and therapy and reduce emergence of drug resistance by more appropriate and targeted antimicrobial therapy.
Full conference title:
- ICAAC 41st