Antifungal Resistance: The Clinical Front
December 3rd 2004The emergence of resistance and changes in the spectrum ofCandida infections have led to an increased interest in susceptibilitytesting of antifungal drugs. Such testing may be particularly useful inpatients with invasive candidiasis who have been previously treated withazole antifungals, those whose infections are not responding to treatment,and those with infections caused by non-albicans species of Candida.The choice of a specific antifungal depends on the clinical statusof the patient, the relative toxicity and efficacy of the drug in the givenpatient population, the infecting species and antifungal susceptibilityof the isolate, and the patient’s prior exposure to antifungal agents.Infectious Diseases Society of America recommendations for the initialmanagement of candidemia and acute disseminated candidiasisinclude an azole, caspofungin, amphotericin B (AmB), or a combinationof fluconazole plus AmB. Caspofungin and voriconazole show goodactivity against most Candida species and may be good alternatives forpatients with Candida glabrata and Candida krusei infections and forthose with relapsing infections.
Invasive Candida Infections: The Changing Epidemiology
December 3rd 2004Candida is recognized as the fourth most common cause of bloodstreaminfection in the United States, with a high attributable mortalityrate. While Candida albicans remains the most common pathogen, nonalbicansCandida species, including Candida glabrata and Candidakrusei, with greater resistance to triazoles are being increasingly isolated.These epidemiologic changes are attributable to a combinationof factors, such as the use of fluconazole prophylaxis, changes in patientdemographics and underlying diseases, and use of therapeuticstrategies that may pose unique risks. Of particular concern is the increasedprevalence of species that are resistant to the azole antifungals.Candida glabrata, for example, is often resistant to fluconazole,and its ability to become cross-resistant to newer azole antifungals is arecent concern. Increasing evidence underscores the need to carefullyevaluate antifungal treatment options, according to both host and therapeuticrisks for drug resistance.