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©2013 UpToDate ® Print Email Indications for antifungal susceptibility testing Clinical setting Recommendation Routine • Species level identification of all Candida isolates from deep sites (eg, blood, normally sterile fluids, tissues, abscesses). • Species level identification of Aspergillus , genus level for all other molds. • Species level (if possible) identification of non-candidal yeast isolates from deep sites (eg, blood, normally sterile fluids, tissues, abscesses). • Selection of therapy is generally based on published consensus guidelines and review of survey data on the organism-drug combination in question. • Routine susceptibility testing of fluconazole, voriconazole, and an echinocandin against C. glabrata and fluconazole against non-candidal yeast isolates from deep sites (eg, blood, normally sterile fluids, tissues, abscesses). • Susceptibility testing of fluconazole, voriconazole, an echinocandin, and flucytosine against other species of Candida may be helpful in special circumstances, but not routinely, since susceptibility is usually predictable. • Susceptibility of Candida spp other than C. glabrata to echinocandins may be assumed unless initial response is suboptimal. Susceptibility testing of isolates to an echinocandin should be considered if there is a prior history of exposure to this class of agents. Mucosal candidiasis • Susceptibility testing may be useful for patients unresponsive to therapy. Invasive disease with clinical failure of initial therapy • Consider susceptibility testing. - Candida spp: amphotericin B, flucytosine, fluconazole, voriconazole, echinocandins - C. neoformans : fluconazole, amphotericin B, flucytosine - Aspergillus species: amphotericin B, posaconazole, itraconazole, voriconazole • Consultation with an experienced microbiologist recommended Infection with species with high rates of intrinsic or acquired resistance • Susceptibility testing not necessary when intrinsic resistance is known. - A. terreus : amphotericin B - C. krusei : fluconazole, flucytosine - Cryptococcus and Trichosporon : echinocandins - Rhodotorula : azoles, echinocandins - Mucorales : voriconazole, echinocandins • For species with significant rates of acquired resistance, monitor closely for signs of failure and perform susceptibility testing as needed. - C. glabrata : fluconazole, voriconazole, amphotericin B, echinocandins - C. krusei : amphotericin B - C. lusitaniae : amphotericin B

- Rhodotorula : azoles, echinocandins - Mucorales : voriconazole, echinocandins • For species with significant rates of acquired resistance, monitor closely for signs of failure and perform susceptibility testing as needed. - C. glabrata : fluconazole, voriconazole, amphotericin B, echinocandins - C. krusei : amphotericin B - C. lusitaniae : amphotericin B - C. rugosa : amphotericin B, fluconazole - Candida spp: flucytosine, when used for endocarditis Unusual organisms • Susceptibility testing may be helpful when treating patients infected with unusual organisms for which susceptibility patterns have not been well established or are unpredictable. Mold infections • Species level identification of Aspergillus , genus level for all other molds. • Routine susceptibility testing not recommended. • Susceptibility of Aspergillus species to itraconazole, voriconazole, and posaconazole may help to determine cross-resistance. • Clinical interpretive criteria have not been established for any agents. Data from: Pfaller MA. Antifungal susceptibility testing methods. Curr Drug Targets 2005; 6:929. Rex JH, Pfaller MA. Has antifungal susceptibility testing come of age? Clin Infect Dis 2002; 35:982. Pappas PG, Kauffman CA, Andes D, et al. Clinical practice guidelines for the management of candidiasis: 2009 update by the Infectious Diseases Society of America. Clin Infect Dis 2009; 48:503. Pfaller MA, Wu WL. Antifungal susceptibility testing: new technology and clinical applications. Infect Dis Clin N Am 2001; 15:1227. Spellberg BJ, Filler SG, Edwards JE Jr. Current treatment strategies for disseminated candidiasis. Clin Infect Dis 2006; 42:244.