In vitro, species-specific, antifungal susceptibility patterns of all currently available systemic antifungal and Scedosporium

Lackner M., De Hoog G.S., Geersten E., Verweij P.E., Klaassen C. and Meis J.F.

Abstract: 

Scedosporium infections are among the most difficult to treat fungal infections, as many strains carry multiple resistances against most or all systemically active antifungal compounds. In contrast to Aspergillus strains, Scedosporium strains are also able to cause deep infections in immunocompetent persons, e.g., after a near-drowning event or after traumatic inoculation. Few data exist on species-specific susceptibility profiles, in particular for the recently separated species Pseudallescheria boydii and P. apiosperma. This study presents susceptibility profiles of a worldwide set of more than 300 Scedosporium strains from a wide variety of clinical/environmental sources. Eight systemically active antifungal compounds (amphotericin B, anidulafungin, caspofungin, Isavuconazole, itraconazole, micafungin, posaconazole, and voriconazole) were tested using the micro-dilution method according to CLSI standard M38-2. Strains were identified according to state of the art taxonomic standards using amplified fragment length polymorphism (AFLP). Pseudallescheria apiosperma (n = 155) and P. boydii strains (n = 76) had similar AFSP, while those of S. aurantiacum (n = 23), S. prolificans (n = 38) and S. dehoogii (n = 25) were deviant from each other. Pseudallescheria apiosperma and P. boydii were mostly susceptible to micafungin, anidulafungin and posaconazole, while itraconazole, Isavuconazole, and amphotericin B showed poor activity. Scedosporium aurantiacum strains were susceptible to voriconazole only. In contrast, some strains of S. prolificans were found susceptible to anidulafungin, micafungin and caspofungin, while strains of S. dehoogii were most susceptible to micafungin. In conclusion, anidulafungin and micafungin should be taken into account as possible therapy options against P. apiosperma, P. boydii, and S. prolificans, preferably in combination with voriconazole.

    • TIMM 5th (2013)