Journal of Chemotherapy Vol. 16 - n. 5 (468-473) - 2004 © E.S.I.F.T. srl - Firenze ISSN 1120-009X INTRODUCTION The impact and severity of fungal infections have grown in recent decades and now involve a wide range of fungal pathogens as etiological agents. Intense periods of immunosuppression following transplantation, HIV infection, long-term therapy with corticoids or antibiotics, etc, have been widely reviewed as predisposing factors 1-4 . The manage- ment of fungal infections is affected by the ability to carry out rapid and effective diagnosis and by the availability of antifungal agents with the proper spec- trum of activity. In addition, clinicians have the most reliable guide to therapy in clinical response rather than susceptibility tests due to the lack of in vivo-in vitro correlation of some drugs while in others this has been found 5-8 . Antifungal in vitro susceptibility testing should provide useful information for selecting the most active drug against etiological agents and also to predict treatment outcome or explain some resis- tance cases 5-10 . Although a high standardization degree has been reached and experimental condi- tions in macro or microdilution methods are con- densed, the predictive value of these tests remains a topic of study, especially of the available commercial methods. Some commercial test conditions agree with the NCCLS guidelines, adding a high correla- tion with standardized reference methods while sav- ing time. For those laboratories performing antifun- gal susceptibility testing with a reduced number of samples, commercial methods are often opposite the reference tests 5 . In vitro antifungal susceptibility testing with filamentous fungi is not recommended for routine use due to the complexity, lack of stan- dardization and reduced in vitro antifungal activity Antifungal Activity of Amphotericin B and Itraconazole against Filamentous Fungi: Comparison of the Sensititre Yeast One ® and NCCLS M38-A Reference Methods A.J. CARRILLO-MUÑOZ 1 - G. QUINDÓS 2 - O. DEL VALLE 3 J.M. HERNÁNDEZ-MOLINA 4 - P. SANTOS 5 1 ACIA, Barcelona, Spain. 2 D. Imnunología, Microbiología y Parasitología, Fac. Medicina, Universidad del País Vasco, Bilbao, Spain. 3 S. Microbiología, Hospital Vall d´Hebrón, Barcelona, Spain. 4 S. Microbiología, Hospital La Inmaculada, Huercal-Overa, Almería, Spain. 5Hospital de Pediatría Pablo Garrahan, Buenos Aires, Argentina. Correspondence: Dr. Alfonso-Javier Carrillo-Muñoz, Dept. Microbiología, ACIA, P.O. Box 10178, E-08080 Barcelona, Spain. Tel/Fax: +34 93 429 71 20. E-mail: acarrillo@ya.com Summary The susceptibilities of 81 clinical isolates of Aspergillus spp., Fusarium spp., and Scedosporium spp., to amphotericin B and itraconazole were determined by the colorimetric microdilution method Sensititre® and the reference microdilution method of NCCLS standard M38-A for filamentous fungi. No major discrepancies were found and agreement ranged between 86.4% to 84% and 69.1% to 86.4% for amphotericin B and itraconazole respectively at 48 h and 72 h of incubation by using the recommended endpoints. Within two two-fold dilutions, high levels of agreement were found in general for amphotericin B at 48 or 72 h (86.4 to 87.7%) and itraconazole (91.4 to 93.8%). Relatively better agreement was found for itra- conazole at 72 h of incubation and 48 for amphotericin B. Key words: Sensititre, amphotericin B, itraconazole, susceptibility, filamentous fungi. REPRINT REVIEW