Correlation of antifungal susceptibility testing with clinical outcome

There has been a dramatic increase in systemic fungal infections associated with increased use of broad spectrum antibiotics, corticosteroids, chemotherapy and transplantation. To assist in optimizing therapy, antifungal susceptibility testing was introduced at NMH. To correlate susceptibility testing with clinical outcome, we examined response to therapy in 114 patients with clinically significant fungal infections from Mar 1995 to May 1996. Testing was performed using amicrotiter method with EMEM and RPMI 1640 incubated at 30°C and 35°C. Organism (# of isolates) Ampho B Flu 5-FC Itra Keto C. albicans (51) 100 84 90 60 96 T. glabrata (17) 100 94 94 56 100 C. tropicalis (15) 100 80 87 69 86 C parapsilosis (7) 100 86 100 80 71 C. neoformans (6) 100 67 100 75 100 C. krusei (5) 80 0 0 40 100 A. fumigatus(5) 80 0 0 0 0 Of the 102 evaluable episodes of infection, patients responded in 77 (75%). Antifungal susceptibility testing predicted response in 69% of the patients and predicted failure in 71%. Of the 13 patients with susceptible organisms who did not respond, the majority were profoundly immunocompromised including 6 with end-stage AIDS. In conclusion, antifungal susceptibility testing using our methodology correlated well with clinical outcome in patients with a wide variety of fungal infections and reliably determined fungal resistance.