Identification of Fusarium species involved in human infections by 28S rRNA gene sequencing

Fusarium spp. have emerged as major opportunistic fungal agents. Since new antifungal agents exhibit variable activity against Fusarium isolates depen ding on the species, rapid identification at the species level is required. Conventional culture methods are difficult, fastidious, and sometimes inco nclusive, In this work, we sequenced a 440-bp fragment encoding the 28S rRN A from 33 Fusarium isolates belonging to six Fusarium species associated wi th human infections. The data mere then analyzed by the neighbor-joining me thod. By using distance matrix analysis and constructing the phylogram, we could easily distinguish the different species for all but one isolate, The method also allowed differentiation between the closely related genera Acr emonium and Cylindrocarpon. In contrast to the case with conventional metho ds, the results could be obtained within 48 h from a 3-day culture and are independent of mycologist experience, making this method rapid and reliable for identification of Fusarium species isolated from patients.