STRAIN DELINEATION AND ANTIFUNGAL SUSCEPTIBILITIES OF EPIDEMIOLOGICALLY RELATED AND UNRELATED ISOLATES OF CANDIDA-LUSITANIAE

Candida lusitaniae is an important nosocomial pathogen that may expres s resistance to one or more antifungal agents including amphotericin B . We investigated the genotypic diversity and antifungal susceptibilit y among 47 clinical isolates from 33 patients hospitalized in 12 diffe rent medical centers. Strain delineation was performed by restriction endonuclease analysis of genomic DNA (REAG) with the restriction enzym e Sfi I followed by pulsed-field gel electrophoresis and by electropho retic karyotyping (EK). Antifungal susceptibility of the isolates to a mphotericin B, 5-fluorocytosine (5FC), fluconazole, and itraconazole w as determined using National Committee for Clinical Laboratory Standar ds standard methods. Minimum inhibitory concentration (MIG)(90) values ranged from 0.5 mu g/ml for itraconazole to 512 mu g/ml for 5FC. In g eneral, isolates from a given patient or epidemiologically related iso lates from a nosocomial cluster were identical by molecular typing met hods. Epidemiologically unrelated isolates were all distinctly differe nt by both EK and REAG typing methods. Although elevated amphotericin B MICs (greater than or equal to 2 mu g/ml) were observed in only thre e isolates, extended incubation (72 h) revealed amphotericin B MICs of 2-16 mu g/ml in a subset of isolates suggesting potential amphoterici n B resistance. These data document the genetic diversity, nosocomial transmission, and antifungal susceptibility of clinical isolates of C. lusitaniae.