title: In vitro activity of two amphotericin B formulations against Malassezia furfur strains recovered from patients with bloodstream infections.
abstract: Although guidelines for the treatment of Malassezia furfur fungemia are not yet defined, clinical data suggest that amphotericin B (AmB) is effective for treating systemic infections. In the absence of clinical breakpoints for Malassezia yeasts, epidemiological cut-off values (ECVs) are useful to discriminate between isolates with and without drug resistance. This study aimed to compare the distribution of minimal inhibitory concentration (MIC) and the ECVs for AmB of both deoxycholate (d-AmB) and liposomal (l-AmB) formulations of M. furfur isolates. The 84 M. furfur strains analyzed, which included 56 from blood, sterile sites and catheters, and 28 from skin, were isolated from patients with bloodstream infections. MICs were determined by the modified broth microdilution method of the Clinical and Laboratory Standards Institute (CLSI). The l-AmB MIC and the ECVs were two-fold lower than those of d-AmB and a lower l-AmB mean MIC value was found for blood isolates than from skin. The ECVs for l-AmB and d-AmB were 8 mg/l and 32 mg/l, respectively. Three strains (3.6%) showed l-AmB MIC higher than ECV (MIC > 8 mg/l) of which two were isolated from the catheter tip of patients treated with micafugin, l-Amb and fluconazole, and one from skin. The results showed that the l-AmB might be employed for assessing the in vitro antifungal susceptibility of M. furfur by a modified CLSI protocol and that ECVs might be useful for detecting the emergence of resistance.
authors: Dipartimento di Medicina Veterinaria, Università degli Studi di Bari, Italy.
authors: Roberta
authors: R
authors: Iatta
authors: Dipartimento di Medicina Veterinaria, Università degli Studi di Bari, Italy.
authors: Davide
authors: D
authors: Immediato
authors: Dipartimento di Scienze Biomediche e Oncologia Umana, Università degli Studi di Bari, Italy.
authors: Maria Teresa
authors: MT
authors: Montagna
authors: Dipartimento di Medicina Veterinaria, Università degli Studi di Bari, Italy.
authors: Domenico
authors: D
authors: Otranto
authors: Dipartimento di Medicina Veterinaria, Università degli Studi di Bari, Italy claudia.cafarchia@uniba.it.
authors: Claudia
authors: C
authors: Cafarchia
mesh_terms: D000666:Amphotericin B / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology*; D001769:Blood / Q000382:microbiology; D057785:Catheters / Q000382:microbiology; D003840:Deoxycholic Acid / Q000494:pharmacology*; D004338:Drug Combinations; D016469:Fungemia / Q000382:microbiology*; D006801:Humans; D008290:Malassezia / Q000187:drug effects* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D012867:Skin / Q000382:microbiology
chemical_list: D000935:Antifungal Agents; D004338:Drug Combinations; C068538:liposomal amphotericin B; D003840:Deoxycholic Acid; D000666:Amphotericin B; C059765:amphotericin B, deoxycholate drug combination
keywords: CLSI; Malassezia furfur; amphotericin B susceptibility; bloodstream infections; epidemiological cut-off