title: Comparison of the Sensititre YeastOne colorimetric antifungal panel and Etest with the NCCLS M38-A method to determine the activity of amphotericin B and itraconazole against clinical isolates of Aspergillus spp.
abstract: OBJECTIVE
  The evaluation of the Sensititre YeastOne and Etest methods for determining susceptibility to amphotericin B and itraconazole by comparing the MICs obtained by these methods at different times of reading with those of the M38-A broth microdilution method.
  
  
  METHODS
  Sixty-three clinical isolates of Aspergillus spp. (23 Aspergillus flavus, 24 Aspergillus fumigatus, nine Aspergillus niger, three Aspergillus glaucus, two Aspergillus terreus and two Aspergillus flavipes) were assayed. Two itraconazole-resistant strains (NCPF7100 and 7099) were also included.
  
  
  RESULTS
  Itraconazole MICs for the two resistant strains were >4 mg/L by the three methods. The overall agreement (+/-2 log2) between M38-A (48 h) and colorimetric (48 h) method was 93.4% for amphotericin B and 90.2% for itraconazole. By the Etest, the best agreement with M38-A was obtained when readings were made at 24 h: 88.5% for amphotericin B and 67.2% for itraconazole. Etest MICs were higher for all species except A. niger.
  
  
  CONCLUSIONS
  The colorimetric method appears to be a suitable alternative procedure for antifungal susceptibility testing of Aspergillus spp. and is able to detect resistance to itraconazole. The range of MICs for amphotericin B by Etest is wider and for some strains is >16 mg/L, suggesting that this method could be useful for detecting resistant strains as occur in yeasts.
authors.affiliation: Servicio de Microbiología, Hospital Universitario de Valme, Sevilla, Spain.
authors.forename: Estrella
authors.initials: E
authors.lastname: Martín-Mazuelos
authors.forename: Javier
authors.initials: J
authors.lastname: Pemán
authors.forename: Anastasio
authors.initials: A
authors.lastname: Valverde
authors.forename: Mónica
authors.initials: M
authors.lastname: Chaves
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Serrano
authors.forename: Emilia
authors.initials: E
authors.lastname: Cantón
mesh_terms: D000666:Amphotericin B / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology*; D001228:Aspergillosis / Q000382:microbiology*; D001230:Aspergillus / Q000187:drug effects*; D003124:Colorimetry; D025141:Drug Resistance, Fungal; D006801:Humans; D017964:Itraconazole / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests / Q000295:instrumentation*; D015203:Reproducibility of Results
chemical_list: D000935:Antifungal Agents; D017964:Itraconazole; D000666:Amphotericin B