title: Effect of increasing inoculum sizes of Aspergillus hyphae on MICs and MFCs of antifungal agents by broth microdilution method.
abstract: In order to investigate the influence of different hyphal inoculum sizes on minimal inhibition concentrations (MICs) and minimum fungicidal concentrations (MFCs) of amphotericin B (AMB), voriconazole and itraconazole, five isolates each of Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger and Aspergillus terreus were studied using a broth microdilution method. Three inoculum sizes were used: 1 x 10(3)-5 x 10(3), 1 x 10(4)-5 x 10(4) and 1 x 10(5)-5 x 10(5) cfu/ml. MICs and MFCs were read at 24 and 48 h at 35 degrees C. For all species tested, AMB MICs and MFCs were minimally affected by inoculum size on. However inoculum size significantly affected MICs and MFCs of voriconazole and itraconazole; there was an increase of up to 6-fold in MICs and MFCs for the various aspergilli when the inoculum increased from 10(3) to 10(5) cfu/ml (P<0.05). Thus azoles showed significant inoculum effects, while AMB showed comparatively minimum inoculum effects against Aspergillus spp.
authors.affiliation: Institute of Hygiene and Social Medicine, Leopold-Franzens University of Innsbruck, Fritz-Pregl-Strasse 3, 6020 Innsbruck, Austria. cornelia.lass-floerl@uibk.ac.at
authors.forename: Cornelia
authors.initials: C
authors.lastname: Lass-Flörl
authors.forename: C
authors.initials: C
authors.lastname: Speth
authors.forename: G
authors.initials: G
authors.lastname: Kofler
authors.forename: M P
authors.initials: MP
authors.lastname: Dierch
authors.forename: E
authors.initials: E
authors.lastname: Gunsilius
authors.forename: R
authors.initials: R
authors.lastname: Würzner
mesh_terms: D000666:Amphotericin B / Q000008:administration & dosage; D000935:Antifungal Agents / Q000008:administration & dosage*; D001230:Aspergillus / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification / Q000472:pathogenicity; D001231:Aspergillus flavus / Q000187:drug effects / Q000254:growth & development; D001232:Aspergillus fumigatus / Q000187:drug effects / Q000254:growth & development; D001234:Aspergillus niger / Q000187:drug effects / Q000254:growth & development; D015169:Colony Count, Microbial; D004305:Dose-Response Relationship, Drug; D025141:Drug Resistance, Fungal; D006801:Humans; D066298:In Vitro Techniques; D017964:Itraconazole / Q000008:administration & dosage; D011743:Pyrimidines / Q000008:administration & dosage; D014230:Triazoles / Q000008:administration & dosage; D065819:Voriconazole
chemical_list: D000935:Antifungal Agents; D011743:Pyrimidines; D014230:Triazoles; D017964:Itraconazole; D000666:Amphotericin B; D065819:Voriconazole