title: In vitro susceptibility testing of Malassezia pachydermatis to gentamicin.
abstract: BACKGROUND
  Two studies have observed that growth media containing gentamicin can inhibit the growth of the yeast organism Malassezia pachydermatis. The minimum inhibitory concentration (MIC) of this bactericidal antibiotic for this organism has not been previously determined.
  
  
  OBJECTIVE
  To evaluate the susceptibility of M. pachydermatis isolates to gentamicin.
  
  
  METHODS
  The MIC of gentamicin was determined using a modified version of the M27-A3 microdilution method following the guidelines of the Clinical and Laboratory Standards Institute. A modified Christensen's urea broth was used to enhance the growth of the M. pachydermatis isolates. Visual and spectrophotometric end-point readings were performed to detect the presence or absence of yeast growth.
  
  
  RESULTS
  The MIC50 and MIC90 of gentamicin were 8.12 μg/mL and 32.5 μg/mL, respectively; M. pachydermatis strains were classified as susceptible (S), intermediate (I) and resistant (R). The susceptibility of these isolates to gentamicin in vitro, by visual and spectrophotometric end-point reading, was: S, 54-56%; I, 40-41%; and R, 3-6%.
  
  
  CONCLUSIONS
  Prospective MICs for M. pachydermatis have been established for gentamicin.
authors.affiliation: Instituto Universitario de Sanidad Animal y Seguridad Alimentaria (IUSA), Universidad de Las Palmas de Gran Canaria, 35413, Arucas, Las Palmas, Spain.
authors.forename: Freddy A
authors.initials: FA
authors.lastname: Silva
authors.affiliation: Departamento de Patología Animal, Facultad de Veterinaria, Universidad de Las Palmas de Gran Canaria, 35413, Arucas, Las Palmas, Spain.
authors.forename: Otilia
authors.initials: O
authors.lastname: Ferrer
authors.affiliation: Instituto Universitario de Sanidad Animal y Seguridad Alimentaria (IUSA), Universidad de Las Palmas de Gran Canaria, 35413, Arucas, Las Palmas, Spain.
authors.forename: Soraya
authors.initials: S
authors.lastname: Déniz
authors.affiliation: Instituto Universitario de Sanidad Animal y Seguridad Alimentaria (IUSA), Universidad de Las Palmas de Gran Canaria, 35413, Arucas, Las Palmas, Spain.
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Rosario
authors.affiliation: Departamento de Patología Animal, Facultad de Veterinaria, Universidad de Las Palmas de Gran Canaria, 35413, Arucas, Las Palmas, Spain.
authors.forename: Magnolia
authors.initials: M
authors.lastname: Conde-Felipe
authors.affiliation: Departamento de Patología Animal, Facultad de Veterinaria, Universidad de Las Palmas de Gran Canaria, 35413, Arucas, Las Palmas, Spain.
authors.forename: Esther L
authors.initials: EL
authors.lastname: Díaz
authors.affiliation: Instituto Universitario de Sanidad Animal y Seguridad Alimentaria (IUSA), Universidad de Las Palmas de Gran Canaria, 35413, Arucas, Las Palmas, Spain.
authors.forename: Begoña
authors.identifier: http://orcid.org/0000-0002-0397-4244
authors.initials: B
authors.lastname: Acosta-Hernández
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D025141:Drug Resistance, Fungal; D005839:Gentamicins / Q000494:pharmacology*; D066298:In Vitro Techniques; D008290:Malassezia / Q000187:drug effects*; D008826:Microbial Sensitivity Tests
chemical_list: D000935:Antifungal Agents; D005839:Gentamicins