title: Antifungal susceptibility testing of Candida tropicalis biofilms against fluconazole using calorimetric indicator resazurin.
abstract: BACKGROUND
  C.tropicalis is an important cause of nosocomial infections particularly in immunocompromised patients. Infections caused by Candida spp. are often associated with biofilm formation on implanted medical devices or on epithelial cell surfaces. Phenotypic characteristics of sessile cells in biofilms are known to be different from those of their free-living, planktonic counterparts. Biofilm forming strains often show increased resistance to antimicrobial agents.
  
  
  METHODS
  We measured susceptibility to fluconazole of fifty C.tropicalis isolates from immunocompromised (29) and immunocompetent (21) patients by minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC) assays. MBIC was done using the calorimetric indicator resazurin, to measure the metabolically active cells.
  
  
  RESULTS
  Biofilm forming cells showed increased resistance to fluconazole.
  
  
  CONCLUSIONS
  The resazurin dye test was found to be a good method for determining MBIC.
authors.affiliation: Department of Microbiology, Dr. A L Mudaliar Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani, Chennai, India.
authors.forename: P M
authors.initials: PM
authors.lastname: Punithavathy
authors.forename: K
authors.initials: K
authors.lastname: Nalina
authors.forename: Thangam
authors.initials: T
authors.lastname: Menon
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D041022:Candida tropicalis / Q000187:drug effects* / Q000302:isolation & purification / Q000502:physiology; D002177:Candidiasis / Q000382:microbiology; D003124:Colorimetry / Q000379:methods*; D015725:Fluconazole / Q000494:pharmacology*; D006801:Humans; D016867:Immunocompromised Host; D008826:Microbial Sensitivity Tests / Q000379:methods; D010078:Oxazines / Q000378:metabolism*; D013194:Staining and Labeling / Q000379:methods*; D014966:Xanthenes / Q000378:metabolism*
chemical_list: D000935:Antifungal Agents; D010078:Oxazines; D014966:Xanthenes; C005843:resazurin; D015725:Fluconazole