title: In vivo Candida glabrata biofilm development on foreign bodies in a rat subcutaneous model.
abstract: OBJECTIVE
  Biofilm studies have been mostly dedicated to the major human fungal pathogen Candida albicans, whereas much less is known about this virulence factor in Candida glabrata, certainly under in vivo conditions. This study provides a deeper understanding of the biofilm development of C. glabrata, its architecture and susceptibility profile to fluconazole and echinocandins.
  
  
  METHODS
  In vitro and in vivo C. glabrata biofilms were developed inside serum-coated triple-lumen catheters placed in 24-well polystyrene plates or implanted subcutaneously in the back of a rat, respectively. Scanning electron microscopy and confocal scanning laser microscopy were used to visualize the biofilm architecture. Quantitative real-time PCR was used to demonstrate the expression profile of EPA1, EPA3, EPA6 and AWP1-AWP7 during in vivo biofilm formation.
  
  
  RESULTS
  Mature biofilms were observed within the first 48 h and the amount of biofilm reached its maximum by 6 days. Architecturally, mature C. glabrata biofilms consisted of a thick network of yeast cells embedded in an extracellular matrix. Moreover, in vivo biofilms were susceptible to echinocandin drugs, whereas fluconazole remained ineffective. Gene expression profiling revealed that EPA3, EPA6, AWP2, AWP3 and AWP5 were up-regulated in in vivo biofilms compared with in vitro biofilms.
  
  
  CONCLUSIONS
  C. glabrata is a unique microorganism, which, despite the lack of transition to the hyphal form, formed thick biofilms inside foreign bodies in vivo. To our knowledge, this is the first study that has described in vivo C. glabrata biofilm development and its architectural changes in detail and provides an insight into the susceptibility profile, as well as the gene expression machinery, of biofilm-associated infections.
authors.affiliation: Department of Molecular Microbiology, VIB, KU Leuven, Leuven, Belgium Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Kasteelpark Arenberg 31, B-3001 Heverlee-Leuven, Belgium.
authors.forename: Soňa
authors.initials: S
authors.lastname: Kucharíková
authors.affiliation: Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, B-3001 Heverlee-Leuven, Belgium.
authors.forename: Bram
authors.initials: B
authors.lastname: Neirinck
authors.affiliation: Department of Molecular Microbiology, VIB, KU Leuven, Leuven, Belgium Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Kasteelpark Arenberg 31, B-3001 Heverlee-Leuven, Belgium.
authors.forename: Nidhi
authors.initials: N
authors.lastname: Sharma
authors.affiliation: Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, B-3001 Heverlee-Leuven, Belgium.
authors.forename: Jef
authors.initials: J
authors.lastname: Vleugels
authors.affiliation: Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium.
authors.forename: Katrien
authors.initials: K
authors.lastname: Lagrou
authors.affiliation: Department of Molecular Microbiology, VIB, KU Leuven, Leuven, Belgium Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Kasteelpark Arenberg 31, B-3001 Heverlee-Leuven, Belgium patrick.vandijck@mmbio.vib-kuleuven.be.
authors.forename: Patrick
authors.initials: P
authors.lastname: Van Dijck
mesh_terms: D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D041221:Candida glabrata / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D002177:Candidiasis / Q000382:microbiology* / Q000473:pathology*; D004195:Disease Models, Animal; D054714:Echinocandins / Q000494:pharmacology; D005260:Female; D015725:Fluconazole / Q000494:pharmacology; D005547:Foreign Bodies / Q000150:complications*; D005656:Fungal Proteins / Q000235:genetics; D020869:Gene Expression Profiling; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D016896:Treatment Outcome
chemical_list: D000935:Antifungal Agents; D054714:Echinocandins; D005656:Fungal Proteins; D015725:Fluconazole
keywords: C. glabrata; echinocandins; fluconazole; in vitro biofilms; in vivo biofilms