title: Candida albicans promotes invasion and colonisation of Candida glabrata in a reconstituted human vaginal epithelium.
abstract: OBJECTIVE
  The principal aim of this study was to investigate the in vitro co-infection of a reconstituted human vaginal epithelium (RHVE) by Candida albicans and Candida glabrata.
  
  
  METHODS
  The ability of both species to invade and colonise the RHVE was examined using species-specific peptide nucleic acid (PNA) probe hybridisation, confocal laser scanning microscopy (CLSM) and a novel qRT-PCR protocol for Candida quantification in the tissues. RHVE damage was evaluated by measuring lactate dehydrogenase (LDH) activity. Candida virulence gene expression (HWP1, ALS, EPA, PLB, PLD and SAP) was evaluated by quantitative RT-PCR.
  
  
  RESULTS
  The results showed that whilst both species induced damage to the RHVE, this was notably less with C. glabrata. Interestingly, there was a significant increase in C. glabrata RHVE colonisation and invasiveness when it was added to the tissue with C. albicans. The extent of RHVE damage caused by the two species appeared to be primarily dependent on the process of invasion. Of the virulence genes assayed, HWP1, PLD1 and ALS3 were deemed to be most associated with pathogenicity in the model.
  
  
  CONCLUSIONS
  For the first time, we have demonstrated that the RHVE model coupled with specific tools of analysis, allows assessment of Candida colonisation and invasion in single and co-infection. Using this model we have demonstrated that C. albicans enhanced C. glabrata colonisation, invasion and tissue damage, which was also evidenced by the expression of virulence genes.
authors.affiliation: CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, 4710-057 Braga, Portugal.
authors.forename: Carlos Tiago
authors.initials: CT
authors.lastname: Alves
authors.affiliation: Tissue Engineering & Reparative Dentistry, School of Dentistry, Cardiff University, Cardiff CF14 4XY, United Kingdom.
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Wei
authors.affiliation: CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, 4710-057 Braga, Portugal.
authors.forename: Sónia
authors.initials: S
authors.lastname: Silva
authors.affiliation: CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, 4710-057 Braga, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Azeredo
authors.affiliation: CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, 4710-057 Braga, Portugal. Electronic address: mcrh@deb.uminho.pt.
authors.forename: Mariana
authors.initials: M
authors.lastname: Henriques
authors.affiliation: Tissue Engineering & Reparative Dentistry, School of Dentistry, Cardiff University, Cardiff CF14 4XY, United Kingdom. Electronic address: williamsdd@cf.ac.uk.
authors.forename: David W
authors.initials: DW
authors.lastname: Williams
mesh_terms: D002176:Candida albicans / Q000472:pathogenicity*; D041221:Candida glabrata / Q000472:pathogenicity*; D002177:Candidiasis / Q000382:microbiology*; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism; D060085:Coinfection / Q000382:microbiology*; D015169:Colony Count, Microbial; D004848:Epithelium / Q000382:microbiology; D005260:Female; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D046509:Tissue Culture Techniques; D014621:Vagina / Q000382:microbiology*
chemical_list: C109455:ALA1 protein, Candida albicans; D015815:Cell Adhesion Molecules; D005656:Fungal Proteins
keywords: Candida albicans; Candida glabrata; Candidosis; Co-infection; RHVE; Yeast PNA FISH