title: Influence of bacterial presence on biofilm formation of Candida albicans.
abstract: OBJECTIVE
  Candida albicans is an opportunistic pathogen that is commonly found in human microflora. Biofilm formation (BF) is known as a major virulence factor of C. albicans. The aim of this study was to examine the influence of bacterial presence on biofilm formation of C. albicans.
  
  
  METHODS
  The BF of Candida was investigated when it was co-cultured with C. albicans (C. albicans 53, a yeast with a low BF ability, and C. albicans 163, a yeast with high BF ability) and bacteria. BF was assessed with XTT reduction assay. A scanning electron microscope was used to determine the structure of the biofilm, and real-time reverse transcriptase polymerase chain reaction was used to amplify and quantify hyphae-associated genes.
  
  
  RESULTS
  Co-culturing with two different types of bacteria increased the BF value. Co-culturing with C. albicans 53 and 163 also increased the BF value compared to the value that was obtained when the C. albicans was cultured individually. However, co-culturing with bacteria decreased the BF value of C. albicans, and the BF of C. albicans 163 was markedly inhibited. The expression of adherence and morphology transition related genes were significantly inhibited by co-culturing with live bacteria.
  
  
  CONCLUSIONS
  Bacteria have a negative effect on the formation of biofilm by C. albicans. This mechanism is the result of the suppression of genes associated with the hyphae transition of C. albicans, and bacteria particles physically affected the biofilm architecture and biofilm formation.
authors.affiliation: Department of Microbiology, Yonsei University Wonju College of Medicine, 20 Ilsan-ro, Wonju 220-701, Korea. leekh@yonsei.ac.kr.
authors.forename: Su Jung
authors.initials: SJ
authors.lastname: Park
authors.forename: Kyoung-Hee
authors.initials: KH
authors.lastname: Han
authors.forename: Joo Young
authors.initials: JY
authors.lastname: Park
authors.forename: Sun Ju
authors.initials: SJ
authors.lastname: Choi
authors.forename: Kyoung-Ho
authors.initials: KH
authors.lastname: Lee
mesh_terms: D016282:Aspartic Acid Endopeptidases / Q000235:genetics; D018441:Biofilms / Q000254:growth & development*; D002176:Candida albicans / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D018920:Coculture Techniques; D004926:Escherichia coli / Q000502:physiology; D005656:Fungal Proteins / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D006801:Humans; D025301:Hyphae / Q000235:genetics; D008562:Membrane Glycoproteins / Q000235:genetics; D011514:Proteus vulgaris / Q000502:physiology; D011550:Pseudomonas aeruginosa / Q000502:physiology; D013211:Staphylococcus aureus / Q000302:isolation & purification / Q000502:physiology; D013297:Streptococcus pyogenes / Q000302:isolation & purification / Q000502:physiology
chemical_list: C082909:ECE1 protein, Candida albicans; D005656:Fungal Proteins; C118102:HWP1 protein, Candida albicans; D008562:Membrane Glycoproteins; D016282:Aspartic Acid Endopeptidases; C090755:SAP5 protein, Candida albicans
keywords: Candida albicans; bacteria; biofilm; co-culture