title: Resistance ofCandida albicansBiofilms to Drugs and the Host Immune System.
abstract: BACKGROUND
  Candida albicansis a commensal fungus that resides on mucosal surfaces and in the gastrointestinal and genitourinary tracts in humans. However, it can cause an infection when the immune system of the host is impaired or if a niche becomes available. ManyC. albicansinfections are due to the organism's ability to form a biofilm on implanted medical devices. A biofilm represents an optimal medium for the growth ofC. albicansas it allows cells to be enclosed by a self-produced extracellular matrix (ECM).
  
  
  OBJECTIVE
  The present work investigated certain aspects of the resistance ofC. albicansbiofilms to drugs and the host immune system.
  
  
  RESULTS
  An ECM was found to provide the infrastructure for biofilm formation, prevent disaggregation, and shield encapsulatedC. albicanscells from antifungal drugs and the host's immune system. By influencingFKS1and upregulating multiple glucan modification genes, β-1, 3-glucan, an important component of ECM, was shown to be responsible for many of the biofilm's drug-resistant properties. On being engulfed by ECM, the fungal cell was found to switch from glycolysis to gluconeogenesis. Resembling the cellular response to starvation, this was followed by the activation of the glyoxylate cycle that allowed the use of simple molecules as energy sources.
  
  
  CONCLUSIONS
  Mature biofilms were found to be much more resistant to antifungal agents and the host immune system than free cells. The factors responsible for high resistance included the complex architecture of biofilms, ECM, increased expression of drug efflux pumps, and metabolic plasticity.
authors.affiliation: Infectomics Cluster, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Malaysia.
authors.forename: Doblin
authors.initials: D
authors.lastname: Sandai
authors.affiliation: Infectomics Cluster, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Malaysia.
authors.forename: Yasser M
authors.initials: YM
authors.lastname: Tabana
authors.affiliation: School of Pharmacy, Lebanese American University, Byblos, Lebanon.
authors.forename: Ahmad El
authors.initials: AE
authors.lastname: Ouweini
authors.affiliation: Infectomics Cluster, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Malaysia.
authors.forename: Ishola Oluwaseun
authors.initials: IO
authors.lastname: Ayodeji
keywords: Arsenite Transporting ATPases; Biofilms; Candida albicans; Fungal Drug Resistance; Glucans