Regulator of Fungal Biofilm Identified

August 7, 2006 

Like all biomaterials, the plastic tubes, or catheters, that are inserted into those who are sick or frail can become colonized over time by microbes.  When the colonizers are single celled fungi of the genus Candida, healthcare workers waste no time in replacing the catheter.  And with good reason.  Candida biofilms, the tightly packed fungal communities that adhere to the tubes, are extremely resistant to antifungal agents and can lead to infections that are expensive to treat and potentially deadly.  Replacing a tainted catheter, however, may not be easy for all people, especially those with blood clotting problems or a limited number of accessible veins.  Thus, there is a great need for approaches that eliminate Candida while the catheter remains attached to the body.  In the July issue of the journal Infection and Immunity, NIDCR grantees and colleagues report an enzyme produced by the species Candida albicans, one of the main fungal pathogens in people, might be the answer to controlling its biofilm.  The scientists demonstrated that the enzyme, called alcohol dehydrogenase, naturally restricts the ability of C. albicans to form thick, mature biofilms.  Because the enzyme is known biologically to catalyze the production of ethanol, the group followed up in animal studies and showed that ethanol greatly inhibited C. albicans biofilm formation on indwelling catheters.  Interestingly, ethanol had no inhibitory effect on the biofilms of two commonly studied bacteria.  According to the authors, their data marks the first report of a specific regulator of a fungal biofilm and may point to novel treatment strategies for fungal infections.