New findings challenge the idea that each pathogen forms only a single type of biofilm, which can form inside the body, particularly on implanted medical devices, contributing to disease. The fungus Candida albicans can actually make two different biofilms, according to research published earlier this week (August 2) in PLoS Biology: while about 90 percent of the cells form traditional pathogenic biofilms, the other 10 percent comprised sexual biofilms—whose cells, unlike those of the pathogenic biofilms, are sexually competent.
Sexuality comes at a cost, however. The fungal cells of the sexual biofilm are susceptible to drugs and immune attacks, in contrast to the pathogenic biofilms, which are nearly impervious to antimicrobial agents, antibodies or white blood cells. Thus, while the majority of the biofilms could not be penetrated by the immune cells or antibiotics, the few sexual ones may provide a vulnerable target for attack. The two biofilms looked the same, but expressed different signaling pathways, according to the study.
"Having two outwardly similar, but functionally different, biofilms provides us with one means of finding out what makes the pathogenic biofilm resistant to all challenges, and the sexual biofilm nonresistant," study author David Soll, a biologist at the University of Iowa, said in a press release. "Whatever that difference is will represent a major target for future drug discovery."