Biofilm inhibition.

Candida albicans 17-88, 5 × 10⁵ cell/ml, was allowed to form biofilm for 16 h, washed three times with 200 μl phosphate-buffered saline (PBS), and subsequently challenged immediately or following 24 h with the test articles to assess effects on biofilm formation or preformed biofilm inhibition, respectively (39). The dAMPs or fluconazole were diluted in RPMI 1640 with a final well concentration of 64, 32, 16, or 8 μg/ml and compared to control wells containing only RPMI. Each condition contained 3 replicates. Following a total incubation time of 40 h, the wells were washed three times with 200 μl PBS, and then 200 μl XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide salt) and menadione solution were added to each well. The plates were incubated at 37°C for 2 h and absorbance read, and data presented, at 490 nm for assessment of inhibition of metabolism. The endpoint was a statistically significant reduction compared to an untreated concurrent control.