Alexidine dihydrochloride displays activity against most Candida spp.; MIC values of ≤1.5 μg/mL are observed for all isolates tested under planktonic conditions, with the exception of Candida parapsilosis and Candida krusei. Interestingly, Alexidine dihydrochloride also displays striking activity against clinically relevant fluconazole-resistant Candida isolates: C. albicans (CA2, CA6, and CA10), C. glabrata (CG2 and CG5), C. parapsilosis (CP5), and C. auris (CAU-09 and CAU-03).
Inhibition of planktonic growth by Alexidine dihydrochloride reveals a complete inhibition of filamentation or proliferation of the imaged fungi. Alexidine dihydrochloride is able to decimate at low concentrations (1.5 to 6 μg/mL) mature biofilms of Candida, Cryptococcus, and Aspergillus spp. that are known to be resistant to almost all classes of antifungal drugs. In fact, at 10-fold-lower concentrations (150 ng/mL) of planktonic MICs, Alexidine dihydrochloride could inhibit lateral yeast formation and biofilm dispersal in C. albicans.
Alexidine dihydrochloride results in 50% killing of HUVECs and lung epithelial cells, at concentrations 5- to 10-fold higher than the MIC required to kill planktonically growing fungal pathogens.