Influence of serum and albumin on echinocandin in vitro potency and pharmacodynamics

The echinocandins target fungi by inhibiting the production of (1,3)-β-d-glucan, an essential component of the fungal cell wall. These agents have less toxicity to mammalian cells, as compared to other antifungals; however, they maintain potent activity against many pathogenic fungi, including polyene- and azole-resistant isolates. Members of this class are highly protein-bound, and the addition of serum or albumin to the growth medium has profound effects on their in vitro potency and pharmacodynamics. In addition, studies have demonstrated an association between in vitro activity, in the presence of serum, and outcomes in animal models of invasive fungal infections. Serum and albumin may also be useful to help detect echinocandin-resistant Candida isolates with point mutations in the gene that encodes for glucan synthase. Thus, in vitro studies evaluating echinocandins in the presence of protein can provide valuable insight regarding their potency and pharmacodynamics.