*2.2. Citropin 1.1*

Citropin 1.1 is a wide-spectrum amphibian antimicrobial cationic peptide produced by the glands of the green tree frog, *Litoria citropa* [21].

An experimental study conducted in 2006 evaluated the efficacy of citropin 1.1, minocycline, and rifampicin in the prevention of *S. aureus* central venous catheter (CVC)-associated infection using the antibiotic-lock technique. In vitro studies show that biofilms were strongly affected by the presence of citropin 1.1, which also acts synergistically with hydrophobic antibiotics. In vivo studies confirm the same results; in fact, citropin 1.1 alone not only reduced bacterial load on the CVC from 10<sup>7</sup> to 103 CFU/mL but also enhanced the effect of commonly used antibiotics, reducing bacterial load to 101 CFU/mL [22].
