Biomolecules from snakes don’t often fight bacterial infections in mice, but a peptide called cathelicidin from a Burmese python (Python bivittatus) does just that. Cathelicidins are immune system peptides that help protect animals from microbial infections. Isolated mostly from humans and other mammals, they are being tested as possible antibacterial drugs, but their stability and longevity of action have been limited. In an effort to find better drug prospects, Yipeng Wang of Soochow University, Haining Yu of Dalian University of Technology, and coworkers found six novel cathelicidins from a new animal source, P. bivittatus, in a biomedical and genomic database. When they made the cathelicidins in a peptide synthesizer and tested them, they found that one called CATHPb1 is indeed more stable in blood serum and works longer in mice than its mammalian peptide relatives (J. Med. Chem. 2018, DOI: 10.1021/acs.jmedchem.8b00036). CATHPb1 protected mice from methicillin- and vancomycin-resistant Staphylococcus aureus infections when injected one day before or four hours after the mice were infected. It didn’t show significant toxicity, and it resists protease breakdown, suggesting that oral administration may be possible. The researchers believe the peptide’s favorable properties give it good prospects for development as an antibiotic to treat multi-drug-resistant Staph infections.