LAUSR

BACKGROUND Animals and animal-derived products have been used as traditional medicine for centuries based on belief that such animals possess properties to counter disease. Intriguingly, animals such as snakes feed on germ-infested rodents, while water monitor lizards thrive on rotten matter in unhygienic conditions. We hypothesized that such creatures survive the assault of superbugs and are able to fend off disease by producing antimicrobial substances. The overall aim of this study was to investigate the potential antibacterial activity in sera/lysates of animals living in polluted environments. METHODS Among various animals, we selected snake (Reticulatus malayanus) that feed on germ-infested rodents, rats (Rattus rattus), water monitor lizard (Varanus salvator), frog (Lithobates catesbeianus), fish (Oreochromis mossambicus), chicken (Gallus gallus domesticus), and pigeon (Columba livia). Species were dissected and their organ lysates/sera were collected. Crude extracts were tested for bactericidal effects against neuropathogenic E. coli K1, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Pseudomonas aeruginosa, Bacillus cereus and Klebsiella pneumoniae. To determine whether lysates/sera protect human cells against bacterial-mediated damage, cytotoxicity assays were performed by measuring lactate dehydrogenase release as an indicator of cell death. Lysates/sera were partially characterized using heat-treatment and pronase-treatment and peptide sequences were determined using Liquid chromatography mass spectrometry (LC-MS). RESULTS The findings revealed that snake and water monitor lizard sera exhibited potent broad-spectrum bactericidal effects against all bacteria tested. Heat inactivation and pronase-treatment inhibited bactericidal effects indicating that activity is heat-labile and pronase-sensitive suggesting that active molecules are proteinaceous in nature. LCMS analyses revealed the molecular identities of peptides. CONCLUSION The results revealed that python that feed on germ-infested rodents and water monitor lizards that feed on rotten organic waste possess antibacterial activity in a heat-sensitive manner and several peptides were identified through LC-MS. We hope that the discovery of antibacterial activity in the sera of animals living in polluted environments will stimulate research in finding antibacterial agents from unusual sources as this has potential for the development of novel strategies in the control of infectious diseases.