[Photo] Common Frog, Rana temporaria. (Credit: Image courtesy of Wikimedia Commons)

ScienceDaily (Jan. 23, 2008) ??? Researchers from Italy found that a naturally occurring agent in frog skin may inhibit multi-drug resistant bacterial strains associated with hospital-acquired infections.

Resistance to current antibiotic therapies is on the rise in both hospital and community settings. With some bacterial strains now resistant to every available drug, a return to the preantibiotic era in regard to such infections is cause for great concern. Researchers have identified antimicrobial peptides (AMPs) as one of the most promising candidates for future therapeutic use and they have found amphibian skin to be one of the richest sources of such AMPs.

Nosocomial infections are linked to various drug-resistant bacterial strains and are commonly acquired in a hospital setting as a secondary illness. In the study researchers tested five AMPs (temporins A, B, and G, esculentin 1b, and bombinin H2) from three different frog and toad species (Rana temporaria, Rana esculenta, and Bombina variegata) for antibacterial activity against multi-drug resistant strains often associated with human nosocomial infections. Initial results showed that all the peptides acted as antibacterial agents against the species tested. Further studies found that the temporins were more active against gram-positive bacteria; esculentin 1b produced an antibacterial response within 2 to 20 minutes of exposure, and bombinin H2 displayed similar activity toward all bacterial isolates.

“This peptide is an attractive molecule for use in the development of new compounds for the treatment of infectious diseases,” say the researchers.

Reference: M.L. Mangoni, G. Maisetta, M.D. Luca, L.M.H. Gaddi, S. Esin, W. Florio, F.L. Brancatisano, D. Barra, M. Campa, G. Batoni. 2008. Comparative analysis of the bactericidal activities of amphibian peptide analogues against multi-drug-resistant nosocomial bacterial strains. Antimicrobial Agents and Chemotherapy, 52. 1: 85-91.

Adapted from materials provided by American Society for Microbiology, via EurekAlert!, a service of AAAS.