Author(s): Subhashini D* and Geetha V
Antimicrobial peptides (AMPS) like Lactoferrin and parasin was selected to determine synergistic antibacterial activity against mastitis causing pathogens was framed as a primary objective in the study. The synergistic activity of a lactoferrin and a parasin on the test bacteria was determined by the standard checker board titration method. The results revealed that Staphylococcus aureus and Escherichia coli showed complete synergistic effect for lactoferrin and parasin combination. E. coli showed complete synergy with the mean MIC value 0.03 μg/ml and with best FICI value 0.24 (p<0.5). And S. aureus showed complete synergy with the mean MIC value 0.12 μg/ml and with best FICI value 0.72 (p<0.5). The synergistic antibacterial activity of AMPs in combination was reported with substantial evidence against a wide variety of Gram-negative and Gram-positive bacteria. The antibacterial activity of AMPs obtained from lactoferrin and parasin in combinations was evaluated against the test organisms by well diffusion method. Maximum inhibitory zones were recorded for lactoferrin and parasin (50µg concentration). Depending on the concentration gradient of AMPs, increase in inhibitory zones was recorded. Inhibitory zones of about 9mm, 12mm, 18mm and 22mm was obtained for its respected concentrations (20µg, 30µg, 40µg and 50µg) against E. coli. Similarly, respected inhibitory zones of like 9mm, 11mm, 19mm and 21mm was obtained for the tested concentrations viz., 20µg, 30µg, 40µg and 50µg) against S. aureus. The obtained results were substantially supported when compared with the checker board titration method to describe the synergistic characters of the tested AMPs.