In vivo efficacy and molecular docking of designed peptide that exhibits potent antipneumococcal activity and synergises in combination with penicillin.

We have previously designed a series of antimicrobial peptides (AMPs) and in the current study， the in vivo therapeutic efficacy and toxicity were investigated. Among all the peptides， DM3 conferred protection to a substantial proportion of the lethally infected mice caused by a strain of penicillin-resistant Streptococcus pneumoniae. Synergism was reported and therapeutic efficacy was significantly enhanced when DM3 was formulated in combination with penicillin (PEN). No toxicity was observed in mice receiving these treatments. The in silico molecular docking study results showed that， DM3 has a strong affinity towards three protein targets; autolysin and pneumococcal surface protein A (pspA). Thus AMPs could serve as supporting therapeutics in combination with conventional antibiotics to enhance treatment outcome.