Antibacterial Activity of RM12, a Tachykinin Derivative, Against Pseudomonas aeruginosa

Bacterial infections are increasing in recent years and developing with more resistance to antibiotics. There is a need of designing antimicrobial peptides (AMP) against these bacterial pathogens. In this study, we derived an AMP, substance P (SP) named RM12, from tachykinin protein obtained from an earlier developed transcriptome library of a teleost, Channa striatus. This, RM12 which is similar to SP was functional against multidrug resistance bacteria (MDR) or one of the ESKAPE pathogen, Pseudomonas aeruginosa ATCC 25668 which causes nosocomial infections in human beings. The RM12 peptide sequence obtained from tachykinin protein was screened using antimicrobial prediction programs, which showed the possible antimicrobial performance of RM12, thus the peptide was synthesized with 96.83% HPLC purity. The toxicity of RM12 was analyzed using human blood cells and human dermal fibroblast (HDF) cells that showed the safeties of RM12 usage. The antibacterial activities of RM12 including antibiofilm were determined using different assays and exhibited the peptide potent against the MDR or ESKAPE pathogen, P. aeruginosa ATCC 25668. Moreover, the mechanism of action of RM12 against P. aeruginosa ATCC 25668 was determined using field emission scanning electron microscopy and fluorescence assisted cell sorter flow cytometer analysis; both the analysis confirmed bacterial membrane disruption due to RM12. Further, in vitro infectivity assays were performed in HDF cells infected with P. aeruginosa ATCC 25668 that showed the longer duration, as well as the higher concentration of RM12, reduced the bacterial viability. Hence, it can be concluded that RM12 can be used as a potent antimicrobial source against the MDR or ESKAPE pathogen, P. aeruginosa ATCC 25668; however, further clinical trials need to be carried out to find out the possibility of RM12 usage in the pharmaceutical industry.