In vitro and in silico comparative evaluation of anti-Acinetobacter baumannii peptides

To control the infection caused by a multi-drug resistant bacterial pathogen, Acinetobacter baumannii, antimicrobial peptides (AMPs) are being considered as a viable option because of their broad range of antimicrobial activity and non-specific mode of action. However, high cost of synthesis of AMPs has led to the development of several computational tools to predict the biological and physicochemical properties of AMPs. In the present study, a comparative analysis has been done between in vitro activity of seven anti-Acinetobacter α-helical peptides with in silico prediction tools for studying antimicrobial related properties of AMPs. Database of Antimicrobial Activity and Structure of Peptides (DBAASP) and two algorithms, Support Vector Machine (SVM) and Random Forest (RF) of another server, Collection of Antimicrobial Peptides (CAMP) were compared with in vitro results of AMP/non-AMP nature of anti-Acinetobacter peptides. The results of the influence of biophysical properties of peptides on their antimicrobial activity suggested that amphipathicity is more important than spatial arrangement and charge of α-helical peptides. No correlation was observed between the MIC50 values and the hydropathy of AMPs. Based on the present study, it is suggested that with further refinements in the available servers/algorithms for correctly predicting the antimicrobial nature of the peptides, in silico tools can be used to assist the development of new antimicrobial agents.