Antibiotic resistance has become a major risk to community health over last few years because of antibiotics overuse around the globe and lack of new antibiotics development. Phages and their lytic enzymes are considered as an effective alternative of antibiotics to control drug resistant bacterial pathogens. Endolysins prove to be a promising class of antibacterials due to their specificity and less chances of resistance development in bacterial pathogens. Though large number of endolysins has been reported against gram positive bacteria, very few reported against gram negative bacteria due to the presence of outer membrane, which acts as physical barrier against endolysin attack to peptidoglycan. In the current study, we have expressed endolysin (RL_Lys) and holin fused at the N terminus of endolysin (RL_Hlys) from RL phage infecting multi drug resistant (MDR) Pseudomonas aeruginosa. Both endolysin variants were found active against wide range of MDR strains P. aeruginosa, Klebsella pneumonia, Salmonella Sp. and Methicillin Resistant Staphylococcus aureus (MRSA). Broth reduction assay showed that RL_Hlys is more active than RL_Lys due to presence of holin, which assist the endolysin access towards cell wall. The protein ligand docking and molecular dynamic simulation results showed that C- terminus region of endolysin play vital role in cell wall binding and even in the absence of holin, hydrolyze a broad range of gram negative bacterial pathogens. The significant activity of RL-Lys and RL_Hlys against a broad range of MDR gram negative and positive bacterial pathogens makes them good candidates for antibiotic alternatives.

过去几年，由于抗生素在全球范围内过度使用以及缺乏新的抗生素开发，抗生素耐药性已成为社区健康的主要风险。噬菌体及其裂解酶被认为是控制耐药细菌病原体的有效抗生素替代品。内溶素被证明是一类很有前途的抗菌剂，因为它们具有特异性并且在细菌病原体中产生抗药性的机会较小。尽管已经报道了大量的内溶素对抗革兰氏阳性菌，但由于外膜的存在，很少有报道对抗革兰氏阴性菌，外膜作为内溶素攻击肽聚糖的物理屏障。在目前的研究中，铜绿假单胞菌。发现这两种内溶素变体对广泛的 MDR 菌株铜绿假单胞菌、肺炎克雷伯菌、沙门氏菌属具有活性。和耐甲氧西林金黄色葡萄球菌(MRSA)。肉汤还原试验表明，RL_Hlys 比 RL_Lys 更活跃，这是由于 holin 的存在，这有助于内溶素进入细胞壁。蛋白质配体对接和分子动力学模拟结果表明，内溶素的C端区域在细胞壁结合中起着至关重要的作用，即使在没有孔蛋白的情况下，也能水解广泛的革兰氏阴性细菌病原体。RL-Lys 和 RL_Hlys 对多种 MDR 革兰氏阴性和阳性细菌病原体的显着活性使其成为抗生素替代品的良好候选者。