中文摘要：由于常见细菌病原体的抗生素耐药率越来越高，噬菌体内溶素及其衍生物具有很强的抗菌剂潜力。肽聚糖降解肽酶CHAPk是葡萄球菌噬菌体K内溶素（LysK）的一种截短衍生物，能很好地防止和破坏葡萄球菌生物膜。然而，先前研究发现消除固定相细胞群所需的CHAPk浓度比对数相细胞高4倍，而CHAPk介导的固定相细胞裂解比对数相培养慢。本文将含有CHAPk的165个氨基酸片段与含有细菌素溶葡萄球菌酶细胞结合域的136个氨基酸片段融合，在载体pET28a中产生一种命名为CHAPk-SH3blys的嵌合酶。嵌合蛋白的浓度低至5μg/mL，即可令7日龄的培养物浊度降低，而原始CHAPk至少需要20μg/mL才能达到这一效果。当用在7日龄的液体培养物时，嵌合酶的MIC比CHAPk低16倍。预防生物被膜方面，1μg/mL的嵌合酶浓度已足够，而CHAPk则需要125μg/mL。此外，使用5μg/mL浓度4小时，嵌合酶完全破坏生物膜，而CHAPk在此浓度下只能部分破坏。研究表明，溶葡萄球菌酶的细胞结合域可以增强噬菌体内溶素CHAPk对固着葡萄球菌细胞的效果。
外文摘要：Bacteriophage endolysins and their derivatives have strong potential as antibacterial agents considering the increasing prevalence of antibiotic resistance in common bacterial pathogens. The peptidoglycan degrading peptidase CHAPk, a truncated derivate of staphylococcal phage K endolysin (LysK), has proven efficacy in preventing and disrupting staphylococcal biofilms. Nevertheless, the concentration of CHAPk required to eliminate populations of stationary-phase cells was previously found to be four-fold higher than that for log-phase cells. Moreover, CHAPk-mediated lysis of stationary-phase cells was observed to be slower than for log-phase cultures. In the present study, we report the fusion of a 165 amino acid fragment containing CHAPk with a 136 amino acid fragment containing the cell-binding domain of the bacteriocin lysostaphin to create a chimeric enzyme designated CHAPk-SH3blys in the vector pET28a. The chimeric protein was employed in concentrations as low as 5 mu g/mL, producing a reduction in turbidity in 7-day-old cultures, whereas the original CHAPk required at least 20 mu g/mL to achieve this. Where 7-day old liquid cultures were used, the chimeric enzyme exhibited a 16-fold lower MIC than CHAPk. In terms of biofilm prevention, a concentration of 1 mu g/mL of the chimeric enzyme was sufficient, whereas for CHAPk, 125 mu g/mL was needed. Moreover, the chimeric enzyme exhibited total biofilm disruption when 5 mu g/mL was employed in 4-h assays, whereas CHAPk could only partially disrupt the biofilms at this concentration. This study demonstrates that the cell-binding domain from lysostaphin can make the phage endolysin CHAPk more effective against sessile staphylococcal cells.
外文关键词：endolysins；S. aureus；LysK；lysostaphin；biofilms；phage therapy
作者：Arroyo-Moreno, S；Begley, M；Dembicka, K；Coffey, A
作者单位：Munster Technol Univ；Univ Coll
期刊名称：ANTIBIOTICS-BASEL
期刊影响因子：3.893
出版年份：2021
出版刊次：6
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