Abstract：
This study was designed to assess the possibility of using bacteriophage-encoded endolysins for controlling planktonic and biofilm cells. The endolysins, LysEP114 and LysEP135, were obtained from plasmid vectors containing the endolysin genes derived from Escherichia coli phages. The high identity (>96%) was observed between LysEP114 and LysEP135. LysEP114 and LysEP135 were characterized by pH, thermal, and lactic acid stability, lytic spectrum, antibacterial activity, and biofilm eradication. The molecular masses of LysEP114 and LysEP135 were 18.2 kDa, identified as muramidases. LysEP114 and LysEP135 showed high lytic activity against the outer membrane-permeabilized E. coli KCCM 40405 at below 37°C, between pH 5 to 11, and below 70 mM of lactic acid. LysEP114 and LysEP135 showed the broad rang of lytic activity against E. coli KACC 10115, S. Typhimurium KCCM 40253, S. Typhimurium CCARM 8009, tetracycline-resistant S. Typhimurium, polymyxin B-resistant S. Typhimurium, chloramphenicol-resistant S. Typhimurium, K. pneumoniae ATCC 23357, K. pneumoniae CCARM 10237, and Shigella boydii KACC 10792. LysEP114 and LysEP135 effectively reduced the numbers of planktonic E. coli KCCM by 1.7 and 2.1 log, respectively, when treated with 50 mM lactic acid. The numbers of biofilm cells were reduced from 7.3 to 4.1 log CFU/ml and 2.2 log CFU/ml, respectively, when treated with LysEP114- and LysEP135 in the presence of 50 mM lactic acid. The results suggest that the endolysins in combination with lactic acid could be potential alternative therapeutic agents for controlling planktonic and biofilm cells.
摘要：
这项研究旨在评估使用噬菌体编码的内溶素控制浮游和生物膜细胞的可能性。内溶素，LysEP114和LysEP135是从含有来自大肠杆菌噬菌体的内溶素基因的质粒载体获得的。在LysEP114和LysEP135之间观察到高同一性(>96%)。LysEP114和LysEP135以pH为特征，热,和乳酸稳定性，裂解光谱，抗菌活性，和生物膜根除。LysEP114和LysEP135的分子量为18.2kDa,鉴定为鼠酰胺酶。LysEP114和LysEP135在低于37°C时对外膜透化大肠杆菌KCCM40405显示出高裂解活性，在pH5至11之间，并且低于70mM的乳酸。LysEP114和LysEP135对大肠杆菌KACC10115，鼠伤寒沙门氏菌KCCM40253，鼠伤寒沙门氏菌CCARM8009，四环素抗性鼠伤寒沙门氏菌，多粘菌素B抗性鼠伤寒沙门氏菌，耐氯霉素的鼠伤寒沙门氏菌，肺炎克雷伯菌ATCC23357、肺炎克雷伯菌CCCARM10237和博氏志贺氏菌KACC10792。LysEP114和LysEP135有效地将浮游大肠杆菌KCCM的数量减少了1.7和2.1个log，分别,当用50mM乳酸处理时。生物膜细胞的数量从7.3减少到4.1logCFU/ml和2.2logCFU/ml，分别,当在50mM乳酸存在下用LysEP114-和LysEP135处理时。结果表明，内溶素与乳酸的组合可能是控制浮游和生物膜细胞的潜在替代治疗剂。
