Bacteriophage endolysins have been shown to hold great promise as new antibacterial agents for animal and human health in food preservation. In the present study, endolysin from Staphylococcus aureus subsp. aureus ATCC 27692-B1 bacteriophage 52 (LysSA52) was cloned, expressed, and characterized for its antimicrobial properties. Following DNA extraction from bacteriophage 52, a 1446-bp DNA fragment containing the endolysin gene (lysSA52) was obtained by PCR amplification and cloned into pET SUMO expression vector. The positive clone was validated by sequencing and open-reading frame analysis. The LysSA52 sequence shared high homology with staphylococcal phage endolysins of the SA12, SA13, and DSW2 phages and others. The cloned lysSA52 gene encoding 481 amino acids endolysin was expressed in Escherichia coli BL21 with a calculated molecular mass of 66 kDa (LysSA52). This recombinant endolysin LysSA52 exhibited lytic activity against 8 of 10 Gram-positive bacteria via agar spot-on lawn antimicrobial assay, including methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, Streptococcus pneumonia, Streptococcus pyogenes, Enterococcus faecium, Enterococcus faecalis, and Bacillus atrophaeus. In addition, the 0.50 mg/mL, LysSA52 endolysins reduced about 60% of the biofilms of S. aureus and S. epidermidis established on a microtiter plate in 12 h treatment. The data from this study indicate that LysSA52 endolysin could be used as an antibacterial protein to prevent and treat infections caused by staphylococci and several other Gram-positive pathogenic bacteria irrespective of their antibiotic resistance.

噬菌体内溶素已被证明作为新型抗菌剂在食品保存方面对动物和人类健康具有巨大的前景。在本研究中，来自金黄色葡萄球菌亚种的细胞内溶素。对金黄色葡萄球菌ATCC 27692-B1 噬菌体 52 (LysSA52) 进行了克隆、表达和抗菌特性表征。从噬菌体52中提取DNA后，通过PCR扩增获得含有细胞内溶素基因( lysSA52 )的1446bp DNA片段，并将其克隆至pET SUMO表达载体中。通过测序和开放阅读框分析验证阳性克隆。LysSA52 序列与 SA12、SA13 和 DSW2 噬菌体等的葡萄球菌噬菌体内溶素具有高度同源性。克隆的编码481个氨基酸内溶素的lys SA52基因在大肠杆菌BL21中表达，计算分子量为66 kDa（LysSA52）。该重组细胞内溶素 LysSA52 通过琼脂点滴草坪抗菌测定对 10 种革兰氏阳性细菌中的 8 种表现出溶解活性，包括耐甲氧西林金黄色葡萄球菌、表皮葡萄球菌、溶血葡萄球菌、肺炎链球菌、化脓性链球菌、屎肠球菌、粪肠球菌和萎缩芽孢杆菌。此外，0.50 mg/mL LysSA52 内溶素在 12 小时处理中减少了微量滴定板上建立的金黄色葡萄球菌和表皮葡萄球菌生物膜的约 60%。这项研究的数据表明，LysSA52 内溶素可用作抗菌蛋白，用于预防和治疗葡萄球菌和其他几种革兰氏阳性病原菌引起的感染，无论其抗生素耐药性如何。