中文摘要：金黄色葡萄球菌是一种臭名昭著的食源性病原体，能产生包括耐热肠毒素在内的各种毒素，形成生物膜，进化为耐甲氧西林金黄色葡萄球菌(MRSA)等耐多药菌株，对抗抗生素，威胁公共健康，越来越多地引起了研究人员和食品工业对生物防治的兴趣。近年来，噬菌体细胞裂解酶成为了新兴抗菌剂，它能降解细菌必需的细胞壁。本研究中，源自MRSA噬菌体GH15的细胞裂解酶LysGH15，及其单独的催化结构域CHAP（LysGH15），对金黄色葡萄球菌具有广泛的裂解谱，裂解了包括MRSA在内的6株金黄色葡萄球菌。LysGH15和CHAP（LysGH15）对一株MRSA菌株（MRSA 2701）表现出不同的特性，在不同的条件下（LysGH15为35℃，pH6.0；CHAP（LysGH15）为40℃，pH9.0）活性最高。特别是两种酶对食品中NaCl浓度的敏感性不同，其中500mm的NaCl对LysGH15的有效裂解必不可少，而高浓度的NaCl则削弱了CHAP（LysGH15）的活性。CHAP（LysGH15）对NaCl的敏感性和较高的最适抗菌pH值（9.0）使其能用于鲜肉等低盐、非酸性食品中，解决了食品工业的一个难题。LysGH15和CHAP（LysGH15）分别在高盐食品和低盐食品中表现出良好的生物防治效果。用0.4nmol/cm（2）的LysGH15和CHAP（LysGH15）分别处理腊肉和新鲜猪肉，2h后能有效地将MRSA从10（4）降至0 CFU/cm（2）。
外文摘要：Staphylococcus aureus is a notorious foodborne pathogen capable of producing various toxins including heat-stable enterotoxin, forming biofilm, evolving to multidrug-resistant strains including methicillin-resistant S. aureus (MRSA) against antibiotics, and threatening public health, of which the biocontrol garners increasing interest from both researchers and food industry. Recently, bacteriophage lysins, degrading cell wall that is indispensable for bacteria, are deemed promising antimicrobial agents. In this work, the lysin LysGH15 from MRSA phage GH15 demonstrated a broad lytic spectrum to S. aureus, cleaving six test S. aureus strains including MRSA, as well as its catalytic domain CHAP(LysGH15) alone. LysGH15 and CHAP(LysGH15) exhibited different characteristics to one MRSA strain (MRSA 2701), reaching the highest activity at different conditions (35 degrees C and pH of 6.0 for LysGH15, 40 degrees C and pH of 9.0 for CHAP(LysGH15)). Especially, the different sensitivities of two enzymes to NaCl concentration in foods were found, where 500 mM of NaCl was indispensable for LysGH15's efficient lytic action while high concentration of NaCl impaired the activity of CHAP(LysGH15). The susceptibility to NaCl and high optimal antimicrobial pH (9.0) of CHAP(LysGH15) enabled its application in low-salt and non-acid foods such as fresh meat, of which the preservation is always an issue in food industry. LysGH15 and CHAP(LysGH15) presented a promising biocontrol effect in high-salt food and low-salt food, respectively. The 0.4 nmol/cm(2) of LysGH15 and CHAP(LysGH15) were applied in Chinese bacon and fresh pork, where they could efficiently decrease MRSA from 10(4) to 0 CFU/cm(2) after 2 h (LysGH15 to bacon, and CHAP(LysGH15) to fresh pork).
外文关键词：Staphylococcus aureus；Lysin；High-salt food；Low-salt food；Biopreservation
作者：Yan, JA；Yang, RJ；Yu, SH；Zhao, W
作者单位：Jiangnan Univ
期刊名称：FOOD BIOSCIENCE
期刊影响因子：3.067
出版年份：2021
出版刊次：41
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