郭国威 许坚锋 陈锦文

【摘要】 目的：了解ε-聚赖氨酸（ε-Poly-L-lysine，ε-PL）对大肠杆菌、金黄色葡萄球菌、粪肠球菌及铜绿假单胞菌等四种尿液中常见细菌的体外抑菌效果，并探讨其对尿蛋白测定的影响。

方法：使用肉汤稀释法将ε-PL倍比稀释后加入等量细菌悬液中，于35 ℃温箱内24 h后观察ε-PL对大肠杆菌、金黄色葡萄球菌、粪肠球菌、铜绿假单胞菌的最小抑菌浓度（MIC）。同时将不同浓度的ε-PL加入尿液中，分析其对尿蛋白测定的干扰。结果：ε-PL溶液对大肠杆菌、金黄色葡萄球菌、粪肠球菌及铜绿假单胞菌等尿液中常见细菌的体外抑菌均有明显效果，MIC分别为0.02、0.01、0.04及0.01 mg/mL，其中ε-PL对金黄色葡萄球菌和铜绿假单胞菌的抑菌效果最好；原尿液、加蒸馏水尿液中尿蛋白含量比较，差异无统计学意义（P>0.05）；含不同浓度ε-PL尿液标本中尿蛋白含量均明显高于原尿液，比较差异均有统计学意义（P<0.05），且随着尿液中ε-PL浓度的增加对蛋白测定的影响就越大。结论：ε-PL能有效抑制尿液常见细菌的生长，能用于尿液样本防腐，但不适用于24 h尿蛋白测定标本的防腐。

【关键词】 ε-聚赖氨酸； 最小抑菌浓度； 尿蛋白； 干扰

【Abstract】 Objective：To understand the in vitro bacteriostatic effect of ε-Poly-L-lysine（ε-PL） on four common bacteria in urine，including Escherichia coli，Staphylococcus aureus，Enterococcus faecalis and Pseudomonas aeruginosa，and to explore its influence on urinary protein determination.Method：The broth dilution method was used to dilute the ratio of ε-PL and add the same amount of bacterial suspension.The MIC of ε-PL to Escherichia coli，Staphylococcus aureus，Enterococcus faecalis and Pseudomonas aeruginosa was observed after 24 hours in the incubator at 35℃.At the same time，different concentrations of ε-PL were added into the urine to analyze the interference of urine protein determination.Result：Solution ε-PL has obvious bacteriostatic effect on common bacteria in urine，such as Escherichia coli，Staphylococcus aureus，Enterococcus faecalis and Pseudomonas aeruginosa，MIC were 0.02，0.01，0.04 and 0.01 mg/mL respectively，among them，ε-PL had the best bacteriostatic effect on Staphylococcus aureus and Pseudomonas aeruginosa.The urine protein in original urine and urine added with distilled water was compared，the differences was not statistically significant（P>0.05）.The urine protein in urine samples containing different concentrations of ε-PL were significantly higher than those of original urine，the differences were statistically significant（P<0.05），and the higher the concentration of ε-PL in urine，the greater the effect on the determination of protein.Conclusion：ε-PL can effectively inhibit the growth of common bacteria in urine，and can be used for the preservation of urine samples，but not for the preservation of 24 hours urine protein test specimens.

【Key words】 ε-Poly-L-lysine； MIC； Urine protein； Interference

First-authors address：Guangdong Hospital of Traditional Chinese Medicine Zhuhai Hospital，Zhuhai 519015，China

doi：10.3969/j.issn.1674-4985.2018.33.038

ε-聚赖氨酸（ε-Poly-L-lysine，ε-PL）是1977年由日本科学家在放线菌培养过滤液中发现的一种新型天然防腐剂，是由25～30个赖氨酸残基的同型单体聚合物组成，赖氨酸通过α-羧基和ε-氨基形成的酰胺键连接在一起而成[1]。ε-PL是由微生物分泌的、具广谱抗微生物活性的多肽性类物质，易被生物降解，对人体无害，目前广泛应用于食品防腐中[2]。尿液樣本在常温下长时间存放会有细菌生长从而影响尿液某些成分发生改变而影响检验结果，为了保证检测结果的准确性，通常采用加入防腐剂的方法来抑制细菌生长。……