ε-聚赖氨酸对鲍曼不动杆菌生长及生物膜形成的影响

目的 探究ε-聚赖氨酸(ε-poly-L-lysine, ε-PL)对鲍曼不动杆菌(Acinetobacter baumannii, Ab)生长和生物膜形成的影响；ε-PL对鲍曼不动杆菌抗菌机制的初步研究。方法 以鲍曼不动杆菌ATCC19606和鲍曼不动杆菌临床分离株为实验菌株，参考CLSI-M100文件中微量肉汤稀释法测定最低抑菌浓度(minimum inhibitory concentration, MIC)和最低杀菌浓度(minimum bactericidal concentration, MBC)，吸光度法测定鲍曼不动杆菌ATCC19606的生长曲线。通过结晶紫染色检测ε-PL对Ab生物膜形成的影响。比较测定药物处理前和药物处理后菌体丙二醛(MDA)和活性氧(ROS)含量。结果 ε-PL对ATCC19606和临床菌株的MIC均为4.096mg/mL，MBC均为8.192mg/mL。随着ε-PL浓度的增加，鲍曼不动杆菌的生长和生物膜的抑制作用越来越明显。 从抑菌-时间曲线结果来看，ε-PL在6h时明显抑制了鲍曼不动杆菌ATCC19606的浮游菌。鲍曼不动杆菌使用ε-PL作用后MDA和ROS含量升高。结论 ε-PL可有效抑制鲍曼不动杆菌的生长和生物膜的形成。使用ε-PL作用后可以使鲍曼不动杆菌菌体内产生大量ROS和MDA，提示ε-PL可能通过氧化作用发挥抑菌效果。

Effects of ε-poly-L-lysine on the growth and biofilm formation of #br# Acinetobacter baumannii

Objective To study the effects of ε-poly-L-lysine (ε-PL) on the growth and biofilm formation of Acinetobacter baumannii, and explore the cytostatic mechanism of ε-PL to Acinetobacter baumannii. Methods Acinetobacter baumannii standard strain ATCC19606 and Acinetobacter baumannii clinical strains were used as test strains. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC)were determined by using a micro broth dilution method according to CLSI-M100. The growth curve of each strain of Acinetobacter baumannii was observed by the spectrophotometry. The formation of biofilm of each strain was detected by the 96-well plate crystal violet dyeing method, the malondialdehyde (MDA) and reactive oxygen species (ROS) levels in Acinetobacter baumannii before and after treated with ε-PL were compared. Results The MIC of ε-PL for ATCC19606 and clinical strains was 4.096mg/mL, and the MBC was 8.192mg/mL. With the increase of ε-PL concentration, the inhibition of Acinetobacter baumannii growth and biofilm was more and more obvious. According to the bacteriostatic-time curve results, ε-PL had a significant inhibitory effect on the planktonic bacteria of Acinetobacter baumannii after 6h. The content of MDA and ROS of Acinetobacter baumannii was increased after the use of ε-PL. Conclusion ε-PL can effectively inhibit the growth of Acinetobacter baumannii and the formation of biofilm. The use of ε-PL can produce a large amount of ROS and MDA in Acinetobacter baumannii. It suggests that ε-PL may exert bacteriostatic effects through