In this study susceptibility to different antimicrobial peptides was investigated on colistin-susceptible and colistin-resistant identical pulsotype strains of KPC-2 producing Klebsiella pneumoniae ST258 as well as colistin-susceptible and colistin-resistant Enterobacter asburiae strains isolated from clinical samples. In our test, bacteria were exposed to 50 mg/ml lactoferrin, lysozyme and protamine - cationic antimicrobial peptides belonging to innate immune system and having structural similarity to polymyxins - in separate reactions. After 18 hours incubation of colonies were counted. 40% of colistin-resistant K. pneumoniae strains and 97% of colistin-susceptible counterpart strains were lysed by protamine whereas 87% and 100% colony forming unit decrease by lysozyme was seen, respectively. In the case of colistin-resistant E. asburiae strains 1 log10 cell count increase were observed after treatment with lysozyme and 1.56 log10 after lactoferrin exposure compared to the initial number whereas the colistin-susceptible showed no relevant cell count increase. Our findings suggest that acquired colistin-resistance in Enterobacteriaceae is associated with tolerance against antimicrobial peptides.

中文翻译：

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抗菌肽对肺炎克雷伯氏菌和白色肠杆菌的大肠菌素敏感和大肠菌素耐药菌株的影响。

在这项研究中，研究对生产KPC-2的大肠埃希菌敏感和耐大肠菌素耐药性相同的脉冲型菌株产生肺炎克雷伯菌ST258以及从临床样本中分离出的大肠埃希菌敏感和耐大肠菌素的肠杆菌阿布里亚氏菌。在我们的测试中，细菌在单独的反应中暴露于50 mg / ml乳铁蛋白，溶菌酶和鱼精蛋白-属于先天免疫系统并与多粘菌素结构相似的阳离子抗菌肽。孵育18小时后，计数菌落。鱼精蛋白溶解了40％的大肠菌素耐药性肺炎克雷伯菌菌株和97％的大肠菌素易感对应菌株，而溶菌酶则分别减少了87％和100％的菌落形成单位。如果是大肠埃希菌，则为E. 与初始数量相比，溶菌酶处理后的阿斯布鲁菌菌株的细胞数增加了1 log10，乳铁蛋白暴露后的细菌数量增加了1.56 log10，而大肠菌素敏感性则没有相关的细胞数增加。我们的发现表明，肠杆菌科细菌获得性大肠菌素耐药性与对抗菌肽的耐受性有关。