BACKGROUND The antimicrobial resistance of clinical, environmental and control strains of the WHO "Priority 1: Critical group" organisms, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa to various classes of antibiotics, colistin and surfactin (biosurfactant) was determined. METHODS Acinetobacter baumannii was isolated from environmental samples and antibiotic resistance profiling was performed to classify the test organisms [A. baumannii (n = 6), P. aeruginosa (n = 5), E. coli (n = 7) and K. pneumoniae (n = 7)] as multidrug resistant (MDR) or extreme drug resistant (XDR). All the bacterial isolates (n = 25) were screened for colistin resistance and the mobilised colistin resistance (mcr) genes. Biosurfactants produced by Bacillus amyloliquefaciens ST34 were solvent extracted and characterised using ultra-performance liquid chromatography (UPLC) coupled to electrospray ionisation mass spectrometry (ESI-MS). The susceptibility of strains, exhibiting antibiotic and colistin resistance, to the crude surfactin extract (cell-free supernatant) was then determined. RESULTS Antibiotic resistance profiling classified four A. baumannii (67%), one K. pneumoniae (15%) and one P. aeruginosa (20%) isolate as XDR, with one E. coli (15%) and three K. pneumoniae (43%) strains classified as MDR. Many of the isolates [A. baumannii (25%), E. coli (80%), K. pneumoniae (100%) and P. aeruginosa (100%)] exhibited colistin resistance [minimum inhibitory concentrations (MICs) ≥ 4 mg/L]; however, only one E. coli strain isolated from a clinical environment harboured the mcr-1 gene. UPLC-MS analysis then indicated that the B. amyloliquefaciens ST34 produced C13-16 surfactin analogues, which were identified as Srf1 to Srf5. The crude surfactin extract (10.00 mg/mL) retained antimicrobial activity (100%) against the MDR, XDR and colistin resistant A. baumannii, P. aeruginosa, E. coli and K. pneumoniae strains. CONCLUSION Clinical, environmental and control strains of A. baumannii, P. aeruginosa, E. coli and K. pneumoniae exhibiting MDR and XDR profiles and colistin resistance, were susceptible to surfactin analogues, confirming that this lipopeptide shows promise for application in clinical settings.

中文翻译：

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探索世界卫生组织关键优先名单细菌菌株的抗菌药物耐药性概况。

背景 确定了世界卫生组织“优先级 1：关键组”生物体、鲍曼不动杆菌、大肠杆菌、肺炎克雷伯菌和铜绿假单胞菌的临床、环境和对照菌株对各类抗生素、粘菌素和表面活性剂（生物表面活性剂）的抗菌耐药性。方法 从环境样本中分离出鲍曼不动杆菌，并进行抗生素耐药性分析以对测试微生物进行分类 [A. 鲍曼不动杆菌 (n = 6)、铜绿假单胞菌 (n = 5)、大肠杆菌 (n = 7) 和肺炎克雷伯菌 (n = 7)] 具有多重耐药性 (MDR) 或极端耐药性 (XDR)。对所有细菌分离株 (n = 25) 进行了粘菌素抗性和动员的粘菌素抗性 (mcr) 基因的筛选。对解淀粉芽孢杆菌 ST34 产生的生物表面活性剂进行溶剂萃取，并使用超高效液相色谱 (UPLC) 与电喷雾电离质谱 (ESI-MS) 联用进行表征。然后测定表现出抗生素和粘菌素抗性的菌株对粗表面活性素提取物（无细胞上清液）的敏感性。结果 抗生素耐药性分析将 4 种鲍曼不动杆菌 (67%)、1 种肺炎克雷伯菌 (15%) 和 1 种铜绿假单胞菌 (20%) 菌株分类为 XDR，其中 1 种大肠杆菌 (15%) 和 3 种肺炎克雷伯菌 ( 43%）菌株被归类为MDR。许多分离株[A. 鲍曼不动杆菌 (25%)、大肠杆菌 (80%)、肺炎克雷伯菌 (100%) 和铜绿假单胞菌 (100%)] 表现出粘菌素耐药性 [最低抑菌浓度 (MIC) ≥ 4 mg/L]；然而，只有一种从临床环境中分离出来的大肠杆菌菌株含有 mcr-1 基因。UPLC-MS分析表明解淀粉芽孢杆菌ST34产生C13-16表面活性素类似物，被鉴定为Srf1至Srf5。粗表面活性素提取物 (10.00 mg/mL) 对 MDR、XDR 和粘菌素耐药的鲍曼不动杆菌、铜绿假单胞菌、大肠杆菌和肺炎克雷伯菌菌株保留了抗菌活性 (100%)。结论 表现出 MDR 和 XDR 特征以及粘菌素耐药性的鲍曼不动杆菌、铜绿假单胞菌、大肠杆菌和肺炎克雷伯菌的临床、环境和对照菌株对表面活性素类似物敏感，证实了这种脂肽在临床环境中的应用前景。