Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran.
Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
Microb Pathog. 2019 Oct;135:103646. doi: 10.1016/j.micpath.2019.103646. Epub 2019 Jul 22.
Escherichia coli is a gram-negative bacterium and it causes a variety of diseases in humans. It causes a wide range of clinical infections in humans; urinary tract infections is the most prevalent infection caused by uropathogenic Escherichia coli. In recent years, the observation of antibiotic-resistant genes such as resistance to colistin, makes the Escherichia coli resistant to antibiotics like colistin (polymyxin E), because of that the use of new therapies like peptide nucleic acid (PNA) has attracted the consideration of scientists. The aim of this study is the assessment of the inhibitory role of PNA against mcr-1 gene and reduction of mcr-1 gene expression and MIC in colistin resistant E. coli by PNA. NCBI database was used to design PNA. Our study was carried out on E. coli KP81 bacteria containing the mcr-1 gene. Microbroth dilution (MIC) method was used to survey phenotypic sensitivity and determine the sensitivity of the bacteria to the colistin antibiotic. E. coli KP81 isolates were further investigated by polymerase chain reaction to assess the presence of mcr-1 genes and target genes were quantified by real-time PCR assay using specific primers. The MIC result after treatment with specific PNA showed that the resistance to colistin reduced about three fold and the resistance level dropped from 32 μg/ml to 4 μg/ml. The expression analysis of mcr-1 gene in E. coli KP81 isolate indicates the PNA, 95% reduced the expression of the mcr-1 gene. Our observations showed that by inhibiting the expression of mcr-1, sensitivity to colistin can be defeated. Using higher concentrations of PNA and an in vivo study can reveal more clinical application of this method.
大肠杆菌是一种革兰氏阴性细菌，它会导致人类患上多种疾病。它会导致人类患上多种临床感染；尿路感染是由尿路致病性大肠杆菌引起的最常见感染。近年来，观察到对抗粘菌素等抗生素的耐药基因，使大肠杆菌对粘菌素（多粘菌素 E）等抗生素产生耐药性，因此，像肽核酸（PNA）这样的新疗法引起了科学家的关注。本研究的目的是评估 PNA 对 mcr-1 基因的抑制作用以及 PNA 降低耐粘菌素大肠杆菌中 mcr-1 基因表达和 MIC。使用 NCBI 数据库设计 PNA。我们的研究是在含有 mcr-1 基因的大肠杆菌 KP81 细菌上进行的。微量肉汤稀释（MIC）法用于检测表型敏感性，并确定细菌对粘菌素抗生素的敏感性。通过聚合酶链反应进一步研究大肠杆菌 KP81 分离株，以评估 mcr-1 基因的存在，并使用特异性引物通过实时 PCR 测定法对靶基因进行定量。用特异性 PNA 处理后的 MIC 结果表明，对粘菌素的耐药性降低了约三倍，耐药水平从 32μg/ml 降至 4μg/ml。大肠杆菌 KP81 分离株中 mcr-1 基因的表达分析表明，PNA 使 mcr-1 基因的表达减少了 95%。我们的观察结果表明，通过抑制 mcr-1 的表达，可以克服对粘菌素的敏感性。使用更高浓度的 PNA 和体内研究可以揭示这种方法更多的临床应用。
