Ragupathi Naveen Kumar Devanga, Sethuvel Dhiviya Prabaa Muthuirulandi, Anandan Shalini, Murugan Dhivya, Asokan Kalaiarasi, Neethi Mohan Ramya Gajaraj, Vasudevan Karthick, D Thirumal Kumar, C George Priya Doss, Veeraraghavan Balaji
Department of Clinical Microbiology, Christian Medical College, Vellore - 632004, India.
School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore - 632014, India.
Access Microbiol. 2020 Feb 17;2(4):acmi000103. doi: 10.1099/acmi.0.000103. eCollection 2020.
Recent findings demonstrate the origin of the plasmid-mediated colistin resistance gene from aeromonads. The present study aimed to screen for plasmid-mediated colistin resistance among 30 clinical multidrug-resistant (MDR) spp. PCR was used to screen for the presence of , , and , which revealed in a colistin-susceptible isolate (FC951). All other isolates were negative for . Sequencing of FC951 revealed that the () identified was different from previously reported variants and had 95.62 and 95.28 % nucleotide similarity with and . Hybrid assembly using IonTorrent and MinION reads revealed structural genetic information for with an insertion of IS within the gene. Due to this, was non-expressive, which makes FC951 susceptible to colistin. Further, sequence and protein structural analysis confirmed the new variant. To the best of our knowledge, this is the first report on a novel variant from India. The significant role of -like genes in different species remains unknown and requires additional investigation to obtains insights into the mechanism of colistin resistance.
最近的研究结果表明，质粒介导的黏菌素耐药基因起源于气单胞菌。本研究旨在筛选30株临床多重耐药（MDR）菌中的质粒介导黏菌素耐药性。采用聚合酶链反应（PCR）筛选mcr-1、mcr-2、mcr-3和mcr-4的存在情况，结果在一株对黏菌素敏感的分离株（FC951）中发现了mcr-1。所有其他分离株的mcr-1均为阴性。对FC951进行测序发现，鉴定出的mcr-1与先前报道的变体不同，与mcr-1和mcr-3的核苷酸相似性分别为95.62%和95.28%。使用IonTorrent和MinION读数进行混合组装，揭示了mcr-1的结构遗传信息，该基因内插入了一段插入序列（IS）。因此，mcr-1无表达，这使得FC951对黏菌素敏感。此外，mcr-1序列和蛋白质结构分析证实了这一新变体。据我们所知，这是印度首次报道新型mcr-1变体。类mcr-1基因在不同气单胞菌物种中的重要作用尚不清楚，需要进一步研究以深入了解黏菌素耐药机制。
