First hybrid complete genome of Aeromonas veronii reveals chromosome-mediated novel structural variant mcr-3.30 from a human clinical sample
Naveen Kumar Devanga Ragupathi, Dhiviya Prabaa Muthuirulandi Sethuvel, Shalini Anandan, Dhivya Murugan, Kalaiarasi Asokan, Ramya Gajaraj Neethi Mohan, Karthick Vasudevan, D. Thirumal Kumar, C. George Priya Doss, Balaji Veeraraghavan
Abstract
Recent findings demonstrate the origin of the plasmid-mediated colistin resistance gene mcr-3 from aeromonads. The present study aimed to screen for plasmid-mediated colistin resistance among 30 clinical multidrug-resistant (MDR) Aeromonas spp. PCR was used to screen for the presence of mcr-1 , mcr-2 , mcr-3 and mcr-4 , which revealed mcr-3 in a colistin-susceptible isolate (FC951). All other isolates were negative for mcr . Sequencing of FC951 revealed that the mcr-3 ( mcr-3.30 ) identified was different from previously reported variants and had 95.62 and 95.28 % nucleotide similarity with mcr-3.3 and mcr-3.10 . Hybrid assembly using IonTorrent and MinION reads revealed structural genetic information for mcr-3.30 with an insertion of IS As18 within the gene. Due to this, mcr-3.30 was non-expressive, which makes FC951 susceptible to colistin. Further, in silico sequence and protein structural analysis confirmed the new variant. To the best of our knowledge, this is the first report on a novel mcr-3 variant from India. The significant role of mcr -like genes in different Aeromonas species remains unknown and requires additional investigation to obtains insights into the mechanism of colistin resistance.