{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,27]],"date-time":"2026-09-27T02:37:07Z","timestamp":1790476627468,"version":"4.1.0"},"reference-count":46,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2021,6,21]],"date-time":"2021-06-21T00:00:00Z","timestamp":1624233600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001843","name":"Science and Engineering Research Board","doi-asserted-by":"publisher","award":["EMR\/2015\/001804"],"award-info":[{"award-number":["EMR\/2015\/001804"]}],"id":[{"id":"10.13039\/501100001843","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Cell. Infect. Microbiol."],"abstract":"<jats:sec><jats:title>Background<\/jats:title><jats:p>Increasing use of colistin has led to the world-wide emergence of mobile colistin resistant gene (<jats:italic>mcr<\/jats:italic>). The present study aimed to identify and characterise mcr and other drug-resistant genes in colistin resistant <jats:italic>Klebsiella pneumoniae<\/jats:italic> clinical isolates.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Twenty-two colistin resistant <jats:italic>K. pneumoniae<\/jats:italic> were analysed for mcr and other drug-resistant genes, efflux pumps, and virulence genes, and for their biofilm forming ability. Pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) were performed for all <jats:italic>mcr-1<\/jats:italic> positive isolates. S1-PFGE and Southern hybridisation were performed for localisation of <jats:italic>mcr-1<\/jats:italic> and <jats:italic>bla<\/jats:italic><jats:sub>NDM<\/jats:sub>.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Nineteen colistin resistant <jats:italic>K. pneumoniae<\/jats:italic> harboured <jats:italic>mcr-1<\/jats:italic> and 3 had <jats:italic>mgrB<\/jats:italic> disruption. All isolates harboured <jats:italic>bla<\/jats:italic><jats:sub>OXA-48<\/jats:sub>-type and ESBL genes; eight strains (five with <jats:italic>mcr-1<\/jats:italic> and three with <jats:italic>mgrB<\/jats:italic> disruption) co-harboured <jats:italic>bla<\/jats:italic><jats:sub>NDM<\/jats:sub>. Efflux pumps genes <jats:italic>AcrAB<\/jats:italic> and <jats:italic>mdtK<\/jats:italic> were detected in all 22 and <jats:italic>tol-C<\/jats:italic> in 21 isolates. Virulence-related genes entB and <jats:italic>irp-1<\/jats:italic> were detected in all 22, <jats:italic>mrkD<\/jats:italic> in 20, and <jats:italic>fimH-1<\/jats:italic> in 18 isolates; 11 isolates were strong biofilm producers. PFGE clustered <jats:italic>mcr-1<\/jats:italic> positive isolates into eight groups based on \u226590% similarity; MLST revealed diverse sequence types, predominant being ST-15 (n = 4) and ST-16 (n = 4). Both <jats:italic>mcr-1<\/jats:italic> and <jats:italic>bla<\/jats:italic><jats:sub>NDM<\/jats:sub> were localised on plasmid and chromosome; <jats:italic>mcr-1<\/jats:italic> was present on IncFII type and <jats:italic>bla<\/jats:italic><jats:sub>NDM<\/jats:sub> on IncFIB and IncA\/C type plasmids.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>Colistin resistance in <jats:italic>K. pneumoniae<\/jats:italic> was predominantly mediated by <jats:italic>mcr-1<\/jats:italic>. Co-existence of colistin, carbapenem, and other drug-resistant genes along with efflux pumps indicates towards enormous genomic plasticity in <jats:italic>K. pneumoniae<\/jats:italic> with ability to emerge as super-spreader of drug-resistance.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fcimb.2021.666030","type":"journal-article","created":{"date-parts":[[2021,6,21]],"date-time":"2021-06-21T10:05:15Z","timestamp":1624269915000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":28,"title":["Genetic Characterisation of Colistin Resistant Klebsiella pneumoniae Clinical Isolates From North India"],"prefix":"10.3389","volume":"11","author":[{"given":"Sanjay","family":"Singh","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ashutosh","family":"Pathak","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohibur","family":"Rahman","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Avinash","family":"Singh","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Soumyabrata","family":"Nag","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chinmoy","family":"Sahu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kashi Nath","family":"Prasad","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2021,6,21]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.3389\/fmicb.2021.609840","article-title":"Colistin Resistance Among Multiple Sequence Types of Klebsiella Pneumoniae Is Associated With Diverse Resistance Mechanisms: A Report From India","volume":"12","author":"Azam","year":"2021","journal-title":"Front. 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