{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,26]],"date-time":"2026-09-26T20:57:10Z","timestamp":1790456230124,"version":"4.1.0"},"reference-count":16,"publisher":"S. Karger AG","issue":"6","license":[{"start":{"date-parts":[[2017,1,1]],"date-time":"2017-01-01T00:00:00Z","timestamp":1483228800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/www.karger.com\/Services\/SiteLicenses"},{"start":{"date-parts":[[2017,1,1]],"date-time":"2017-01-01T00:00:00Z","timestamp":1483228800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.karger.com\/Services\/SiteLicenses"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Chemotherapy"],"published-print":{"date-parts":[[2017]]},"abstract":"<b><i>Background\/Aims:<\/i><\/b> Colistin resistance is increasingly recognized among carbapenemase-producing <i>Klebsiella pneumoniae<\/i> isolates in several European regions. The current study documents the appearance of colistin resistance among KPC-2 and SHV-5-produning <i>K. pneumoniae<\/i> strains in Bulgaria. <b><i>Methods:<\/i><\/b> Four colistin-resistant <i>K. pneumoniae<\/i> isolates were recovered from 2 patients hospitalized in the anesthesiology and resuscitation clinic of a tertiary care university hospital in Sofia, Bulgaria. Microbial identification and antimicrobial susceptibility testing was performed by Vitek 2 (Biomerieux, France). \u03b2-Lactamase genes were amplified using a panel of primers for detection of all MBL-types, KPCs, plasmid-mediated AmpCs in single PCR reactions, OXA-type carbapenemases, extended-spectrum \u03b2-lactamases (ESBLs) and TEM enzymes. The colistin-resistant <i>mcr-1<\/i> gene was also investigated using previously described primers and conditions. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to investigate clonality. <b><i>Results:<\/i><\/b> The 4 <i>K. pneumoniae<\/i> isolates exhibited colistin MICs >16 mg\/L and showed multidrug-resistant phenotypes, remaining intermediately susceptible only to gentamicin. They were clustered into a single PFGE clonal type and MLST assigned them to sequence type 258. All isolates possessed KPC-2 carbapenemase and SHV-5 ESBL. They were negative for the plasmid-mediated colistin-resistant <i>mcr-1<\/i> gene, possibly implying an intrinsic mechanism of resistance. <b><i>Conclusions:<\/i><\/b> Although colistin use in Bulgaria only started moderately during 2014, the findings of the current study notify the appearance of colistin resistance among carbapenemase-producing <i>Klebsiella<\/i> species in another European region.<\/jats:p>","DOI":"10.1159\/000464275","type":"journal-article","created":{"date-parts":[[2017,7,24]],"date-time":"2017-07-24T21:01:22Z","timestamp":1500930082000},"page":"339-342","source":"Crossref","is-referenced-by-count":11,"title":["Colistin Resistance in KPC-2- and SHV-5-Producing <b><i>Klebsiella pneumoniae<\/i><\/b> Clinical Isolates in Bulgaria"],"prefix":"10.1159","volume":"62","author":[{"given":"Encho","family":"Savov","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Iva","family":"Todorova","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lida","family":"Politi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Angelina","family":"Trifonova","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maja","family":"Borisova","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elena","family":"Kioseva","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Athanassios","family":"Tsakris","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"127","published-online":{"date-parts":[[2017,7,22]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","DOI":"10.1128\/CMR.00006-08"},{"key":"ref2","doi-asserted-by":"publisher","DOI":"10.1159\/000320943"},{"key":"ref3","doi-asserted-by":"publisher","DOI":"10.1086\/677170"},{"key":"ref4","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/dkv467"},{"key":"ref5","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/dku105"},{"key":"ref6","doi-asserted-by":"publisher","DOI":"10.1016\/S1473-3099(15)00424-7"},{"key":"ref7","doi-asserted-by":"publisher","DOI":"10.3389\/fmicb.2014.00643"},{"key":"ref8","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/dku323"},{"key":"ref9","doi-asserted-by":"publisher","DOI":"10.1128\/JCM.02234-12"},{"key":"ref10","doi-asserted-by":"publisher","DOI":"10.1016\/j.jsb.2011.04.010"},{"key":"ref11","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M706172200"},{"key":"ref12","doi-asserted-by":"publisher","DOI":"10.1186\/1423-0127-17-60"},{"key":"ref13","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.01480-13"},{"key":"ref14","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.04763-14"},{"key":"ref15","doi-asserted-by":"publisher","DOI":"10.2807\/1560-7917.ES.2016.21.13.30183"},{"key":"ref16","doi-asserted-by":"publisher","DOI":"10.1007\/s10096-010-0921-3"}],"container-title":["Chemotherapy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/464275","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/464275","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,4,23]],"date-time":"2025-04-23T17:32:51Z","timestamp":1745429571000},"score":1,"resource":{"primary":{"URL":"https:\/\/karger.com\/article\/doi\/10.1159\/000464275"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017]]},"references-count":16,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2017,11,2]]}},"URL":"https:\/\/doi.org\/10.1159\/000464275","archive":["Portico"],"relation":{},"ISSN":["0009-3157","1421-9794"],"issn-type":[{"value":"0009-3157","type":"print"},{"value":"1421-9794","type":"electronic"}],"subject":[],"published":{"date-parts":[[2017]]}}}