{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T11:40:03Z","timestamp":1790768403575,"version":"4.1.0"},"reference-count":0,"publisher":"SAGE Publications","issue":"2","license":[{"start":{"date-parts":[[2009,6,1]],"date-time":"2009-06-01T00:00:00Z","timestamp":1243814400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Microbial Drug Resistance"],"published-print":{"date-parts":[[2009,6]]},"abstract":"<jats:p>\n                    Cefuroxime resistance in\n                    <jats:italic toggle=\"yes\">Escherichia coli<\/jats:italic>\n                    strains susceptible to extended-spectrum cephalosporins is not uncommon, but the resistance mechanisms have so far not been elucidated. Therefore, 14 clinical non-extended-spectrum \u03b2-lactamase isolates of\n                    <jats:italic toggle=\"yes\">E. coli<\/jats:italic>\n                    were examined, 11 of which were cefuroxime resistant. Quantitative RT-PCR was used to examine the transcription levels of the genes\n                    <jats:italic toggle=\"yes\">acrA<\/jats:italic>\n                    (encoding AcrA, part of the AcrAB-TolC efflux pump system) and\n                    <jats:italic toggle=\"yes\">ompF<\/jats:italic>\n                    (encoding the porin OmpF). Isoelectric focusing was used for detection of \u03b2-lactamases, and a spectrophotometric assay was used to measure AmpC activity. Among the 11 cefuroxime-resistant isolates, 7 had increased\n                    <jats:italic toggle=\"yes\">acrA<\/jats:italic>\n                    transcription (from 2.4 to 38 times the ATCC strain), 3 isolates had very low\n                    <jats:italic toggle=\"yes\">ompF<\/jats:italic>\n                    transcription levels (\u22640.01 times the ATCC strain), and 2 isolates showed increased AmpC activity (confirmed by 3-aminophenylboronic acid inhibition). We suggest that efflux, impermeability, and increased AmpC activity all contribute to cefuroxime resistance in\n                    <jats:italic toggle=\"yes\">E. coli<\/jats:italic>\n                    .\n                  <\/jats:p>","DOI":"10.1089\/mdr.2009.0883","type":"journal-article","created":{"date-parts":[[2009,5,11]],"date-time":"2009-05-11T11:31:48Z","timestamp":1242041508000},"page":"91-95","source":"Crossref","is-referenced-by-count":17,"title":["Interplay of Efflux, Impermeability, and AmpC Activity Contributes to Cefuroxime Resistance in Clinical, Non-ESBL-Producing Isolates of\n                    <i>Escherichia coli<\/i>"],"prefix":"10.1177","volume":"15","author":[{"given":"Owe","family":"K\u00e4llman","sequence":"first","affiliation":[{"name":"Karolinska University Hospital","place":["Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christian G.","family":"Giske","sequence":"additional","affiliation":[{"name":"Karolinska University Hospital","place":["Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"\u00d8rjan","family":"Samuelsen","sequence":"additional","affiliation":[{"name":"University Hospital of North Norway","place":["Norway"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bengt","family":"Wretlind","sequence":"additional","affiliation":[{"name":"Karolinska University Hospital","place":["Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mats","family":"Kalin","sequence":"additional","affiliation":[{"name":"Karolinska University Hospital","place":["Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Barbro","family":"Olsson-Liljequist","sequence":"additional","affiliation":[{"name":"Swedish Institute for Infectious Disease Control","place":["Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2009,6]]},"container-title":["Microbial Drug Resistance"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1089\/mdr.2009.0883","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1089\/mdr.2009.0883","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T20:25:24Z","timestamp":1777667124000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.sagepub.com\/doi\/full\/10.1089\/mdr.2009.0883"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2009,6]]},"references-count":0,"journal-issue":{"issue":"2","published-print":{"date-parts":[[2009,6]]}},"alternative-id":["10.1089\/mdr.2009.0883"],"URL":"https:\/\/doi.org\/10.1089\/mdr.2009.0883","relation":{},"ISSN":["1076-6294","1931-8448"],"issn-type":[{"value":"1076-6294","type":"print"},{"value":"1931-8448","type":"electronic"}],"subject":[],"published":{"date-parts":[[2009,6]]}}}