{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,9]],"date-time":"2026-10-09T03:43:07Z","timestamp":1791517387192,"version":"4.3.4"},"reference-count":26,"publisher":"SAGE Publications","issue":"3","license":[{"start":{"date-parts":[[2011,8,1]],"date-time":"2011-08-01T00:00:00Z","timestamp":1312156800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Microbial Drug Resistance"],"published-print":{"date-parts":[[2011,8]]},"abstract":"<jats:p>\n                    A total of 59 and 74 nonduplicate plasmid-mediated quinolone resistance (PMQR) genes-carrying\n                    <jats:italic toggle=\"yes\">Klebsiella pneumoniae<\/jats:italic>\n                    and\n                    <jats:italic toggle=\"yes\">Escherichia coli<\/jats:italic>\n                    isolates were collected. All strains were assayed for fluoroquinolone susceptibility and the prevalence of quinolone resistance-determining regions (QRDRs) mutation. The association between PMQR determinants and common \u03b2-lactamase genes was also analyzed. Genetic relatedness of the isolates was analyzed by pulsed-field gel electrophoresis (PFGE). The PMQR genes-carrying\n                    <jats:italic toggle=\"yes\">K. pneumoniae<\/jats:italic>\n                    and\n                    <jats:italic toggle=\"yes\">E. coli<\/jats:italic>\n                    isolates exhibited high fluoroquinolone resistance rates, indicating that PMQR determinants play an essential role in the development of fluoroquinolone resistance. Remarkably, most\n                    <jats:italic toggle=\"yes\">qnr<\/jats:italic>\n                    -carrying strains had only a single or no QRDR mutation in GyrA or ParC, and most exhibited decreased ciprofloxacin (CIP) susceptibility or low-level CIP resistance. However, 71.4% and 98.4% of\n                    <jats:italic toggle=\"yes\">qnr<\/jats:italic>\n                    -negative\n                    <jats:italic toggle=\"yes\">K. pneumoniae<\/jats:italic>\n                    and\n                    <jats:italic toggle=\"yes\">E. coli<\/jats:italic>\n                    contained double QRDR mutations, and most presented high-level CIP resistance. Additionally,\n                    <jats:italic toggle=\"yes\">K. pneumoniae<\/jats:italic>\n                    presented a lower CIP resistance rate than\n                    <jats:italic toggle=\"yes\">E. coli<\/jats:italic>\n                    (59.3% vs. 91.9%) and low carriage of double QRDR mutations (38.9% vs. 89.9%). Also, most (88.1%)\n                    <jats:italic toggle=\"yes\">K. pneumoniae<\/jats:italic>\n                    examined in this study carried\n                    <jats:italic toggle=\"yes\">qnr<\/jats:italic>\n                    and only 14.9% of\n                    <jats:italic toggle=\"yes\">E. coli<\/jats:italic>\n                    were\n                    <jats:italic toggle=\"yes\">qnr<\/jats:italic>\n                    positive. Thus, the high fluoroquinolone susceptibility of\n                    <jats:italic toggle=\"yes\">K. pneumoniae<\/jats:italic>\n                    isolates is primarily due to fewer QRDR substitutions as a result of high prevalence of\n                    <jats:italic toggle=\"yes\">qnr<\/jats:italic>\n                    alleles in the host. Our findings support the hypothesis that chromosomal resistance mutations could be affected by the presence of Qnr, in other words, Qnr may protect the QRDR domains in the gyrase and topoisomerase IV from mutations under the inhibition of fluoroquinolones. Another remarkable finding was that the PMQR genes-carrying\n                    <jats:italic toggle=\"yes\">K. pneumoniae<\/jats:italic>\n                    exhibited much higher proportions of extended-spectrum \u03b2-lactamases (ESBLs)-positive phenotype than\n                    <jats:italic toggle=\"yes\">E. coli<\/jats:italic>\n                    (73.5% vs. 59.5%). This is due to not only the high prevalence of SHV-type ESBL-conferring enzymes in\n                    <jats:italic toggle=\"yes\">K. pneumoniae<\/jats:italic>\n                    but also the interference of DHA-producing\n                    <jats:italic toggle=\"yes\">K. pneumoniae<\/jats:italic>\n                    as a result of the strong association between\n                    <jats:italic toggle=\"yes\">qnrB<\/jats:italic>\n                    and\n                    <jats:italic toggle=\"yes\">bla<\/jats:italic>\n                    <jats:sub>DHA<\/jats:sub>\n                    .\n                  <\/jats:p>","DOI":"10.1089\/mdr.2011.0034","type":"journal-article","created":{"date-parts":[[2011,5,12]],"date-time":"2011-05-12T18:16:53Z","timestamp":1305224213000},"page":"363-367","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":13,"title":["Diverse Phenotypic and Genotypic Characterization Among Clinical\n                    <i>Klebsiella pneumoniae<\/i>\n                    and\n                    <i>Escherichia coli<\/i>\n                    Isolates Carrying Plasmid-Mediated Quinolone Resistance Determinants"],"prefix":"10.1177","volume":"17","author":[{"given":"Jiyong","family":"Yang","sequence":"first","affiliation":[{"name":"Chinese PLA General Hospital","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yanping","family":"Luo","sequence":"additional","affiliation":[{"name":"Chinese PLA General Hospital","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shenghui","family":"Cui","sequence":"additional","affiliation":[{"name":"State Food and Drug Administration","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Weiwei","family":"Wang","sequence":"additional","affiliation":[{"name":"Chinese PLA Institute for Disease Control and Prevention","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Li","family":"Han","sequence":"additional","affiliation":[{"name":"Chinese PLA Institute for Disease Control and Prevention","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2011,8]]},"reference":[{"key":"e_1_3_2_2_2","doi-asserted-by":"crossref","first-page":"4292","DOI":"10.1128\/AAC.01664-08","article-title":"Impact of low-level resistance to fluoroquinolones due to qnrA1 and qnrS1 genes or a gyrA mutation on ciprofloxacin bactericidal activity in a murine model of Escherichia coli urinary tract infection","volume":"53","author":"Allou N.","year":"2009","unstructured":"Allou N., , Cambau E., , Massias L., , Chau F., , Fantin B. 2009. Impact of low-level resistance to fluoroquinolones due to qnrA1 and qnrS1 genes or a gyrA mutation on ciprofloxacin bactericidal activity in a murine model of Escherichia coli urinary tract infection. Antimicrob. Agents Chemother., 53:4292\u20134297.","journal-title":"Antimicrob. Agents Chemother."},{"key":"e_1_3_2_3_2","doi-asserted-by":"publisher","DOI":"10.2174\/092986709787581879"},{"key":"e_1_3_2_4_2","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/dkm204"},{"key":"e_1_3_2_5_2","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/dkn077"},{"key":"e_1_3_2_6_2","volume-title":"No. 3. CLSI 940 West Valley Road","author":"CLSI","year":"2009","unstructured":"CLSI. 2009. Performance Standards for Antimicrobial Susceptibility Testing, 19th Informational Supplement (M100-S19) 29 No. 3. CLSI 940 West Valley Road. 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