{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T19:46:27Z","timestamp":1760384787881,"version":"3.40.4"},"reference-count":14,"publisher":"S. Karger AG","issue":"1","license":[{"start":{"date-parts":[[2007,12,7]],"date-time":"2007-12-07T00:00:00Z","timestamp":1196985600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/www.karger.com\/Services\/SiteLicenses"},{"start":{"date-parts":[[2007,12,7]],"date-time":"2007-12-07T00:00:00Z","timestamp":1196985600000},"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":[[2008]]},"abstract":"<i>Background:<\/i> Some clinical isolates of <i>Serratia marcescens <\/i>showed high-level resistance to expanded-spectrum cephalosporins alone and in combination with \u03b2-lactamase inhibitor, but the \u03b2-lactamase extracted from these strains was sensitive to the inhibitors. This study examines the possible mechanisms responsible for the discrepancy. <i>Methods and Results:<\/i> Three clinical isolates of<i> S. marcescens<\/i> bore the <i>bla<\/i><sub>TEM<\/sub> gene coded on a plasmid. This was confirmed by detection of the <i>bla<\/i> gene using PCR analysis and by transferring resistance determinants to <i>Escherichia coli<\/i> via conjugation and transformation. All of the <i>E. coli<\/i> transconjugants and transformants acquired a similar level of resistance to penicillins and narrow-spectrum cephalosporins, and showed the reduced susceptibility to expanded-spectrum cephalosporins alone and in combination with clavulanate. As a result of the highly constitutive expression of the TEM gene, up to 247\u2013690 U of \u03b2-lactamase were produced by 10<sup>10<\/sup> cells of wild-type <i>S. marcescens<\/i> and the transconjugants and transformants. In the presence of 0.24 U\/ml of TEM enzyme, the minimum inhibition concentrations of cefotaxime against <i>E. coli<\/i> ATCC 25922 increased from 0.125 to 512 \u00b5g\/ml. The TEM-type \u03b2-lactamase extracted from these strains was sensitive to clavulanate, and 62.2\u201392.1% of its activity was inhibited after preincubation with 0.1 m<i>M<\/i> clavulanate. <i>Conclusion:<\/i>The TEM-type \u03b2-lactamase plays a critical role in the resistance of<i> S. marcescens<\/i> to \u03b2-lactams, and the hyperproduction of inhibitor-susceptible TEM \u03b2-lactamase is responsible for the resistance to \u03b2-lactam-\u03b2-lactamase inhibitor combinations.<\/jats:p>","DOI":"10.1159\/000112315","type":"journal-article","created":{"date-parts":[[2007,12,14]],"date-time":"2007-12-14T10:31:44Z","timestamp":1197628304000},"page":"31-37","source":"Crossref","is-referenced-by-count":3,"title":["Hyperproduction of Inhibitor-Susceptible TEM \u03b2-Lactamase Is Responsible for Resistance of<i> Serratia marcescens<\/i> to \u03b2-Lactam-\u03b2-Lactamase Inhibitor Combinations"],"prefix":"10.1159","volume":"54","author":[{"given":"Wei-Hua","family":"Zhao","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhi-Qing","family":"Hu","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gelin","family":"Chen","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ribu","family":"Ito","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tadakatsu","family":"Shimamura","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"127","published-online":{"date-parts":[[2007,12,7]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","DOI":"10.1159%2F000007304"},{"key":"ref2","doi-asserted-by":"publisher","DOI":"10.1093%2Fjac%2Fdkf147"},{"key":"ref3","doi-asserted-by":"publisher","DOI":"10.1093%2Fjac%2F13.1.15"},{"key":"ref4","doi-asserted-by":"publisher","DOI":"10.1093%2Fjac%2F41.suppl_4.25"},{"key":"ref5","doi-asserted-by":"publisher","DOI":"10.1128%2FJCM.43.5.2452-2455.2005"},{"key":"ref6","doi-asserted-by":"publisher","DOI":"10.1128%2FAAC.45.8.2331-2339.2001"},{"key":"ref7","doi-asserted-by":"publisher","DOI":"10.1038%2F208239a0"},{"key":"ref8","doi-asserted-by":"publisher","DOI":"10.1128%2FCMR.14.4.933-951.2001"},{"key":"ref9","doi-asserted-by":"publisher","DOI":"10.1159%2F000007128"},{"key":"ref10","doi-asserted-by":"publisher","DOI":"10.1093%2Fjac%2F43.4.447"},{"key":"ref11","doi-asserted-by":"publisher","DOI":"10.1128%2FAAC.46.7.2266-2268.2002"},{"key":"ref12","doi-asserted-by":"publisher","DOI":"10.1211%2F002235703765951320"},{"key":"ref13","doi-asserted-by":"publisher","DOI":"10.1093%2Fjac%2F41.2.189"},{"key":"ref14","doi-asserted-by":"publisher","DOI":"10.1128%2FAAC.49.4.1495-1501.2005"}],"container-title":["Chemotherapy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/112315","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/112315","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,4,24]],"date-time":"2025-04-24T02:26:22Z","timestamp":1745461582000},"score":1,"resource":{"primary":{"URL":"https:\/\/karger.com\/article\/doi\/10.1159\/000112315"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2007,12,7]]},"references-count":14,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2007,12,1]]}},"URL":"https:\/\/doi.org\/10.1159\/000112315","archive":["Portico"],"relation":{},"ISSN":["0009-3157","1421-9794"],"issn-type":[{"type":"print","value":"0009-3157"},{"type":"electronic","value":"1421-9794"}],"subject":[],"published":{"date-parts":[[2007,12,7]]}}}