{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,21]],"date-time":"2025-10-21T15:35:41Z","timestamp":1761060941608},"reference-count":35,"publisher":"American Society for Microbiology","issue":"9","license":[{"start":{"date-parts":[[1998,9,1]],"date-time":"1998-09-01T00:00:00Z","timestamp":904608000000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["J Clin Microbiol"],"published-print":{"date-parts":[[1998,9]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n          <jats:p>\n            Among clinical isolates of\n            <jats:italic>Escherichia coli<\/jats:italic>\n            ,\n            <jats:italic>Klebsiella pneumoniae<\/jats:italic>\n            , and\n            <jats:italic>Klebsiella oxytoca<\/jats:italic>\n            , there is an ever-increasing prevalence of \u03b2-lactamases that may confer resistance to newer \u03b2-lactam antibiotics that is not detectable by conventional procedures. Therefore, 75 isolates of these species producing well-characterized \u03b2-lactamases were studied using two MicroScan conventional microdilution panels, Gram Negative Urine MIC 7 (NU7) and Gram Negative MIC Plus 2 (N+2), to determine if results could be utilized to provide an accurate indication of \u03b2-lactamase production in the absence of frank resistance to expanded-spectrum cephalosporins and aztreonam. The enzymes studied included Bush groups 1 (AmpC), 2b (TEM-1, TEM-2, and SHV-1), 2be (extended spectrum \u03b2-lactamases [ESBLs] and K1), and 2br, alone and in various combinations. In tests with\n            <jats:italic>E. coli<\/jats:italic>\n            and\n            <jats:italic>K. pneumoniae<\/jats:italic>\n            and the NU7 panel, cefpodoxime MICs of \u22652 \u03bcg\/ml were obtained only for isolates producing ESBLs or AmpC \u03b2-lactamases. Cefoxitin MICs of &gt;16 \u03bcg\/ml were obtained for all strains producing AmpC \u03b2-lactamase and only 1 of 33 strains producing ESBLs. For the N+2 panel, ceftazidime MICs of \u22654 \u03bcg\/ml correctly identified 90% of ESBL producers and 100% of AmpC producers among isolates of\n            <jats:italic>E. coli<\/jats:italic>\n            and\n            <jats:italic>K. pneumoniae<\/jats:italic>\n            . Cefotetan MICs of \u2265 8 \u03bcg\/ml were obtained for seven of eight producers of AmpC \u03b2-lactamase and no ESBL producers. For tests performed with either panel and isolates of\n            <jats:italic>K. oxytoca<\/jats:italic>\n            , MICs of ceftazidime, cefotaxime, and ceftizoxime were elevated for strains producing ESBLs, while ceftriaxone and aztreonam MICs separated low-level K1 from high-level K1 producers within this species. These results suggest that microdilution panels can be used by clinical laboratories as an indicator of certain \u03b2-lactamases that may produce hidden but clinically significant resistance among isolates of\n            <jats:italic>E. coli<\/jats:italic>\n            ,\n            <jats:italic>K. pneumoniae<\/jats:italic>\n            , and\n            <jats:italic>K. oxytoca<\/jats:italic>\n            . Although it may not always be possible to differentiate between strains that produce ESBLs and those that produce AmpC, this differentiation is not critical since therapeutic options for patients infected with such organisms are similarly limited.\n          <\/jats:p>","DOI":"10.1128\/jcm.36.9.2575-2579.1998","type":"journal-article","created":{"date-parts":[[2019,12,31]],"date-time":"2019-12-31T17:36:11Z","timestamp":1577813771000},"page":"2575-2579","update-policy":"http:\/\/dx.doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":37,"title":["Can Results Obtained with Commercially Available MicroScan Microdilution Panels Serve as an Indicator of \u03b2-Lactamase Production among\n            <i>Escherichia coli<\/i>\n            and\n            <i>Klebsiella<\/i>\n            Isolates with Hidden Resistance to ExpandedSpectrum Cephalosporins and Aztreonam?"],"prefix":"10.1128","volume":"36","author":[{"given":"Ellen Smith","family":"Moland","sequence":"first","affiliation":[{"name":"<!--label omitted: 1-->Center for Research in Anti-Infectives and Biotechnology, Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska 68178"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Christine C.","family":"Sanders","sequence":"additional","affiliation":[{"name":"<!--label omitted: 1-->Center for Research in Anti-Infectives and Biotechnology, Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska 68178"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kenneth S.","family":"Thomson","sequence":"additional","affiliation":[{"name":"<!--label omitted: 1-->Center for Research in Anti-Infectives and Biotechnology, Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska 68178"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"235","reference":[{"key":"e_1_3_2_2_2","doi-asserted-by":"publisher","DOI":"10.1007\/BF01647010"},{"key":"e_1_3_2_3_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.38.4.761"},{"key":"e_1_3_2_4_2","doi-asserted-by":"publisher","DOI":"10.1007\/BF01690090"},{"key":"e_1_3_2_5_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.39.6.1211"},{"key":"e_1_3_2_6_2","doi-asserted-by":"publisher","DOI":"10.1007\/BF01645567"},{"key":"e_1_3_2_7_2","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/38.1.127"},{"key":"e_1_3_2_8_2","doi-asserted-by":"publisher","DOI":"10.1128\/jcm.34.8.1880-1884.1996"},{"key":"e_1_3_2_9_2","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/32.4.595"},{"key":"e_1_3_2_10_2","doi-asserted-by":"publisher","DOI":"10.1128\/jcm.34.4.908-911.1996"},{"key":"e_1_3_2_11_2","doi-asserted-by":"publisher","DOI":"10.1128\/jcm.32.3.691-696.1994"},{"key":"e_1_3_2_12_2","doi-asserted-by":"publisher","DOI":"10.1128\/CMR.8.4.557"},{"key":"e_1_3_2_13_2","doi-asserted-by":"publisher","DOI":"10.1099\/00221287-88-1-169"},{"key":"e_1_3_2_14_2","doi-asserted-by":"crossref","unstructured":"Medeiros A. A. 1997. Evolution and dissemination of \u03b2-lactamases accelerated by generations of \u03b2-lactam antibiotics. Clin. Infect. Dis. 24 (Suppl. 1) : S19\u2013S45.","DOI":"10.1093\/clinids\/24.Supplement_1.S19"},{"key":"e_1_3_2_15_2","doi-asserted-by":"publisher","DOI":"10.7326\/0003-4819-119-5-199309010-00001"},{"key":"e_1_3_2_16_2","unstructured":"National Committee for Clinical Laboratory Standards\nMethods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically. Approved standard M7-A4.\n1997\nNational Committee for Clinical Laboratory Standards\nWayne Pa"},{"key":"e_1_3_2_17_2","unstructured":"National Committee for Clinical Laboratory Standards\nPerformance standards for antimicrobial disk susceptibility tests. Approved standard M2-A6.\n1997\nNational Committee for Clinical Laboratory Standards\nWayne Pa"},{"key":"e_1_3_2_18_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.36.9.1991"},{"key":"e_1_3_2_19_2","doi-asserted-by":"publisher","DOI":"10.1007\/BF01690097"},{"key":"e_1_3_2_20_2","unstructured":"O\u2019Callaghan\nC. H.\nMuggleton\nP. W.\nRoss\nG. W.\nEffects of \u03b2-lactamase from gram-negative organisms on cephalosporins and penicillins\nAntimicrob. Agents Chemother.\n1969\n57\n63 1968."},{"key":"e_1_3_2_21_2","doi-asserted-by":"publisher","DOI":"10.1093\/infdis\/159.5.1005"},{"key":"e_1_3_2_22_2","doi-asserted-by":"publisher","DOI":"10.1007\/BF01650727"},{"key":"e_1_3_2_23_2","unstructured":"Pitout\nJ. D. D.\nMoland\nE. S.\nSanders\nC. C.\nChanges in porin expression associated with the stepwise increase in resistance to cefoxitin in Klebsiella pneumoniae involved in nosocomial infections abstr. C39\nAbstracts of the 36th Interscience Conference on Antimicrobial Agents and Chemotherapy.\n1996\n41\nAmerican Society for Microbiology\nWashington D.C"},{"key":"e_1_3_2_24_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.37.12.2760"},{"key":"e_1_3_2_25_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.34.11.2193"},{"key":"e_1_3_2_26_2","unstructured":"Sambrook\nJ.\nFritsch\nE. F.\nManiatis\nT.\nMolecular cloning: a laboratory manual\n2nd ed.\n1989\nCold Spring Harbor Laboratory Press\nCold Spring Harbor N.Y"},{"key":"e_1_3_2_27_2","doi-asserted-by":"publisher","DOI":"10.1093\/clinids\/14.5.1089"},{"key":"e_1_3_2_28_2","doi-asserted-by":"publisher","DOI":"10.1128\/jcm.34.12.2997-3001.1996"},{"key":"e_1_3_2_29_2","doi-asserted-by":"publisher","DOI":"10.1093\/clind\/15.5.824"},{"key":"e_1_3_2_30_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.30.6.951"},{"key":"e_1_3_2_31_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.36.8.1677"},{"key":"e_1_3_2_32_2","unstructured":"Thomson\nK. S.\nMoland\nE. S.\nSanders\nC. C.\nUse of Microdilution panels with and without \u03b2-lactamase inhibitors as a specific test for \u03b2-lactamase production among E. coli and Klebsiella.\n1998Submitted for publication."},{"key":"e_1_3_2_33_2","first-page":"151","article-title":"Novel plasmid-mediated \u03b2-lactamases in Enterobacteriaceae: emerging problems for new \u03b2-lactam antibiotics","volume":"16","author":"Thomson K. S.","year":"1996","unstructured":"Thomson K. S. Prevan A. M. Sanders C. C. Novel plasmid-mediated \u03b2-lactamases in Enterobacteriaceae: emerging problems for new \u03b2-lactam antibiotics Current clinical topics in infectious diseases Remington J. S. Swartz M. N. 16 1996 151 163 Blackwell Science, Inc. Cambridge, Mass","journal-title":"Current clinical topics in infectious diseases"},{"key":"e_1_3_2_34_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-0691.1997.tb00306.x"},{"key":"e_1_3_2_35_2","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/26.5.635"},{"key":"e_1_3_2_36_2","doi-asserted-by":"publisher","DOI":"10.1128\/jcm.35.9.2191-2197.1997"}],"container-title":["Journal of Clinical Microbiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/JCM.36.9.2575-2579.1998","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/JCM.36.9.2575-2579.1998","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,3,4]],"date-time":"2022-03-04T23:48:05Z","timestamp":1646437685000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.asm.org\/doi\/10.1128\/JCM.36.9.2575-2579.1998"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1998,9]]},"references-count":35,"journal-issue":{"issue":"9","published-print":{"date-parts":[[1998,9]]}},"alternative-id":["10.1128\/JCM.36.9.2575-2579.1998"],"URL":"https:\/\/doi.org\/10.1128\/jcm.36.9.2575-2579.1998","relation":{},"ISSN":["0095-1137","1098-660X"],"issn-type":[{"value":"0095-1137","type":"print"},{"value":"1098-660X","type":"electronic"}],"subject":[],"published":{"date-parts":[[1998,9]]},"assertion":[{"value":"1998-03-30","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"1998-06-14","order":1,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"1998-09-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}