{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T05:18:18Z","timestamp":1788326298618,"version":"build-2803163510"},"reference-count":31,"publisher":"American Society for Microbiology","issue":"6","license":[{"start":{"date-parts":[[2002,6,1]],"date-time":"2002-06-01T00:00:00Z","timestamp":1022889600000},"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":["Antimicrob Agents Chemother"],"published-print":{"date-parts":[[2002,6]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n          <jats:p>\n            The class C \u03b2-lactamase from\n            <jats:italic>Enterobacter cloacae<\/jats:italic>\n            P99 confers resistance to a wide range of broad-spectrum \u03b2-lactams but not to the newer cephalosporin cefepime. Using PCR mutagenesis of the\n            <jats:italic>E. cloacae<\/jats:italic>\n            P99\n            <jats:italic>ampC<\/jats:italic>\n            gene, we obtained a Leu-293-Pro mutant of the P99 \u03b2-lactamase conferring a higher MIC of cefepime (MIC, 8 \u03bcg\/ml, compared with 0.5 \u03bcg\/ml conferred by the wild-type enzyme). In addition, the mutant enzyme produced higher resistance to ceftazidime but not to the other \u03b2-lactams tested. Mutants with 15 other replacements of Leu-293 were prepared by site-directed random mutagenesis. None of these mutant enzymes conferred MICs of cefepime higher than that conferred by Leu-293-Pro. We determined the kinetic parameters of the purified\n            <jats:italic>E. cloacae<\/jats:italic>\n            P99 \u03b2-lactamase and the Leu-293-Pro mutant enzyme. The catalytic efficiencies (\n            <jats:italic>k<\/jats:italic>\n            <jats:sub>cat<\/jats:sub>\n            \/\n            <jats:italic>\n              K\n              <jats:sub>m<\/jats:sub>\n            <\/jats:italic>\n            ) of the Leu-293-Pro mutant \u03b2-lactamase for cefepime and ceftazidime were increased relative to the respective catalytic efficiencies of the wild-type P99 \u03b2-lactamase. These differences likely contribute to the higher MICs of cefepime and ceftazidime conferred by this mutant \u03b2-lactamase.\n          <\/jats:p>","DOI":"10.1128\/aac.46.6.1966-1970.2002","type":"journal-article","created":{"date-parts":[[2002,7,27]],"date-time":"2002-07-27T10:09:29Z","timestamp":1027764569000},"page":"1966-1970","update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":39,"title":["Mutational Replacement of Leu-293 in the Class C\n            <i>Enterobacter cloacae<\/i>\n            P99 \u03b2-Lactamase Confers Increased MIC of Cefepime"],"prefix":"10.1128","volume":"46","author":[{"given":"Sergei B.","family":"Vakulenko","sequence":"first","affiliation":[{"name":"Departments of Medicine"},{"name":"Biochemistry and Molecular Biology"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dasantila","family":"Golemi","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Wayne State University, Detroit, Michigan 48202"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bruce","family":"Geryk","sequence":"additional","affiliation":[{"name":"Departments of Medicine"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maxim","family":"Suvorov","sequence":"additional","affiliation":[{"name":"Departments of Medicine"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"James R.","family":"Knox","sequence":"additional","affiliation":[{"name":"Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shahriar","family":"Mobashery","sequence":"additional","affiliation":[{"name":"Biochemistry and Molecular Biology"},{"name":"Institute for Drug Design, Wayne State University, Detroit, Michigan 48201"},{"name":"Department of Chemistry, Wayne State University, Detroit, Michigan 48202"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stephen A.","family":"Lerner","sequence":"additional","affiliation":[{"name":"Departments of Medicine"},{"name":"Biochemistry and Molecular Biology"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"235","reference":[{"key":"e_1_3_2_2_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.42.9.2352"},{"key":"e_1_3_2_3_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1574-6968.2001.tb10519.x"},{"key":"e_1_3_2_4_2","doi-asserted-by":"publisher","DOI":"10.3349\/ymj.1998.39.6.520"},{"key":"e_1_3_2_5_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.43.8.1924"},{"key":"e_1_3_2_6_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.40.1.221"},{"key":"e_1_3_2_7_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.35.1.73"},{"key":"e_1_3_2_8_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.44.9.2549-2553.2000"},{"key":"e_1_3_2_9_2","first-page":"71","year":"1998","unstructured":"Bush, K., and S. Mobashery. 1998. How \u03b2-lactamases have driven pharmaceutical drug discovery: from mechanistic knowledge to clinical circumvention, p. 71-98. In B. P. Rosen and S. Mobashery (ed.), Resolving the antibiotic paradox: progress in understanding drug resistance and development of new antibiotics. Plenum Press, New York, N.Y.","journal-title":"Resolving the antibiotic paradox: progress in understanding drug resistance and development of new antibiotics"},{"key":"e_1_3_2_10_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.27.4.555"},{"key":"e_1_3_2_11_2","doi-asserted-by":"crossref","first-page":"721","DOI":"10.1016\/S0025-7125(16)30035-9","volume":"79","year":"1995","unstructured":"Cunha, B. A., and M. V. Gill. 1995. Cefepime. Med. Clin. N. Am.79:721-732.","journal-title":"Med. Clin. N. Am."},{"key":"e_1_3_2_12_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.38.5.1182"},{"key":"e_1_3_2_13_2","doi-asserted-by":"publisher","DOI":"10.1042\/bj2550123"},{"key":"e_1_3_2_14_2","doi-asserted-by":"crossref","first-page":"789","DOI":"10.1007\/BF01700407","volume":"16","year":"1997","unstructured":"Garau, J., J. Blanquer, L. Cobo, S. Corcia, M. Daguerre, F. J. de Latorre, C. Leon, F. Del Nogal, A. Net, and J. Rello. 1997. Prospective, randomised, multicentre study of meropenem versus imipenem\/cilastatin as empiric monotherapy in severe nosocomial infections. Eur. J. Clin. Microbiol. Infect. Dis.16:789-796.","journal-title":"Eur. J. Clin. Microbiol. Infect. Dis."},{"key":"e_1_3_2_15_2","first-page":"419","volume":"42","year":"1998","unstructured":"Gazouli, M., L. S. Tzouvelekis, A. C. Vatopoulos, and E. Tzelepi. 1998. Transferable class C beta-lactamases in Escherichia coli strains isolated in Greek hospitals and characterization of two enzyme variants (LAT-3 and LAT-4) closely related to Citrobacter freundii AmpC beta-lactamase. J. Antimicrob. Chemother.42:419-425.","journal-title":"J. Antimicrob. Chemother."},{"key":"e_1_3_2_16_2","first-page":"1","volume":"29","year":"1992","unstructured":"Hancock, R. E. W., and F. Bellido. 1992. Factors involved in the enhanced efficacy against Gram-negative bacteria of fourth generation cephalosporins. J. Antimicrob. Chemother.29(Suppl. A):1-6.","journal-title":"J. Antimicrob. Chemother."},{"key":"e_1_3_2_17_2","doi-asserted-by":"crossref","first-page":"779","DOI":"10.1093\/clinids\/23.4.779","volume":"23","year":"1996","unstructured":"Itokazu, G. S., J. P. Quinn, C. Bell-Dixon, F. M. Kahan, and R. A. Weinstein. 1996. Antimicrobial resistance rates among aerobic gram-negative bacilli recovered from patients in intensive care units: evaluation of a national postmarketing surveillance program. Clin. Infect. Dis.23:779-784.","journal-title":"Clin. Infect. Dis."},{"key":"e_1_3_2_18_2","doi-asserted-by":"publisher","DOI":"10.1016\/0732-8893(94)90048-5"},{"key":"e_1_3_2_19_2","doi-asserted-by":"publisher","DOI":"10.1107\/S0021889891004399"},{"key":"e_1_3_2_20_2","doi-asserted-by":"publisher","DOI":"10.1046\/j.1365-2958.1999.01150.x"},{"key":"e_1_3_2_21_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.90.23.11257"},{"key":"e_1_3_2_22_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.44.9.2534-2536.2000"},{"key":"e_1_3_2_23_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.43.7.1669"},{"key":"e_1_3_2_24_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1574-6968.1998.tb13131.x"},{"key":"e_1_3_2_25_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.34.2.337"},{"key":"e_1_3_2_26_2","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.270.11.5729"},{"key":"e_1_3_2_27_2","doi-asserted-by":"publisher","DOI":"10.1021\/bi980184i"},{"key":"e_1_3_2_28_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.41.1.35"},{"key":"e_1_3_2_29_2","first-page":"369","volume":"17","year":"1993","unstructured":"Sanders, C. C. 1993. Cefepime: the next generation? Clin. Infect. Dis.17:369-379.","journal-title":"Clin. Infect. Dis."},{"key":"e_1_3_2_30_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.74.12.5463"},{"key":"e_1_3_2_31_2","first-page":"235","volume":"169","year":"1998","unstructured":"Verdet, C., G. Arlet, S. Ben Redjeb, A. Ben Hassen, P. H. Lagrange, and A. Philippon. 1998. Characterization of CMY-4, an Amp C-type plasmid-mediated \u03b2-lactamase in a Tunisian clinical isolate of Proteus mirabilis. FEMS Microbiol. Lett.169:235-240.","journal-title":"FEMS Microbiol. Lett."},{"key":"e_1_3_2_32_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.43.6.1350"}],"container-title":["Antimicrobial Agents and Chemotherapy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/AAC.46.6.1966-1970.2002","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/AAC.46.6.1966-1970.2002","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,2,21]],"date-time":"2022-02-21T17:47:14Z","timestamp":1645465634000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.asm.org\/doi\/10.1128\/AAC.46.6.1966-1970.2002"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2002,6]]},"references-count":31,"journal-issue":{"issue":"6","published-print":{"date-parts":[[2002,6]]}},"alternative-id":["10.1128\/AAC.46.6.1966-1970.2002"],"URL":"https:\/\/doi.org\/10.1128\/aac.46.6.1966-1970.2002","relation":{},"ISSN":["0066-4804","1098-6596"],"issn-type":[{"value":"0066-4804","type":"print"},{"value":"1098-6596","type":"electronic"}],"subject":[],"published":{"date-parts":[[2002,6]]},"assertion":[{"value":"2001-06-13","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2002-03-16","order":1,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2002-06-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}