{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,13]],"date-time":"2026-02-13T06:53:51Z","timestamp":1770965631123,"version":"3.50.1"},"reference-count":0,"publisher":"American Society for Microbiology","issue":"11","license":[{"start":{"date-parts":[[1993,11,1]],"date-time":"1993-11-01T00:00:00Z","timestamp":752112000000},"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":[[1993,11]]},"abstract":"<jats:p>Bacteroides fragilis CS30 is a clinical isolate resistant to high concentrations of benzylpenicillin and cephaloridine but not to cephamycin or penem antibiotics. beta-Lactam resistance is mediated by a chromosomally encoded cephalosporinase produced at a high level. The gene encoding this beta-lactamase was cloned from genomic libraries constructed in Escherichia coli and then mated with B. fragilis 638 for identification of ampicillin-resistant (Apr) strains. Apr transconjugants contained a nitrocefin-reactive protein with the physical and enzymatic properties of the original CS30 isolate. The beta-lactamase gene (cepA) was localized by deletion analysis and subcloned, and its nucleotide sequence was determined. The 903-bp cepA open reading frame encoded a 300-amino-acid precursor protein (predicted molecular mass, 34,070 Da). A beta-lactamase-deficient mutant strain of B. fragilis 638 was constructed by insertional inactivation with the cepA gene of CS30, demonstrating strict functional homology between these chromosomal beta-lactamase genes. An extensive comparison of the CepA protein sequence by alignment with other beta-lactamases revealed the strict conservation of at least four elements common to Ambler class A. A further comparison of the CepA protein sequence with protein sequences of beta-lactamases from two other Bacteroides species indicated that they constitute their own distinct subgroup of class A beta-lactamases.<\/jats:p>","DOI":"10.1128\/aac.37.11.2391","type":"journal-article","created":{"date-parts":[[2012,6,28]],"date-time":"2012-06-28T00:05:50Z","timestamp":1340841950000},"page":"2391-2400","update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":79,"title":["Cloning and characterization of the endogenous cephalosporinase gene, cepA, from Bacteroides fragilis reveals a new subgroup of Ambler class A beta-lactamases"],"prefix":"10.1128","volume":"37","author":[{"given":"M B","family":"Rogers","sequence":"first","affiliation":[{"name":"Department of Microbiology and Immunology, School of Medicine, East Carolina University, Greenville 27858-4354."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"A C","family":"Parker","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, School of Medicine, East Carolina University, Greenville 27858-4354."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"C J","family":"Smith","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, School of Medicine, East Carolina University, Greenville 27858-4354."}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"235","container-title":["Antimicrobial Agents and Chemotherapy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/AAC.37.11.2391","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/AAC.37.11.2391","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,2,21]],"date-time":"2022-02-21T15:31:24Z","timestamp":1645457484000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.asm.org\/doi\/10.1128\/AAC.37.11.2391"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1993,11]]},"references-count":0,"journal-issue":{"issue":"11","published-print":{"date-parts":[[1993,11]]}},"alternative-id":["10.1128\/AAC.37.11.2391"],"URL":"https:\/\/doi.org\/10.1128\/aac.37.11.2391","relation":{},"ISSN":["0066-4804","1098-6596"],"issn-type":[{"value":"0066-4804","type":"print"},{"value":"1098-6596","type":"electronic"}],"subject":[],"published":{"date-parts":[[1993,11]]},"assertion":[{"value":"1993-11-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}