{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,15]],"date-time":"2026-06-15T23:57:49Z","timestamp":1781567869973,"version":"3.54.5"},"reference-count":33,"publisher":"Microbiology Society","issue":"8","funder":[{"DOI":"10.13039\/501100001704","name":"European Society of Clinical Microbiology and Infectious Diseases","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100001704","id-type":"DOI","asserted-by":"crossref"}]},{"name":"Szegedi Tudom\u00e1nyegyetem, \u00c1ltal\u00e1nos Orvostudom\u00e1nyi Kar"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2021,8,31]]},"abstract":"\n Introduction.<\/jats:bold> There are several \u03b2-lactamase genes described for \n \n Bacteroide<\/jats:ext-link>\n <\/jats:named-content>\n <\/jats:italic>s strains, of which cepA<\/jats:italic> and cfiA<\/jats:italic> are specific for \n \n Bacteroides fragilis<\/jats:ext-link>\n <\/jats:named-content>\n <\/jats:italic> and define two genetic divisions. The expression and phenotypic effects of these genes are usually regulated by insertional activation.<\/jats:p>\n \n Hypotheses\/Gap Statement.<\/jats:bold> Information is lacking about how cepA<\/jats:italic> is regulated for most of the \n \n B. fragilis<\/jats:ext-link>\n <\/jats:named-content>\n <\/jats:italic> strains and whether there could be a genetic element for it.<\/jats:p>\n \n Aim.<\/jats:bold> We aimed to investigate the molecular background of ampicillin (and other \u03b2-lactam) resistance among \n \n Bacteroides<\/jats:ext-link>\n <\/jats:named-content>\n <\/jats:italic> strains as mediated mainly by cepA<\/jats:italic> and also to find a genetic element for it as known for cfiA<\/jats:italic>.<\/jats:p>\n \n Methodology.<\/jats:bold> Various PCR methods were used for \u03b2-lactamase-resistance gene and insertion sequence (IS) element detection in 42 \n \n Bacteroides<\/jats:ext-link>\n <\/jats:named-content>\n <\/jats:italic> strains. \u03b2-Lactamase activity measurements and antimicrobial-susceptibility testing using agar dilution were also applied. Further molecular experiments involved sequencing, gene targeting, Southern blotting and bioinformatic analyses.<\/jats:p>\n \n Results.<\/jats:bold> We found that high antibiotic resistance and \u03b2-lactamase levels are brought about by insertional activation of the cepA<\/jats:italic> gene or by similar or dissimilar activation of cfxA<\/jats:italic> or cfiA<\/jats:italic>, or by the newly described pbbA<\/jats:italic> genes. Non-activated cepA<\/jats:italic> genes produced low levels of specific \u03b2-lactamase activities that did not correlate with ampicillin resistance. We found a genetic element for cepA<\/jats:italic> and another region close to it that are characteristic for division I \n \n B. fragilis<\/jats:ext-link>\n <\/jats:named-content>\n <\/jats:italic> strains, which are replaced by other sequences in division II \n \n B. fragilis<\/jats:ext-link>\n <\/jats:named-content>\n <\/jats:italic> strains.<\/jats:p>\n \n Conclusion.<\/jats:bold> \n cepA<\/jats:italic> usually is not activated by IS elements and usually produces low \u03b2-lactamase activities that do not correlate with the ampicillin MICs; therefore, it probably involves some non-\u03b2-lactamase-mediated resistance mechanism(s). pbpA<\/jats:italic> is a newly described, effective \u03b2-lactamase gene that is located on a plasmid, and cepA<\/jats:italic> resides on a well-defined chromosomal segment that is mutually replaced in division II \n \n B. fragilis<\/jats:ext-link>\n <\/jats:named-content>\n <\/jats:italic> strains. This latter finding demonstrates the genetic dichotomy of cepA\u2013cfiA<\/jats:italic> in \n \n B. fragilis<\/jats:ext-link>\n <\/jats:named-content>\n <\/jats:italic> and requires further investigation.<\/jats:p>","DOI":"10.1099\/jmm.0.001393","type":"journal-article","created":{"date-parts":[[2021,8,31]],"date-time":"2021-08-31T14:15:51Z","timestamp":1630419351000},"source":"Crossref","is-referenced-by-count":12,"title":["An update on ampicillin resistance and \u03b2-lactamase genes of Bacteroides spp."],"prefix":"10.1099","volume":"70","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9230-8907","authenticated-orcid":false,"given":"J\u00f3zsef","family":"S\u00f3ki","sequence":"first","affiliation":[{"name":"Institute of Medical Microbiology, Faculty of Medicine, University of Szeged, Szeged, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anik\u00f3","family":"Kesz\u0151cze","sequence":"additional","affiliation":[{"name":"Present address: National Institute of Oncology, Budapest, Hungary"},{"name":"Institute of Medical Microbiology, Faculty of Medicine, University of Szeged, Szeged, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2528-9173","authenticated-orcid":false,"given":"Istv\u00e1n","family":"Nagy","sequence":"additional","affiliation":[{"name":"Institute of Biochemistry, Biological Research Centre, Szeged, Hungary"},{"name":"SEQOMICS Ltd., M\u00f3rahalom, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katalin","family":"Buri\u00e1n","sequence":"additional","affiliation":[{"name":"Institute of Medical Microbiology, Faculty of Medicine, University of Szeged, Szeged, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6590-1879","authenticated-orcid":false,"given":"Elisabeth","family":"Nagy","sequence":"additional","affiliation":[{"name":"Institute of Medical Microbiology, Faculty of Medicine, University of Szeged, Szeged, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"345","reference":[{"key":"R1","doi-asserted-by":"publisher","DOI":"10.1128\/CMR.00008-07"},{"key":"R2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.37.11.2391"},{"key":"R3","doi-asserted-by":"publisher","DOI":"10.1099\/jmm.0.031336-0"},{"key":"R4","doi-asserted-by":"publisher","DOI":"10.5495\/wjcid.v3.i1"},{"key":"R5","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.01514-08"},{"key":"R6","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/dkw175"},{"key":"R7","doi-asserted-by":"publisher","DOI":"10.1099\/jmm.0.05452-0"},{"key":"R8","doi-asserted-by":"publisher","DOI":"10.1128\/JB.183.11.3531-3535.2001"},{"key":"R9","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2958.1994.tb00999.x"},{"key":"R10","doi-asserted-by":"publisher","DOI":"10.1128\/jb.176.14.4376-4384.1994"},{"key":"R11","volume-title":"Performance Standards for Antimicrobial Susceptibility Testing, 21st Informational Supplement, M100-S29","year":"2018"},{"key":"R12","volume-title":"Clinical Breakpoints for Bacteria","year":"2019"},{"key":"R13","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/dki443"},{"key":"R14","doi-asserted-by":"publisher","DOI":"10.1080\/23744235.2017.1418530"},{"key":"R15","doi-asserted-by":"publisher","DOI":"10.1038\/ncomms11607"},{"key":"R16","volume-title":"Molecular Cloning: a Laboratory Manual","author":"Sambrook","year":"1989"},{"key":"R17","doi-asserted-by":"publisher","DOI":"10.1128\/jb.164.1.294-301.1985"},{"key":"R18","doi-asserted-by":"crossref","first-page":"1711","DOI":"10.1128\/AAC.38.8.1711","article-title":"Molecular and genetic analysis of the Bacteroides uniformis cephalosporinase gene, cblA, encoding the species-specific beta-lactamase","volume":"38","author":"Smith","year":"1994","journal-title":"Antimicrob Agents and Chemother"},{"key":"R19","doi-asserted-by":"crossref","first-page":"6077","DOI":"10.1128\/JB.186.18.6077-6092.2004","article-title":"The Bacteroides fragilis pathogenicity island is contained in a putative novel conjugative transposon","volume":"1 86","author":"Franco","year":"2004","journal-title":"J Bacteriol"},{"key":"R20","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/dkn347"},{"key":"R21","doi-asserted-by":"crossref","first-page":"2492","DOI":"10.1093\/jac\/dkr339","article-title":"Molecular analysis of the effector mechanisms of cefoxitin resistance among Bacteroides strains","volume":"66","author":"S\u00f3ki","year":"2011","journal-title":"J Antimicrob Chemotherapy"},{"key":"R22","doi-asserted-by":"publisher","DOI":"10.1128\/jb.177.18.5270-5275.1995"},{"key":"R23","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijantimicag.2004.06.017"},{"key":"R24","doi-asserted-by":"crossref","first-page":"257","DOI":"10.1099\/00207713-28-2-257","article-title":"Taxonomy of Bacteroides II. 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