{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T22:15:28Z","timestamp":1791843328497,"version":"4.3.4"},"reference-count":31,"publisher":"American Society for Microbiology","issue":"9","license":[{"start":{"date-parts":[[1999,9,1]],"date-time":"1999-09-01T00:00:00Z","timestamp":936144000000},"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":[[1999,9]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n          <jats:p>\n            In vitro pharmacodynamic studies investigating the antimicrobial properties of five fluoroquinolones, (trovafloxacin, sparfloxacin, clinafloxacin, levofloxacin, and ciprofloxacin) against\n            <jats:italic>Bacteroides fragilis<\/jats:italic>\n            ATCC 23745 were conducted. The times required to reduce the viable counts by 3 log units were as follows: clinafloxacin, 2.9 h; levofloxacin, 4.6 h; trovafloxacin, 6 h; and sparfloxacin, 10 h. Exposure to ciprofloxacin did not achieve a 3-log decrease in viable counts. The susceptibility of\n            <jats:italic>B. fragilis<\/jats:italic>\n            was determined both prior to exposure and following 24 h of exposure to each of the five fluoroquinolones tested. The MICs of clinafloxacin, levofloxacin, trovafloxacin, sparfloxacin, ciprofloxacin, metronidazole, cefoxitin, chloramphenicol, and clindamycin were determined by the broth microdilution method. The MICs for\n            <jats:italic>B. fragilis<\/jats:italic>\n            preexposure were as follows: clinafloxacin, 0.25 \u03bcg\/ml; trovafloxacin, 0.5 \u03bcg\/ml; sparfloxacin, 2 \u03bcg\/ml; levofloxacin, 2 \u03bcg\/ml; and ciprofloxacin, 8 \u03bcg\/ml. Similar pre- and postexposure MICs were obtained for cultures exposed to trovafloxacin, clinafloxacin, levofloxacin, and ciprofloxacin. However, following 24 h of exposure to sparfloxacin, a fluoroquinolone-resistant strain emerged. The MICs for this strain were as follows: clinafloxacin, 1 \u03bcg\/ml; trovafloxacin, 4 \u03bcg\/ml; sparfloxacin, 16 \u03bcg\/ml; levofloxacin, 16 \u03bcg\/ml; and ciprofloxacin, 32 \u03bcg\/ml. No changes in the susceptibility of\n            <jats:italic>B. fragilis<\/jats:italic>\n            pre- and postexposure to sparfloxacin were noted for metronidazole (MIC, 1 \u03bcg\/ml), cefoxitin (MIC, 4 \u03bcg\/ml), chloramphenicol (MIC, 4 \u03bcg\/ml), and clindamycin (MIC, 0.06 \u03bcg\/ml). Resistance remained stable as the organism was passaged on antibiotic-free agar for 10 consecutive days. Mutant\n            <jats:italic>B. fragilis<\/jats:italic>\n            strains with decreased susceptibility to clinafloxacin, trovafloxacin, sparfloxacin, levofloxacin, and ciprofloxacin were selected on brucella blood agar containing 8\u00d7 the MIC of levofloxacin at a frequencies of 6.4 \u00d7 10\n            <jats:sup>\u22129<\/jats:sup>\n            , 4\u00d7 the MICs of trovafloxacin and sparfloxacin at frequencies of 2.2 \u00d7 10\n            <jats:sup>\u22129<\/jats:sup>\n            and 3.3 \u00d7 10\n            <jats:sup>\u221210<\/jats:sup>\n            , respectively, and 2\u00d7 the MIC of clinafloxacin at a frequency of 5.5 \u00d7 10\n            <jats:sup>\u221211<\/jats:sup>\n            ; no mutants were selected with ciprofloxacin. The susceptibilities of strains to trovafloxacin, levofloxacin, clinafloxacin, sparfloxacin, and ciprofloxacin before and after exposure to sparfloxacin were modestly affected by the presence of reserpine (20 \u03bcg\/ml), an inhibitor of antibiotic efflux. The mechanism of fluoroquinolone resistance is being explored, but it is unlikely to be efflux due to a lack of cross-resistance to unrelated antimicrobial agents and to the fact that the MICs for strains before and after exposure to sparfloxacin are minimally affected by reserpine.\n          <\/jats:p>","DOI":"10.1128\/aac.43.9.2251","type":"journal-article","created":{"date-parts":[[2018,10,9]],"date-time":"2018-10-09T00:35:31Z","timestamp":1539045331000},"page":"2251-2255","update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":20,"title":["Fluoroquinolone Resistance in\n            <i>Bacteroides fragilis<\/i>\n            following Sparfloxacin Exposure"],"prefix":"10.1128","volume":"43","author":[{"given":"M. L.","family":"Peterson","sequence":"first","affiliation":[{"name":"<!--label omitted: 1-->College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455,1 and"},{"name":"<!--label omitted: 2-->Antibiotic Pharmacodynamic Modeling Institute, Regions Hospital, St. Paul, Minnesota 551012"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"L. B.","family":"Hovde","sequence":"additional","affiliation":[{"name":"<!--label omitted: 2-->Antibiotic Pharmacodynamic Modeling Institute, Regions Hospital, St. Paul, Minnesota 551012"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"D. H.","family":"Wright","sequence":"additional","affiliation":[{"name":"<!--label omitted: 1-->College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455,1 and"},{"name":"<!--label omitted: 2-->Antibiotic Pharmacodynamic Modeling Institute, Regions Hospital, St. Paul, Minnesota 551012"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"A. D.","family":"Hoang","sequence":"additional","affiliation":[{"name":"<!--label omitted: 1-->College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455,1 and"},{"name":"<!--label omitted: 2-->Antibiotic Pharmacodynamic Modeling Institute, Regions Hospital, St. Paul, Minnesota 551012"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J. K.","family":"Raddatz","sequence":"additional","affiliation":[{"name":"<!--label omitted: 1-->College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455,1 and"},{"name":"<!--label omitted: 2-->Antibiotic Pharmacodynamic Modeling Institute, Regions Hospital, St. Paul, Minnesota 551012"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"P. J.","family":"Boysen","sequence":"additional","affiliation":[{"name":"<!--label omitted: 2-->Antibiotic Pharmacodynamic Modeling Institute, Regions Hospital, St. Paul, Minnesota 551012"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J. C.","family":"Rotschafer","sequence":"additional","affiliation":[{"name":"<!--label omitted: 1-->College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455,1 and"},{"name":"<!--label omitted: 2-->Antibiotic Pharmacodynamic Modeling Institute, Regions Hospital, St. Paul, Minnesota 551012"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"235","reference":[{"key":"e_1_3_2_2_2","doi-asserted-by":"crossref","first-page":"S67","DOI":"10.1093\/clinids\/24.Supplement_1.S67","article-title":"Trends in bacterial resistance to fluoroquinolones.","volume":"24","author":"Acar J. F.","year":"1997","unstructured":"Acar J. F. Goldstein F. W. Trends in bacterial resistance to fluoroquinolones. Clin. Infect. Dis. 24 (Suppl. 1) 1997 S67 S73","journal-title":"Clin. Infect. 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Chem."},{"key":"e_1_3_2_4_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.38.7.1671"},{"key":"e_1_3_2_5_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.38.6.1442"},{"key":"e_1_3_2_6_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.41.10.2312"},{"key":"e_1_3_2_7_2","doi-asserted-by":"crossref","first-page":"4722","DOI":"10.1073\/pnas.74.11.4772","article-title":"Nalidixic acid resistance: a second genetic character involved in DNA gyrase activity.","volume":"74","author":"Gellert M.","year":"1977","unstructured":"Gellert M. Mizuuchi K. O\u2019Dea M. H. Itoh T. Tomizawa J. Nalidixic acid resistance: a second genetic character involved in DNA gyrase activity. Proc. Natl. Acad. Sci. USA 74 1977 4722 4776","journal-title":"Proc. Natl. Acad. Sci. 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D.\n              Raddatz\n              J.-K.\n              Horde\n              L. B.\n              Rotschafer\n              J. C.\n          Stable fluoroquinolone (FQ) class resistance seen with Bacteroides fragilis (BF) after exposure to sparfloxacin (S) abstr. E-169\n          Program and abstracts of the 37th Interscience Conference on Antimicrobial Agents and Chemotherapy.\n          1997\n          144\n          American Society for Microbiology\n          Washington D.C"},{"key":"e_1_3_2_22_2","unstructured":"Peterson\n              M. L.\n              Hovde\n              L. B.\n              Wright\n              D. H.\n              Hoang\n              A. D.\n              Rotschafer\n              J. C.\n          Trovafloxacin and levofloxacin resistance in Bacteroides fragilis abstr. E32\n          Program and abstracts of the 38th Interscience Conference on Antimicrobial Agents and Chemotherapy.\n          1998\n          176\n          American Society for Microbiology\n          Washington D.C"},{"key":"e_1_3_2_23_2","unstructured":"Peterson\n              M. L.\n              Hovde\n              L. B.\n              Wright\n              D. H.\n              Hoang\n              A. D.\n              Rotschafer\n              J. C.\n          Pharmacodynamic outcome parameters as predictors for fluoroquinolones in the treatment of anaerobic infections abstr. A-85\n          Program of the 98th General Meeting of the American Society for Microbiology 1998.\n          1998\n          52\n          American Society for Microbiology\n          Washington D.C"},{"key":"e_1_3_2_24_2","doi-asserted-by":"crossref","first-page":"29","DOI":"10.2165\/00003495-199500492-00006","article-title":"Mechanisms of resistance to fluoroquinolones: state-of-the-art 1992\u20131994.","volume":"49","author":"Piddock L. J. V.","year":"1995","unstructured":"Piddock L. J. V. Mechanisms of resistance to fluoroquinolones: state-of-the-art 1992\u20131994. Drugs 49 (Suppl. 2) 1995 29 35","journal-title":"Drugs"},{"key":"e_1_3_2_25_2","doi-asserted-by":"publisher","DOI":"10.1093\/clinids\/24.Supplement_1.S110"},{"key":"e_1_3_2_26_2","unstructured":"Ricci\n              V.\n              Piddock\n              L. J. 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B) 1997 23 27","journal-title":"J. Antimicrob. Chemother."},{"key":"e_1_3_2_28_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.38.10.2471"},{"key":"e_1_3_2_29_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.42.3.521"},{"key":"e_1_3_2_30_2","unstructured":"Weigelt\n              J. A.\n          Role of fluoroquinolones in surgical infections abstr. 81.004.\n          Proceedings of the 8th International Congress on Infectious Diseases\n          1998"},{"key":"e_1_3_2_31_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.37.6.1377"},{"key":"e_1_3_2_32_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.37.11.2454"}],"container-title":["Antimicrobial Agents and Chemotherapy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/AAC.43.9.2251","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/AAC.43.9.2251","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,2,21]],"date-time":"2022-02-21T16:32:30Z","timestamp":1645461150000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.asm.org\/doi\/10.1128\/AAC.43.9.2251"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1999,9]]},"references-count":31,"journal-issue":{"issue":"9","published-print":{"date-parts":[[1999,9]]}},"alternative-id":["10.1128\/AAC.43.9.2251"],"URL":"https:\/\/doi.org\/10.1128\/aac.43.9.2251","relation":{},"ISSN":["0066-4804","1098-6596"],"issn-type":[{"value":"0066-4804","type":"print"},{"value":"1098-6596","type":"electronic"}],"subject":[],"published":{"date-parts":[[1999,9]]},"assertion":[{"value":"1997-10-29","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"1999-06-14","order":1,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"1999-09-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}