title: Antibiotic selection of Escherichia coli sequence type 131 in a mouse intestinal colonization model.
abstract: The ability of different antibiotics to select for extended-spectrum β-lactamase (ESBL)-producing Escherichia coli remains a topic of discussion. In a mouse intestinal colonization model, we evaluated the selective abilities of nine common antimicrobials (cefotaxime, cefuroxime, dicloxacillin, clindamycin, penicillin, ampicillin, meropenem, ciprofloxacin, and amdinocillin) against a CTX-M-15-producing E. coli sequence type 131 (ST131) isolate with a fluoroquinolone resistance phenotype. Mice (8 per group) were orogastrically administered 0.25 ml saline with 10(8) CFU/ml E. coli ST131. On that same day, antibiotic treatment was initiated and given subcutaneously once a day for three consecutive days. CFU of E. coli ST131, Bacteroides, and Gram-positive aerobic bacteria in fecal samples were studied, with intervals, until day 8. Bacteroides was used as an indicator organism for impact on the Gram-negative anaerobic population. For three antibiotics, prolonged colonization was investigated with additional fecal CFU counts determined on days 10 and 14 (cefotaxime, dicloxacillin, and clindamycin). Three antibiotics (cefotaxime, dicloxacillin, and clindamycin) promoted overgrowth of E. coli ST131 (P < 0.05). Of these, only clindamycin suppressed Bacteroides, while the remaining two antibiotics had no negative impact on Bacteroides or Gram-positive organisms. Only clindamycin treatment resulted in prolonged colonization. The remaining six antibiotics, including ciprofloxacin, did not promote overgrowth of E. coli ST131 (P > 0.95), nor did they suppress Bacteroides or Gram-positive organisms. The results showed that antimicrobials both with and without an impact on Gram-negative anaerobes can select for ESBL-producing E. coli, indicating that not only Gram-negative anaerobes have a role in upholding colonization resistance. Other, so-far-unknown bacterial populations must be of importance for preventing colonization by incoming E. coli.
authors.affiliation: Department of Clinical Microbiology, Hvidovre University Hospital, Hvidovre, Denmark Department of Biology, University of Copenhagen, Copenhagen, Denmark Statens Serum Institut, Copenhagen, Denmark fbh@dadlnet.dk.
authors.forename: Frederik Boetius
authors.initials: FB
authors.lastname: Hertz
authors.affiliation: Department of Biology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Løbner-Olesen
authors.affiliation: Department of Clinical Microbiology, Hvidovre University Hospital, Hvidovre, Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Frimodt-Møller
mesh_terms: D000560:Amdinocillin / Q000494:pharmacology; D000667:Ampicillin / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002439:Cefotaxime / Q000494:pharmacology; D002444:Cefuroxime / Q000494:pharmacology; D002939:Ciprofloxacin / Q000494:pharmacology; D002981:Clindamycin / Q000494:pharmacology; D004009:Dicloxacillin / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects; D000077731:Meropenem; D051379:Mice; D010406:Penicillins / Q000494:pharmacology; D013845:Thienamycins / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D010406:Penicillins; D013845:Thienamycins; D002981:Clindamycin; D002939:Ciprofloxacin; D000667:Ampicillin; D004009:Dicloxacillin; D000077731:Meropenem; D002439:Cefotaxime; D002444:Cefuroxime; D000560:Amdinocillin
references.citation: Arch Intern Med. 2008 Sep 22;168(17):1897-902
references.pmid: 18809817
references.citation: Mem Inst Oswaldo Cruz. 2006 Jun;101(4):415-21
references.pmid: 16951813
references.citation: Acta Pathol Microbiol Immunol Scand B. 1987 Jun;95(3):159-65
references.pmid: 3630711
references.citation: Antimicrob Agents Chemother. 2011 Jun;55(6):2585-9
references.pmid: 21422202
references.citation: Nat Rev Microbiol. 2004 Feb;2(2):123-40
references.pmid: 15040260
references.citation: Clin Infect Dis. 2001 Apr 15;32(8):1162-71
references.pmid: 11283805
references.citation: J Med Microbiol. 2014 Apr;63(Pt 4):582-589
references.pmid: 24464694
references.citation: Microb Drug Resist. 2014 Aug;20(4):316-24
references.pmid: 24517383
references.citation: PLoS One. 2013 May 01;8(5):e62578
references.pmid: 23658749
references.citation: Int J Antimicrob Agents. 2013 Oct;42(4):347-51
references.pmid: 23992646
references.citation: Drugs. 2010 Feb 12;70(3):313-33
references.pmid: 20166768
references.citation: Antimicrob Agents Chemother. 1995 May;39(5):1030-7
references.pmid: 7625784
references.citation: Antimicrob Agents Chemother. 2010 Oct;54(10):4085-91
references.pmid: 20660675
references.citation: J Clin Microbiol. 1996 Jul;34(7):1646-8
references.pmid: 8784562
references.citation: Anaerobe. 2006 Oct-Dec;12(5-6):249-53
references.pmid: 17070078
references.citation: J Antimicrob Chemother. 2012 Oct;67(10):2438-44
references.pmid: 22685162
references.citation: J Antimicrob Chemother. 2009 Aug;64(2):274-7
references.pmid: 19474064
references.citation: Antimicrob Agents Chemother. 2003 Mar;47(3):1002-9
references.pmid: 12604534
references.citation: Antimicrob Agents Chemother. 2001 Apr;45(4):1078-85
references.pmid: 11257018
references.citation: Clin Infect Dis. 2006 Dec 1;43(11):1407-14
references.pmid: 17083012
references.citation: J Clin Microbiol. 2011 Sep;49(9):3441
references.pmid: 21734023
references.citation: Front Microbiol. 2012 Jan 19;3:9
references.pmid: 22294983
references.citation: Lancet Infect Dis. 2008 Mar;8(3):159-66
references.pmid: 18291338
references.citation: J Antimicrob Chemother. 2011 Jan;66(1):1-14
references.pmid: 21081548
references.citation: Antimicrob Agents Chemother. 2012 May;56(5):2364-70
references.pmid: 22354301
references.citation: Antimicrob Agents Chemother. 2010 Jun;54(6):2391-400
references.pmid: 20308386
references.citation: Int J Antimicrob Agents. 2010 Apr;35(4):316-21
references.pmid: 20060273
references.citation: Ann Surg. 1982 Apr;195(4):444-50
references.pmid: 7039527
references.citation: J Antimicrob Chemother. 1997 Nov;40(5):679-86
references.pmid: 9421316
references.citation: J Microbiol Methods. 2005 Dec;63(3):229-38
references.pmid: 15979748
references.citation: Eur J Clin Microbiol Infect Dis. 2013 Mar;32(3):431-6
references.pmid: 23129461