This study compared the potential synergy of levofloxacin and ciprofloxacin in combination with cefepime, ceftazidime, imipenem, piperacillin/tazobactam or amikacin, against extended-spectrum β-lactamase (ESBL)-producing Escherichia coli by using checkerboard and time kill studies. Moreover, selection of resistance was determined by frequency of mutations and by calculating the increase in minimum inhibitory concentrations (MICs) after five serial subcultures on antibiotic-containing plates. Synergy occurred more often with levofloxacin combined with imipenem (7/10 strains) and with levofloxacin or ciprofloxacin with amikacin (10/10) than for the other combinations. Time kill studies showed synergy for levofloxacin combined with amikacin, ceftazidime, imipenem or piperacillin/tazobactam, and for ciprofloxacin combined with amikacin, cefepime or imipenem. Antibiotic combinations selected for resistance less frequently than antibiotics alone. Mutation frequency was <10 -12 for all combinations. In conclusion, the combination of a fluoroquinolone with a β-lactam or amikacin may provide improved antimicrobial activity and help limit the occurrence of resistance in ESBL-producing E. coli strains.

In vitro synergy and selection of resistance by fluoroquinolones plus amikacin or β-lactams against extended-spectrum β-lactamase-producing Escherichia coli / L. Drago, E. De Vecchi, L. Nicola, D. Legnani, A. Lombardi, M.R. Gismondo. - In: JOURNAL OF CHEMOTHERAPY. - ISSN 1120-009X. - 17:1(2005 Feb), pp. 46-53. [10.1179/joc.2005.17.1.46]

In vitro synergy and selection of resistance by fluoroquinolones plus amikacin or β-lactams against extended-spectrum β-lactamase-producing Escherichia coli

L. Drago
Primo
;
E. De Vecchi
Secondo
;
M.R. Gismondo
2005

Abstract

This study compared the potential synergy of levofloxacin and ciprofloxacin in combination with cefepime, ceftazidime, imipenem, piperacillin/tazobactam or amikacin, against extended-spectrum β-lactamase (ESBL)-producing Escherichia coli by using checkerboard and time kill studies. Moreover, selection of resistance was determined by frequency of mutations and by calculating the increase in minimum inhibitory concentrations (MICs) after five serial subcultures on antibiotic-containing plates. Synergy occurred more often with levofloxacin combined with imipenem (7/10 strains) and with levofloxacin or ciprofloxacin with amikacin (10/10) than for the other combinations. Time kill studies showed synergy for levofloxacin combined with amikacin, ceftazidime, imipenem or piperacillin/tazobactam, and for ciprofloxacin combined with amikacin, cefepime or imipenem. Antibiotic combinations selected for resistance less frequently than antibiotics alone. Mutation frequency was <10 -12 for all combinations. In conclusion, the combination of a fluoroquinolone with a β-lactam or amikacin may provide improved antimicrobial activity and help limit the occurrence of resistance in ESBL-producing E. coli strains.
No
English
Escherichia coli; fluoroquinolones; amp; #x03B2; lactams; levofloxacin; ciprofloxacin; amikacin; synergy; resistance; β-lactams
Settore MED/07 - Microbiologia e Microbiologia Clinica
Articolo
Esperti anonimi
Pubblicazione scientifica
feb-2005
Taylor & Francis
17
1
46
53
8
Pubblicato
Periodico con rilevanza internazionale
Aderisco
info:eu-repo/semantics/article
In vitro synergy and selection of resistance by fluoroquinolones plus amikacin or β-lactams against extended-spectrum β-lactamase-producing Escherichia coli / L. Drago, E. De Vecchi, L. Nicola, D. Legnani, A. Lombardi, M.R. Gismondo. - In: JOURNAL OF CHEMOTHERAPY. - ISSN 1120-009X. - 17:1(2005 Feb), pp. 46-53. [10.1179/joc.2005.17.1.46]
reserved
Prodotti della ricerca::01 - Articolo su periodico
6
262
Article (author)
no
L. Drago, E. De Vecchi, L. Nicola, D. Legnani, A. Lombardi, M.R. Gismondo
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/212371
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