Emergence of quinolone-resistant, topoisomerase-mutant Brucella after treatment with fluoroquinolones in a macrophage experimental infection model.
Enferm Infecc Microbiol Clin
; 33(4): 248-52, 2015 Apr.
Article
in En
| MEDLINE
| ID: mdl-24913992
ABSTRACT
AIM OF THE STUDY To determine the activity of fluoroquinolones (FQ) and the selection of FQ-resistant mutants in a macrophage experimental infection model (MEIM). MATERIAL AND METHODS:
Canine macrophages were inoculated with Brucella melitensis ATCC 23457 (WT), achieving intracellular counts of around 105 CFU/mL. Cell cultures were incubated in the presence of ciprofloxacin (CIP), levofloxacin (LEV), moxifloxacin (MOX), and doxycycline (DOX). After cell lysis, surviving microorganisms were plated for count purposes, and plated onto antibiotics-containing media for mutant selection. Topoisomerases mutations were detected by PCR and sequencing.RESULTS:
Bacterial counts after cell lysis were 14.3% (CIP), 65.3% (LEV), and 75% (MOX) lower compared to the control. Quinolone-resistant mutants emerged in cell cultures containing CIP and LEV with a frequency of around 0.5×10(-3). All mutants showed an Ala87Val change in GyrA. Mutants had FQs MICs around 10×WT. The ability of these mutants for infecting new macrophages and the intracellular lysis after antibiotic exposure did not change significantly. No 2nd step FQ-resistant mutants were selected from 1st step mutants.CONCLUSIONS:
Intracellular activity of FQs is low against WT and gyrA-mutant Brucella. FQs easily select gyrA mutants in MEIM. The ability of mutants for infecting new macrophages remains unchanged. In this MEIM, 2nd step mutants do not emerge.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Bacterial Proteins
/
Brucella melitensis
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Macrophages, Peritoneal
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Fluoroquinolones
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DNA Gyrase
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Anti-Bacterial Agents
Limits:
Animals
Language:
En
Journal:
Enferm Infecc Microbiol Clin
Journal subject:
DOENCAS TRANSMISSIVEIS
/
MICROBIOLOGIA
Year:
2015
Document type:
Article
Affiliation country:
Spain
Publication country:
ES
/
ESPANHA
/
ESPAÑA
/
SPAIN