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In vitro selection and characterization of Bacillus anthracis mutants with high-level resistance to ciprofloxacin.

ABSTRACT: Mutants of attenuated Bacillus anthracis with high-level ciprofloxacin resistance were isolated using a three-step in vitro selection. Ciprofloxacin MICs were 0.5 micro g/ml for first-step mutants, which had one of two gyrA quinolone resistance-determining region (QRDR) mutations. Ciprofloxacin MICs were 8 and 16 microg/ml for second-step mutants, which had one of three parC QRDR mutations. Ciprofloxacin MICs for third-step mutants were 32 and 64 microg/ml. Mutants for which MICs were 64 microg/ml had one of two additional mutations within the gyrA QRDR or one of two mutations within the gyrB QRDR. Mutants for which MICs were 32 microg/ml had no additional target modifications but showed evidence of enhanced ciprofloxacin efflux.

SUBMITTER: Price LB

PROVIDER: S-EPMC161847 | biostudies-literature | 2003 Jul

REPOSITORIES: biostudies-literature

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In vitro selection and characterization of Bacillus anthracis mutants with high-level resistance to ciprofloxacin.

Price Lance B LB Vogler Amy A Pearson Talima T Busch Joseph D JD Schupp James M JM Keim Paul P

Antimicrobial agents and chemotherapy 20030701 7

Mutants of attenuated Bacillus anthracis with high-level ciprofloxacin resistance were isolated using a three-step in vitro selection. Ciprofloxacin MICs were 0.5 micro g/ml for first-step mutants, which had one of two gyrA quinolone resistance-determining region (QRDR) mutations. Ciprofloxacin MICs were 8 and 16 microg/ml for second-step mutants, which had one of three parC QRDR mutations. Ciprofloxacin MICs for third-step mutants were 32 and 64 microg/ml. Mutants for which MICs were 64 microg/ ...[more]

PMID: 12821500

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