Affiliation:
1. Service de Bactériologie-Virologie-Hygiène, Hôpital Henri Mondor, Créteil,1 and
2. Faculté de Pharmacie, Lille,2France
Abstract
ABSTRACT
We determined whether
gyrA
mutations were present in fluoroquinolone-resistant laboratory mutants derived from the
Bacteroides fragilis
reference strain ATCC 25285 and in clinical isolates of
B. fragilis
. The two first-step mutants selected on ciprofloxacin (CIP) were devoid of
gyrA
mutations, whereas two of the three CIP-selected second-step mutants studied presented the same
gyrA
mutation leading to a Ser82Phe change. Unusual GyrA alterations, Asp81Asn or Ala118Val, were detected in two of the three first-step mutants selected on trovafloxacin (TRO), Mt3 and Mt1, respectively. The Ala118Val change had no effect on the susceptibility of Mt1 to CIP. No second-step mutant could be obtained with TRO as a selector. For the 12 clinical isolates studied, a Ser82Phe change in GyrA was found only in the 3 strains which showed the highest levels of TRO resistance (MIC, 4 μg/ml). Thus, the resistance phenotypes and genotypes observed in fluoroquinolone-resistant clinical isolates of
B. fragilis
were similar to those found in CIP-selected laboratory mutants, whereas peculiar mutational events could be selected in vitro with TRO.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Pharmacology (medical),Pharmacology
Cited by
22 articles.
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