Previous Article | Next Article ![]()
Antimicrobial Agents and Chemotherapy, August 2001, p. 2348-2353, Vol. 45, No. 8
Department of Internal Medicine, Division of
Infectious Diseases, University of California-Davis, Medical Center,
Sacramento, California,1 and Institute
for Medical Microbiology and Epidemiology of Infectious Diseases,
University of Leipzig, 04103 Leipzig,2
Merlin Diagnostika mbH, 53332 Bornheim-Hersel,3 and Department of
Pharmaceutical Biology, Institute of Pharmacy, University of Hamburg,
20146 Hamburg,4 Germany
Received 21 December 2000/Returned for modification 12 February
2001/Accepted 24 May 2001
Clostridium difficile is the etiological agent of
antibiotic-associated colitis and the most common cause of
hospital-acquired infectious diarrhea. Fluoroquinolones such as
ciprofloxacin are associated with lower risks of C. difficile-associated diarrhea. In this study, we have analyzed 72 C. difficile isolates obtained from patients with different
clinical courses of disease, such as toxic megacolon and relapses; the
hospital environment; public places; and horses. They were investigated
for their susceptibilities to moxifloxacin (MXF), metronidazole (MEO),
and vancomycin (VAN). Mutants highly resistant to fluoroquinolones were
selected in vitro by stepwise exposure to increasing concentrations of
MXF. The resulting mutants were analyzed for the presence of mutations in the quinolone resistance-determining regions of DNA gyrase (gyrA), the production of toxins A and B, and the
epidemiological relationship of these isolates. These factors were also
investigated using PCR-based methods. All strains tested were
susceptible to MEO and VAN. Twenty-six percent of the clinical isolates
(19 of 72) were highly resistant to MXF (MIC
0066-4804/01/$04.00+0 DOI: 10.1128/AAC.45.8.2348-2353.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Resistance to Moxifloxacin in Toxigenic
Clostridium difficile Isolates Is Associated with Mutations
in gyrA
16 µg/ml).
Fourteen of these 19 strains contained nucleotide changes resulting in
amino acid substitutions at position 83 in the gyrA
protein. Resistant strains selected in vitro did not contain mutations
at that position. These findings indicate that resistance to MXF in a
majority of cases may be due to amino acid substitution in the
gyrA gene.
*
Corresponding author. Mailing address: University of
California-Davis Medical Center, Division of Infectious Diseases,
Department of Internal Medicine, PSSB, Suite 500, 4150 V St.,
Sacramento, CA 95817. Phone: (916) 734-3741. Fax: (916) 734-0518. E-mail: grit.ackermann{at}ucdmc.ucdavis.edu.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»