Cloning and nucleotide sequence of the gyrA gene from Campylobacter fetus subsp. fetus ATCC 27374 and characterization of ciprofloxacin-resistant laboratory and clinical isolates.

D E Taylor, A S Chau

Department of Medical Microbiology & Immunology, University of Alberta, Edmonton, Canada. diane.taylor@ualberta.ca

Antimicrobial agents and chemotherapy 1997 Mar

filter terms:

The gyrA gene of Campylobacter fetus subsp. fetus, which encodes the A subunit of DNA gyrase, was cloned, and its nucleotide sequence was determined. An open reading frame of 2,586 nucleotides which encodes a polypeptide of 862 amino acids with an Mr of 96,782 was identified. C. fetus subsp. fetus GyrA is most closely related to Campylobacter jejuni GyrA, with 73% homology at the nucleotide level and 78% identity between polypeptides. The next most closely related GyrA was that from Helicobacter pylori, with both DNA homology and amino acid identity of 63%. The gyrA and gyrB (DNA gyrase B subunit) genes were located on the genomic map of C. fetus subsp. fetus ATCC 27374 and shown to be separate. A clinical isolate of C. fetus subsp. fetus and a laboratory-derived mutant of ATCC 27374, both resistant to ciprofloxacin, had identical mutations within the quinolone resistance determining region. In both mutants a G-->T transversion, corresponding to a substitution of Asp-91 to Tyr in GyrA, was linked to ciprofloxacin resistance, giving MICs of 8 to 16 micrograms/ml.

Citation

D E Taylor, A S Chau. Cloning and nucleotide sequence of the gyrA gene from Campylobacter fetus subsp. fetus ATCC 27374 and characterization of ciprofloxacin-resistant laboratory and clinical isolates. Antimicrobial agents and chemotherapy. 1997 Mar;41(3):665-71