Cloning and nucleotide sequence of the Campylobacter jejuni gyrA gene and characterization of quinolone resistance mutations.
The gyrA gene of Campylobacter jejuni UA580, which encodes the A subunit of DNA gyrase, was cloned and its nucleotide sequence was determined. An open reading frame of 2,589 nucleotides was identified, which could code for a polypeptide of 863 amino acids with a M(r) of 97 kDa. Both the nucleotide sequence and the putative amino acid sequence show ca. 50% identity with those of other gyrA genes from gram-positive and gram-negative bacteria. The locations of the gyrA gene on genome maps of both C. jejuni UA580 and Campylobacter coli UA417 were determined. Six nalidixic acid-resistant isolates of C. jejuni were shown to carry mutations in gyrA. Three clinical isolates had Thr-86-to-Ile substitutions. Three laboratory mutants had substitutions of Thr-86 to Ile, Asp-90 to Ala, and Ala-70 to Thr, respectively. The mutation at Thr-86, which is homologous to Ser-83 in Escherichia coli, was associated with high-level resistance to ciprofloxacin in C. jejuni.
Department of Medical Microbiology, University of Alberta, Edmonton, Canada.
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Huang
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Taylor
D042462:4-Quinolones; D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001483:Base Sequence; D016123:Campylobacter jejuni / Q000737:chemistry / Q000187:drug effects / Q000235:genetics*; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial / Q000737:chemistry; D003001:Cloning, Molecular; D004250:DNA Topoisomerases, Type II / Q000235:genetics* / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000302:isolation & purification; D004352:Drug Resistance, Microbial / Q000235:genetics; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D059005:Topoisomerase II Inhibitors
D042462:4-Quinolones; D000890:Anti-Infective Agents; D004269:DNA, Bacterial; D059005:Topoisomerase II Inhibitors; D004250:DNA Topoisomerases, Type II