Oxolinic acid (OA), a quinolone, inhibits the activity of DNA gyrase composed of GyrA and GyrB and shows antibacterial activity against Burkholderia glumae. Since B. glumae causes bacterial seedling rot and grain rot of rice, both of which are devastating diseases, the emergence of OA-resistant bacteria has important implications on rice cultivation in Japan. Based on the MIC of OA, 35 B. gluma...

As only the type II topoisomerase is capable of introducing negative supercoiling, DNA gyrase is involved in crucial cellular processes. Although the other domains of DNA gyrase are better understood, the mechanism of DNA binding by the C-terminal domain of the DNA gyrase A subunit (GyrA-CTD) is less clear. Here, we investigated the DNA-binding sites in the GyrA-CTD of Mycobacterium tuberculosi...

A sparfloxacin-susceptible clinical isolate of Staphylococcus aureus was grown in increased concentrations of sparfoxacin. The presence of mutations in gyrA, gyrB, grlA and grlB genes was analyzed. The primary point mutation was located in the gyrA gene (Glu-88 to Lys). Two further mutation steps appeared in the amino acid change Ser-80 to Tyr in GrlA. No mutations occurred in the gyrB or grlB ...

The minimum inhibitory concentrations (MICs), mutation prevention concentrations (MPCs) and contribution of quinolone resistance-determining region (QRDR) mutations to fluoroquinolone (ciprofloxacin, enrofloxacin and orbifloxacin) susceptibility in 23 Pasteurella multocida (Pm) isolates were investigated. Fluoroquinolone-susceptible isolates (MICs ≤0.25 µg/ml, 9 isolates) had no QRDR mutations,...

OBJECTIVES We investigated the contribution of gyrA and parC mutational mechanism in decreased ciprofloxacin susceptibility of Acinetobacter baumannii isolated from burn wound infections. MATERIALS AND METHODS Ciprofloxacin susceptibility of 50 A. baumannii isolates was evaluated by disk diffusion and agar dilution methods. PCR and sequencing were performed for detection of mutation in gyrA a...

By real-time quantitative PCR (RTQ-PCR), two different standardisation methods were used to quantify expression of three target genes (RNAII and RNAIII transcripts of agr locus and ica transcript of icaADBC locus): (i) a relative quantification, using a transcript of three housekeeping genes (gyrase A, gyrA; guanylate kinase, gmk and 16S rRNA, 16S) as internal standard, and (ii) an absolute qua...

clinical condition of the patient improved and he was discharged several days later. R esistance to the newer quinolones in H. influenz ae is rare. In a large Canadian study in 1992 and 1993, all of 1688 strains were susceptible to ciprofloxacin. 2 Jones found 1% of 7961 H. influenz ae isolates to be moderately susceptible, 3 and 1% resistant to lomefloxacin. Barriere & H indler 4 and G ould et...

Background Little is known about the evolutionary process and emergence time of resistance mutations to fluoroquinolone in Salmonella enterica serovar Typhi. Methods We analyzed S. Typhi isolates collected from returned travelers between 2001 and 2016. Based on ciprofloxacin susceptibility, isolates were categorized as highly resistant (minimum inhibitory concentration [MIC] ≥ 4 μg/mL [CIPHR]...