Staphylococcus aureus BM4626 (ciprofloxacin MIC, 0.5 microgram/ml) and BM4627 (ciprofloxacin MIC, 32 microgram/ml) were isolated from the same patient before and during pefloxcin therapy for septic tibial nonunion, respectively. The two strains had similar serotypes and indistinguishable phage types and SmaI-generated restriction fragment length polymorphisms. Portions of the gyrA (codons 60 to...

The antibiotic resistance of 16 Aeromonas (A.) salmonicida strains isolated from diseased fish and environmental samples in Korea from 2006 to 2009 were investigated in this study. Tetracycline or quinolone resistance was observed in eight and 16 of the isolates, respectively, based on the measured minimal inhibitory concentrations. Among the tetracycline-resistant strains, seven of the isolate...

Twelve quinolone-resistant clinical isolates of Escherichia coli (nalidixic acid MICs, 64 to 512 micrograms/ml; norfloxacin MICs, 0.25 to 8 micrograms/ml) were transformed with plasmid pJSW101 carrying the gyrA+ gene and with plasmid pJB11 carrying the gyrB+ gene to examine the proportion of gyrA and gyrB mutations. Transformation with pJSW101 resulted in complementation (nalidixic acid MICs, 4...

A clinical isolate of Pseudomonas aeruginosa G48, became resistant during fluoroquinolone treatment giving rise to the post-therapy isolate, G49. To determine whether mutation in gyrA gave rise to fluoroquinolone resistance, G49 was transformed with a plasmid encoding gyrA (pNJR3-2); this reduced the MIC of fluoroquinolones for G49 two-fold. DNA sequencing of gyrA of G49 demonstrated a mutation...

Sir, A recent review by Smith et al.1 and associated correspondence2,3 raised important unresolved issues regarding which quinolones exert dual activity through gyrase and topoisomerase IV in Streptococcus pneumoniae. Dual action involves the substantial engagement of both enzyme killing pathways and is of particular interest in potentially limiting the emergence of resistance. Smith et al.3 co...

The A subunit of DNA gyrase in mycobacteria is frequently subjected to splicing events as its gene, gyrA, harbours an insertion encoding an intein. Investigation of a number of different isolates of Mycobacterium kansasii, Mycobacterium malmoense, Mycobacterium marinum, Mycobacterium ulcerans and Mycobacterium xenopi demonstrated that the presence of GyrA inteins is not random but a taxonomic c...

background rapid detection of resistant strains of helicobacter pylori in human clinical samples is of major importance in clinical settings. inability of conventional clinical laboratory techniques in detection of these strains usually leads to failure of prescribed therapeutic regimens. objectives the aim of this study was designing a simple and rapid allele-specific pcr (as-pcr)-based method...

A total of 91 non-typhoid Salmonella isolated from pediatric patients with diarrhea in Seoul from 2003 to 2009 was tested for antimicrobial susceptibility of nalidixic acid (NA). Forty strains of NA resistance or intermediate susceptible non-typhoid Salmonella were identified and their minimum inhibitory concentrations (MICs) of NA, ciprofloxacin (CIP), and norfloxacin (NOR) were determined. Of...

This study was undertaken to identify and characterize amino acid substitutions in gyrA and parC related with quinolone resistance of 27 nalidixic acid-resistant (NaR) Salmonella isolates collected in poultry slaughterhouses in Korea. A total of 51 Salmonella isolates were detected from 44.8% (47/105) of the total samples from 15 poultry slaughterhouses examined, among which 27 (52.9%) NaR isol...

Part of the gyrase A gene (gyrA) of Acholeplasma laidlawii was cloned and incorporated directly downstream from a 6 x His tag segment of the pQE expression vector. The 23-kDa fusion protein was expressed as a 6 x His-tagged protein in Escherichia coli. The fusion protein was purified and used as an antigen for rabbit immunization. Western immunoblot analysis revealed that the antiserum raised a...