To the Editor: Fluoroquinolone (FQ)-resistant Salmonella has been isolated from patients in Taiwan (1–7). Recently, a report further indicated that several patients were infected with Salmonella enterica serovar Schwarzengrund with high-level FQ resistance (1). S. Schwarzengrund has never been isolated from food animals in Taiwan. We report the isolation of FQresistant strains from pork and bro...

Ciprofloxacin resistant Shigella sonnei across the globe have been increasing alarmingly. In order to understand the emergence of S.sonnei with respect to ciprofloxacin resistance in our patient population, the following study was carried out. Of the 184 Shigella sp. Isolated from 2012 to 2015, 34 S.sonnei which were confirmed by standard methods and subjected to antimicrobial susceptibility te...

OBJECTIVES We conducted a study to determine the role played by amino acid mutations in DNA gyrase and topoisomerase IV, and the AcrAB efflux pump in resistance to fluoroquinolones in clinical isolates of Proteus mirabilis. METHODS Nine clinical isolates of P. mirabilis containing eight fluoroquinolone-resistant isolates and one fluoroquinolone-susceptible isolate as the causative pathogen we...

We examined the antimicrobial susceptibilities of 85 Neisseria gonorrhoeae isolates, classified according to the presence of amino acid substitutions in the GyrA and ParC proteins, to 12 fluoroquinolones and 7 other antibiotics. Sitafloxacin and HSR-903 showed excellent activity against N. gonorrhoeae, including strains with both GyrA and ParC substitutions. Among the strains with various GyrA ...

background: acinetobacter baumannii plays an important role in some types of nosocomial infections as an opportunist microorganism which increases levels of resistance to antibacterial drugs and disinfectants. objectives: the aim of this study was to determine the resistance and sensitivity of a. baumannii to different antibiotics and evaluate the minimal inhibitory concentration (mic) for cipr...

quinolones are a large and widely consumed class of synthetic drugs. expanded-spectrum quinolones, like ciprofloxacin are highly effective against gram-negative bacteria, especially escherichia coli. in e. coli the major target for quinolones is dna gyrase. this enzyme is composed of two subunits, gyra and gyrb encoding by gyra and gyrb, respectively. mutations in either of these genes cause qu...

The 2.7 A crystal structure of the 55-kDa N-terminal breakage-reunion domain of topoisomerase (topo) IV subunit A (ParC) from Streptococcus pneumoniae, the first for the quinolone targets from a gram-positive bacterium, has been solved and reveals a 'closed' dimer similar in fold to Escherichia coli DNA gyrase subunit A (GyrA), but distinct from the 'open' gate structure of Escherichia coli Par...

Eighteen quinolone-resistant isolates of Escherichia coli were selected by exposing ten clinical isolates to increasing concentrations of norfloxacin and lomefloxacin. The mutant isolates showed a multiple-antibiotic-resistance phenotype. All of them contained single mutations in gyrA consisting of the substitution of Ser-83-->Leu (n = 14), Val (n = 1) or Ala (n = 1) and the substitution of Asp...

OBJECTIVES To analyse the mutations and epidemiology associated with fluoroquinolone-resistant pneumococci collected as part of the PROTEKT global surveillance programme during 1999-2000. METHODS Sixty-nine centres in 25 countries submitted a total of 3362 Streptococcus pneumoniae isolates, for which the MICs of antimicrobial agents were determined using NCCLS methodology. RESULTS Levofloxa...