quinolones are a very important family of antibacterial agents that are widely prescribed for the treatment of infections in humans. since their discovery in the early 1960s, the quinolone group of antibacterials has generated considerable clinical and scientific interest. two major groups of compounds have been developed from the basic molecule: quinolones and naphthyridones. the 4-pyridone-3-...

INTRODUCTION Typhoid fever is endemic in Egypt; and quinolones are the empirical treatment of choice. There are very limited data reporting quinolone resistance among Egyptian typhoidal Salmonella isolates. We previously reported that all typhoidal Salmonella were sensitive to quinolones. This study aimed to isolate and identify typhoidal Salmonella from cases suffering from enteric fever at Mi...

The quinolones trap DNA gyrase and DNA topoisomerase IV on DNA as complexes in which the DNA is broken but constrained by protein. Early studies suggested that drug binding occurs largely along helix-4 of the GyrA (gyrase) and ParC (topoisomerase IV) proteins. However, recent X-ray crystallography shows drug intercalating between the -1 and +1 nucleotides of cut DNA, with only one end of the dr...

The increased use of fluoroquinolones has led to increasing resistance to these antimicrobials, with rates of resistance that vary by both organism and geographic region. Resistance to fluoroquinolones typically arises as a result of alterations in the target enzymes (DNA gyrase and topoisomerase IV) and of changes in drug entry and efflux. Mutations are selected first in the more susceptible t...

Antibiotic use has led to increased resistance to certain group markers: penicillin, erythromycin and ciprofloxacin for beta-lactams, macrolides and quinolones, respectively. The influence of resistance to markers in decreasing susceptibility to the drugs included (on the basis of chemical structure) in the corresponding antibiotic group can be defined as 'resistance class effect'. In the case ...

Objective(s) Extensive use of quinolones has been associated with raising level of resistance. In the current, we focused on assessing the prevalence of Escherichia coli resistance to quinolones and frequency of qnrA, qnrB and qnrS in non ESBLs (extended spectrum beta-lactamases) and ESBLs producing E. coli with blaSHV and blaTEM. Materials and Methods One hundred and fifty E. coli isolates ...

OBJECTIVES Pentapeptide repeat proteins (PRPs) QnrA, QnrB and QnrS confer reduced susceptibility to quinolones. This study presents an in vitro analysis of the genetic evolution of quinolone resistance mediated by changes in the coding sequences and promoter regions of qnrA1, qnrS1 and qnrB1 genes. METHODS A random mutagenesis technique was used to predict the evolutionary potential of these ...

Antimicrobial resistance among human pathogens which is not related to veterinary use 6 Mechanism of (fluoro)quinolone resistance and interpretation of susceptibility tests....... 6 Selection for resistance in food borne pathogens when using (fluoro)quinolones in food-MANDATE The Scientific Advisory Group on Antimicrobials (SAGAM) was mandated to give advice to the CVMP on the need to exercise ...