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...

Introduction: Antibiotic resistance, especially in Gram-negative uropathogens such as Escherichia coli, is the main barrier to treat urinary tract infection (UTI). In recent years, the dramatically increased resistance of E. coli to quinolones, a group of widely used antibiotics, has become a significant concern. Methods: In this descriptive cross-sectional study, we collected 261 E. coli isola...

A comparative Hansch type QSAR study was conducted using multiple regression analysis on various sets of quinoxalines, quinoxalin-4-ones, quinazoline-2-carboxylates, 4-hydroxyquinolin-2(1H)-ones, 2-carboxytetrahydroquinolines, phenyl-hydroxy-quinolones, nitroquinolones and 4-substituted-3-phenylquinolin-2(1H)-ones as selective glycine/NMDA site antagonists. Ten statistically validated equations...

Some quinolone antibiotics cause increases in levels of theophylline in plasma that lead to serious adverse effects. We investigated the mechanism of this interaction by developing an in vitro system of human liver microsomes. Theophylline (1,3-dimethylxanthine) was incubated with human liver microsomes in the presence of enoxacin, ciprofloxacin, norfloxacin, or ofloxacin. Theophylline, its dem...

Resistance to the quinolones almost always arises from the accumulation of mutations in chromosomal genes responsible for the drug targets, permeability, or active efflux. This resistance can be depicted as a stepwise process in which each step, represented by separate mutations, diminishes susceptibility on average 4- to 8-fold. The precise path followed in this stepwise process differs with t...

This study evaluated bacterial etiology and antibiotic susceptibility in patients diagnosed with community-acquired perforated appendicitis over a 12-year-period. We retrospectively reviewed records of adult patients diagnosed with perforated appendicitis at an 800-bed teaching hospital between January 2000 and December 2011. In total, 415 culture-positive perforated appendicitis cases were ana...

Quinolones are widely used in the treatment of respiratory infections, in large part because of their activity against Streptococcus pneumoniae and other commonly encountered respiratory tract pathogens. Pneumococcal isolates that are resistant to these "respiratory quinolones" have now begun to emerge. Resistance is attributable to mutations affecting the intracellular targets of these drugs, ...

Of 94 clinical isolates of Staphylococcus aureus (n = 51) and coagulase-negative staphylococci (CNS) (n = 43), mutations in the quinolone resistance-determining region of topoisomerases GrlA, GrlB, GyrA, and GyrB together with MICs of six quinolones were analyzed. Amino acid substitutions at identical residues (GrlA residues 80 and 84; GyrA residues 84 and 88) were found in S. aureus and CNS. A...

An epidemiological study of filariasis in three villages along the coast at Matara has shown a prevalence of microfilaraemia of 4.4% and a geometric mean microfilaraemia density of 20.6 microfilariae/60ul of fingerprick blood. These are higher than previous values for the area. Prevalence is lower in females compared to males, and also in males under 20 years compared to the older males. Clinic...