This study investigated the presence and distribution of 22 antibiotics, including eight quinolones, nine sulfonamides and five macrolides, in the water, sediments, and biota samples from Baiyangdian Lake, China. A total of 132 samples were collected in 2008 and 2010, and laboratory analyses revealed that antibiotics were widely distributed in the lake. Sulfonamides were the dominant antibiotic...

Quinolones (nalidixic acid--NAL, norfloxacin--NOR, ciprofloxacin--CIP and gatifloxacin--GAT) were tested against Escherichia coli isolated from urine (385 patient samples) by disk diffusion (DD) and agar dilution (AD) methods. Fifty-three samples (13.8%) were classified as resistant to at least one of the quinolones tested. CIP and NOR susceptibilities were the same (91.4%) and they were simila...

Sixty recent Streptococcus pneumoniae isolates with different susceptibilities to ciprofloxacin (14 with MIC 0.5 mg/L, 10 with MIC 1 mg/L, eight with MIC 2 mg/L, 11 with MIC 4 mg/L and 17 with MIC > or =8 mg/L) were tested against five new quinolones using Todd-Hewitt broth with and without 80% serum. The final inoculum was 5 x 10(5) cfu/mL. Gemifloxacin and clinafloxacin exhibited the lowest M...

Currently, a standard third-line therapy for Helicobacter pylori (H. pylori) eradication remains to be established. Quinolones show good oral absorption, no major side effects, and marked activity against H. pylori. Several authors have studied quinolone-based third-line therapy and reported encouraging results, with the reported H. pylori cure rates ranging from 60% to 84%. Resistance to quino...

Quinolones were examined for rapid lethal activity against Mycobacterium smegmatis in the presence and absence of chloramphenicol, an inhibitor of protein synthesis. C-8 methoxy, C-6 fluorine, and particular C-7 ring substituents enhanced rapid killing. With the surprising exception of moxifloxacin, higher quinolone concentrations were required for lethal activity in the presence of chloramphen...

Quinolones are one of the largest classes of antimicrobial agents used worldwide. This review considers the quinolones that are available currently and used widely in Europe (norfoxacin, ciprofloxacin, ofloxacin, levofloxacin and moxifloxacin) within their historical perspective, while trying to position them in the context of recent and possible future advances based on an understanding of: (1...

Quinolones are antibacterial drugs that are thought to bind preferentially to disturbed regions of DNA. They do not fall into the classical categories of intercalators, groove binders or electrostatic binders to the backbone. We solved the 3D structure of the DNA duplex (ACGCGU-NA)2, where NA denotes a nalidixic acid residue covalently linked to the 2'-position of 2'-amino-2'-deoxyuridine, by N...

INTRODUCTION It is estimated that 150 million urinary tract infections (UTIs) occur yearly worldwide, resulting in more than 6 billion dollar in direct healthcare cost. The etiology of UTIs is predictable, with Escherichia coli, an Enterobacteriaceae being the principal pathogen. Quinolones are usually the drug of choice. In this study, we report the resistance pattern of Enterobacteriaceae iso...

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 mechanism of quinolone resistance in Mycoplasma genitalium remains poorly understood due to difficulties with in vitro culture, especially of clinical isolates. In this study, to confirm the association between mutations in topoisomerases and antimicrobial susceptibilities to quinolones, ciprofloxacin-resistant mutant strains were selected using the cultivable type strain ATCC 33530. Sequen...