نتایج جستجو برای: gyra mutants
تعداد نتایج: 77178 فیلتر نتایج به سال:
Helicobacter pylori strains with reduced susceptibility to fluoroquinolones have a mutation at either codon 87 Asn or 91 Asp of the gyrA gene. A rapid test based on an allele-specific PCR (AS-PCR) was designed to detect the gyrA mutations. Clinical H. pylori isolates were obtained from the stomachs of 51 patients with H. pylori infections who showed treatment failure. The MICs of gatifloxacin (...
The cloning and characterization of DNA gyrase genes from Mycobacterium smegmatis is described. The DNA sequence of 5119 bp encoding both gyrB and gyrA genes was determined. The gene gyrB precedes gyrA with a short intergenic region of 29 nucleotides. The proteins encoded, GyrB and GyrA, exhibit 45-80% identity to gyrase polypeptides from other bacteria. The genes were further engineered for ov...
زمینه و هدف: فلوروکینولونها نقش مهمی در درمان عفونتهای سودوموناس آئروژینوزا بر عهده دارند. بنظر میرسد مهمترین مکانیسم مقاومت به فلوروکینولونها جهش در ناحیه QRDR ژن های gyrA و parC باشد. هدف از این مطالعه بررسی نقش جهش های مذکور بر میزان مقاومت به سیپروفلوکساسین در ایزوله های بالینی سودوموناس آئروژینوزا میباشد. روش کار: تعداد 75 ایزوله بالینی سودوموناس آئروژینوزا از مراکز آموزشی درمانی شهر ت...
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 ...
Increasing numbers of fluoroquinolone-resistant Campylobacter coli isolates received at the Minnesota State Public Health Laboratory and at the Centers for Disease Control and Prevention have been a cause for concern. The gyrA quinolone resistance-determining regions of several fluoroquinolone-resistant isolates were sequenced to examine the mechanism of resistance. Ciprofloxacin-resistant C. c...
Escherichia coli DNA gyrase contains a 1:1 ratio of protomers coded by the genes gyrA and gyrB. This along with previous results shows that the enzyme has two copies of each protomer and thus a molecular weight of 400,000. Abortion of the gyrase reaction results in double-strand breakage of the DNA and covalent attachment of both gyrA protomers to the 5'-cut ends. We conclude that the gyrA prot...
OBJECTIVES To investigate the molecular events involved in the development of quinolone resistance in enterococci. METHODS Clinical isolates of Enterococcus faecium and Enterococcus faecalis were exposed to inhibitory and subinhibitory concentrations of DX-619, ciprofloxacin, levofloxacin, gatifloxacin and moxifloxacin. Mutational frequencies were calculated and susceptibility changes were de...
در این مطالعه به منظور ارزیابی میزان مقاومت جدایه های ای کولی به انروفلوکساسین در طی یک دوره پرورش جوجه های گوشتی و ارتباط این مقاومت با موتاسیون های روی داده در ژن های مقاومت کوئینولونی gyra و parc، از 20 مزرعه پرورش جوجه های گوشتی در طی سه مرحله (جوجه های یک روزه، 35-25 روزگی و یک روز قبل از ارسال به کشتارگاه) نمونه گیری صورت گرفت. روند مقاومت برعلیه برخی از آنتی بیوتیک های رایج در 367 جدایه ...
Ability of daily sequential subcultures in subinhibitory concentrations of clinafloxacin, ciprofloxacin, and trovafloxacin to select resistant mutants was studied in 10 pneumococci (ciprofloxacin MICs, 1 to 4 microg/ml, and clinafloxacin and trovafloxacin MICs, 0.06 to 0.125 microg/ml [n = 9]; ciprofloxacin, clinafloxacin, and trovafloxacin MICs, 32, 0.5, and 2 microg/ml, respectively [n = 1])....
Mycobacterium tuberculosis is a significant source of global morbidity and mortality. Moxifloxacin and other fluoroquinolones are important therapeutic agents for the treatment of tuberculosis, particularly multidrug-resistant infections. To guide the development of new quinolone-based agents, it is critical to understand the basis of drug action against M. tuberculosis gyrase and how mutations...
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