The in-vitro antimicrobial activity of HSR-903, a new fluoroquinolone, was tested against 51 clinical Neisseria gonorrhoeae isolates in comparison with ciprofloxacin, levofloxacin and sparfloxacin. The MICs of HSR-903 for 11 isolates with alterations in both GyrA and ParC, for 19 isolates with alterations only in GyrA and for 21 isolates without alterations in either GyrA or ParC ranged from 0....

Background: Emergence Klebsiella pneumoniae resistant to quinolone antibiotics due to mutations in gyrA and parC genes created problem for treatment of patients in different hospitals in Iran. The objective of this study was to determine the amino acid substitutions of GyrA and ParC proteins in certain clonal lineages of the K. pneumoniae conferring high level quinolone resistance. Methods: One...

For 10 strains of Neisseria gonorrhoeae exhibiting decreased susceptibility to new quinolones (MIC, > or = 0.1 microgram/ml) isolated and preserved from patients with gonococcal urethritis during the period from February 1991 through January 1992. We investigated the mechanisms for development of resistance to new quinolones. After selecting 3 PCG-sensitive and new quinolone-resistant strains f...

Interleukin-4 (IL-4) is a multifunctional cytokine that plays a critical role in apoptosis, differentiation and proliferation. The intensity of IL4 response depends upon binding to its receptor, IL-4R. The therapeutic efficiency of interleukins can be increased by generating structural mutants having greater stability. In the present work, attempts were made to increase the stability of human I...

In this study, we systematically examined in vitro frequencies and spectra of the spontaneous mutations in Helicobacter pylori that confer resistance to clarithromycin (Cla(r)), metronidazole (Mtz(r)), amoxicillin (Amx(r)), ciprofloxacin (Cip(r)), and rifampin (Rif(r)). The mutation rate of Rif(r) or Cip(r) determined in a fluctuation assay is 1 x 10(-8) to 2 x 10(-8) per cell per division. In ...

An oligonucleotide biochip that specifically detects point mutations in the gyrA and parC genes of Neisseria gonorrhoeae was designed and subsequently evaluated with 87 untreated clinical specimens. The susceptibilities of the N. gonorrhoeae strains were tested to determine the prevalence of ciprofloxacin-resistant strains in Anhui Province, People's Republic of China. Conventional DNA sequenci...

We developed a novel rapid assay to detect the gyrA mutations that cause quinolone resistance in typhoid and paratyphoid fever Salmonella spp. using high-resolution melting (Idaho Technology, Salt Lake City, UT) analysis of polymerase chain reaction amplicons. The presence of gyrA mutations led to small but consistent changes in amplicon melting temperatures that allowed quinolone-resistant iso...

HIGHLIGHTS Mutational analysis of antibiotic resistant genes E. coli in UTI Patients. These were detected by PCR and sequenced using NGS. isolates positive for GyrA gene, GyrB tetB tetR gene. The novel mutation was gyrB gene at codon554.

Mutations causing antibiotic resistance usually incur a fitness cost in the absence of antibiotics. The magnitude of such costs is known to vary with the environment. Little is known about the fitness effects of antibiotic resistance mutations when bacteria confront the host's immune system. Here, we study the fitness effects of mutations in the rpoB, rpsL, and gyrA genes, which confer resistan...