The quinolones exert their anti-bacterial activity by binding to DNA gyrase A (GyrA), an essential enzyme in maintenance of DNA topology within bacterial cell. The mutations conferring resistance to quinolones arise within the quinolone-resistance-determining region (QRDR) of GyrA. Therefore, quinolones interaction with wild and mutated GyrA can provide the molecular explanation for resistance....

BACKGROUND Quinolone is recommended as an antimicrobial prophylaxis to prevent infectious complication after transrectal ultrasound-guided biopsy, but the increased appearance of quinolone-resistant organism has raised concerns about the efficacy of quinolone. The current study was performed to evaluate various clinical factors including antimicrobial regimens associated with infectious complic...

Eighty-nine clinical isolates of Staphylococcus aureus that were resistant to both ciprofloxacin (MIC, greater than or equal to 3.13 micrograms/ml) and methicillin (MIC, greater than or equal to 12.5 micrograms/ml) were divided into two groups with respect to their susceptibilities to AT-4140. Most isolates that were moderately resistant to ciprofloxacin (MICs, 3.13 to 12.5 micrograms/ml) or of...

WCK 771, the arginine salt of S-(-)-nadifloxacin, was evaluated in animal models of staphylococcal infection and in vitro. For 302 methicillin-susceptible strains the MIC at which 50% of isolates are inhibited (MIC50) and the MIC90 of WCK 771 were 0.03 and 0.03 microg/ml, respectively, and for 198 methicillin-resistant strains the MIC50 and the MIC90 were 0.5 and 1.0 microg/ml, respectively. Al...

PURPOSE Reports evaluating diagnosis and cross reactivity of quinolone hypersensitivity have revealed contradictory results. Furthermore, there are no reports investigating the cross-reactivity between gemifloxacin (GFX) and the others. We aimed to detect the usefulness of diagnostic tests of hypersensitivity reactions to quinolones and to evaluate the cross reactivity between different quinolo...

Numerous species of bacteria use an elegant regulatory mechanism known as quorum sensing to control the expression of specific genes in a cell-density dependent manner. In Gram-negative bacteria, quorum sensing systems function through a cell-to-cell signal molecule (autoinducer) that consists of a homoserine lactone with a fatty acid side chain. Such is the case in the opportunistic human path...

Rifamycins have proven efficacy in the treatment of persistent bacterial infections. However, the frequency with which bacteria develop resistance to rifamycin agents restricts their clinical use to antibiotic combination regimens. In a program directed toward the synthesis of rifamycins with a lower propensity to elicit resistance development, a series of compounds were prepared that covalentl...

Pseudomonas aeruginosa is an opportunistic human pathogen which relies on several intercellular signaling systems for optimum population density-dependent regulation of virulence genes. The Pseudomonas quinolone signal (PQS) is a 3-hydroxy-4-quinolone with a 2-alkyl substitution which is synthesized by the condensation of anthranilic acid with a 3-keto-fatty acid. The pqsABCDE operon has been i...

Raulinoa is a monospecific genus and the species Raulinoa echinata Cowan (Rutaceae) is endemic in the Itajaí Valley, SC, Brazil. This perennial woody shrub is characterized by the presence of spines and has only been found in a short interval (1000 m) on the frequently inundated banks of Itajaí river in an approximate altitude of 100 m, showing a high degree of adaptation to the environment. We...