The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Giancarlo Marconi - One of the best experts on this subject based on the ideXlab platform.
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gaining an insight into the photoreactivity of a drug in a protein environment a case study on Nalidixic Acid and serum albumin
Journal of Physical Chemistry B, 2008Co-Authors: Sandra Monti, Ilse Manet, Francesco Manoli, Massimo L Capobianco, Giancarlo MarconiAbstract:The binding of Nalidixic Acid (NA) with human and bovine serum albumin (HSA and BSA) in buffer solution at pH 7.4 was investigated using circular dichroism (CD), UV absorption and fluorescence spec...
Anna Longdoh Njunda - One of the best experts on this subject based on the ideXlab platform.
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treatment failure in a typhoid patient infected with Nalidixic Acid resistant s enterica serovar typhi with reduced susceptibility to ciprofloxacin a case report from cameroon
BMC Infectious Diseases, 2005Co-Authors: Njinkeng J Nkemngu, Etienne D N Asonganyi, Anna Longdoh NjundaAbstract:Fluoroquinolones or third generation cephalosporins are the drugs of choice for the treatment of typhoid fever. Treatment failure with fluoroquinolones has been reported in Asia and Europe. We report a case of ciprofloxacin treatment failure in typhoid fever in Cameroon. A 29-year-old female patient with suspected typhoid fever from Kumba, Cameroon, yielded growth of Salmonella enterica serovar Typhi in blood culture. The isolate was resistant to Nalidixic Acid but sensitive to ciprofloxacin by disc diffusion test. However, the patient did not respond to treatment with ciprofloxacin, although the isolate was apparently susceptible to ciprofloxacin. Treatment failure with ciprofloxacin in our case indicates the presence of Nalidixic Acid resistant S. enterica serovar Typhi (NARST) with reduced susceptibility to ciprofloxacin in Cameroon (Central Africa).
Mohammad Tabish - One of the best experts on this subject based on the ideXlab platform.
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investigating the mechanism of binding of Nalidixic Acid with deoxyribonucleic Acid and serum albumin a biophysical and molecular docking approaches
Journal of Biomolecular Structure & Dynamics, 2021Co-Authors: Sharmin Siddiqui, Anam Mujeeb, Faisal Ameen, Hassan Mubarak Ishqi, Sayeed Ur Rehman, Mohammad TabishAbstract:Nalidixic Acid is a bacterial DNA gyrase inhibitor and the first member of the synthetic quinolone antibiotics. It is used in the treatment of various infectious diseases like urinary tract infecti...
Chintana Saiwan - One of the best experts on this subject based on the ideXlab platform.
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sorption and transport of acetaminophen 17α ethynyl estradiol Nalidixic Acid with low organic content aquifer sand
Water Research, 2007Co-Authors: Oranuj Lorphensri, David A Sabatini, Khemarath Osathaphan, Tohren C G Kibbey, Chintana SaiwanAbstract:Abstract The sorption and transport of three pharmaceutical compounds (acetaminophen, an analgesic; Nalidixic Acid, an antibiotic; and 17α-ethynyl estradiol, a synthetic hormone) were examined by batch sorption experiments and solute displacement in columns of silica, alumina, and low organic carbon aquifer sand at neutral pH. Silica and alumina were used to represent negatively-charged and positively-charged fractions of subsurface media. Column transport experiments were also conducted at pH values of 4.3, 6.2, and 8.2 for the ionizable Nalidixic Acid. The computer program UFBTC was used to fit the breakthrough data under equilibrium and nonequilibrium conditions with linear/nonlinear sorption. Good agreement was observed between the retardation factors derived from column model studies and estimated from equilibrium batch sorption studies. The sorption and transport of Nalidixic Acid was observed to be highly pH dependent, especially when the pH was near the pKa of Nalidixic Acid (5.95). Thus, near a compound's pKa it is especially important that the batch studies be performed at the same pH as the column experiment. While for ionic pharmaceuticals, ion exchange to oppositely-charged surfaces, appears to be the dominant adsorption mechanism, for neutral pharmaceuticals (i.e., acetaminophen, 17α-ethynyl estradiol) the sorption correlated well with the Kow of the pharmaceuticals, suggesting hydrophobically motivated sorption as the dominant mechanism.
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sorption of acetaminophen 17α ethynyl estradiol Nalidixic Acid and norfloxacin to silica alumina and a hydrophobic medium
Water Research, 2006Co-Authors: Oranuj Lorphensri, Jittipong Intravijit, David A Sabatini, Khemarath Osathaphan, Tohren C G Kibbey, Chintana SaiwanAbstract:Abstract Two pure minerals and a hydrophobic medium were selected to study sorption of pharmaceuticals. The sorption of four pharmaceuticals, acetaminophen (analgesic), 17α-ethynyl estradiol (synthetic hormone), Nalidixic Acid (antibiotic), and norfloxacin (antibiotic), was evaluated with silica, alumina, and Porapak P (a hydrophobic medium). Alumina and silica were selected to represent positively charged and negatively charged aquifer mineral surfaces at neutral pH, respectively, while Porapak P was selected to represent the hydrophobic organic content of an aquifer medium. At neutral pH, acetaminophen, the least hydrophobic pharmaceutical, showed no significant sorption to any of the media, while 17α-ethynyl estradiol, the most hydrophobic pharmaceutical, showed significant sorption to Porapak P. Nalidixic Acid, which has a carboxyl functional group that is anionic at neutral pH, showed significant adsorption to the positively charged alumina. Norfloxacin, with both a carboxyl (anionic) and a piperazynyl (cationic) group, can exist in four forms (neutral, cationic, anionic, and zwitterionic) depending on the aqueous pH. Norfloxacin also showed significant adsorption to alumina at neutral pH, albeit a lower adsorption than Nalidixic Acid. Both Nalidixic Acid and norfloxacin adsorbed to silica and Porapak P to a much lower extent. The pH dependence of Nalidixic Acid and norfloxacin adsorption to silica and alumina was also studied by varying the pH between 4 and 11. The maximum adsorption of Nalidixic Acid to alumina occurred near its pKa (pH∼6), where the combination of cationic alumina and anionic Nalidixic produced maximum adsorption. The maximum adsorption of norfloxacin to alumina was observed at pH∼7, which was the region where the zwitterionic form dominated. This research demonstrates that the adsorption of ionizable pharmaceuticals is strongly dependent on the system pH, the pharmaceutical properties (pKa and hydrophobicity), and the nature of the surface charge (point of zero charge). For pharmaceuticals that are uncharged at environmentally relevant pH values, the main sorption factor is their solubility or hydrophobicity; for charged forms, ion exchange is also an important adsorption mechanism.
Jordi Vila - One of the best experts on this subject based on the ideXlab platform.
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high prevalence of Nalidixic Acid resistant ciprofloxacin susceptible phenotype among clinical isolates of escherichia coli and other enterobacteriaceae
Diagnostic Microbiology and Infectious Disease, 2002Co-Authors: Joaquim Ruiz, Anna Ribera, Julian Gomez, Margarita M Navia, J Sierra, Francesc Marco, Josep Mensa, Jordi VilaAbstract:Therapeutic failure of infections during their treatment with quinolones has been often described. This may be due to the development of resistance during treatment of an infecting strain which already had diminished susceptibility to quinolones, even though the initial MIC did not exceed the breakpoint. In this study the prevalence of the Nalidixic Acid resistant, ciprofloxacin susceptible phenotype among Enterobacteriaceae was analyzed. The results showed that 113 out of 151 (74.83%) strains of the Enterobacteriaceae with diminished susceptibility to ciprofloxacin (MICs from 0.06 to 1 μg/ml) were resistant to Nalidixic Acid (MICs > 32 μg/ml). The Escherichia coli strains presenting this phenotype already have a mutation in the amino Acid codon Ser-83 of the gyrA gene, so that the possibility of developing a second mechanism of resistance during treatment is very high.
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effect of an efflux pump inhibitor on the mic of Nalidixic Acid for acinetobacter baumannii and stenotrophomonas maltophilia clinical isolates
Journal of Antimicrobial Chemotherapy, 2002Co-Authors: Anna Ribera, Joaquim Ruiz, Teresa Jiminez M De Anta, Jordi VilaAbstract:The results show that this inhibitor only affects the MIC of Nalidixic Acid, while the MIC of ciprofloxacin did not change. In 45% of the A. baumannii clinical isolates the MIC of Nalidixic Acid decreased at least eight-fold in the presence of this compound, while the MIC decreased in only 18% of the S. maltophilia clinical isolates (Table). The results obtained show that this efflux pump inhibitor affects A. baumannii such that the only MIC changes observed were those of Nalidixic Acid. The prevalence of strains of S. maltophilia in which the MIC of Nalidixic Acid was affected by this inhibitor was very low in comparison with A. baumannii. As well as these two quinolones, we tested the MIC of norfloxacin for some strains of the two species, in the presence and the absence of MC 207,110, and did not find any change in the MIC of this fluoroquinolone for any of the strains tested. These results indicate that A. baumannii possesses an efflux pump that is
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analysis of the mechanism of quinolone resistance in Nalidixic Acid resistant clinical isolates of salmonella serotype typhimurium
Journal of Medical Microbiology, 1997Co-Authors: Joaquim Ruiz, Dolores Castro, P Goni, J A Santamaria, Juan J Borrego, Jordi VilaAbstract:Over a period of 2.5 years, 42 cases of gastro-enteritis caused by Nalidixic Acid-resistant Salmonella serotype Typhimurium occurred in Malaga. The epidemiological relationship among the strains involved was investigated by analysis of plasmid profile and of chromosomal DNA by pulsed-field gel electrophoresis (PFGE). Despite having different plasmid profiles, all 42 Nalidixic-Acid resistant Typhimurium isolates had evolved from one clone as shown by analysis of chromosomal DNA by PFGE. The mechanism of quinolone resistance in these Typhimurium isolates was also investigated. Analysis of outer-membrane proteins and lipopolysaccharide from quinolone-susceptible and -resistant clinical isolates tested showed no differences. All Nalidixic Acid-resistant isolates had MICs for ciprofloxacin of 0.25 mg/L and for Nalidixic Acid of 1024 mg/L. Polymerase chain reaction fragments of 285 bp, containing the quinolone resistance-determining region of the gyrA gene, and of 237 bp, containing the region of parC homologous to the quinolone resistance-determining region of the gyrA gene, were sequenced. All resistant isolates presented a change at Ser-83 to Phe in the GyrA protein, but no changes were observed in the ParC protein. These findings indicated that this mutation in gyrA plays a major role in the acquisition of Nalidixic-Acid resistance in clinical isolates of Typhimurium.
