The Experts below are selected from a list of 228 Experts worldwide ranked by ideXlab platform
M. F. Michel - One of the best experts on this subject based on the ideXlab platform.
-
In vitro development and stability of tolerance to Cloxacillin and vancomycin in Staphylococcus aureus
European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology, 1994Co-Authors: G. P. Voorn, J. Thompson, Wil H. F. Goessens, P. H. M. Broeders, W. C. Schmal-bauer, M. F. MichelAbstract:The stability of tolerance ofStaphylococcus aureus during subculturing at 37°C and development of this property after repeated exposure to Cloxacillin or vancomycin were investigated in vitro. Four of five tolerant strains lost this property during repeated subculturing at 37°C for 50 days. Conversely, tolerance emerged in two of four nontolerant strains after repeated cycles of exposure to 25 µg of Cloxacillin/ml or 10 µg of vancomycin/ml alternating with growth in antibiotic-free medium. Previous in vivo exposure to Cloxacillin did not enhance the development of tolerance in vitro. MICs of both Cloxacillin and vancomycin did not change significantly during this procedure. Whether the conversion of nontolerant strains to the tolerant state can also occur during antibiotic exposure in treatment of patients remains to be determined.
-
Role of Tolerance in Cloxacillin Prophylaxis of Experimental Staphylococcus aureus Endocarditis
The Journal of infectious diseases, 1992Co-Authors: G. P. Voorn, J. Thompson, Wil H. F. Goessens, W. Schmall-bauer, P. H. M. Broeders, M. F. MichelAbstract:The role of tolerance was investigated in the prophylaxis of Staphylococcus aureus endocarditis with Cloxacillin in rats. The effect of a single dose of 500 mg/kg, two 80 mg/kg doses 3 h apart, and a single dose of 80 mg/kg, alone or in combination with a single dose of 4 mg of gentamicin/kg, were compared for a tolerant strain of S. aureus and its isogenic nontolerant variant. At all dosages, Cloxacillin was significantly less effective in preventing endocarditis with the tolerant strain than with the nontolerant variant. With the high dose of Cloxacillin or two successive lower doses, nearly complete protection could be obtained against the nontolerant strain. However, for the tolerant strain, only the combination of Cloxacillin and gentamicin afforded almost complete protection. For the tolerant strain, no serum bactericidal activity was found at the time of bacterial challenge after an injection of any dose of Cloxacillin. These results suggest that the in vitro phenomenon of tolerance may have relevance in vivo.
-
Role of Tolerance in Cloxacillin Treatment of Experimental Staphylococcus aureus Endocarditis
The Journal of infectious diseases, 1991Co-Authors: G. P. Voorn, J. Thompson, Wil H. F. Goessens, P. H. M. Broeders, W. C. Schmal-bauer, M. F. MichelAbstract:The role of Staphylococcus aureus tolerance was investigated in endocarditis in rats. The efficacies of Cloxacillin, gentamicin, and a combination of the two were compared for animals infected with a tolerant strain, its kill-sensitive variant, or a nonisogenic nontolerant strain of S. aureus. Cloxacillin was significantly less effective for treating the tolerant than for the nontolerant strains. The addition of gentamicin to Cloxacillin reduced bacterial numbers in endocardial vegetations for the tolerant strain comparable to the reduction by Cloxacillin alone for the nontolerant strains, but had no additional effect for the nontolerant strains. Isolates from animals infected with the tolerant or nontolerant strains during antibiotic treatment remained tolerant or nontolerant. These results show that the in vitro phenomenon of tolerance is relevant in vivo.
Malay Chaudhuri - One of the best experts on this subject based on the ideXlab platform.
-
photocatalytic degradation of amoxicillin ampicillin and Cloxacillin antibiotics in aqueous solution using uv tio2 and uv h2o2 tio2 photocatalysis
Desalination, 2010Co-Authors: Emad S Elmolla, Malay ChaudhuriAbstract:Degradation of amoxicillin, ampicillin and Cloxacillin antibiotics in aqueous solution by TiO2 photocatalysis under UVA (365 nm) irradiation was studied. Enhancement of photocatalysis by addition of H2O2 was also evaluated. The results showed that no significant degradation occurred by 300-min UVA irradiation per se and pH had a great effect on antibiotic degradation. Photocatalytic reactions approximately followed a pseudo-first order kinetics and the rate constants (k) were 0.007, 0.003 and 0.029 min− 1 for amoxicillin, ampicillin and Cloxacillin, respectively. Addition of H2O2 at ambient pH ∼ 5 and TiO2 1.0 g/L resulted in complete degradation of amoxicillin, ampicillin and Cloxacillin in 30 min. Dissolved organic carbon (DOC) removal, and nitrate (NO3−), ammonia (NH3) and sulphate (SO42−) formation during degradation indicated mineralization of organic carbon, nitrogen and sulphur. UV/H2O2/TiO2 photocatalysis is effective for degradation of amoxicillin, ampicillin and Cloxacillin in aqueous solution.
-
degradation of amoxicillin ampicillin and Cloxacillin antibiotics in aqueous solution by the uv zno photocatalytic process
Journal of Hazardous Materials, 2010Co-Authors: Emad S Elmolla, Malay ChaudhuriAbstract:Abstract The study examined the effect of operating conditions (zinc oxide concentration, pH and irradiation time) of the UV/ZnO photocatalytic process on degradation of amoxicillin, ampicillin and Cloxacillin in aqueous solution. pH has a great effect on amoxicillin, ampicillin and Cloxacillin degradation. The optimum operating conditions for complete degradation of antibiotics in an aqueous solution containing 104, 105 and 103 mg/L amoxicillin, ampicillin and Cloxacillin, respectively were: zinc oxide 0.5 g/L, irradiation time 180 min and pH 11. Under optimum operating conditions, complete degradation of amoxicillin, ampicillin and Cloxacillin occurred and COD and DOC removal were 23.9 and 9.7%, respectively. The photocatalytic reactions under optimum conditions approximately followed a pseudo-first order kinetics with rate constant (k) 0.018, 0.015 and 0.029 min−1 for amoxicillin, ampicillin and Cloxacillin, respectively. UV/ZnO photocatalysis can be used for amoxicillin, ampicillin and Cloxacillin degradation in aqueous solution.
-
optimization of fenton process for treatment of amoxicillin ampicillin and Cloxacillin antibiotics in aqueous solution
Journal of Hazardous Materials, 2009Co-Authors: Emad S Elmolla, Malay ChaudhuriAbstract:The study examined the effect of operating conditions of the Fenton process on biodegradability improvement and mineralization of amoxicillin, ampicillin and Cloxacillin antibiotics in aqueous solution. In addition, degradation of amoxicillin, ampicillin and Cloxacillin under optimum operating conditions were evaluated. The optimum operating conditions for an aqueous solution containing 104, 105 and 103 mg/L amoxicillin, ampicillin, and Cloxacillin, respectively were observed to be COD/H2O2/Fe2+ molar ratio 1:3:0.30 and pH 3. Under optimum operating conditions, complete degradation of amoxicillin, ampicillin and Cloxacillin occurred in 2 min. In addition, biodegradability improved from ∼0 to 0.37 in 10 min, and COD and DOC degradation were 81.4% and 54.3%, respectively in 60 min. Maximum biodegradability (BOD5/COD ratio) improvement was achieved in 10, 20 and 40 min at antibiotics concentration 100, 250 and 500 mg/L, respectively for each antibiotic in aqueous solution. Increase in nitrate and ammonia concentration were observed due to mineralization of organic nitrogen, concentration of nitrate increased from 0.3 to 10 mg/L and concentration of ammonia increased from 8 to 13 mg/L in 60 min. The study indicated that Fenton process can be used for pretreatment of amoxicillin, ampicillin and Cloxacillin wastewater for biological treatment.
G. P. Voorn - One of the best experts on this subject based on the ideXlab platform.
-
In vitro development and stability of tolerance to Cloxacillin and vancomycin in Staphylococcus aureus
European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology, 1994Co-Authors: G. P. Voorn, J. Thompson, Wil H. F. Goessens, P. H. M. Broeders, W. C. Schmal-bauer, M. F. MichelAbstract:The stability of tolerance ofStaphylococcus aureus during subculturing at 37°C and development of this property after repeated exposure to Cloxacillin or vancomycin were investigated in vitro. Four of five tolerant strains lost this property during repeated subculturing at 37°C for 50 days. Conversely, tolerance emerged in two of four nontolerant strains after repeated cycles of exposure to 25 µg of Cloxacillin/ml or 10 µg of vancomycin/ml alternating with growth in antibiotic-free medium. Previous in vivo exposure to Cloxacillin did not enhance the development of tolerance in vitro. MICs of both Cloxacillin and vancomycin did not change significantly during this procedure. Whether the conversion of nontolerant strains to the tolerant state can also occur during antibiotic exposure in treatment of patients remains to be determined.
-
Role of Tolerance in Cloxacillin Prophylaxis of Experimental Staphylococcus aureus Endocarditis
The Journal of infectious diseases, 1992Co-Authors: G. P. Voorn, J. Thompson, Wil H. F. Goessens, W. Schmall-bauer, P. H. M. Broeders, M. F. MichelAbstract:The role of tolerance was investigated in the prophylaxis of Staphylococcus aureus endocarditis with Cloxacillin in rats. The effect of a single dose of 500 mg/kg, two 80 mg/kg doses 3 h apart, and a single dose of 80 mg/kg, alone or in combination with a single dose of 4 mg of gentamicin/kg, were compared for a tolerant strain of S. aureus and its isogenic nontolerant variant. At all dosages, Cloxacillin was significantly less effective in preventing endocarditis with the tolerant strain than with the nontolerant variant. With the high dose of Cloxacillin or two successive lower doses, nearly complete protection could be obtained against the nontolerant strain. However, for the tolerant strain, only the combination of Cloxacillin and gentamicin afforded almost complete protection. For the tolerant strain, no serum bactericidal activity was found at the time of bacterial challenge after an injection of any dose of Cloxacillin. These results suggest that the in vitro phenomenon of tolerance may have relevance in vivo.
-
Role of Tolerance in Cloxacillin Treatment of Experimental Staphylococcus aureus Endocarditis
The Journal of infectious diseases, 1991Co-Authors: G. P. Voorn, J. Thompson, Wil H. F. Goessens, P. H. M. Broeders, W. C. Schmal-bauer, M. F. MichelAbstract:The role of Staphylococcus aureus tolerance was investigated in endocarditis in rats. The efficacies of Cloxacillin, gentamicin, and a combination of the two were compared for animals infected with a tolerant strain, its kill-sensitive variant, or a nonisogenic nontolerant strain of S. aureus. Cloxacillin was significantly less effective for treating the tolerant than for the nontolerant strains. The addition of gentamicin to Cloxacillin reduced bacterial numbers in endocardial vegetations for the tolerant strain comparable to the reduction by Cloxacillin alone for the nontolerant strains, but had no additional effect for the nontolerant strains. Isolates from animals infected with the tolerant or nontolerant strains during antibiotic treatment remained tolerant or nontolerant. These results show that the in vitro phenomenon of tolerance is relevant in vivo.
Emad S Elmolla - One of the best experts on this subject based on the ideXlab platform.
-
photocatalytic degradation of amoxicillin ampicillin and Cloxacillin antibiotics in aqueous solution using uv tio2 and uv h2o2 tio2 photocatalysis
Desalination, 2010Co-Authors: Emad S Elmolla, Malay ChaudhuriAbstract:Degradation of amoxicillin, ampicillin and Cloxacillin antibiotics in aqueous solution by TiO2 photocatalysis under UVA (365 nm) irradiation was studied. Enhancement of photocatalysis by addition of H2O2 was also evaluated. The results showed that no significant degradation occurred by 300-min UVA irradiation per se and pH had a great effect on antibiotic degradation. Photocatalytic reactions approximately followed a pseudo-first order kinetics and the rate constants (k) were 0.007, 0.003 and 0.029 min− 1 for amoxicillin, ampicillin and Cloxacillin, respectively. Addition of H2O2 at ambient pH ∼ 5 and TiO2 1.0 g/L resulted in complete degradation of amoxicillin, ampicillin and Cloxacillin in 30 min. Dissolved organic carbon (DOC) removal, and nitrate (NO3−), ammonia (NH3) and sulphate (SO42−) formation during degradation indicated mineralization of organic carbon, nitrogen and sulphur. UV/H2O2/TiO2 photocatalysis is effective for degradation of amoxicillin, ampicillin and Cloxacillin in aqueous solution.
-
degradation of amoxicillin ampicillin and Cloxacillin antibiotics in aqueous solution by the uv zno photocatalytic process
Journal of Hazardous Materials, 2010Co-Authors: Emad S Elmolla, Malay ChaudhuriAbstract:Abstract The study examined the effect of operating conditions (zinc oxide concentration, pH and irradiation time) of the UV/ZnO photocatalytic process on degradation of amoxicillin, ampicillin and Cloxacillin in aqueous solution. pH has a great effect on amoxicillin, ampicillin and Cloxacillin degradation. The optimum operating conditions for complete degradation of antibiotics in an aqueous solution containing 104, 105 and 103 mg/L amoxicillin, ampicillin and Cloxacillin, respectively were: zinc oxide 0.5 g/L, irradiation time 180 min and pH 11. Under optimum operating conditions, complete degradation of amoxicillin, ampicillin and Cloxacillin occurred and COD and DOC removal were 23.9 and 9.7%, respectively. The photocatalytic reactions under optimum conditions approximately followed a pseudo-first order kinetics with rate constant (k) 0.018, 0.015 and 0.029 min−1 for amoxicillin, ampicillin and Cloxacillin, respectively. UV/ZnO photocatalysis can be used for amoxicillin, ampicillin and Cloxacillin degradation in aqueous solution.
-
optimization of fenton process for treatment of amoxicillin ampicillin and Cloxacillin antibiotics in aqueous solution
Journal of Hazardous Materials, 2009Co-Authors: Emad S Elmolla, Malay ChaudhuriAbstract:The study examined the effect of operating conditions of the Fenton process on biodegradability improvement and mineralization of amoxicillin, ampicillin and Cloxacillin antibiotics in aqueous solution. In addition, degradation of amoxicillin, ampicillin and Cloxacillin under optimum operating conditions were evaluated. The optimum operating conditions for an aqueous solution containing 104, 105 and 103 mg/L amoxicillin, ampicillin, and Cloxacillin, respectively were observed to be COD/H2O2/Fe2+ molar ratio 1:3:0.30 and pH 3. Under optimum operating conditions, complete degradation of amoxicillin, ampicillin and Cloxacillin occurred in 2 min. In addition, biodegradability improved from ∼0 to 0.37 in 10 min, and COD and DOC degradation were 81.4% and 54.3%, respectively in 60 min. Maximum biodegradability (BOD5/COD ratio) improvement was achieved in 10, 20 and 40 min at antibiotics concentration 100, 250 and 500 mg/L, respectively for each antibiotic in aqueous solution. Increase in nitrate and ammonia concentration were observed due to mineralization of organic nitrogen, concentration of nitrate increased from 0.3 to 10 mg/L and concentration of ammonia increased from 8 to 13 mg/L in 60 min. The study indicated that Fenton process can be used for pretreatment of amoxicillin, ampicillin and Cloxacillin wastewater for biological treatment.
P. H. M. Broeders - One of the best experts on this subject based on the ideXlab platform.
-
In vitro development and stability of tolerance to Cloxacillin and vancomycin in Staphylococcus aureus
European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology, 1994Co-Authors: G. P. Voorn, J. Thompson, Wil H. F. Goessens, P. H. M. Broeders, W. C. Schmal-bauer, M. F. MichelAbstract:The stability of tolerance ofStaphylococcus aureus during subculturing at 37°C and development of this property after repeated exposure to Cloxacillin or vancomycin were investigated in vitro. Four of five tolerant strains lost this property during repeated subculturing at 37°C for 50 days. Conversely, tolerance emerged in two of four nontolerant strains after repeated cycles of exposure to 25 µg of Cloxacillin/ml or 10 µg of vancomycin/ml alternating with growth in antibiotic-free medium. Previous in vivo exposure to Cloxacillin did not enhance the development of tolerance in vitro. MICs of both Cloxacillin and vancomycin did not change significantly during this procedure. Whether the conversion of nontolerant strains to the tolerant state can also occur during antibiotic exposure in treatment of patients remains to be determined.
-
Role of Tolerance in Cloxacillin Prophylaxis of Experimental Staphylococcus aureus Endocarditis
The Journal of infectious diseases, 1992Co-Authors: G. P. Voorn, J. Thompson, Wil H. F. Goessens, W. Schmall-bauer, P. H. M. Broeders, M. F. MichelAbstract:The role of tolerance was investigated in the prophylaxis of Staphylococcus aureus endocarditis with Cloxacillin in rats. The effect of a single dose of 500 mg/kg, two 80 mg/kg doses 3 h apart, and a single dose of 80 mg/kg, alone or in combination with a single dose of 4 mg of gentamicin/kg, were compared for a tolerant strain of S. aureus and its isogenic nontolerant variant. At all dosages, Cloxacillin was significantly less effective in preventing endocarditis with the tolerant strain than with the nontolerant variant. With the high dose of Cloxacillin or two successive lower doses, nearly complete protection could be obtained against the nontolerant strain. However, for the tolerant strain, only the combination of Cloxacillin and gentamicin afforded almost complete protection. For the tolerant strain, no serum bactericidal activity was found at the time of bacterial challenge after an injection of any dose of Cloxacillin. These results suggest that the in vitro phenomenon of tolerance may have relevance in vivo.
-
Role of Tolerance in Cloxacillin Treatment of Experimental Staphylococcus aureus Endocarditis
The Journal of infectious diseases, 1991Co-Authors: G. P. Voorn, J. Thompson, Wil H. F. Goessens, P. H. M. Broeders, W. C. Schmal-bauer, M. F. MichelAbstract:The role of Staphylococcus aureus tolerance was investigated in endocarditis in rats. The efficacies of Cloxacillin, gentamicin, and a combination of the two were compared for animals infected with a tolerant strain, its kill-sensitive variant, or a nonisogenic nontolerant strain of S. aureus. Cloxacillin was significantly less effective for treating the tolerant than for the nontolerant strains. The addition of gentamicin to Cloxacillin reduced bacterial numbers in endocardial vegetations for the tolerant strain comparable to the reduction by Cloxacillin alone for the nontolerant strains, but had no additional effect for the nontolerant strains. Isolates from animals infected with the tolerant or nontolerant strains during antibiotic treatment remained tolerant or nontolerant. These results show that the in vitro phenomenon of tolerance is relevant in vivo.