Penicillin G acylase(PGA) was immobilized on the magnetic hydrophilic polymer microspheres with average pore size of 17.1 nm,specific surface area of 128.2 m2/g and saturate magnetization of 6.4 emu/g.The 96.7%ampicil...Penicillin G acylase(PGA) was immobilized on the magnetic hydrophilic polymer microspheres with average pore size of 17.1 nm,specific surface area of 128.2 m2/g and saturate magnetization of 6.4 emu/g.The 96.7%ampicillin yield with 1.60 of the synthesis/hydrolysis(S/H) ratio from 6-aminopenicillanic acid(6-APA) and D-(-)-alpha-phenylglycine methyl ester(D-PGME) can be achieved using the resultant magnetic biocatalyst in ethylene glycol,where only 82.1%yield with 1.40 of the S/H ratio was obtained using the free PGA under the identical reaction conditions.The immobilized PGA can be separated magnetically and recycled for five times without obvious loss of its catalytic activity.展开更多
Surface molecularly imprinted polymers (SMIPs) for selective adsorption of ampicillin sodium were synthesized using surface molecular imprinting technique with silica gel as a support. The physical and morphological...Surface molecularly imprinted polymers (SMIPs) for selective adsorption of ampicillin sodium were synthesized using surface molecular imprinting technique with silica gel as a support. The physical and morphological characteristics of the polymers were investigated by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), elemental analysis and nitrogen adsorption-desorption test. The obtained results showed that the SMIPs displayed great adsorption capacity (13.5 lag/mg), high recognition ability (the imprinted factor is 3.2) and good binding kinetics for ampicillin sodium. Finally, as solid phase extraction adsorbents, the SMIPs coupled with HPLC method were validated and applied for the enrichment, purification and determination of anapicillin sodium in real milk and blood samples. The averages of spiked accuracy ranged from 92.1% to 107.6%. The relative standard deviations of intra- and inter-day precisions were less than 4.6%. This study provides a new and promising method for enriching, extracting and determining ampicillin sodium in complex biological samples.展开更多
The aim of this study is a present of a simple solvothermal synthesis approach to preparation of Cu-based magnetic metal organic framework(MMOF)and subsequently its application as sorbent for ultrasound assisted magne...The aim of this study is a present of a simple solvothermal synthesis approach to preparation of Cu-based magnetic metal organic framework(MMOF)and subsequently its application as sorbent for ultrasound assisted magnetic solid phase extraction(UAMSPE)of ampicillin(AMP)from cow milk samples prior to high performance liquid chromatography-Ultraviolet(HPLC-UV)determination.Characteristics of prepared MMOF were fully investigated by different techniques which showed the exclusive properties of proposed sorbent in terms of proper functionality,desirable magnetic property and also high specific surface area.Different influential factors on extraction recovery including sorbent dosage,ultrasonic time,washing solvent volume and eluent solvent volume were assessed using central composite design(CCD)based response surface methodology(RSM)as an operative and powerful optimization tool.This is the first report for determination of AMP using MMOF.The proposed method addressed some drawbacks of other methods and sorbents for determination of AMP.The presented method decreases the extraction time(4 min)and also enhances adsorption capacity(250 mg/g).Moreover,the magnetic property of presented sorbent(15 emu/g)accelerates the extraction process which does not need filtration,centrifuge and precipitation procedures.Under the optimized conditions,the proposed method is applicable for linear range of 1.0-5000.0 μg/L with detection limit of 0.29 μg/L,satisfactory recoveries(≥95.0%)and acceptable repeatability(RSD less than 4.0%).The present study indicates highly promising perspectives of MMOF for highly effective analysis of AMP in complicated matrices.展开更多
The stabilities of two kinds of solutions (30 mg/mL) of Ampicillin sodium in 0.9% NaCl in water (NS, normal saline) and in sterile water (SW) in the intravenous elastomeric infusion device (Accufuser®) were ev...The stabilities of two kinds of solutions (30 mg/mL) of Ampicillin sodium in 0.9% NaCl in water (NS, normal saline) and in sterile water (SW) in the intravenous elastomeric infusion device (Accufuser®) were evaluated based on recommended solutions and storage periods. The injectable NS- and SW-Ampicillin solutions in the Accufuser® device were stored and evaluated at controlled temperature (room temperature, 25℃ ± 2℃ and cold temperature, 4℃ ± 2℃) during 7 days. Effects of the periods of storage (from 0 to 7 days) and the temperatures of storage (RT and CT) on the physico-chemical appearances and concentrations of active compounds were determined. The visual clarity, pH, and concentrations of Ampicillin were determined by stability-indicating high-performance liquid chromatography (HPLC)-ultraviolet (UV) detection. The results showed that the amount of Ampicillin in studied solutions gradually decreased with time. The Ampicillin in NS, which was stored in CT, was relatively stable, retaining 94% of its original amount up to 7 days. The solution that showed least stability was Ampicillin in SW, which was stored in RT, retaining 80% of its original amount. Generally, solutions that were stored in CT were more stable than the solutions that were stored in RT. No significant changes in physical appearance or color of the solutions were observed during the study. Particles were not detected in any solution samples. In summary, two kinds of solutions of Ampicillin sodium, in NS and SW, showed different chemical stabilities with time in intravenous infusion device without any significant physical changes and retained about 94% vs 89% and 83% vs 80% of initial concentrations after 7 days in CT and RT, respectively. We suggest that 30 mg/mL of Ampicillin sodium in NS solution in an Accufuser® infusion device which is stored in CT can be applicable for 7 days in clinical situations.展开更多
To overcome ampicillin-resistance of bacteria which is believed to attribute their endogenous B-lactamase, we designed three 10-23 DNAzymes(Dz1, Dz2. Dz3) targeting the coding region of B-lactamase mRNA and examined...To overcome ampicillin-resistance of bacteria which is believed to attribute their endogenous B-lactamase, we designed three 10-23 DNAzymes(Dz1, Dz2. Dz3) targeting the coding region of B-lactamase mRNA and examined their inhibitory capabilities of the ampicillin-resistance of TEM-1 and TEM-3 bacteria. Dz1 was a traditional 10-23 DNAzyme, Dz2 was the mutant of Dz1 by addition of the protected nucleotide to each ann of the enzyme, and Dz3 was a mutant of Dz1 at antisense arms of which phosphorothioate modifications were made. Kinetic analysis, bacterial growth, and β-lactamase activity measurement showed that all the three DNAzymes worked efficiently in vitro and in vivo. A 9 hours bacterial growth inhibition test showed that the inhibition rates of TEM-1 bacteria by Dz1, Dz2, and Dz3 were 27%, 50%, and 29%, respectively. In addition, the inhibition rates of TEM-3 bacteria by those three DNAzymes were found io be 49%, 58%, and 45%, respectively. The current findings suggest that DNAzymes may become potential candidates of alternative inhibitors for bacteria drug-resistance.展开更多
This work describes the construction and the evaluation of the general performance of new ampicilli-nate-selective electrodes based on manganese (III) tetraphenylporphyrin [Mn(III) TPP-Cl] as ionophore, incorporated i...This work describes the construction and the evaluation of the general performance of new ampicilli-nate-selective electrodes based on manganese (III) tetraphenylporphyrin [Mn(III) TPP-Cl] as ionophore, incorporated in both PVC and sol-gel membranes and directly applied onto a conductive graphite/epoxy resin support. The units were constructed without inner reference solution adopting conventional configuration and in the case of PVC membrane the tubular configuration was also adopted. The good working characteristics of these electrodes, made possible its application to the determination of ampicillin in pharmaceuticals formulations, both in conventional batch analysis and in flow conditions, when the electrodes were coupled to a SIA system. In the last case the potentiometric sensors presented linear response towards ampicillin concentration between 5.0 × 10–4 and 5.0 × 10–2 mol?l–1 with slopes of –57.4 and –63.5 mV?dec–1 for the PVC and sol-gel membranes, respectively. The developed procedures enable mean relative standard deviations better than 3% for all the samples analysed. The obtained results do not statistically differ from those furnished by applying the HPLC reference method.展开更多
The complexes formed by the interaction of human serum albumin and ampicillin sodium in aqueous solutions were investigated at 25 ± 0.1℃, ionic strength I = 0.085 mol·kg-1, pH 4.9, 5.8 and 7.4. The results ...The complexes formed by the interaction of human serum albumin and ampicillin sodium in aqueous solutions were investigated at 25 ± 0.1℃, ionic strength I = 0.085 mol·kg-1, pH 4.9, 5.8 and 7.4. The results of static light scattering have suggested that at pH 7.4, 5.8, 4.9, the molecular weight of the protein/drug complexes is 210,000 g·mol-1, 418,000 g·mol-1, 448,000 g·mol-1, re- spectively. The z-average root-mean-square radius of gyration and the second virial coefficients de- crease with pH decreasing. Dynamic light scattering provides information on diffusion coefficient and particle distributions of protein/drug complexes under different conditions, which suggests a broad hydrodynamic diameter range of scatters. The diffusion coefficients of the systems change with am- picillin sodium concentration and pH changing.展开更多
Antibiotic resistance is a serious public health risk that may spread via potable and reclaimed water. Effective disinfection is important for inactivation of antibiotic-resistant bacteria and disruption of antibiotic...Antibiotic resistance is a serious public health risk that may spread via potable and reclaimed water. Effective disinfection is important for inactivation of antibiotic-resistant bacteria and disruption of antibiotic resistance genes. Ampicillin is a widely prescribed antibiotic but its effectiveness is increasingly undermined by resistance. In this study, changes in ampicillin resistance for Escherichia coli (E. coli) CGMCC 1.1595 were analyzed after exposure to different doses of ultraviolet (UV) or chlorine, and damage incurred by the plasmid encoding ampicillin resistance gene blaTEM-1 was assessed. We reported a greater stability in ampicillinresistant E. coli CGMCC 1.1595 after UV irradiation or chlorination when compared with previously published data for other E. coli strains. UV irradiation and chlorination led to a shift in the mortality frequency distributions of ampicillin-resistant E. coli when subse-quently exposed to ampicillin. The ampicillin hemiinhibitory concentration (IC5o) without disinfection was 3800mg·L^-1, and an increment was observed after UV irradiation or chlorination. The IC50 of ampicillin-resistant E. coli was 1.5-fold higher at a UV dose of 40 mJ·cm^-2, and was 1.4-fold higher when exposed to 2.0 mg·L^-1 chlorine. These results indicate that UV irradiation and chlorination can potentially increase the risk of selection for E. coli strains with high ampicillin resistance. There was no evident damage to blaTEM-1 after 1-10 mg Cl2· L^-1 chlorination, while a UV dose of 80 mJ·cm^-2 yielded a damage ratio for blaTEM-1 of approximately 1.2-log.Therefore, high UV doses are required for effective disruption of antibiotic resistance genes in bacteria.展开更多
A visible-light-driven self-powered photoelectrochemical(PEC)aptasensor was developed for ampicillin(AMP)detecting based on carbon dots(CDs)hybrid MIL-68(In)-derived In2O_(3)eIn_(2)S_(3) hollow tubular heterojunction(...A visible-light-driven self-powered photoelectrochemical(PEC)aptasensor was developed for ampicillin(AMP)detecting based on carbon dots(CDs)hybrid MIL-68(In)-derived In2O_(3)eIn_(2)S_(3) hollow tubular heterojunction(CDs/In2O_(3)eIn_(2)S_(3)).In_(2)S_(3) nanosheets uniformly grew in-situ on the surface of In2O_(3) hollow tubes,forming a close contact heterogeneous interface,which significantly promoted the transfer and separation of photo-generated carriers,and provided a large specific surface area and rich active sites for the PEC aptasensing platform.Furthermore,the CDs/In2O_(3)eIn_(2)S_(3)/ITO electrode,which was obtained by dipping assembly,showed remarkable and stable photoelectric signals at zero-bias under visible light irradiation.The amino-functionalized AMP aptamer was fixed on the working electrode as a biological recognition element,and the concentration of AMP was determined by observing the change in photocurrent intensity caused by the specific capture of AMP molecules in solution.Under optimized conditions,the developed PEC aptasensor displayed a relatively wide linear range from 0.001 ng mL^(-1) to 300 ng mL^(-1),as well as a low detection limit(LOD)of 0.06 pg mL^(-1).Besides,the novel self-powered PEC AMP-aptasensor exhibited excellent reproducibility,good stability and selectivity,which open a potential avenue for antibiotic residues detection in environmental media.展开更多
建立基于石墨化多壁碳纳米管(G-MWCNTs)的改良QuEChERS法结合液质联用技术测定柑橘中氨苄青霉素(Ampicillin)的简便、快速、准确的检测方法。在优选的色谱及质谱条件下,首先考察不同提取溶剂对氨苄青霉素提取回收率的影响;然后考察4种...建立基于石墨化多壁碳纳米管(G-MWCNTs)的改良QuEChERS法结合液质联用技术测定柑橘中氨苄青霉素(Ampicillin)的简便、快速、准确的检测方法。在优选的色谱及质谱条件下,首先考察不同提取溶剂对氨苄青霉素提取回收率的影响;然后考察4种吸附剂的用量对氨苄青霉素回收率的影响,并优化净化剂使用量。结果表明,氨苄青霉素在0.5~100ng/mL浓度范围内线性关系良好,相关系数(R^(2))均大于0.999,基质效应(matrix effect,MEs)在9.0%~21.2%之间,低、中、高(2、40、200μg/kg)3水平下的平均回收率为85.9%~102.4%,相对标准偏差(Relative Standard Deviation,RSD)为2.1%~5.8%,检测限(Limit of Detection,LOD)和定量限(Limit of Quantity,LOQ)分别为1.0μg/kg和4.0μg/kg。在降解动态试验中,氨苄青霉素在沃柑和脐橙中的降解半衰期分别为1.2d和1.1d。该方法简便、快速、灵敏、准确,可为柑橘的质量评价提供有效的检测方法。展开更多
Background:Urinary tract infections(UTIs)are among the most common bacterial infections worldwide and have become more difficult to treat over the years.Inappropriate antibiotic use has led to increased antibiotic res...Background:Urinary tract infections(UTIs)are among the most common bacterial infections worldwide and have become more difficult to treat over the years.Inappropriate antibiotic use has led to increased antibiotic resistance.Materials and methods:We examined 1921 urine culture samples from a single hospital and analyzed them for bacterial spectrum and antibiotic susceptibility.We further analyzed changes in the rates of detected bacteria and of the sensitivity of these uropathogens to antibiotics over the years.Results:In our hospital-based analysis,cystitis was the most frequently diagnosed UTI in women(76%)and men(79%).Escherichia coli(48%)was the most commonly identified uropathogen.Samples demonstrated an increase in the proportion of E.coli(p<0.001)and a decrease in Enterococcus faecalis(p<0.001)over the study time period.Antimicrobial susceptibility analysis showed an increase over time in the number of isolates with resistance to ampicillin/sulbactam(p<0.001)and to third-generation cephalosporins cefotaxime(p=0.043)and ceftazidime(p<0.001).Conclusions:Ampicillin/sulbactam and third-generation cephalosporins are antibiotics frequently used in the treatment of UTIs.When selecting an optimal antimicrobial treatment regimen for patients with UTIs,it is imperative to understand regional and timedependent differences in the prevalence of various uropathogens and antimicrobial resistance patterns.Therefore,continuous surveillance of local pathogen and antimicrobial susceptibility patterns for frequently used antibiotics should be prioritized.展开更多
基金supported by The National Basic Research Program 973 of China(No.2010CB534916)the National Natural Science Foundation of China(Nos.50662004,20564002).
文摘Penicillin G acylase(PGA) was immobilized on the magnetic hydrophilic polymer microspheres with average pore size of 17.1 nm,specific surface area of 128.2 m2/g and saturate magnetization of 6.4 emu/g.The 96.7%ampicillin yield with 1.60 of the synthesis/hydrolysis(S/H) ratio from 6-aminopenicillanic acid(6-APA) and D-(-)-alpha-phenylglycine methyl ester(D-PGME) can be achieved using the resultant magnetic biocatalyst in ethylene glycol,where only 82.1%yield with 1.40 of the S/H ratio was obtained using the free PGA under the identical reaction conditions.The immobilized PGA can be separated magnetically and recycled for five times without obvious loss of its catalytic activity.
基金financially supported by the National Natural Science Foundation of China (Nos. 81573391 and 81173024)the National Key Projects of China (No. 812277802)
文摘Surface molecularly imprinted polymers (SMIPs) for selective adsorption of ampicillin sodium were synthesized using surface molecular imprinting technique with silica gel as a support. The physical and morphological characteristics of the polymers were investigated by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), elemental analysis and nitrogen adsorption-desorption test. The obtained results showed that the SMIPs displayed great adsorption capacity (13.5 lag/mg), high recognition ability (the imprinted factor is 3.2) and good binding kinetics for ampicillin sodium. Finally, as solid phase extraction adsorbents, the SMIPs coupled with HPLC method were validated and applied for the enrichment, purification and determination of anapicillin sodium in real milk and blood samples. The averages of spiked accuracy ranged from 92.1% to 107.6%. The relative standard deviations of intra- and inter-day precisions were less than 4.6%. This study provides a new and promising method for enriching, extracting and determining ampicillin sodium in complex biological samples.
基金This work was financially supported by Graduate School and Research Council of Yasouj University.
文摘The aim of this study is a present of a simple solvothermal synthesis approach to preparation of Cu-based magnetic metal organic framework(MMOF)and subsequently its application as sorbent for ultrasound assisted magnetic solid phase extraction(UAMSPE)of ampicillin(AMP)from cow milk samples prior to high performance liquid chromatography-Ultraviolet(HPLC-UV)determination.Characteristics of prepared MMOF were fully investigated by different techniques which showed the exclusive properties of proposed sorbent in terms of proper functionality,desirable magnetic property and also high specific surface area.Different influential factors on extraction recovery including sorbent dosage,ultrasonic time,washing solvent volume and eluent solvent volume were assessed using central composite design(CCD)based response surface methodology(RSM)as an operative and powerful optimization tool.This is the first report for determination of AMP using MMOF.The proposed method addressed some drawbacks of other methods and sorbents for determination of AMP.The presented method decreases the extraction time(4 min)and also enhances adsorption capacity(250 mg/g).Moreover,the magnetic property of presented sorbent(15 emu/g)accelerates the extraction process which does not need filtration,centrifuge and precipitation procedures.Under the optimized conditions,the proposed method is applicable for linear range of 1.0-5000.0 μg/L with detection limit of 0.29 μg/L,satisfactory recoveries(≥95.0%)and acceptable repeatability(RSD less than 4.0%).The present study indicates highly promising perspectives of MMOF for highly effective analysis of AMP in complicated matrices.
基金supported by Division of Molecular Therapeutics Development,Hanyang Biomedical Research Institute,Hanyang University and Woo Young Medical Co.LTD.,Seoul,South Korea.
文摘The stabilities of two kinds of solutions (30 mg/mL) of Ampicillin sodium in 0.9% NaCl in water (NS, normal saline) and in sterile water (SW) in the intravenous elastomeric infusion device (Accufuser®) were evaluated based on recommended solutions and storage periods. The injectable NS- and SW-Ampicillin solutions in the Accufuser® device were stored and evaluated at controlled temperature (room temperature, 25℃ ± 2℃ and cold temperature, 4℃ ± 2℃) during 7 days. Effects of the periods of storage (from 0 to 7 days) and the temperatures of storage (RT and CT) on the physico-chemical appearances and concentrations of active compounds were determined. The visual clarity, pH, and concentrations of Ampicillin were determined by stability-indicating high-performance liquid chromatography (HPLC)-ultraviolet (UV) detection. The results showed that the amount of Ampicillin in studied solutions gradually decreased with time. The Ampicillin in NS, which was stored in CT, was relatively stable, retaining 94% of its original amount up to 7 days. The solution that showed least stability was Ampicillin in SW, which was stored in RT, retaining 80% of its original amount. Generally, solutions that were stored in CT were more stable than the solutions that were stored in RT. No significant changes in physical appearance or color of the solutions were observed during the study. Particles were not detected in any solution samples. In summary, two kinds of solutions of Ampicillin sodium, in NS and SW, showed different chemical stabilities with time in intravenous infusion device without any significant physical changes and retained about 94% vs 89% and 83% vs 80% of initial concentrations after 7 days in CT and RT, respectively. We suggest that 30 mg/mL of Ampicillin sodium in NS solution in an Accufuser® infusion device which is stored in CT can be applicable for 7 days in clinical situations.
基金the National Natural Science Foundation of China(Nos.20771030 and 20671025)
文摘To overcome ampicillin-resistance of bacteria which is believed to attribute their endogenous B-lactamase, we designed three 10-23 DNAzymes(Dz1, Dz2. Dz3) targeting the coding region of B-lactamase mRNA and examined their inhibitory capabilities of the ampicillin-resistance of TEM-1 and TEM-3 bacteria. Dz1 was a traditional 10-23 DNAzyme, Dz2 was the mutant of Dz1 by addition of the protected nucleotide to each ann of the enzyme, and Dz3 was a mutant of Dz1 at antisense arms of which phosphorothioate modifications were made. Kinetic analysis, bacterial growth, and β-lactamase activity measurement showed that all the three DNAzymes worked efficiently in vitro and in vivo. A 9 hours bacterial growth inhibition test showed that the inhibition rates of TEM-1 bacteria by Dz1, Dz2, and Dz3 were 27%, 50%, and 29%, respectively. In addition, the inhibition rates of TEM-3 bacteria by those three DNAzymes were found io be 49%, 58%, and 45%, respectively. The current findings suggest that DNAzymes may become potential candidates of alternative inhibitors for bacteria drug-resistance.
基金supported by the University of the Basque Country(Spain)through Project UPV 171.363-E-15923/2004this University for the Ph.D.Grant 98/13828/01.
文摘This work describes the construction and the evaluation of the general performance of new ampicilli-nate-selective electrodes based on manganese (III) tetraphenylporphyrin [Mn(III) TPP-Cl] as ionophore, incorporated in both PVC and sol-gel membranes and directly applied onto a conductive graphite/epoxy resin support. The units were constructed without inner reference solution adopting conventional configuration and in the case of PVC membrane the tubular configuration was also adopted. The good working characteristics of these electrodes, made possible its application to the determination of ampicillin in pharmaceuticals formulations, both in conventional batch analysis and in flow conditions, when the electrodes were coupled to a SIA system. In the last case the potentiometric sensors presented linear response towards ampicillin concentration between 5.0 × 10–4 and 5.0 × 10–2 mol?l–1 with slopes of –57.4 and –63.5 mV?dec–1 for the PVC and sol-gel membranes, respectively. The developed procedures enable mean relative standard deviations better than 3% for all the samples analysed. The obtained results do not statistically differ from those furnished by applying the HPLC reference method.
基金This work was supported by the National Natural Science Foundation of China (Grant No.20275014).
文摘The complexes formed by the interaction of human serum albumin and ampicillin sodium in aqueous solutions were investigated at 25 ± 0.1℃, ionic strength I = 0.085 mol·kg-1, pH 4.9, 5.8 and 7.4. The results of static light scattering have suggested that at pH 7.4, 5.8, 4.9, the molecular weight of the protein/drug complexes is 210,000 g·mol-1, 418,000 g·mol-1, 448,000 g·mol-1, re- spectively. The z-average root-mean-square radius of gyration and the second virial coefficients de- crease with pH decreasing. Dynamic light scattering provides information on diffusion coefficient and particle distributions of protein/drug complexes under different conditions, which suggests a broad hydrodynamic diameter range of scatters. The diffusion coefficients of the systems change with am- picillin sodium concentration and pH changing.
基金The author thanks the National Natural Science Foundation of China (Key Project, Grant No. 51138006) and State Key Joint Laboratory of Environment Simulation and Pollution Control (Project, No. 13L01ESPC) for financial support. The research is also supported by the Collaborative Innovation Center for Regional Environmental Quality.
文摘Antibiotic resistance is a serious public health risk that may spread via potable and reclaimed water. Effective disinfection is important for inactivation of antibiotic-resistant bacteria and disruption of antibiotic resistance genes. Ampicillin is a widely prescribed antibiotic but its effectiveness is increasingly undermined by resistance. In this study, changes in ampicillin resistance for Escherichia coli (E. coli) CGMCC 1.1595 were analyzed after exposure to different doses of ultraviolet (UV) or chlorine, and damage incurred by the plasmid encoding ampicillin resistance gene blaTEM-1 was assessed. We reported a greater stability in ampicillinresistant E. coli CGMCC 1.1595 after UV irradiation or chlorination when compared with previously published data for other E. coli strains. UV irradiation and chlorination led to a shift in the mortality frequency distributions of ampicillin-resistant E. coli when subse-quently exposed to ampicillin. The ampicillin hemiinhibitory concentration (IC5o) without disinfection was 3800mg·L^-1, and an increment was observed after UV irradiation or chlorination. The IC50 of ampicillin-resistant E. coli was 1.5-fold higher at a UV dose of 40 mJ·cm^-2, and was 1.4-fold higher when exposed to 2.0 mg·L^-1 chlorine. These results indicate that UV irradiation and chlorination can potentially increase the risk of selection for E. coli strains with high ampicillin resistance. There was no evident damage to blaTEM-1 after 1-10 mg Cl2· L^-1 chlorination, while a UV dose of 80 mJ·cm^-2 yielded a damage ratio for blaTEM-1 of approximately 1.2-log.Therefore, high UV doses are required for effective disruption of antibiotic resistance genes in bacteria.
基金supported by the National Key Scientific Instrument and Equipment Development Project of China(No.21627809)National Natural Science Foundation of China(Nos.21505051,21575050,21607055,21777056)+1 种基金the Youth Creative Talents Introduction and Cultivation Plan in Universities of Shandong Province,Jinan Scientific Research Leader Workshop Project(2018GXRC024)Ju thanks the Special Foundation for Taishan Scholar Professorship of Shandong Province(No.ts201712052)and UJN.
文摘A visible-light-driven self-powered photoelectrochemical(PEC)aptasensor was developed for ampicillin(AMP)detecting based on carbon dots(CDs)hybrid MIL-68(In)-derived In2O_(3)eIn_(2)S_(3) hollow tubular heterojunction(CDs/In2O_(3)eIn_(2)S_(3)).In_(2)S_(3) nanosheets uniformly grew in-situ on the surface of In2O_(3) hollow tubes,forming a close contact heterogeneous interface,which significantly promoted the transfer and separation of photo-generated carriers,and provided a large specific surface area and rich active sites for the PEC aptasensing platform.Furthermore,the CDs/In2O_(3)eIn_(2)S_(3)/ITO electrode,which was obtained by dipping assembly,showed remarkable and stable photoelectric signals at zero-bias under visible light irradiation.The amino-functionalized AMP aptamer was fixed on the working electrode as a biological recognition element,and the concentration of AMP was determined by observing the change in photocurrent intensity caused by the specific capture of AMP molecules in solution.Under optimized conditions,the developed PEC aptasensor displayed a relatively wide linear range from 0.001 ng mL^(-1) to 300 ng mL^(-1),as well as a low detection limit(LOD)of 0.06 pg mL^(-1).Besides,the novel self-powered PEC AMP-aptasensor exhibited excellent reproducibility,good stability and selectivity,which open a potential avenue for antibiotic residues detection in environmental media.
文摘建立基于石墨化多壁碳纳米管(G-MWCNTs)的改良QuEChERS法结合液质联用技术测定柑橘中氨苄青霉素(Ampicillin)的简便、快速、准确的检测方法。在优选的色谱及质谱条件下,首先考察不同提取溶剂对氨苄青霉素提取回收率的影响;然后考察4种吸附剂的用量对氨苄青霉素回收率的影响,并优化净化剂使用量。结果表明,氨苄青霉素在0.5~100ng/mL浓度范围内线性关系良好,相关系数(R^(2))均大于0.999,基质效应(matrix effect,MEs)在9.0%~21.2%之间,低、中、高(2、40、200μg/kg)3水平下的平均回收率为85.9%~102.4%,相对标准偏差(Relative Standard Deviation,RSD)为2.1%~5.8%,检测限(Limit of Detection,LOD)和定量限(Limit of Quantity,LOQ)分别为1.0μg/kg和4.0μg/kg。在降解动态试验中,氨苄青霉素在沃柑和脐橙中的降解半衰期分别为1.2d和1.1d。该方法简便、快速、灵敏、准确,可为柑橘的质量评价提供有效的检测方法。
文摘Background:Urinary tract infections(UTIs)are among the most common bacterial infections worldwide and have become more difficult to treat over the years.Inappropriate antibiotic use has led to increased antibiotic resistance.Materials and methods:We examined 1921 urine culture samples from a single hospital and analyzed them for bacterial spectrum and antibiotic susceptibility.We further analyzed changes in the rates of detected bacteria and of the sensitivity of these uropathogens to antibiotics over the years.Results:In our hospital-based analysis,cystitis was the most frequently diagnosed UTI in women(76%)and men(79%).Escherichia coli(48%)was the most commonly identified uropathogen.Samples demonstrated an increase in the proportion of E.coli(p<0.001)and a decrease in Enterococcus faecalis(p<0.001)over the study time period.Antimicrobial susceptibility analysis showed an increase over time in the number of isolates with resistance to ampicillin/sulbactam(p<0.001)and to third-generation cephalosporins cefotaxime(p=0.043)and ceftazidime(p<0.001).Conclusions:Ampicillin/sulbactam and third-generation cephalosporins are antibiotics frequently used in the treatment of UTIs.When selecting an optimal antimicrobial treatment regimen for patients with UTIs,it is imperative to understand regional and timedependent differences in the prevalence of various uropathogens and antimicrobial resistance patterns.Therefore,continuous surveillance of local pathogen and antimicrobial susceptibility patterns for frequently used antibiotics should be prioritized.