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1.
Se Pu ; 37(7): 735-741, 2019 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-31271013

RESUMO

An analytical method was developed for the determination of streptomycin and dihydrostreptomycin in honey using hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS). The streptomycin and dihydrostreptomycin residues in the test samples were extracted with 20 g/L trichloroacetic acid aqueous solution (including 50 mmol/L phosphate, pH 6.8) and cleaned on an Oasis HLB solid phase extraction column. The products were separated on a SIELC Obelisc R column with gradient elution using 0.5% (v/v) formic acid aqueous solution and acetonitrile as mobile phases. Streptomycin and dihydrostreptomycin were detected by liquid chromatography-tandem mass spectrometry in the positive ion mode using the external standard method. Under the optimal conditions, streptomycin and dihydrostreptomycin showed good linearity (r>0.99) in the range of 2.5-100 µg/L. The LOD and LOQ of the method was 2.0 µg/kg and 5.0 µg/kg, respectively. The spiked recoveries of the analytes from blank honey samples at the three levels of 5.0, 20.0 and 100.0 µg/kg were in the range of 86.9%-113.2% with the relative standard deviations less than 10%. With the advantages of convenience, rapidity, sensitivity and good repeatability, the method is suitable for the detection of streptomycin and dihydrostreptomycin in honey.


Assuntos
Sulfato de Di-Hidroestreptomicina/análise , Resíduos de Drogas/análise , Mel/análise , Estreptomicina/análise , Cromatografia Líquida , Interações Hidrofóbicas e Hidrofílicas , Extração em Fase Sólida , Espectrometria de Massas em Tandem
2.
J Agric Food Chem ; 66(25): 6388-6393, 2018 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-29862808

RESUMO

The purpose of this research was to evaluate the persistence of penicillin G and dihydrostreptomycin in milk of lactating buffaloes following intramuscular injection of procaine penicillin G (200000 IU/mL) and dihydrostreptomycin sulfate (250 mg/mL) every 24 h for 3 days. Milk samples were collected twice daily up to the 13th milking post-treatment and analyzed by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry. The analytical method has been validated according to Commission Decision 2002/657/EC. The highest concentrations of penicillin G (275 µg kg-1) and dihydrostreptomycin (220.5 µg kg-1) were detected in the milk of the first milkings post-treatment, and levels were below the maximum residue limit of 4 and 200 µg kg-1 in all treated buffaloes at milkings 12 and 2, respectively. The results of this study demonstrate that a nine-milking withdrawal time set for bovine milk was not adequate for depletion of penicillin G in lactating buffaloes.


Assuntos
Antibacterianos/análise , Cromatografia Líquida de Alta Pressão/métodos , Sulfato de Di-Hidroestreptomicina/análise , Resíduos de Drogas/análise , Leite/química , Penicilina G/análise , Espectrometria de Massas em Tandem/métodos , Animais , Búfalos , Feminino , Leite/metabolismo
3.
PLoS Biol ; 14(6): e1002473, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27280286

RESUMO

The primary mechanism of action of the antibiotic dihydrostreptomycin is binding to and modifying the function of the bacterial ribosome, thus leading to decreased and aberrant translation of proteins; however, the routes by which it enters the bacterial cell are largely unknown. The mechanosensitive channel of large conductance, MscL, is found in the vast majority of bacterial species, where it serves as an emergency release valve rescuing the cell from sudden decreases in external osmolarity. While it is known that MscL expression increases the potency of dihydrostreptomycin, it has remained unclear if this effect is due to a direct interaction. Here, we use a combination of genetic screening, MD simulations, and biochemical and mutational approaches to determine if dihydrostreptomycin directly interacts with MscL. Our data strongly suggest that dihydrostreptomycin binds to a specific site on MscL and modifies its conformation, thus allowing the passage of K+ and glutamate out of, and dihydrostreptomycin into, the cell.


Assuntos
Sulfato de Di-Hidroestreptomicina/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Canais Iônicos/metabolismo , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Sítios de Ligação/genética , Membrana Celular/metabolismo , Cisteína/química , Cisteína/genética , Cisteína/metabolismo , Sulfato de Di-Hidroestreptomicina/química , Sulfato de Di-Hidroestreptomicina/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , Ácido Glutâmico/metabolismo , Ativação do Canal Iônico , Canais Iônicos/química , Canais Iônicos/genética , Mecanorreceptores/química , Mecanorreceptores/metabolismo , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Mutação , Potássio/metabolismo , Ligação Proteica , Conformação Proteica
4.
Wei Sheng Yan Jiu ; 45(1): 61-4, 2016 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-26987198

RESUMO

OBJECTIVE: To develop a method for simultaneous determination of streptomycin and dihydrostreptomycin residues in tomato ketchup by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). METHODS: The sample was dissolved with phosphorus solution (pH 2) and extracted by ultrasonic. The pigment was removed with n-hexane. Then, the sample was cleaned up by HLB SPE. The HILIC chromatographic column (100 mm x 2.1 mm, 1.7 µm) was used to complete the separation under gradient elution. The mixed solution of 0.1% formic acid solution and acetonitrile was used as mobile phase. The detection of streptomycin and dihydrostreptomycin were carried out by MS/MS under multiple reaction monitoring (MRM) mode. The external standard method was used for quantitative analysis. RESULTS: The calibration curves for streptomycin and dihydrostreptomycin were indicated in the range of 0.005 - 0.100 mg/kg, and the detection limits were both 0.005 mg/kg. The recoveries of streptomycin and dihydrostreptomycin were ranged from 79.5% to 93.9% with relative standard deviations no more than 10%. CONCLUSION: The method is simple and accurate to meet the requirements for determination of streptomycin and dihydrostreptomycin residues in tomato ketchup.


Assuntos
Sulfato de Di-Hidroestreptomicina/análise , Contaminação de Alimentos/análise , Lycopersicon esculentum/química , Estreptomicina/análise , Espectrometria de Massas em Tandem/métodos , Cromatografia Líquida de Alta Pressão , Resíduos de Drogas/análise , Alimentos , Hexanos , Extração em Fase Sólida
5.
J Neurosci ; 36(2): 336-49, 2016 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-26758827

RESUMO

UNLABELLED: The transduction of sound into electrical signals depends on mechanically sensitive ion channels in the stereociliary bundle. The molecular composition of this mechanoelectrical transducer (MET) channel is not yet known. Transmembrane channel-like protein isoforms 1 (TMC1) and 2 (TMC2) have been proposed to form part of the MET channel, although their exact roles are still unclear. Using Beethoven (Tmc1(Bth/Bth)) mice, which have an M412K point mutation in TMC1 that adds a positive charge, we found that Ca(2+) permeability and conductance of the MET channel of outer hair cells (OHCs) were reduced. Tmc1(Bth/Bth) OHCs were also less sensitive to block by the permeant MET channel blocker dihydrostreptomycin, whether applied extracellularly or intracellularly. These findings suggest that the amino acid that is mutated in Bth is situated at or near the negatively charged binding site for dihydrostreptomycin within the permeation pore of the channel. We also found that the Ca(2+) dependence of the operating range of the MET channel was altered by the M412K mutation. Depolarization did not increase the resting open probability of the MET current of Tmc1(Bth/Bth) OHCs, whereas raising the intracellular concentration of the Ca(2+) chelator BAPTA caused smaller increases in resting open probability in Bth mutant OHCs than in wild-type control cells. We propose that these observations can be explained by the reduced Ca(2+) permeability of the mutated MET channel indirectly causing the Ca(2+) sensor for adaptation, at or near the intracellular face of the MET channel, to become more sensitive to Ca(2+) influx as a compensatory mechanism. SIGNIFICANCE STATEMENT: In the auditory system, the hair cells convert sound-induced mechanical movement of the hair bundles atop these cells into electrical signals through the opening of mechanically gated ion channels at the tips of the bundles. Although the nature of these mechanoelectrical transducer (MET) channels is still unclear, recent studies implicate transmembrane channel-like protein isoform 1 (TMC1) channels in the mammalian cochlea. Using a mutant mouse model (Beethoven) for progressive hearing loss in humans (DFNA36), which harbors a point mutation in the Tmc1 gene, we show that this mutation affects the MET channel pore, reducing its Ca(2+) permeability and its affinity for the permeant blocker dihydrostreptomycin. A number of phenomena that we ascribe to Ca(2+)-dependent adaptation appear stronger, in compensation for the reduced Ca(2+) entry.


Assuntos
Antibacterianos/farmacologia , Cálcio/metabolismo , Sulfato de Di-Hidroestreptomicina/farmacologia , Células Ciliadas Auditivas Externas/efeitos dos fármacos , Mecanotransdução Celular/efeitos dos fármacos , Proteínas de Membrana/genética , Mutação Puntual/genética , Animais , Animais Recém-Nascidos , Cálcio/farmacologia , Quelantes/farmacologia , Relação Dose-Resposta a Droga , Ácido Egtázico/análogos & derivados , Ácido Egtázico/farmacologia , Células Ciliadas Auditivas Externas/fisiologia , Técnicas In Vitro , Mecanotransdução Celular/genética , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Transgênicos , Fibras Nervosas/efeitos dos fármacos , Fibras Nervosas/fisiologia , Órgão Espiral/citologia , Técnicas de Patch-Clamp
6.
Microb Drug Resist ; 21(5): 562-9, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26061440

RESUMO

Dissemination of antimicrobial resistance is a major global public health concern. To clarify the role of flies in disseminating antimicrobial resistance between farms, we isolated and characterized tetracycline-resistant Escherichia coli strains isolated from flies and feces of livestock from four locations housing swine (abattoir, three farms) and three cattle farms. The percentages of isolates from flies resistant to tetracycline, dihydrostreptomycin, ampicillin, and chloramphenicol (80.8%, 61.5%, 53.8%, and 50.0%, respectively) and those from animal feces (80.5%, 78.0%, 41.5%, and 46.3%, respectively) in locations housing swine were significantly higher than those from cattle farms (p<0.05). The rates of resistance in E. coli derived from flies reflected those derived from livestock feces at the same locations, suggesting that antimicrobial resistance spreads between livestock and flies on the farms. The results of pulsed-field gel electrophoresis (PFGE) analysis showed that, with a few exceptions, all E. coli isolates differed. Two pairs of tetracycline-resistant strains harbored similar plasmids with the same tetracycline-resistance genes, although the origin (fly or feces), site of isolation, and PFGE patterns of these strains differed. Therefore, flies may disseminate the plasmids between farms. Our results suggest that flies may be involved not only in spreading clones of antimicrobial-resistant bacteria within a farm but also in the widespread dissemination of plasmids with antimicrobial resistance genes between farms.


Assuntos
Antibacterianos/farmacologia , Dípteros/microbiologia , Farmacorresistência Bacteriana Múltipla/genética , Infecções por Escherichia coli/transmissão , Escherichia coli/genética , Genes Bacterianos , Plasmídeos/metabolismo , Matadouros , Agricultura , Ampicilina/farmacologia , Criação de Animais Domésticos , Animais , Técnicas de Tipagem Bacteriana , Bovinos , Cloranfenicol/farmacologia , Sulfato de Di-Hidroestreptomicina/farmacologia , Eletroforese em Gel de Campo Pulsado , Escherichia coli/classificação , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/veterinária , Fezes/microbiologia , Variação Genética , Japão , Filogenia , Suínos , Tetraciclina/farmacologia
7.
J Pharm Biomed Anal ; 104: 81-9, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25497889

RESUMO

An HPLC-PAD method using a gold working electrode and a triple-potential waveform was developed for the simultaneous determination of streptomycin and dihydrostreptomycin in veterinary drugs. Glucose was used as the internal standard, and the triple-potential waveform was optimized using a factorial and a central composite design. The optimum potentials were as follows: amperometric detection, E1=-0.15V; cleaning potential, E2=+0.85V; and reactivation of the electrode surface, E3=-0.65V. For the separation of the aminoglycosides and the internal standard of glucose, a CarboPac™ PA1 anion exchange column was used together with a mobile phase consisting of a 0.070 mol L(-1) sodium hydroxide solution in the isocratic elution mode with a flow rate of 0.8 mL min(-1). The method was validated and applied to the determination of streptomycin and dihydrostreptomycin in veterinary formulations (injection, suspension and ointment) without any previous sample pretreatment, except for the ointments, for which a liquid-liquid extraction was required before HPLC-PAD analysis. The method showed adequate selectivity, with an accuracy of 98-107% and a precision of less than 3.9%.


Assuntos
Antibacterianos/análise , Sulfato de Di-Hidroestreptomicina/análise , Estreptomicina/análise , Drogas Veterinárias/química , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida de Alta Pressão/veterinária , Técnicas Eletroquímicas/métodos , Técnicas Eletroquímicas/veterinária , Estrutura Molecular , Reprodutibilidade dos Testes
8.
Se Pu ; 32(6): 566-72, 2014 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-25269252

RESUMO

A method was established for the determination of streptomycin (STR) and dihydrostreptomycin (DHS) in pollens based on high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample was extracted and cleaned-up by a C18 solid phase extraction cartridge. The separation was carried out on a Protemix WCX-NP5 column (100 mm x 2.1 mm, 5 microm) with a gradient elution using 5% (v/v) formic acid, 20 mmol/L ammonium acetate and methanol as mobile phases. The analysis of streptomycin and dihydrostreptomycin was performed under electrospray positive ionization mode. The limits of detection (LOD, S/N = 3) and limits of quantification (LOQ, S/N = 10) for the both were 5 microg/kg and 10 microg/kg, respectively. Good linearities (r > 0.99) were achieved for the target compounds over the range of 10-200 microg/L. The recoveries at three spiked levels (10, 20, 50 microg/kg) in the blank matrices, such as pollen pini, corn pollen, camellia pollen, sunflower pollen, rape pollen and bee pollen, were from 76.8% to 100.3% with the relative standard deviations varied from 3.70% to 12.6%. The method is accurate, practical, and can be applied to most of the contaminated matrices. With this method, heptafluorobutyric acid is not required as mobile phase which is harmful to MS spectrometer.


Assuntos
Sulfato de Di-Hidroestreptomicina/análise , Pólen/química , Estreptomicina/análise , Cromatografia Líquida de Alta Pressão , Extração em Fase Sólida , Espectrometria de Massas em Tandem
9.
Nat Commun ; 5: 4891, 2014 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-25205267

RESUMO

The antibiotic streptomycin is widely used in the treatment of microbial infections. The primary mechanism of action is inhibition of translation by binding to the ribosome, but how it enters the bacterial cell is unclear. Early in the study of this antibiotic, a mysterious streptomycin-induced potassium efflux preceding any decrease in viability was observed; it was speculated that this changed the electrochemical gradient such that streptomycin better accessed the cytoplasm. Here we use a high-throughput screen to search for compounds targeting the mechanosensitive channel of large conductance (MscL) and find dihydrostreptomycin among the 'hits'. Furthermore, we find that MscL is not only necessary for the previously described streptomycin-induced potassium efflux, but also directly increases MscL activity in electrophysiological studies. The data suggest that gating MscL is a novel mode of action of dihydrostreptomycin, and that MscL's large pore may provide a mechanism for cell entry.


Assuntos
Antibacterianos/farmacologia , Sulfato de Di-Hidroestreptomicina/farmacologia , Proteínas de Escherichia coli/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Canais Iônicos/efeitos dos fármacos , Potássio/metabolismo , Sulfato de Di-Hidroestreptomicina/metabolismo , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Ensaios de Triagem em Larga Escala , Canais Iônicos/metabolismo , Técnicas de Patch-Clamp , Espectinomicina/farmacologia , Estreptomicina/metabolismo , Estreptomicina/farmacologia , Viomicina/farmacologia
10.
J Dairy Sci ; 97(6): 3509-22, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24731642

RESUMO

Dry cow therapy, administered at the end of lactation, is aimed at eliminating current and preventing future intramammary (IMM) bacterial infections and typically involves intramammary administration of antibiotics. Certified organic dairies in the United States are restricted from using antibiotics and must consider an alternative therapy or no dry cow therapy. The current study compared 2 herbal products to conventional dry cow therapy and no treatment for a total of 5 treatments over 2 trials. Trial 1 was conducted over 3 yr on 1 research farm and trial 2 included 4 commercial farms plus the research herd over 2 yr. Treatments included (1) a conventional IMM antibiotic and internal teat sealant (penicillin-dihydrostreptomycin and bismuth subnitrate; CON); (2) an herbal IMM product purported to act as a teat sealant (Cinnatube, New AgriTech Enterprises, Locke, NY; CIN); (3) an herbal IMM product (Phyto-Mast, Bovinity Health LLC, Narvon, PA; P-M); (4) Phyto-Mast and Cinnatube (PC); or (5) no dry cow therapy (NT). Each treatment group was balanced by breed, lactation number, due date, herd, and year. However, the CON treatment was used only in the research herd because of the intent to avoid antibiotic usage on the other 4 farms. Comparisons among treatments included the difference between pre- and posttreatment 305-d mature equivalent milk production (trial 1), somatic cell score change from dry-off to freshening at the cow and quarter levels (trials 1 and 2), and milk microbiology change over the dry period (trial 2). We detected no significant differences among treatments for milk yield differences between the lactation following treatment and the lactation preceding treatment. Changes in somatic cell score from one lactation to the next also did not differ significantly among treatments in either trial. Cure rates were not significantly different among treatments; only 19.6% of all quarters were infected at dry off. The proportion of quarters with new infections at 3 to 5d postcalving did not significantly differ among treatments, except between CIN and NT. Percentages (least squares means ± standard error) of quarters with new infections were 24 ± 21% for CON, 15 ± 7% for CIN, 30 ± 10% for P-M, 32 ± 11% for PC, and 35 ± 11% for NT. The efficacy of the herbal products was similar to that of conventional therapy, and the herbal products had no apparent adverse effects.


Assuntos
Infecções Bacterianas/veterinária , Medicamentos de Ervas Chinesas/administração & dosagem , Glândulas Mamárias Animais/efeitos dos fármacos , Glândulas Mamárias Animais/microbiologia , Mastite Bovina/tratamento farmacológico , Leite , Animais , Antibacterianos/uso terapêutico , Infecções Bacterianas/tratamento farmacológico , Bismuto/uso terapêutico , Bovinos , Dieta/veterinária , Sulfato de Di-Hidroestreptomicina/uso terapêutico , Feminino , Contaminação de Alimentos/prevenção & controle , Microbiologia de Alimentos , Alimentos Orgânicos/microbiologia , Lactação , Mastite Bovina/microbiologia , Leite/microbiologia , Penicilinas/uso terapêutico
11.
J Neurosci ; 34(16): 5505-14, 2014 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-24741041

RESUMO

Tip links between adjacent stereocilia are believed to gate mechano-electrical transducer (MET) channels and mediate the electrical responses of sensory hair cells. We found that mouse auditory hair cells that lack tip links due to genetic mutations or exposure to the Ca(2+) chelator BAPTA can, however, still respond to mechanical stimuli. These MET currents have unusual properties and are predominantly of the opposite polarity relative to those measured when tip links are present. There are other striking differences, for example, the channels are usually all closed when the hair cell is not stimulated and the currents in response to strong stimuli can be substantially larger than normal. These anomalous MET currents can also be elicited early in development, before the onset of mechano-electrical transduction with normal response polarity. Current-voltage curves of the anomalous MET currents are linear and do not show the rectification characteristic of normal MET currents. The permeant MET channel blocker dihydrostreptomycin is two orders of magnitude less effective in blocking the anomalous MET currents. The findings suggest the presence of a large population of MET channels with pore properties that are distinct from those of normal MET channels. These channels are not gated by hair-bundle links and can be activated under a variety of conditions in which normal tip-link-mediated transduction is not operational.


Assuntos
Permeabilidade da Membrana Celular/fisiologia , Células Ciliadas Auditivas/fisiologia , Canais Iônicos/fisiologia , Mecanotransdução Celular/fisiologia , Animais , Animais Recém-Nascidos , Caderinas/genética , Permeabilidade da Membrana Celular/genética , Quelantes/farmacologia , Sulfato de Di-Hidroestreptomicina/farmacologia , Ácido Egtázico/análogos & derivados , Ácido Egtázico/farmacologia , Embrião de Mamíferos , Feminino , Células Ciliadas Auditivas/citologia , Células Ciliadas Auditivas/efeitos dos fármacos , Técnicas In Vitro , Canais Iônicos/efeitos dos fármacos , Masculino , Mecanotransdução Celular/efeitos dos fármacos , Mecanotransdução Celular/genética , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Miosina VIIa , Miosinas/genética , Órgão Espiral/citologia , Precursores de Proteínas/genética
12.
J Dairy Sci ; 96(10): 6390-9, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23958025

RESUMO

The objective of this randomized noninferiority clinical trial was to compare the effect of treatment with 3 different dry cow therapy formulations at dry-off on cow-level health and production parameters in the first 100 d in milk (DIM) in the subsequent lactation, including 305-d mature-equivalent (305 ME) milk production, linear score (LS), risk for the cow experiencing a clinical mastitis event, risk for culling or death, and risk for pregnancy by 100 DIM. A total of 1,091 cows from 6 commercial dairy herds in 4 states (California, Iowa, Minnesota, and Wisconsin) were randomly assigned at dry-off to receive treatment with 1 of 3 commercial products: Quartermaster (QT; Zoetis Animal Health, Madison, NJ), Spectramast DC (SP; Zoetis Animal Health) or ToMorrow Dry Cow (TM; Boehringer Ingelheim Vetmedica Inc., St Joseph, MO). All clinical mastitis, pregnancy, culling, and death events occurring in the first 100 DIM were recorded by farm staff using an on-farm electronic record-keeping system. Dairy Herd Improvement Association test-day records of milk production and milk component testing were retrieved electronically. Mixed linear regression analysis was used to describe the effect of treatment on 305ME milk production and LS recorded on the last Dairy Herd Improvement Association test day before 100 DIM. Cox proportional hazards regression analysis was used to describe the effect of treatment on risk for experiencing a case of clinical mastitis, risk for leaving the herd, and risk for pregnancy between calving and 100 DIM. Results showed no effect of treatment on adjusted mean 305 ME milk production (QT=11,759 kg, SP=11,574 kg, and TM=11,761 kg) or adjusted mean LS (QT=1.8, SP=1.9, and TM=1.6) on the last test day before 100 DIM. Similarly, no effect of treatment was observed on risk for a clinical mastitis event (QT=14.8%, SP=12.7%, and TM=15.0%), risk for leaving the herd (QT=7.5%, SP=9.2%, and TM=10.3%), or risk for pregnancy (QT=31.5%, SP=26.1%, and TM=26.9%) between calving and 100 DIM.


Assuntos
Antibacterianos/uso terapêutico , Cefapirina/uso terapêutico , Sulfato de Di-Hidroestreptomicina/uso terapêutico , Mastite Bovina/tratamento farmacológico , Penicilina G Procaína/uso terapêutico , Animais , Bovinos , Cefalosporinas/uso terapêutico , Feminino , Lactação/efeitos dos fármacos , Leite/metabolismo , Minnesota , Gravidez , Risco
13.
Microbiol Immunol ; 57(10): 684-91, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23930694

RESUMO

To determine and compare the extent of contamination caused by antimicrobial-resistant lactic acid bacteria (LAB) in imported and domestic natural cheeses on the Japanese market, LAB were isolated using deMan, Rogosa and Sharpe (MRS) agar and MRS agar supplemented with six antimicrobials. From 38 imported and 24 Japanese cheeses, 409 LAB isolates were obtained and their antimicrobial resistance was tested. The percentage of LAB resistant to dihydrostreptomycin, erythromycin, and/or oxytetracycline isolated from imported cheeses (42.1%) was significantly higher than that of LAB resistant to dihydrostreptomycin or oxytetracycline from cheeses produced in Japan (16.7%; P=0.04). Antimicrobial resistance genes were detected in Enterococcus faecalis (tetL, tetM, and ermB; tetL and ermB; tetM) E. faecium (tetM), Lactococcus lactis (tetS), Lactobacillus (Lb.), casei/paracasei (tetM or tetW), and Lb. rhamnosus (ermB) isolated from seven imported cheeses. Moreover, these E. faecalis isolates were able to transfer antimicrobial resistance gene(s). Although antimicrobial resistance genes were not detected in any LAB isolates from Japanese cheeses, Lb. casei/paracasei and Lb. coryniformis isolates from a Japanese farm-made cheese were resistant to oxytetracycline (minimal inhibitory concentration [MIC], 32 µg/mL). Leuconostoc isolates from three Japanese farm-made cheeses were also resistant to dihydrostreptomycin (MIC, 32 to >512 µg/mL). In conclusion, the present study demonstrated contamination with antimicrobial-resistant LAB in imported and Japanese farm-made cheeses on the Japanese market, but not in Japanese commercial cheeses.


Assuntos
Antibacterianos/farmacologia , Queijo/microbiologia , Farmacorresistência Bacteriana , Lactobacillales/efeitos dos fármacos , Lactobacillales/isolamento & purificação , Técnicas Bacteriológicas , Sulfato de Di-Hidroestreptomicina/farmacologia , Eritromicina/farmacologia , Japão , Lactobacillales/genética , Testes de Sensibilidade Microbiana , Oxitetraciclina/farmacologia
14.
J Dairy Sci ; 96(7): 4419-35, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23628244

RESUMO

The study objective was to compare the efficacy of 3 commercial dry cow mastitis formulations regarding quarter-level prevalence of intramammary infections (IMI) postcalving, cure of preexisting infections over the dry period, prevention of new infections during the dry period, and risk for a clinical mastitis case between calving and 100d in milk (DIM). A total of 1,091 cows (4,364 quarters) from 6 commercial dairy herds in 4 different states (California, Iowa, Minnesota, and Wisconsin) were enrolled and randomized to 1 of the 3 treatments at dry-off: Quartermaster (QT; 1,000,000 IU of procaine penicillin G and 1 g of dihydrostreptomycin; Pfizer Animal Health, New York, NY), Spectramast DC (SP; 500 mg of ceftiofur hydrochloride; Pfizer Animal Health), or ToMorrow Dry Cow (TM; 300mg of cephapirin benzathine; Boehringer Ingelheim Vetmedica Inc., St. Joseph, MO). Quarter milk samples were collected for routine bacteriological culture before dry cow therapy treatment at dry-off, 0 to 6 DIM, and 7 to 13 DIM and an on-farm record-keeping system was used to retrieve data on clinical mastitis cases. Noninferiority analysis was used to evaluate the effect of treatment on the primary outcome, risk for a bacteriological cure during the dry period. Multivariable logistic regression techniques were used to describe the effect of treatment on risk for presence of IMI postcalving and risk of a new IMI during the dry period. Cox proportional hazards regression was used to describe the effect of treatment on the risk and time for quarters to experience an episode of clinical mastitis between calving and 100 DIM. The overall crude quarter-level prevalence of infection at dry-off was 19.2%. The most common pathogen isolated from milk samples at dry-off was coagulase-negative Staphylococcus, followed by Aerococcus spp. and other Streptococcus spp. Noninferiority analysis showed no effect of treatment on risk for a cure between dry-off and calving [least squares means (LSM): QT=93.3%, SP=92.6%, and TM=94.0%] and secondary analysis showed no effect of treatment on risk for presence of an IMI at 0 to 6 DIM (LSM: QT=16.5%, SP=14.1%, and TM=16.0%), risk for development of a new IMI between dry-off and 0 to 6 DIM (LSM: QT=14.8%, SP=12.3%, and TM=14.2%), or risk of experiencing a clinical mastitis event between calving and 100 DIM (LSM: QT=5.3%, SP=3.8%, and TM=4.1%). In conclusion, no difference was observed in efficacy among the 3 products evaluated when assessing the aforementioned quarter-level outcomes.


Assuntos
Antibacterianos/uso terapêutico , Mastite Bovina/tratamento farmacológico , Mastite Bovina/prevenção & controle , Animais , California , Bovinos , Cefalosporinas/uso terapêutico , Cefapirina/uso terapêutico , Sulfato de Di-Hidroestreptomicina/uso terapêutico , Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/veterinária , Feminino , Lactação , Mastite Bovina/microbiologia , Leite/microbiologia , Minnesota , New York , Penicilina G/uso terapêutico , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estreptocócicas/tratamento farmacológico , Wisconsin
15.
J Dairy Sci ; 95(12): 7015-26, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22999278

RESUMO

The objective of this study was to investigate the association between mastitis events occurring during the previous lactation, the dry period, and the peripartum period on the incidence of early lactation mastitis in cows receiving ceftiofur hydrochloride or penicillin dihydrostreptomycin as intramammary dry cow antibiotic therapy. Cows (n=402) from 2 large dairy farms in Central Florida were enrolled in the study at the time of dry-off processing and were randomly assigned to 1 of 2 dry cow therapies: ceftiofur hydrochloride or penicillin dihydrostreptomycin. Composite milk samples were collected at dry-off and after calving for bacteriological examination and somatic cell count. Peripartal health disorders were monitored during the first 30 d of lactation and included calving difficulty, metritis, ketosis, and left displaced abomasum. Milk production and individual somatic cell scores (SCS) were recorded monthly by the Dairy Herd Improvement Association. The main outcome variables were the risk of clinical mastitis during the first 30 and 60 d of lactation, and the risk of subclinical mastitis at the first 2 monthly Dairy Herd Improvement Association tests after calving (up to 70 d in milk). Additionally, the SCS and the presence of mastitis pathogens in milk at dry-off and at calving were analyzed. Explanatory variables consisted of events occurring during the previous lactation, at dry-off and during the dry period, at calving, and within the first 30 d after calving. Multiple events occurring during the previous lactation had a significant effect on the incidence of mastitis in the subsequent lactation. These events included low milk yield, intermediate lactation length, clinical mastitis, and lactation SCS average. Similarly, intramammary infections with environmental bacteria at dry-off increased the chances of clinical mastitis the first month after calving. Dry-off therapy had a significant effect on mastitis incidence; cows treated with ceftiofur hydrochloride had lower odds of having clinical and subclinical mastitis in the subsequent early lactation compared with cows treated with penicillin dihydrostreptomycin.


Assuntos
Antibacterianos/uso terapêutico , Cefalosporinas/uso terapêutico , Sulfato de Di-Hidroestreptomicina/uso terapêutico , Lactação/fisiologia , Mastite Bovina/etiologia , Penicilinas/uso terapêutico , Animais , Antibacterianos/administração & dosagem , Bovinos , Sulfato de Di-Hidroestreptomicina/administração & dosagem , Combinação de Medicamentos , Feminino , Mastite Bovina/prevenção & controle , Leite/citologia , Leite/microbiologia , Penicilinas/administração & dosagem , Período Periparto/fisiologia , Gravidez , Fatores de Risco
16.
J Neurosci ; 32(31): 10479-83, 2012 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-22855797

RESUMO

Spontaneous Ca(2+)-dependent electrical activity in the immature mammalian cochlea is thought to instruct the formation of the tonotopic map during the differentiation of sensory hair cells and the auditory pathway. This activity occurs in inner hair cells (IHCs) during the first postnatal week, and the pattern differs along the cochlea. During the second postnatal week, which is before the onset of hearing in most rodents, the resting membrane potential for IHCs is apparently more hyperpolarized (approximately -75 mV), and it remains unclear whether spontaneous action potentials continue to occur. We found that when mouse IHC hair bundles were exposed to the estimated in vivo endolymphatic Ca(2+) concentration (0.3 mm) present in the immature cochlea, the increased open probability of the mechanotransducer channels caused the cells to depolarize to around the action potential threshold (approximately -55 mV). We propose that, in vivo, spontaneous Ca(2+) action potentials are intrinsically generated by IHCs up to the onset of hearing and that they are likely to influence the final sensory-independent refinement of the developing cochlea.


Assuntos
Cálcio/metabolismo , Cóclea/citologia , Células Ciliadas Auditivas Internas/fisiologia , Mecanotransdução Celular/fisiologia , Potenciais da Membrana/fisiologia , Trifosfato de Adenosina/análogos & derivados , Trifosfato de Adenosina/farmacologia , Fatores Etários , Animais , Animais Recém-Nascidos , Biofísica , Cálcio/farmacologia , Cóclea/crescimento & desenvolvimento , Sulfato de Di-Hidroestreptomicina/farmacologia , Relação Dose-Resposta a Droga , Estimulação Elétrica , Endolinfa/metabolismo , Feminino , Glicinérgicos/farmacologia , Células Ciliadas Auditivas Internas/efeitos dos fármacos , Técnicas In Vitro , Potenciais Pós-Sinápticos Inibidores/efeitos dos fármacos , Masculino , Mecanotransdução Celular/efeitos dos fármacos , Potenciais da Membrana/efeitos dos fármacos , Camundongos , Técnicas de Patch-Clamp , Estimulação Física , Estricnina/farmacologia
17.
Se Pu ; 30(1): 33-8, 2012 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-22667088

RESUMO

The method was specifically developed for the simultaneous determination of streptomycin and dihydrostreptomycin residues in tomato paste by tandem dual solid phase extraction (SPE) column cleanup-liquid chromatography-tandem mass spectrometry. The residues were extracted from the samples with phosphate buffer solution (pH 4). The cleanup was performed by the way of dispersive solid phase extraction and tandem dual solid phase extraction column. The polar chromatographic column was used to complete the separation of the analytes under gradient elution and the analytes were detected in multiple reaction monitoring (MRM) mode via positive electrospray ionization (ESI +). The external standard calibration curves were used for the quantification. The linear ranges were from 0.01 to 0.2 mg/L with a good linear relationship (r > 0.999) for streptomycin and dihydrostreptomycin. The limit of quantification (LOQs) was 0.02 mg/kg for the both analytes. The recovery range was from 71% to 101% with the relative standard deviations (RSDs) between 2.3% and 15%. It was indicated that this method is accurate, easier, more sensitive, and has a better purification effect in the monitoring and analysis. The method is accurate and specific to monitor and analyze of streptomycin and dihydrostreptomycin residues in tomato paste and its products.


Assuntos
Cromatografia Líquida/métodos , Sulfato de Di-Hidroestreptomicina/análise , Lycopersicon esculentum/química , Estreptomicina/análise , Espectrometria de Massas em Tandem/métodos , Resíduos de Drogas/análise , Contaminação de Alimentos/análise , Extração em Fase Sólida
18.
Vet J ; 193(2): 600-1, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22365844

RESUMO

This study presents a Brazilian goat herd with reproductive failure over 2009-2010, in which there were abortions (22/50; 44%), embryonic resorption (6/50; 12%) and neonatal deaths (2/50; 4%). A diagnosis of leptospirosis was made, based on serology (microscopic agglutination test - MAT), bacterial culture, and polymerase chain reaction (PCR). Antibiotic therapy, specific vaccination protocols and changes in management practices were instigated. One year after the outbreak, diagnostic methods were repeated and reproductive performance re-analysed. Soon after the outbreak, 61/125 (48.8%) of the goats were seropositive for Leptospira. Pure isolates of Leptospira were not obtained, but Leptospira PCR testing was positive in 48/50 (96%) urine samples. After 1 year only 4.2% were seropositive and the occurrence of reproductive problems decreased roughly 10-fold, although five goats (10.4%) remained PCR-positive. A broad-based management approach, including serological and molecular diagnostic methods, vaccination, antibiotic treatment, and alteration of some environmental aspects, were critical to the control of this outbreak, thereby minimising subsequent reproductive failures and economic losses.


Assuntos
Anticorpos Antibacterianos/urina , Surtos de Doenças/veterinária , Doenças das Cabras/diagnóstico , Doenças das Cabras/terapia , Leptospira/imunologia , Leptospirose/veterinária , Aborto Animal/diagnóstico , Aborto Animal/epidemiologia , Aborto Animal/terapia , Testes de Aglutinação/veterinária , Criação de Animais Domésticos/métodos , Animais , Antibacterianos/uso terapêutico , Vacinas Bacterianas/uso terapêutico , Brasil/epidemiologia , Sulfato de Di-Hidroestreptomicina/uso terapêutico , Perda do Embrião/diagnóstico , Perda do Embrião/epidemiologia , Perda do Embrião/terapia , Feminino , Doenças das Cabras/epidemiologia , Cabras , Leptospira/isolamento & purificação , Leptospirose/diagnóstico , Leptospirose/epidemiologia , Leptospirose/terapia , Reação em Cadeia da Polimerase/veterinária , Estudos Soroepidemiológicos , Vacinas de Produtos Inativados/uso terapêutico
19.
Epidemiol Infect ; 140(11): 2074-81, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22281015

RESUMO

This study determined the prevalence and antimicrobial susceptibility of Salmonella isolated from broiler flocks in Japan. Caecal dropping samples were collected from 288 broiler flocks between November 2007 and February 2010. Salmonella was prevalent in 248 (86·1%) broiler flocks. The top three serovars were S. Infantis, S. Manhattan and S. Schwarzengrund. S. Infantis was found in all regions tested in this study. However, S. Manhattan and S. Schwarzengrund were frequently found only in the western part of Japan. High antimicrobial resistance rates were observed against oxytetracycline (90·2%), dihydrostreptomycin (86·7%) and ampicillin (36·5%), and 258 (90·5%) of 285 isolates were resistant to two or more antimicrobial agents. Interestingly, 26·3% of isolates were resistant to ceftiofur, especially 38·1% of S. Infantis isolates, although its use in broilers has not been approved in Japan. This study showed that Salmonella is highly prevalent (86·1%) in Japanese broiler flocks, that 90·5% of Salmonella isolates were multidrug-resistant, and that S. Infantis frequently exhibited resistance to cephalosporin antimicrobial agents.


Assuntos
Galinhas , Farmacorresistência Bacteriana , Doenças das Aves Domésticas/epidemiologia , Salmonelose Animal/epidemiologia , Salmonella enterica/efeitos dos fármacos , Ampicilina/farmacologia , Animais , Antibacterianos/farmacologia , Cefalosporinas/farmacologia , Sulfato de Di-Hidroestreptomicina/farmacologia , Farmacorresistência Bacteriana Múltipla , Fezes/microbiologia , Japão/epidemiologia , Testes de Sensibilidade Microbiana , Oxitetraciclina/farmacologia , Doenças das Aves Domésticas/microbiologia , Salmonelose Animal/microbiologia , Salmonella enterica/isolamento & purificação
20.
Pharmeur Bio Sci Notes ; 2012: 16-38, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23327890

RESUMO

An international collaborative study was organised to establish the World Health Organization (WHO) 3rd International Standard (IS) for dihydrostreptomycin. Eleven laboratories from different countries participated in the collaborative study. The potency of the candidate batch, a freeze-dried preparation, was estimated by microbiological assays with sensitive microorganisms. To ensure continuity between consecutive batches of the WHO IS, the 2nd IS for dihydrostreptomycin was used as standard. Based on the results of the study, the 3rd IS for dihydrostreptomycin was adopted at the meeting of the WHO Expert Committee on Biological Standardisation (ECBS) in 2011 with an assigned anti-microbiological activity of 19425 International Units (IU) per vial. The 3rd IS for dihydrostreptomycin is available from the EDQM.


Assuntos
Antibacterianos/normas , Sulfato de Di-Hidroestreptomicina/normas , Cooperação Internacional , Testes de Sensibilidade Microbiana/normas , Antibacterianos/química , Antibacterianos/farmacologia , Fenômenos Químicos , Interpretação Estatística de Dados , Sulfato de Di-Hidroestreptomicina/química , Sulfato de Di-Hidroestreptomicina/farmacologia , Estabilidade de Medicamentos , Europa (Continente) , Laboratórios/normas , Farmacopeias como Assunto , Controle de Qualidade , Padrões de Referência , Organização Mundial da Saúde
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