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Zonghui Yuan - One of the best experts on this subject based on the ideXlab platform.
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enhanced treatment effects of Tilmicosin against staphylococcus aureus cow mastitis by self assembly sodium alginate chitosan nanogel
Pharmaceutics, 2019Co-Authors: Kaixiang Zhou, Xiaofang Wang, Lingli Huang, Dongmei Chen, Yuanyuan Yuan, Shuge Wang, Yuanyuan Yan, Qianying Liu, Liwei Shao, Zonghui YuanAbstract:The Staphylococcus aureus (S. aureus) cow mastitis causes great losses to the cow industry. In order to improve the treatment effect of Tilmicosin against cow mastitis, the combination of solid lipid nanoparticle (SLN) technology with in situ hydrogel technology was used to prepare the self-assembly Tilmicosin nanogel (TIL-nanogel). The physicochemical characteristics, in vitro release, antibacterial activity and in vivo treatment efficacy of TIL-SLNs and TIL-nanogel were studied, respectively. The results showed the loading capacity (LC), encapsulation efficiency (EE), size, zeta potential and poly dispersion index (PDI) of TIL-nanogel were 23.33 ± 0.77%, 67.89 ± 3.01%, 431.57 ± 12.87 nm, 8.3 ± 0.06 mv and, 0.424 ± 0.032, respectively. The TIL-nanogel showed stronger sustained release in vitro than TIL-SLNs and commercial injection. The cure rate of half dosage and normal dosage of TIL-nanogel was 58.3% and 75.0%, which was higher than that of commercial injection (50.0%) at normal dosage. The results suggest that the treatment dosage of Tilmicosin for cow mastitis could be reduced by TIL-nanogel. The novel TIL-nanogel will be beneficial by decreasing the usage of Tilmicosin and the treatment costs of cow mastitis.
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development and validation of an indirect competitive enzyme linked immunosorbent assay for the screening of tylosin and Tilmicosin in muscle liver milk honey and eggs
Journal of Agricultural and Food Chemistry, 2012Co-Authors: Dapeng Peng, Menghong Dai, Yulian Wang, Lingli Huang, Dongmei Chen, Yanfei Tao, Zhenli Liu, Xiaoqing Wang, Zonghui YuanAbstract:Incorrect use of tylosin and Tilmicosin could result in allergy and select resistance. To monitor the illegal use of these antibiotics in animals, a monoclonal-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) has been established. Several haptens were synthesized and conjugated to carrier protein. Female Balb/c mice were inoculated with the four different conjugates to produce monoclonal antibodies according to the schemes of immunization. Aftercell fusion and culture several times, nine hybridoma cell lines were isolated. Only one, 3C4 that has isotype IgG2a, was selected for detailed study. The cross-reactivity of the monoclonal antibody 3C4 to tylosin and Tilmicosin was 100% and 51% respectively. The standard curves based on the tylosin and Tilmicosin matrix calibration ranged from 2.5 to 40 μg L(-1), with an IC(50) value of 6.1 μg L(-1) and 12.1 μg L(-1), respectively. The limits of detection of the ic-ELISA ranged from 5.1 μg kg(-1) to 13.8 μg kg(-1) in edible animal tissues. The recoveries were 74.1% to 120.7% with less than 18.6% of the coefficient of variation when tylosin and Tilmicosin were spiked in various biological matrices with the concentrations of 25.0-200.0 μg kg(-1). Good correlations between the results of the ic-ELISA and high performance liquid chromatography were observed in the incurred tissues. These results suggest that the ic-ELISA is a sensitive, accurate and low-cost method that would be a useful tool for the screening of the residues of tylosin and Tilmicosin in muscle, liver, milk, honey and eggs.
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development and validation of an indirect competitive enzyme linked immunosorbent assay for the screening of tylosin and Tilmicosin in muscle liver milk honey and eggs
Journal of Agricultural and Food Chemistry, 2012Co-Authors: Dapeng Peng, Menghong Dai, Yulian Wang, Lingli Huang, Dongmei Chen, Yanfei Tao, Zhenli Liu, Xiaoqing Wang, Zonghui YuanAbstract:Incorrect use of tylosin and Tilmicosin could result in allergy and select resistance. To monitor the illegal use of these antibiotics in animals, a monoclonal-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) has been established. Several haptens were synthesized and conjugated to carrier protein. Female Balb/c mice were inoculated with the four different conjugates to produce monoclonal antibodies according to the schemes of immunization. Aftercell fusion and culture several times, nine hybridoma cell lines were isolated. Only one, 3C4 that has isotype IgG2a, was selected for detailed study. The cross-reactivity of the monoclonal antibody 3C4 to tylosin and Tilmicosin was 100% and 51% respectively. The standard curves based on the tylosin and Tilmicosin matrix calibration ranged from 2.5 to 40 μg L–1, with an IC50 value of 6.1 μg L–1 and 12.1 μg L–1, respectively. The limits of detection of the ic-ELISA ranged from 5.1 μg kg–1 to 13.8 μg kg–1 in edible animal tissues. The recoverie...
Roger D Ayling - One of the best experts on this subject based on the ideXlab platform.
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Veterinary Record (2000)
2016Co-Authors: Papers Articles_, S E Baker, M L Peek, A J Simon, Roger D Ayling, R. A. J. Nicholas, Phd Mibiol VeterinaryAbstract:Comparison of in vitro activity of danofloxacin, florlenicol, oxytetracycline, spectinomycin and Tilmicosin against Mycoplasma mycoides subspecies mycoides small colony typ
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assessing the in vitro effectiveness of antimicrobials against mycoplasma mycoides subsp mycoides small colony type to reduce contagious bovine pleuropneumonia infection
Antimicrobial Agents and Chemotherapy, 2005Co-Authors: Roger D Ayling, John B March, S Bisgaardfrantzen, Kevin GodinhoAbstract:In vitro minimum inhibitory concentrations were determined for 21 antimicrobials against 41 isolates of Mycoplasma mycoides subsp. mycoides small-colony type, the cause of contagious bovine pleuropneumonia. Of the antimicrobials used most widely in Africa, oxytetracycline and Tilmicosin were effective, while the isolates were resistant to tylosin. These results provide a baseline for monitoring antimicrobial resistance.
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comparison of in vitro activity of danofloxacin florfenicol oxytetracycline spectinomycin and Tilmicosin against recent field isolates of mycoplasma bovis
Veterinary Record, 2000Co-Authors: Roger D Ayling, S E Baker, M L Peek, A J Simon, R. A. J. NicholasAbstract:The minimum inhibitory concentrations (MICs) and minimum mycoplasmacidal concentrations (MMCs) of danofloxacin, florfenicol, oxytetracycline, spectinomycin and Tilmicosin against 62 recent British field isolates of Mycoplasma bovis were determined in vitro by a broth microdilution method. The isolates were most susceptible to danofloxacin with MIC 90 and MMC 90 values of 0.5 μg/ml and 1.0 μg/ml, respectively. They were less susceptible to florfenicol with a MIC 90 of 16 μg/ml and MMC 90 of 32 μg/ml. Oxytetracycline and spectinomycin had only a limited effect against the majority of isolates tested with MIC 50 s of 32 μg/ml and 4 μg/ml, respectively and MIC 90 s of 64 μg/ml and more than 128 μg/ml, respectively. Nearly 20 per cent of the isolates were highly resistant to spectinomycin, and Tilmicosin was ineffective, with 92 per cent of the isolates having MIC values of 128 μg/ml or greater. There was no evidence of resistance by M bovis to danofloxacin.
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comparison of in vitro activity of danofloxacin florfenicol oxytetracycline spectinomycin and Tilmicosin against mycoplasma mycoides subspecies mycoides small colony type
Veterinary Record, 2000Co-Authors: Roger D Ayling, S E Baker, M L Peek, R. A. J. Nicholas, A J SimonAbstract:Minimum inhibitory concentrations (Mic) and minimum mycoplasmacidal concentrations (MMc) of the antimicrobials danofloxacin, florfenicol, oxytetracycline, spedinomycin and Tilmicosin were determined in vitro for 20 isolates of Mycoplasma mycoides subspecies mycoides small colony type (Mmmsc), the causative agent of contagious bovine pleuropneumonia (CBPP). The majority of strains were most susceptible to Tilmicosin, followed by danofloxacin, oxytetracycline, florfenicol and spectinomycin with Mic0values of 0-015, 0-25, O-5, 1 and 8 pg/ml, and MMC50 values of 0-06, 0-5, 8, 8 and 16 pg/ml, respectively. However, Tilmicosin had poor mycoplasmacidal activity against two recent strains from Portugal. There was no evidence of resistance to danofloxacin in any of the strains.
Yanfei Tao - One of the best experts on this subject based on the ideXlab platform.
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the epidemiologic and pharmacodynamic cutoff values of Tilmicosin against haemophilus parasuis
Frontiers in Microbiology, 2016Co-Authors: Peng Zhang, Haihong Hao, Menghong Dai, Yulian Wang, Lingli Huang, Dongmei Chen, Yanfei Tao, Ijaz Ahmad, Guyue Cheng, Zhenli LiuAbstract:The aim of this study was to establish antimicrobial susceptibility breakpoints for Tilmicosin against Haemophilus parasuis, which is an important pathogen of respiratory tract infections. The minimum inhibitory concentrations (MICs) of 103 H. parasuis isolates were determined by the agar dilution method. The wild type (WT) distribution and epidemiologic cutoff value (ECV) were evaluated by statistical analysis. The new bronchoaveolar lavage was used to establish intrapulmonary pharmacokinetic (PK) model in swine. The pharmacokinetic (PK) parameters of Tilmicosin, both in pulmonary epithelial lining fluid (PELF) and in plasma, were determined using high performance liquid chromatography method and WinNonlin software. The pharmacodynamic cutoff (COPD) was calculated using Monte Carlo simulation. Our results showed that 100% of WT isolates were covered when the ECV was set at 16 μg/mL. The Tilmicosin had concentration-dependent activity against H. parasuis. The PK data indicated that Tilmicosin concentrations in PELF was rapidly increased to high levels at 4 h and kept stable until 48 h after drug administration, while the Tilmicosin concentration in plasma reached maximum levels at 4 h and continued to decrease during 4-72 h. Using Monte Carlo simulation, COPD was defined as 1 μg/mL. Conclusively, the ECV and COPD of Tilmicosin against H. parasuis were established for the first time based on the MIC distribution and PK-PD analysis in the target tissue, respectively. These values are of great importance for detection of Tilmicosin-resistant H. parasuis and for effective treatment of clinical intrapulmonary infection caused by H. parasuis.
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microbiological toxicity of Tilmicosin on human colonic microflora in chemostats
Regulatory Toxicology and Pharmacology, 2015Co-Authors: Haihong Hao, Junping Yao, Yajing Wei, Menghong Dai, Zahid Iqbal, Xu Wang, Yulian Wang, Lingli Huang, Dongmei Chen, Yanfei TaoAbstract:To evaluate the microbiological safety of Tilmicosin on human intestinal microflora, four chemostat models of healthy human colonic ecosystems were exposed to Tilmicosin (0, 0.436, 4.36, and 43.6 μg/mL) for 7 days. Prior to and during drug exposure, three microbiological endpoints were monitored daily including short-chain fatty acids, bacterial counts and macrolide susceptibility. Colonization resistance of each community was determined by 3 successive daily challenges of Salmonella typhimurium. Genes associated with virulence and macrolide resistance in Enterococcus faecalis were determined by PCR. Transcriptional expression of the virulence gene (gelE) in E. faecalis was determined by real-time RT-PCR. Our results showed that different concentrations of Tilmicosin did not disrupt the colonization resistance in each chemostat. During exposure to 4.36 and 43.6 μg/mL Tilmicosin, the Bacteroides fragilis population was significantly decreased while the proportion of resistant Enterococci increased. After long-term exposure to the highest concentration (43.6 μg/mL) of Tilmicosin, the gelE gene was significantly up-regulated in the high-level macrolide resistant strains that also contained the ermB resistance gene. This study was the first of its kind to evaluate the microbiological toxicity of Tilmicosin using a chemostat model. These findings also provide new insight into the co-occurrence of macrolide resistance and virulence in E. faecalis under Tilmicosin selective pressure.
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development and validation of an indirect competitive enzyme linked immunosorbent assay for the screening of tylosin and Tilmicosin in muscle liver milk honey and eggs
Journal of Agricultural and Food Chemistry, 2012Co-Authors: Dapeng Peng, Menghong Dai, Yulian Wang, Lingli Huang, Dongmei Chen, Yanfei Tao, Zhenli Liu, Xiaoqing Wang, Zonghui YuanAbstract:Incorrect use of tylosin and Tilmicosin could result in allergy and select resistance. To monitor the illegal use of these antibiotics in animals, a monoclonal-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) has been established. Several haptens were synthesized and conjugated to carrier protein. Female Balb/c mice were inoculated with the four different conjugates to produce monoclonal antibodies according to the schemes of immunization. Aftercell fusion and culture several times, nine hybridoma cell lines were isolated. Only one, 3C4 that has isotype IgG2a, was selected for detailed study. The cross-reactivity of the monoclonal antibody 3C4 to tylosin and Tilmicosin was 100% and 51% respectively. The standard curves based on the tylosin and Tilmicosin matrix calibration ranged from 2.5 to 40 μg L(-1), with an IC(50) value of 6.1 μg L(-1) and 12.1 μg L(-1), respectively. The limits of detection of the ic-ELISA ranged from 5.1 μg kg(-1) to 13.8 μg kg(-1) in edible animal tissues. The recoveries were 74.1% to 120.7% with less than 18.6% of the coefficient of variation when tylosin and Tilmicosin were spiked in various biological matrices with the concentrations of 25.0-200.0 μg kg(-1). Good correlations between the results of the ic-ELISA and high performance liquid chromatography were observed in the incurred tissues. These results suggest that the ic-ELISA is a sensitive, accurate and low-cost method that would be a useful tool for the screening of the residues of tylosin and Tilmicosin in muscle, liver, milk, honey and eggs.
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development and validation of an indirect competitive enzyme linked immunosorbent assay for the screening of tylosin and Tilmicosin in muscle liver milk honey and eggs
Journal of Agricultural and Food Chemistry, 2012Co-Authors: Dapeng Peng, Menghong Dai, Yulian Wang, Lingli Huang, Dongmei Chen, Yanfei Tao, Zhenli Liu, Xiaoqing Wang, Zonghui YuanAbstract:Incorrect use of tylosin and Tilmicosin could result in allergy and select resistance. To monitor the illegal use of these antibiotics in animals, a monoclonal-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) has been established. Several haptens were synthesized and conjugated to carrier protein. Female Balb/c mice were inoculated with the four different conjugates to produce monoclonal antibodies according to the schemes of immunization. Aftercell fusion and culture several times, nine hybridoma cell lines were isolated. Only one, 3C4 that has isotype IgG2a, was selected for detailed study. The cross-reactivity of the monoclonal antibody 3C4 to tylosin and Tilmicosin was 100% and 51% respectively. The standard curves based on the tylosin and Tilmicosin matrix calibration ranged from 2.5 to 40 μg L–1, with an IC50 value of 6.1 μg L–1 and 12.1 μg L–1, respectively. The limits of detection of the ic-ELISA ranged from 5.1 μg kg–1 to 13.8 μg kg–1 in edible animal tissues. The recoverie...
Menghong Dai - One of the best experts on this subject based on the ideXlab platform.
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the epidemiologic and pharmacodynamic cutoff values of Tilmicosin against haemophilus parasuis
Frontiers in Microbiology, 2016Co-Authors: Peng Zhang, Haihong Hao, Menghong Dai, Yulian Wang, Lingli Huang, Dongmei Chen, Yanfei Tao, Ijaz Ahmad, Guyue Cheng, Zhenli LiuAbstract:The aim of this study was to establish antimicrobial susceptibility breakpoints for Tilmicosin against Haemophilus parasuis, which is an important pathogen of respiratory tract infections. The minimum inhibitory concentrations (MICs) of 103 H. parasuis isolates were determined by the agar dilution method. The wild type (WT) distribution and epidemiologic cutoff value (ECV) were evaluated by statistical analysis. The new bronchoaveolar lavage was used to establish intrapulmonary pharmacokinetic (PK) model in swine. The pharmacokinetic (PK) parameters of Tilmicosin, both in pulmonary epithelial lining fluid (PELF) and in plasma, were determined using high performance liquid chromatography method and WinNonlin software. The pharmacodynamic cutoff (COPD) was calculated using Monte Carlo simulation. Our results showed that 100% of WT isolates were covered when the ECV was set at 16 μg/mL. The Tilmicosin had concentration-dependent activity against H. parasuis. The PK data indicated that Tilmicosin concentrations in PELF was rapidly increased to high levels at 4 h and kept stable until 48 h after drug administration, while the Tilmicosin concentration in plasma reached maximum levels at 4 h and continued to decrease during 4-72 h. Using Monte Carlo simulation, COPD was defined as 1 μg/mL. Conclusively, the ECV and COPD of Tilmicosin against H. parasuis were established for the first time based on the MIC distribution and PK-PD analysis in the target tissue, respectively. These values are of great importance for detection of Tilmicosin-resistant H. parasuis and for effective treatment of clinical intrapulmonary infection caused by H. parasuis.
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microbiological toxicity of Tilmicosin on human colonic microflora in chemostats
Regulatory Toxicology and Pharmacology, 2015Co-Authors: Haihong Hao, Junping Yao, Yajing Wei, Menghong Dai, Zahid Iqbal, Xu Wang, Yulian Wang, Lingli Huang, Dongmei Chen, Yanfei TaoAbstract:To evaluate the microbiological safety of Tilmicosin on human intestinal microflora, four chemostat models of healthy human colonic ecosystems were exposed to Tilmicosin (0, 0.436, 4.36, and 43.6 μg/mL) for 7 days. Prior to and during drug exposure, three microbiological endpoints were monitored daily including short-chain fatty acids, bacterial counts and macrolide susceptibility. Colonization resistance of each community was determined by 3 successive daily challenges of Salmonella typhimurium. Genes associated with virulence and macrolide resistance in Enterococcus faecalis were determined by PCR. Transcriptional expression of the virulence gene (gelE) in E. faecalis was determined by real-time RT-PCR. Our results showed that different concentrations of Tilmicosin did not disrupt the colonization resistance in each chemostat. During exposure to 4.36 and 43.6 μg/mL Tilmicosin, the Bacteroides fragilis population was significantly decreased while the proportion of resistant Enterococci increased. After long-term exposure to the highest concentration (43.6 μg/mL) of Tilmicosin, the gelE gene was significantly up-regulated in the high-level macrolide resistant strains that also contained the ermB resistance gene. This study was the first of its kind to evaluate the microbiological toxicity of Tilmicosin using a chemostat model. These findings also provide new insight into the co-occurrence of macrolide resistance and virulence in E. faecalis under Tilmicosin selective pressure.
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development and validation of an indirect competitive enzyme linked immunosorbent assay for the screening of tylosin and Tilmicosin in muscle liver milk honey and eggs
Journal of Agricultural and Food Chemistry, 2012Co-Authors: Dapeng Peng, Menghong Dai, Yulian Wang, Lingli Huang, Dongmei Chen, Yanfei Tao, Zhenli Liu, Xiaoqing Wang, Zonghui YuanAbstract:Incorrect use of tylosin and Tilmicosin could result in allergy and select resistance. To monitor the illegal use of these antibiotics in animals, a monoclonal-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) has been established. Several haptens were synthesized and conjugated to carrier protein. Female Balb/c mice were inoculated with the four different conjugates to produce monoclonal antibodies according to the schemes of immunization. Aftercell fusion and culture several times, nine hybridoma cell lines were isolated. Only one, 3C4 that has isotype IgG2a, was selected for detailed study. The cross-reactivity of the monoclonal antibody 3C4 to tylosin and Tilmicosin was 100% and 51% respectively. The standard curves based on the tylosin and Tilmicosin matrix calibration ranged from 2.5 to 40 μg L(-1), with an IC(50) value of 6.1 μg L(-1) and 12.1 μg L(-1), respectively. The limits of detection of the ic-ELISA ranged from 5.1 μg kg(-1) to 13.8 μg kg(-1) in edible animal tissues. The recoveries were 74.1% to 120.7% with less than 18.6% of the coefficient of variation when tylosin and Tilmicosin were spiked in various biological matrices with the concentrations of 25.0-200.0 μg kg(-1). Good correlations between the results of the ic-ELISA and high performance liquid chromatography were observed in the incurred tissues. These results suggest that the ic-ELISA is a sensitive, accurate and low-cost method that would be a useful tool for the screening of the residues of tylosin and Tilmicosin in muscle, liver, milk, honey and eggs.
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development and validation of an indirect competitive enzyme linked immunosorbent assay for the screening of tylosin and Tilmicosin in muscle liver milk honey and eggs
Journal of Agricultural and Food Chemistry, 2012Co-Authors: Dapeng Peng, Menghong Dai, Yulian Wang, Lingli Huang, Dongmei Chen, Yanfei Tao, Zhenli Liu, Xiaoqing Wang, Zonghui YuanAbstract:Incorrect use of tylosin and Tilmicosin could result in allergy and select resistance. To monitor the illegal use of these antibiotics in animals, a monoclonal-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) has been established. Several haptens were synthesized and conjugated to carrier protein. Female Balb/c mice were inoculated with the four different conjugates to produce monoclonal antibodies according to the schemes of immunization. Aftercell fusion and culture several times, nine hybridoma cell lines were isolated. Only one, 3C4 that has isotype IgG2a, was selected for detailed study. The cross-reactivity of the monoclonal antibody 3C4 to tylosin and Tilmicosin was 100% and 51% respectively. The standard curves based on the tylosin and Tilmicosin matrix calibration ranged from 2.5 to 40 μg L–1, with an IC50 value of 6.1 μg L–1 and 12.1 μg L–1, respectively. The limits of detection of the ic-ELISA ranged from 5.1 μg kg–1 to 13.8 μg kg–1 in edible animal tissues. The recoverie...
Yulian Wang - One of the best experts on this subject based on the ideXlab platform.
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the epidemiologic and pharmacodynamic cutoff values of Tilmicosin against haemophilus parasuis
Frontiers in Microbiology, 2016Co-Authors: Peng Zhang, Haihong Hao, Menghong Dai, Yulian Wang, Lingli Huang, Dongmei Chen, Yanfei Tao, Ijaz Ahmad, Guyue Cheng, Zhenli LiuAbstract:The aim of this study was to establish antimicrobial susceptibility breakpoints for Tilmicosin against Haemophilus parasuis, which is an important pathogen of respiratory tract infections. The minimum inhibitory concentrations (MICs) of 103 H. parasuis isolates were determined by the agar dilution method. The wild type (WT) distribution and epidemiologic cutoff value (ECV) were evaluated by statistical analysis. The new bronchoaveolar lavage was used to establish intrapulmonary pharmacokinetic (PK) model in swine. The pharmacokinetic (PK) parameters of Tilmicosin, both in pulmonary epithelial lining fluid (PELF) and in plasma, were determined using high performance liquid chromatography method and WinNonlin software. The pharmacodynamic cutoff (COPD) was calculated using Monte Carlo simulation. Our results showed that 100% of WT isolates were covered when the ECV was set at 16 μg/mL. The Tilmicosin had concentration-dependent activity against H. parasuis. The PK data indicated that Tilmicosin concentrations in PELF was rapidly increased to high levels at 4 h and kept stable until 48 h after drug administration, while the Tilmicosin concentration in plasma reached maximum levels at 4 h and continued to decrease during 4-72 h. Using Monte Carlo simulation, COPD was defined as 1 μg/mL. Conclusively, the ECV and COPD of Tilmicosin against H. parasuis were established for the first time based on the MIC distribution and PK-PD analysis in the target tissue, respectively. These values are of great importance for detection of Tilmicosin-resistant H. parasuis and for effective treatment of clinical intrapulmonary infection caused by H. parasuis.
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microbiological toxicity of Tilmicosin on human colonic microflora in chemostats
Regulatory Toxicology and Pharmacology, 2015Co-Authors: Haihong Hao, Junping Yao, Yajing Wei, Menghong Dai, Zahid Iqbal, Xu Wang, Yulian Wang, Lingli Huang, Dongmei Chen, Yanfei TaoAbstract:To evaluate the microbiological safety of Tilmicosin on human intestinal microflora, four chemostat models of healthy human colonic ecosystems were exposed to Tilmicosin (0, 0.436, 4.36, and 43.6 μg/mL) for 7 days. Prior to and during drug exposure, three microbiological endpoints were monitored daily including short-chain fatty acids, bacterial counts and macrolide susceptibility. Colonization resistance of each community was determined by 3 successive daily challenges of Salmonella typhimurium. Genes associated with virulence and macrolide resistance in Enterococcus faecalis were determined by PCR. Transcriptional expression of the virulence gene (gelE) in E. faecalis was determined by real-time RT-PCR. Our results showed that different concentrations of Tilmicosin did not disrupt the colonization resistance in each chemostat. During exposure to 4.36 and 43.6 μg/mL Tilmicosin, the Bacteroides fragilis population was significantly decreased while the proportion of resistant Enterococci increased. After long-term exposure to the highest concentration (43.6 μg/mL) of Tilmicosin, the gelE gene was significantly up-regulated in the high-level macrolide resistant strains that also contained the ermB resistance gene. This study was the first of its kind to evaluate the microbiological toxicity of Tilmicosin using a chemostat model. These findings also provide new insight into the co-occurrence of macrolide resistance and virulence in E. faecalis under Tilmicosin selective pressure.
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development and validation of an indirect competitive enzyme linked immunosorbent assay for the screening of tylosin and Tilmicosin in muscle liver milk honey and eggs
Journal of Agricultural and Food Chemistry, 2012Co-Authors: Dapeng Peng, Menghong Dai, Yulian Wang, Lingli Huang, Dongmei Chen, Yanfei Tao, Zhenli Liu, Xiaoqing Wang, Zonghui YuanAbstract:Incorrect use of tylosin and Tilmicosin could result in allergy and select resistance. To monitor the illegal use of these antibiotics in animals, a monoclonal-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) has been established. Several haptens were synthesized and conjugated to carrier protein. Female Balb/c mice were inoculated with the four different conjugates to produce monoclonal antibodies according to the schemes of immunization. Aftercell fusion and culture several times, nine hybridoma cell lines were isolated. Only one, 3C4 that has isotype IgG2a, was selected for detailed study. The cross-reactivity of the monoclonal antibody 3C4 to tylosin and Tilmicosin was 100% and 51% respectively. The standard curves based on the tylosin and Tilmicosin matrix calibration ranged from 2.5 to 40 μg L(-1), with an IC(50) value of 6.1 μg L(-1) and 12.1 μg L(-1), respectively. The limits of detection of the ic-ELISA ranged from 5.1 μg kg(-1) to 13.8 μg kg(-1) in edible animal tissues. The recoveries were 74.1% to 120.7% with less than 18.6% of the coefficient of variation when tylosin and Tilmicosin were spiked in various biological matrices with the concentrations of 25.0-200.0 μg kg(-1). Good correlations between the results of the ic-ELISA and high performance liquid chromatography were observed in the incurred tissues. These results suggest that the ic-ELISA is a sensitive, accurate and low-cost method that would be a useful tool for the screening of the residues of tylosin and Tilmicosin in muscle, liver, milk, honey and eggs.
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development and validation of an indirect competitive enzyme linked immunosorbent assay for the screening of tylosin and Tilmicosin in muscle liver milk honey and eggs
Journal of Agricultural and Food Chemistry, 2012Co-Authors: Dapeng Peng, Menghong Dai, Yulian Wang, Lingli Huang, Dongmei Chen, Yanfei Tao, Zhenli Liu, Xiaoqing Wang, Zonghui YuanAbstract:Incorrect use of tylosin and Tilmicosin could result in allergy and select resistance. To monitor the illegal use of these antibiotics in animals, a monoclonal-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) has been established. Several haptens were synthesized and conjugated to carrier protein. Female Balb/c mice were inoculated with the four different conjugates to produce monoclonal antibodies according to the schemes of immunization. Aftercell fusion and culture several times, nine hybridoma cell lines were isolated. Only one, 3C4 that has isotype IgG2a, was selected for detailed study. The cross-reactivity of the monoclonal antibody 3C4 to tylosin and Tilmicosin was 100% and 51% respectively. The standard curves based on the tylosin and Tilmicosin matrix calibration ranged from 2.5 to 40 μg L–1, with an IC50 value of 6.1 μg L–1 and 12.1 μg L–1, respectively. The limits of detection of the ic-ELISA ranged from 5.1 μg kg–1 to 13.8 μg kg–1 in edible animal tissues. The recoverie...
