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Stefan Schwarz - One of the best experts on this subject based on the ideXlab platform.
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novel Florfenicol and chloramphenicol resistance gene discovered in alaskan soil by using functional metagenomics
Applied and Environmental Microbiology, 2010Co-Authors: Kevin S Lang, Stefan Schwarz, Janet M Anderson, Lynn L Williamson, Jo Handelsman, Randall S SingerAbstract:Functional metagenomics was used to search for Florfenicol resistance genes in libraries of cloned DNA isolated from Alaskan soil. A gene that mediated reduced susceptibility to Florfenicol was identified and designated pexA. The predicted PexA protein showed a structure similar to that of efflux pumps of the major facilitator superfamily.
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fexa a novel staphylococcus lentus gene encoding resistance to Florfenicol and chloramphenicol
Antimicrobial Agents and Chemotherapy, 2004Co-Authors: Corinna Kehrenberg, Stefan SchwarzAbstract:The Staphylococcus lentus plasmid pSCFS2 carries a novel Florfenicol-chloramphenicol resistance gene, designated fexA, encoding a protein of 475 amino acids with 14 transmembrane domains. The FexA protein differs from all previously known proteins involved in the efflux of chloramphenicol and Florfenicol. Induction of fexA expression by chloramphenicol and Florfenicol occurs via translational attenuation.
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in vitro activities of Florfenicol against bovine and porcine respiratory tract pathogens
Antimicrobial Agents and Chemotherapy, 2003Co-Authors: Saskia Priebe, Stefan SchwarzAbstract:Florfenicol in vitro activities for a total of 756 bacterial isolates from respiratory tract infections of cattle and swine were comparatively investigated by the agar diffusion method and the microdilution broth method. Florfenicol showed high in vitro activity against Pasteurella multocida, Mannheimia haemolytica, Actinobacillus pleuropneumoniae, and Streptococcus suis, with all of the isolates inhibited by ≤2 μg of Florfenicol per ml.
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identification of a plasmid borne chloramphenicol Florfenicol resistance gene in staphylococcus sciuri
Antimicrobial Agents and Chemotherapy, 2000Co-Authors: Stefan Schwarz, Christiane Susanne Werckenthin, Corinna KehrenbergAbstract:The 16.5-kbp plasmid pSCFS1 from Staphylococcus sciuri mediated combined resistance to chloramphenicol and Florfenicol. The gene responsible for this resistance property, cfr, was cloned and sequenced. The amino acid sequence of the Cfr protein revealed no homology to known acetyltransferases or efflux proteins involved in chloramphenicol and/or Florfenicol resistance or to other proteins whose functions are known.
David G White - One of the best experts on this subject based on the ideXlab platform.
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characterization of chloramphenicol and Florfenicol resistance in escherichia coli associated with bovine diarrhea
Journal of Clinical Microbiology, 2000Co-Authors: Charlene R Hudson, John J Maurer, David G White, Sherry Ayers, Shaohua Zhao, Lance F Bolton, Thomas Foley, Julie S SherwoodAbstract:Florfenicol, a veterinary fluorinated analog of thiamphenicol, is approved for treatment of bovine respiratory pathogens in the United States. However, Florfenicol resistance has recently emerged among veterinary Escherichia coli isolates incriminated in bovine diarrhea. The flo gene, which confers resistance to Florfenicol and chloramphenicol, has previously been identified in Photobacterium piscicida and Salmonella enterica serovar Typhimurium DT104. The flo gene product is closely related to the CmlA protein identified in Pseudomonas aeruginosa. The cmlA gene confers nonenzymatic chloramphenicol resistance via an efflux mechanism. Forty-eight E. coli isolates recovered from calves with diarrhea, including 41 that were both chloramphenicol and Florfenicol resistant, were assayed for the presence of both flo and cmlA genes. Forty-two of the 44 isolates for which Florfenicol MICs were ≥16 μg/ml were positive via PCR for the flo gene. All E. coli isolates for which Florfenicol MICs were ≤8 μg/ml were negative for the flo gene (n = 4). Twelve E. coli isolates were positive for cmlA, and chloramphenicol MICs for all 12 were ≥32 μg/ml. Additionally, eight isolates were positive for both flo and cmlA, and both Florfenicol and chloramphenicol MICs for these isolates were ≥64 μg/ml. DNA sequence analysis of the E. coli flo gene demonstrated 98% identity to the published GenBank sequences of both serovar Typhimurium floSt and P. piscicida pp-flo. The flo gene was identified on high-molecular-weight plasmids of approximately 225 kb among the majority of Florfenicol-resistant E. coli isolates. However, not all of the Florfenicol-resistant E. coli isolates tested contained the large flo-positive plasmids. This suggests that several of the E. coli isolates may possess a chromosomal flo gene. The E. coli flo gene specifies nonenzymatic cross-resistance to both Florfenicol and chloramphenicol, and its presence among bovine E. coli isolates of diverse genetic backgrounds indicates a distribution much wider than previously thought.
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detection of Florfenicol resistance genes in escherichia coli isolated from sick chickens
Antimicrobial Agents and Chemotherapy, 2000Co-Authors: Kathleen Keyes, Charlene R Hudson, John J Maurer, Stephan G Thayer, David G WhiteAbstract:Florfenicol is an antibiotic approved for veterinary use in cattle in the United States in 1996. Although this drug is not used in poultry, we have detected resistance to Florfenicol in clinical isolates of avian Escherichia coli. Molecular typing demonstrated that the Florfenicol resistance gene, flo, was independently acquired and is plasmid encoded.
Huang Xianhui - One of the best experts on this subject based on the ideXlab platform.
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Preparation of inclusion complex of Florfenicol-β-cyclodextrin.
Journal of the South China Agricultural University, 2020Co-Authors: Wei Haitao, Li Lianghua, Luo Biao, Zeng Zhenling, Huang XianhuiAbstract:Florfenicol-β-cyclodextrin was prepared by saturated water solution method;HPLC method was used to determine the solubility and dissolution rate of Florfenicol-β-cyclodextrin;The differential thermal analysis(DTA) method was used to describe the status of Florfenicol in inclusion complex.The results showed that the solubility and dissolution rate of Florfenicol-β-cyclodextrin were significantly raised compared with Florfenicol itself,Florfenicol-β-cyclodextrin can significantly increase its water-solubility.
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The Preparation of Water-soluble Florfenicol
Chinese Journal of Veterinary Drug, 2020Co-Authors: Huang XianhuiAbstract:Solid dispersion technique was explored to enhance the water-solubility and bioavailability of Florfenicol,which could make foundation to dosage evolvement.Solid dispersion(SD) of Florfenicol was prepared by solvent method;HPLC method was used to determine the solubility and dissolution rate of Florfenicol in solid dispersion;The DTA(differential thermal analysis) method was used to describe the status of Florfenicol in carriers.The results showed that,the solubility and dissolution rate of solid dispersion were significantly raised compared with Florfenicol itself,Florfenicol solid dispersion can significantly increase its water-solubility.
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Research Progress on Pharmaceutics of Florfenicol
Chinese Journal of Veterinary Drug, 2020Co-Authors: Huang XianhuiAbstract:Florfenicol has broad spectrum antibacterial activities and is only permitted to be used in animals.It has significant effects on animal diseases which are caused by sensitive organisms.In this article,the national and international researches on pharmaceutics of Florfenicol are summarized.The research progress of water-soluble Florfenicol and sustained-release Florfenicol are introduced separately.
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Acute toxicity test of Florfenicol suspoemulsions in mice
Guangdong Agricultural Sciences, 2020Co-Authors: Huang XianhuiAbstract:In order to observe the actue toxicity of Florfenicol suspoemulsions,modified Korbor’s method was used to study the LD50 in mice.The mice were given Florfenicol suspoemulsions by intraperitoneal injection,and observed for 7 days continuously.The results showed that the LD50 of Florfenicol suspoemulsions was 3 346.57 mg/kg,and 95% confidence limit was 2 855.01～3 922.76 mg/kg.The results confirmed that Florfenicol suspoemulsions belonged to hypotoxicity and it was safe to clinical application.
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Comparative pharmacokinetics of Florfenicol granule and Florfenicol powder in pigs.
Journal of the South China Agricultural University, 2020Co-Authors: Liu Shuaishuai, Yang Gang, Zhao Yongda, Fang Qiuhua, Huang XianhuiAbstract:Fourteen healthy pigs were divided into two groups of 7 pigs each.The pigs in group A were orally administrated with single dose of Florfenicol powder at 30 mg/kg.The pigs in group B were also orally administrated with single dose of Florfenicol granule at 30 mg/kg.Comparative study on the pharmacokinetics of Florfenicol powder and Florfenicol granule was carried out.Plasma concentration of Florfenicol was determined by HPLC.The concentration-time data of Florfenicol were analyzed by non-compartmental model based on pharmacokinetic software WinNonlin 5.2.1.The main pharmacokinetic parameters of powder following oral administration were: t1/2β =(10.22±0.18) h,ke =(0.07±0.01) h-1,tmax =(1.67±0.48) h,Cmax=(24.68±1.13) μg·mL-1,AUC=(190.97±16.60) μg·mL-1·h,MRT=(8.33±0.42) h,tcp=(17.66±1.52) h.The main pharmacokinetic parameters of granule following oral administration were : t1/2β =(16.36±4.14) h,ke=(0.05±0.01) h-1,tmax=(5.71±0.47) h,Cmax=(12.23±0.78) μg·mL-1,AUC=(155.44±6.59) mg·mL-1·h,MRT=(14.96±0.35) h,tcp=(23.03±0.49) h.The results showed the granule of Florfenicol after oral administration had slower elimination and longer effective time of the blood medicine density maintenance.
Liudong Li - One of the best experts on this subject based on the ideXlab platform.
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tissue distribution and elimination of Florfenicol in tilapia oreochromis niloticus o caureus after a single oral administration in freshwater and seawater at 28 c
Aquaculture, 2008Co-Authors: Jingbin Feng, Liudong LiAbstract:Tissue distribution and elimination of Florfenicol in seawater-acclimated tilapia were compared with those in freshwater tilapia at 28 degrees C after they were given a single oral dose of 10 mg/kg body weight (b.w.). In most sampling time points, the concentrations of Florfenicol in the tissues (muscle, liver, kidney, gill and bile) in freshwater tilapia were higher than those in seawater tilapia. In the major elimination phase the elimination half-lives (T-1/2 beta) in all the tissues (except for bile) of freshwater tilapia were longer than those in seawater tilapia. These findings indicated that the distribution level of Florfenicol in freshwater tilapia was higher than that in seawater tilapia and the elimination of Florfenicol in seawater tilapia was more rapid than that in freshwater tilapia. The main excretion pathway (gill excretion) of the drug in seawater-acclimated tilapia was different from that (bile excretion) in freshwater tilapia, which should be responsible for the considerable difference in pharmacokinetics from freshwater tilapia. (c) 2008 Elsevier B.V. All rights reserved.
Yongning Wu - One of the best experts on this subject based on the ideXlab platform.
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technical note development of an enzyme linked immunosorbent assay for the determination of Florfenicol and thiamphenicol in swine feed
Journal of Animal Science, 2011Co-Authors: Wenxiao Jiang, Xia Chen, J Z Shen, Yongning WuAbstract:: One polyclonal antibody against Florfenicol and thiamphenicol was produced and a competitive ELISA was developed for the detection of Florfenicol and thiamphenicol in swine feed. The ELISA gave a 50% inhibiting concentration of 1.02 ng/mL for Florfenicol. For swine feed fortified with 0.05 to 3.0 mg/kg, the interassay recoveries of Florfenicol and thiamphenicol ranged from 86.4 to 118.6%, whereas intraassay recoveries of both drug ranged from 90.1 to 126.5% with less than 15% CV. Results obtained from HPLC-tandem mass spectrometry indicated this ELISA procedure could be used as a convenient method for rapid screening of Florfenicol and thiamphenicol in swine feed.