oxytetracycline--anhydrous and danofloxacin

Topics: Animals; Anti-Bacterial Agents; Cattle; Escherichia coli; Female; Fluoroquinolones; Goats; Humans; Macrolides; Mastitis, Bovine; Oxytetracycline; Staphylococcus; Staphylococcus aureus; Streptococcus; Tylosin

Mycoplasma spp. are highly contagious pathogens and intramammary Mycoplasma infection is a serious issue for the dairy industry. As there is no effective vaccine for Mycoplasma infection, control depends on good husbandry and chemo-antibiotic therapy. In this study, antimicrobial susceptibility of Mycoplasma strains recently isolated from cases of bovine mastitis in Japan was evaluated by minimum inhibitory concentration (MIC). All Mycoplasma bovis strains were sensitive to pirlimycin, danofloxacin and enrofloxacin, but not kanamycin, oxytetracycline, tilmicosin or tylosin. M. californicum and M. bovigenitalium strains were sensitive to pirlimycin, danofloxacin, enrofloxacin, oxytetracycline, tilmicosin and tylosin, but not to kanamycin. This is the first report to describe the MIC of major antimicrobial agents for Mycoplasma species isolated from bovine mastitis in Japan.

Topics: Animals; Anti-Bacterial Agents; Cattle; Clindamycin; Drug Resistance, Bacterial; Enrofloxacin; Female; Fluoroquinolones; Japan; Mastitis, Bovine; Mycoplasma; Mycoplasma Infections; Oxytetracycline; Tylosin

The objectives of this study were to assess the activity of oxytetracycline (OTC), danofloxacin and tulathromycin against Mycoplasma mycoides subsp. mycoides Small Colony, the causative agent of contagious bovine pleuropneumonia, in an in vitro dynamic concentration model and to determine the concentration and/or time dependence of such activity. Time-kill assays that simulated elimination of antimicrobials from the body were performed. Initial antimicrobial concentrations corresponded to various multiples of the MIC and cultures were diluted in a stepwise fashion with either drug-free or drug-containing artificial medium to mimic administration by single-release bolus or infusion, respectively. Where appropriate, data were fitted to sigmoidal E(max) models. OTC produced no change in mycoplasma titre from the initial inoculum size, regardless of the concentration or means of drug exposure. Both danofloxacin and tulathromycin resulted in a decrease in mycoplasma titre but neither was bactericidal (99.9 % kill) over 12 h. A greater antimycoplasmal effect, defined as the change in log(10) (c.f.u. ml(-1)) over 12 h, was achieved when danofloxacin was administered as a single-release bolus, suggesting concentration-dependent activity, whereas the antimycoplasmal effect of tulathromycin was comparable following administration by single-release bolus or infusion, owing to its long half-life.

Topics: Anti-Bacterial Agents; Bacteriological Techniques; Culture Media; Disaccharides; Dose-Response Relationship, Drug; Drug Resistance, Bacterial; Fluoroquinolones; Heterocyclic Compounds; Microbial Sensitivity Tests; Models, Biological; Mycoplasma mycoides; Oxytetracycline; Reproducibility of Results; Time Factors; Virulence

Mycoplasma mycoides subspecies mycoides Small Colony (MmmSC) is the causative agent of Contagious Bovine Pleuropneumonia (CBPP), a disease of substantial economic importance in sub-Saharan Africa. Failure of vaccination to curtail spread of this disease has led to calls for evaluation of the role of antimicrobials in CBPP control. Three major classes of antimicrobial are effective against mycoplasmas, namely tetracyclines, fluoroquinolones and macrolides. Therefore, the objectives of this study were to determine the effector kinetics of oxytetracycline, danofloxacin and tulathromycin against two MmmSC field strains in artificial medium and adult bovine serum.. Minimum inhibitory concentrations (MIC) were determined for oxytetracycline, danofloxacin and tulathromycin against MmmSC strains B237 and Tan8 using a macrodilution technique, and time-kill curves were constructed for various multiples of the MIC over a 24 hour period in artificial medium and serum. Data were fitted to sigmoid E(max) models to obtain 24 hour-area under curve/MIC ratios for mycoplasmastasis and, where appropriate, for mycoplasmacidal activity and virtual mycoplasmal elimination.. Minimum inhibitory concentrations against B237 were 20-fold higher, 2-fold higher and approximately 330-fold lower in serum than in artificial medium for oxytetracycline, danofloxacin and tulathromycin, respectively. Such differences were mirrored in experiments using Tan8. Oxytetracycline was mycoplasmastatic against both strains in both matrices. Danofloxacin elicited mycoplasmacidal activity against B237 and virtual elimination of Tan8; similar maximum antimycoplasmal effects were observed in artificial medium and serum. Tulathromycin effected virtual elimination of B237 but was mycoplasmastatic against Tan8 in artificial medium. However, this drug was mycoplasmastatic against both strains in the more physiologically relevant matrix of serum.. Oxytetracycline, danofloxacin and tulathromycin are all suitable candidates for further investigation as potential treatments for CBPP. This study also highlights the importance of testing drug activity in biological matrices as well as artificial media.

Topics: Animals; Anti-Infective Agents; Cattle; Colony Count, Microbial; Disaccharides; Fluoroquinolones; Heterocyclic Compounds; Microbial Sensitivity Tests; Models, Biological; Mycoplasma mycoides; Oxytetracycline; Pleuropneumonia, Contagious; Time Factors

Efficient methods are needed for analysis of veterinary drug residues in food. A number of methods are available for single analytes. Multiresidue methods are now increasingly available. It is still rare, however, to find methods not involving mass spectrometry which allow for analysis of more than one class of drug residue. An efficient multiresidue method for the simultaneous determination of fluoroquinolones (FQs) and tetracyclines (TCs) in catfish muscle has now been developed. This method involves an extraction of the analytes with a mixture of acetonitrile and citrate buffer containing magnesium chloride. After centrifugation and evaporation of the supernatants, the residues are determined using high performance liquid chromatography with fluorescence detection. With this method, five fluoroquinolones and three tetracyclines were determined in fortified catfish muscle at levels of 20, 50, and 100 ng g(-1). Average recoveries for ciprofloxacin (CIP), sarafloxacin (SAR), danofloxacin (DANO), enrofloxacin (ENRO), difloxacin (DIF), oxytetracycline (OTC), tetracycline (TC), and chlortetracycline (CTC) were in the range of 60-92% with good relative standard deviations. The limits of quantitation ranged from 0.15 to 1.5 ng g(-1). Utilization of the method to successfully analyze catfish muscle samples incurred with enrofloxacin and with oxytetracycline is described.

Topics: Animals; Catfishes; Chlortetracycline; Chromatography, High Pressure Liquid; Ciprofloxacin; Drug Residues; Enrofloxacin; Fluoroquinolones; Muscles; Oxytetracycline; Spectrometry, Fluorescence; Tetracyclines

Minimum inhibitory concentrations (MIC) and minimum mycoplasmacidal concentrations (MMC) of the antimicrobials danofloxacin, florfenicol, oxytetracycline, spectinomycin 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 MIC50 values of 0.015, 0.25, 0.5, 1 and 8 microg/ml, and MMC50 values of 0.06, 0.5, 8, 8 and 16 microg/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.

Topics: Animals; Anti-Bacterial Agents; Cattle; Cattle Diseases; Dose-Response Relationship, Drug; Drug Resistance, Microbial; Fluoroquinolones; Macrolides; Mycoplasma mycoides; Oxytetracycline; Pleuropneumonia, Contagious; Spectinomycin; Thiamphenicol; Tylosin

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 todanofloxacin with MIC90 and MMC90 values of 0.5 microg/ml and 1.0 microg/ml, respectively. They were less susceptible to florfenicol with a MIC90 of 16 microg/ml and MMC90 of 32 microg/ml. Oxytetracycline and spectinomycin had only a limited effect against the majority of isolates tested with MIC50s of 32 microg/ml and 4 microg/ml, respectively and MIC90s of 64 microg/ml and more than 128 microg/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 microg/ml or greater. There was no evidence of resistance by M bovis to danofloxacin.

Topics: Animals; Anti-Bacterial Agents; Cattle; Cattle Diseases; Cells, Cultured; Fluoroquinolones; Macrolides; Microbial Sensitivity Tests; Mycoplasma; Oxytetracycline; Pneumonia, Mycoplasma; Spectinomycin; Thiamphenicol; Tylosin

The activities of danofloxacin, a novel fluoroquinolone, and two other antimicrobials were determined in vitro against field isolates of seven Mycoplasma species of veterinary importance isolated from cattle, swine and poultry in five European countries. The minimum inhibitory concentrations (MIC) of danofloxacin, tylosin and oxytetracycline were determined against a total of 68 isolates. Danofloxacin showed excellent activity against isolates of all Mycoplasma species (range 0.008 to 0.5 microgram ml-1), but in some isolates there was evidence of reduced sensitivity to tylosin (range 0.008 to 2.0 micrograms ml-1) and oxytetracycline (range 0.008 to over 16.0 micrograms ml-1). Danofloxacin was more active than other antimicrobials against M hyopneumoniae, M dispar and M bovigenitalium, and showed activity similar to that of tylosin against M bovis and M gallisepticum. Tylosin was the most active against M synoviae and M hyosynoviae. Generally, oxytetracycline showed the poorest activity, but was superior to tylosin against M bovigenitalium. A second (final) MIC reading was taken for all isolates 14 or 21 days after the initial reading, and MIC values rose during that time. However, the increase seen in danofloxacin values (typically one to two dilutions) was less than that seen for tylosin and oxytetracycline. It is concluded that danofloxacin is highly active in vitro against all of the Mycoplasma species tested, and thus shows great potential for the treatment of respiratory and other infections caused by Mycoplasma species in cattle, pigs and poultry.

Topics: Animals; Anti-Infective Agents; Cattle; Europe; Fluoroquinolones; Microbial Sensitivity Tests; Mycoplasma; Oxytetracycline; Poultry; Quinolones; Species Specificity; Swine; Tylosin

Danofloxacin, a novel fluoroquinolone antimicrobial drug was evaluated in the treatment of acute bacterial pneumonia in recently housed beef cattle of approximately 300 kg liveweight. The clinical responses of 67 pneumonic cattle treated with danofloxacin were compared with those of 65 cattle treated with oxytetracycline, both treatments being given by intramuscular injection for either three or five days, depending on clinical response. Both treatments resulted in a rapid fall in group mean rectal temperature and improved the clinical condition of the majority of cases. However, in comparison with oxytetracycline, danofloxacin therapy was characterised by significantly fewer treatment days, a higher response rate, significantly better reduction of pyrexia and fewer cattle requiring re-treatment.

Topics: 4-Quinolones; Acute Disease; Animals; Anti-Infective Agents; Bacterial Infections; Body Temperature; Cattle; Cattle Diseases; Drug Evaluation; Fever; Fluoroquinolones; Housing, Animal; Oxytetracycline; Pneumonia