A high-performance liquid chromatographic (HPLC) method for the simultaneous determination of tilmicosin, tylosin, spiramycin, and its major metabolite neospiramycin was developed that is suitable for porcine, bovine, and poultry muscles. Macrolide residues were extracted from muscle with acetonitrile, fat was removed by liquid-liquid extraction with isooctane, and the extract was then cleaned ...

Streptococcus uberis UCN60 was resistant to spiramycin (MIC = 8 microg/ml) but susceptible to erythromycin (MIC = 0.06 microg/ml), azithromycin (MIC = 0.12 microg/ml), josamycin (MIC = 0.25 microg/ml), and tylosin (MIC = 0.5 microg/ml). A 2.5-kb HindIII fragment was cloned from S. uberis UCN60 DNA on plasmid pUC18 and introduced into Escherichia coli AG100A, where it conferred resistance to spi...

A total of 151 strains of Mycoplasma hyorhinis isolated from porcine lung lesions (weaned pigs, n=71, and finishers, n=80) were investigated for their in vitro susceptibility to 10 antimicrobial agents. Thirty-one strains (28 from weaned pigs and 3 from finishers) showed resistance to 16-membered macrolide antibiotics and lincomycin. The prevalence of the 16-membered macrolide-resistant M. hyor...

The macrolide class of antibiotics, including tylosin and tilmicosin, is widely used in the veterinary field for prophylaxis and treatment of mycoplasmosis. In vitro susceptibility testing of 50 strains of M. gallisepticum isolated in Israel during the period 1997-2010 revealed that acquired resistance to tylosin as well as to tilmicosin was present in 50% of them. Moreover, 72% (13/18) of the ...

Antibiotics have been used in fish farming for several decades combating diseases but improper application and handling had led to the occurrence of residues animal food such as fish. Animal products whose drug residue limit exceeds maximum (MRL) pose serious concern as; allergy, carcinogensis, antibacterial resistance, disruption intestinal flora, mutagenesis, tetratogenesis among others. The ...

A feedlot (Exp. 1) experiment was conducted to evaluate the effects of an essential oil mixture (EOM), experimental essential oil mixture (EXP), tylosin, and monensin (MON) on performance, carcass characteristics, and liver abscesses. A metabolism experiment (Exp. 2) was conducted to evaluate the effects of EOM, EXP, and MON on ruminal fermentation and digestibility in finishing steers. In Exp....

5-O-Mycarosyltylactone has been isolated as a predominant factor from fermentation broths of a Streptomyces fradiae mutant. The relative configurations of mycarose and tylactone (protylonolide) have been determined by X-ray crystal structure analysis. Hydrolysis of 5-O-mycarosyltylactone yielded (-)-tylactone and L-(-)-mycarose. Taken together, these two experiments establish the absolute confi...

We investigated the susceptibilities against 7 antimicrobial agents in Campylobacter jejuni and C. coli isolates from food-producing animals in 2004. In comparison with the results of past surveillance, no significant difference was observed in resistance rates against all of the antimicrobials tested in Campylobacter isolates. However, slight increase of erythromycin (EM) resistance was found ...