Genotypic characterization by polymerase chain reaction of Staphylococcus aureus isolates associated with bovine mastitis.

Staphylococcus aureus is recognized worldwide as a pathogen causing many serious diseases in humans and animals, and is the most common aetiological agent of clinical and subclinical bovine mastitis. The importance of evaluating the combination of S. aureus virulence factors has been emphasized both in human and veterinary medicine, and knowledge about the genetic variability within different S.

Pre-study and in-study validation of an ultra-high pressure LC method coupled to tandem mass spectrometry for off-line determination of oxytetracycline in nasal secretions of healthy pigs.

In order to quantify oxytetracycline (OTC) in nasal secretions of healthy pigs after intramuscular injection of OTC at doses of 10, 20 and 40 mg/kg bodyweight, an original method based on ultra-high pressure liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) was developed and fully validated. Sample preparation consisted in protein precipitation preceded by the addition of a releasing protein reagent. Metacycline (MTC) was used as internal standard.

Liquid chromatographic determination of enrofloxacin in nasal secretions and plasma of healthy pigs using restricted access material for on-line sample clean-up.

A new fully automated method was developed for the quantitative analysis of an antibacterial drug, enrofloxacin (ENRO), in both nasal secretions and plasma samples of healthy pigs. The method is based on the use of a pre-column packed with restricted access material (RAM), namely RP-18 ADS (alkyl diol silica), for on-line sample clean-up coupled to a liquid chromatographic (LC) column containing octadecyl silica. The only off-line sample preparation was the 50-fold dilution of nasal secretions and plasma samples in the washing liquid composed of 25 mM phosphate buffer of pH 7.

Identification by two-dimensional electrophoresis of a new adhesin expressed by a low-passaged strain of Mycoplasma bovis.

A significant decrease in adherence rates of Mycoplasma bovis to bovine bronchial epithelial (BBE) cells has been observed after passage of the organism in artificial medium. Analysis of the proteins expressed by M. bovis isolate 2610 by two-dimensional (2-D) electrophoresis demonstrated differences between the cells harvested after the 7th and 116th passage.

The p40* adhesin pseudogene of Mycoplasma bovis.

An analogue of the adhesin gene p40 of Mycoplasma agalactiae was found in Mycoplasma bovis. Nucleotide sequence analysis of the p40* gene in M. bovis revealed the presence of a large deletion involving a frameshift that causes premature truncation of the translated protein, indicating that p40* exists as a pseudogene in M.