Development and validation of a potentiometric biosensor assay for tylosin with demonstrated applicability for the detection of two other antimicrobial growth-promoter compounds in feedstuffs.

A potentiometric biosensor assay based on a commercially available polyclonal antibody was developed to detect tylosin residues in animal feed. The method can be used as a rapid (less than 45 min) laboratory-based procedure or as a portable field-test for the simultaneous measurement of up to 12 different samples. For both procedures the qualitative detection capability (CCß) for tylosin was determined as 0.2 mg kg(-1) in a range of animal feeds with a measurement repeatability at concentrations between 0.2 and 4 mg kg(-1) of ≤13% coefficient of variation (%CV). The field-test format was capable of detecting tylosin residues at operating (external air) temperatures ranging between +4 and 37°C, although some reduction in signal was observed at the lower temperatures. The laboratory-based tylosin assay was evaluated using 16 medicated and 22 non-medicated feeds and was found to give comparable data with a confirmatory method based upon liquid chromatography-tandem mass spectrometry (LC-MS/MS). The potential to develop a multi-probe format assay for the simultaneous detection of tylosin, spiramycin and virginiamycin was also demonstrated. Cross-validation in a second laboratory showed the assay to be transferable, reliable and robust.

[Mastoiditis--a forgotten disease?]. / Antritis--choroba zapomniana?

The symptoms and clinical course of latent mastoiditis in 18. children treated in Polish-American Children's Hospital in Cracow were presented. The ultimate diagnosis of mastoiditis was based on typical findings on antrotomy and the presence of granulation on histology of the tissue obtained during the operation. The main symptoms of latent mastoiditis were: a lack of appetite, chronic or recurrent fever and failure to thrive. 11 children (61%) had experienced more than 3 episodes of acute otitis media before the diagnosis of mastoiditis was established. Bacteria most commonly isolated from the middle ear were those of Staphylococcus, Streptococcus and Proteus species. Radiograms of mastoid processes were negative in up to 45% of those children. The mean duration of antibiotic therapy was 10.7 weeks. After antrotomy complete dissolution of symptoms were observed in 14 patients (78%). It is concluded, that in the presence of symptoms suggesting latent mastoiditis, the possibility of antrotomy, which may shorten the period of ineffective antibiotic therapy, should be considered earlier.