الكاتب: Multiple References

San MartõÂn NunÄ ez, B., CanÄ on, H., IraguÈ en, D., Espinoza, S., Lillo, J. Depletion study of trimethoprim and sulphadiazine in milk and its relationship with mastitis pathogenic bacteria strains minimum inhibitory concentrations (MICs) in dairy cows J. vet. Pharmacol. Therap. 24, 83±88. Time-related concentrations in milk of a combination of trimethoprim±sulphadiazine (TMP±SDZ) intramammary formulated infusion and its relationship with pathogenic bacteria strains minimum inhibitory concentrations (MICs) isolated from clinical mastitis cows were analysed. The MICs study was performed for Escherichia coli, Staphylococcus aureus and Streptococcus sp. strains. The SDZ concentrations in milk were analysed using high-performance liquid chromatography (HPLC) and TMP using a microbiological assay. Ten lactating cows milked three times daily were used in the time±concentration studies of TMP±SDZ. Milk samples (approximately 20 mL) from the treated mammary quarters were taken at 6, 12, 24, 30 and 36 h after ®rst administration. In order to de®ne the withdrawal time, milk samples from the treated mammary quarters were taken at 24, 36, 48, 72, 84 and 96 h, after ®nishing the therapy. The MICs ¯uctuated between 1 and 8 lg/mL. Effective therapeutic concentrations lasted for 36 h when intramammary infusion was repeated three times every 12 h. No TMP was detected in milk for 24 h after ®nishing therapy. Milk SDZ concentrations were below 0.1 lg/mL in all treated cows after 84 h ®nishing therapy. At 96 h after ®nishing therapy, no SDZ milk concentrations were found in six animals, although four animals of the experimental group still had concentrations of 0.07 lg/mL.