Introduction: The objective of this study was to determine the current profile of bacteria responsible for the infection of the mammary gland and to assess their sensitivity to selected β-lactam antibiotics.
Material and Methods: The study was conducted on 119 (n = 119) dairy cows of the Polish Black-White breed aged 4 to 10 years with inflammation of the mammary gland. The cows came from different farms: smallholder farms and large dairy cattle farms in the Lublin and Bialystok Provinces. Before the process of collection of milk samples, the teats were cleaned and immersed in a liquid disinfectant. The first streams were collected into containers which were subsequently utilised. Afterwards, 2-4 mL of milk or secretions was milked into sterile disposable tubes. The milk samples were collected into plastic bottles and kept in a cooler with ice until transportation to the laboratory. Tests of resistance to β-lactam antibiotics were performed by disc diffusion.
Results: Contagious and environmental bacteria were isolated from all dairy barns. In the group of contagious bacteria, the presence of typical pathogens responsible for the mammary gland infections, i.e. Staph. aureus, Str. agalactiae, and C. bovis, was detected. A relatively broad group of the isolates was formed by environmental bacteria responsible for inflammation of the mammary gland: Str. dysgalactiae, Str. uberis, Staph. chromogenes, Staph. hyicus, Staph. warneri, and E. coli. Among the environmental organisms, streptococci constituted the largest percentage (23%), followed by staphylococci (13.2%), and E. coli (8.8%). The largest group of infectious pathogens comprised Str. agalactiae (29.6%) and Staph. aureus (20.8%).
Conclusion: Our investigation of the current profile of the isolates responsible for mastitis in the Lublin and Bialystok Provinces showed that environmental bacteria are the major cause of the disease. In view of the substantially varying degrees of sensitivity of the microorganisms isolated from cases of mastitis to β-lactam antibiotics, each therapeutic treatment should be preceded by susceptibility testing.
Introduction: The objective of this study was to describe a pharmacokinetic–pharmacodynamic (PK/PD) approach for determination of a rational dosage of ampicillin (AMP) and depletion of the antibiotic residues in milk after intramammary administration to cows.
Material and Methods: The cows came from different farms from the Lublin Province area. They (n = 9) received 5 g of the drug, containing 75 mg of AMP sodium in physiological solution, through a syringe tube by intramammary administration. Following single intramammary administration, the milk samples (5 mL) were collected after 2, 4, 6, 8, 10, 24, 36, 48, and 60 h. The liquid chromatography-mass spectrometry analysis was performed on the Agilent 1200 system connected to an AB Sciex API 4000™ mass spectrometer. The pharmacokinetic analysis of the concentrations of the antibiotic in milk was performed using software Phoenix® WinNonlin® 6.4. Calculations were made in non-compartmental (slopes, highest, amounts, and moments) and compartmental analysis.
Results: The pharmacokinetic characteristics of AMP after intramammary administration indicate rapid elimination of the drug from milk. The mean residence time had a several-fold lower value than the designated elimination half-life and amounts to only 3.4 h. The concentration of the drug in the milk dropped relatively quickly and the process was very dynamic.
Conclusion: The conducted research confirms the rationale of using the PK/PD model in order to verify the dosing regimen for other antibiotic groups and various indicators of the applied PK/PD model.
Introduction: There are many veterinary products containing β-lactam antibiotics which are used for mastitis treatment in cows. The aim of the study was to determine whether mastitis could have any effect on amoxicillin (AMX) or penicillin G procaine (PEN) withdrawal period from milk, in the context of current maximum residue limits established by the European Commission.
Material and Methods: The study was conducted on 17 dairy Black and White cows with clinical mastitis during the lactation period. The first group (n = 8) received 200 mg of amoxicillin (AMX), whereas the second group (n = 9) received 200,000 IU/mg of penicillin G procaine (PEN) by intramammary administration. For the measurement of AMX and PEN concentrations in milk, the liquid chromatography tandem mass spectrometry method was applied. Pharmacokinetic calculations were performed using Phoenix WinNonlin 6.4 software.
Results: The determined AMX and PEN half-life values in the mammary gland suggest that the drug withdrawal is at a level of 99.9% within 81 h (≈3.5 days) and 116 h (≈5 days) after administration of AMX and PEN, respectively. The present research indicates that, at 60 h after administration, the average PEN concentration in the milk from cows with clinical signs of mastitis may still reach 4.96 g/kg and that of AMX can even be 6.92 g/kg.
Conclusion: The results obtained confirm that, in mastitis cases, a 72-h withdrawal period is sufficient for elimination of AMX to a lower level than the established maximum residue limit (MRL) values. However, in the case of PEN, at 69 h after administration, the drug concentration may be close to that of the determined MRL.
Introduction: Quercetin is a polyphenolic flavonoid which has been used in traditional Chinese medicine as a natural therapeutic agent with a broad spectrum of activities (antioxidant, anticancer, neuroprotective, anti-inflammatory, antiviral and antibacterial). The aim of this study was to develop and validate a rapid and simple ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method for the determination of quercetin in milk.
Material and Methods: Sample preparation was based on a liquid-liquid extraction with 0.5% formic acid in acetonitrile. The chromatographic separation was performed on a ZORBAX SB-C18 column with methanol and 0.5% formic acid as a mobile phase.
Results: The procedure was successfully validated. The mean recovery of the analyte was 98%, with the corresponding intra- and inter-day variation less than 10% and 15%, respectively, and the repeatability and reproducibility were in the range of 3%–7.2% and 6.1%–12%, respectively. The lowest level of quantification was 1.0 μg/kg.
Conclusion: The proposed method was successfully applied in evaluating the pharmacokinetics of quercetin in milk obtained from dairy cows with clinical mastitis after intramammary administration.
An effect of the exposure to chloramphenicol (CAP) at doses used therapeutically was studied in pigs at the age of slaughter. Pigs were treated with CAP intramuscularly (20 mg/kg b.w. two times every 24 hours). Histomorphometrical and immunohistochemical analyses of small intestine and liver were done. CAP increased the thickness of myenteron and submucosa, and the length of villi; decreased the depth of crypts in the duodenum and jejunum. CAP influenced the Auerbach plexus. A decrease in cell proliferation, an increase in the number of apoptotic cells and T lymphocytes in the CAP-treated pigs were observed. CAP induces hepatotoxicity, neurotoxicity and disturbed intestinal epithelium. It can be concluded that short exposure of pigs to CAP at doses used therapeutically results in disturbed digestion and absorption process in the intestine.