Comparative pharmacokinetics of florfenicol in heifers after intramuscular and subcutaneous administration

Florfenicol was administered to five heifers intramuscularly at a dose rate of 20 mg/kg bwt and following wash-out period, subcutaneously at a dose rate of 40 mg/kg bwt. Blood plasma samples were collected from heifers before injection of florfenicol and up to 120 h after intramuscular (IM) injection and up to 264 h after subcutaneous (SC) injection. Florfenicol concentrations in plasma were measured by high-performance liquid chromatography with mass-spectrometric detection. Pharmacokinetics of florfenicol was estimated using non-compartment analysis. Mean maximum plasma concentration, area under the concentration-time curve and elimination half-life for florfenicol were 3.2 μg/ml, 101.5 μg × h/ml and 24.5 h, respectively, after IM injection at 20 mg/kg bwt, and 2.7 μg/ml, 194.5 μg × h/ml and 103.8 h, respectively, after SC injection at 40 mg/kg bwt. The obtained results indicated that both administration routes provided comparable bioavailability, whereas SC route was attributed with lower peak levels and markedly slower absorption of florfenicol from injection site. Both administration routes provided plasma florfenicol levels which are expected to be effective against prevalent infectious agents of cattle.

The role of lipid peroxidation products and antioxidant enzymes in the pathogenesis of aseptic and purulent inflammation in cats

Objective:

The work aimed to determine the state of lipid peroxidation products and the activity of the antioxidant system in cats with aseptic inflammation and purulent-inflammatory processes of varying severity.

Materials and Methods:

The intensity of the process of lipid peroxidation- antioxidant system processes in blood plasma was evaluated using commercial kits. The level of diene conjugates (DC), the content of malondialdehyde (MDA), the level of medium-weight molecules were determined from lipid peroxidation indices. The state of antioxidant protection was assessed by indicators of superoxide dismutase (SOD) activity, catalase (CT), ceruloplasmin (CP) concentration, glutathione peroxidase activity, glutathione reductase (GLR), and total antioxidant activity (AOA).

Results:

With aseptic inflammation in the blood of cats, a slow activation of peroxidation reactions occurred. The DC indicator increased by 1.4 times, the SOD level rose by 1.38 times, the amount of GLR by 1.04 times, and the activation of total AOA by 9.06. In sepsis, the values of DC, MDA, and medium-weight molecules increased by 4.4, 8.4, and 8.8 times, respectively. With abscesses in the blood of cats, an increase in CT, CP, and GLR is observed against a background of a decrease in glutathione peroxidase. With purulent wounds, the total AOA of plasma increases by 2.5 times; with abscesses, the total AOA increases by 1.9 times, and with sepsis, it decreases by 1.5 times.

Conclusion:

With surgical infections in cats, deep biochemical changes or irreversible biochemical changes (in sepsis) occur that indicate a significantly enhanced catabolic orientation of metabolic processes and the accumulation of toxic metabolites, which leads to damage and a decrease in tissue regenerative capacity.

Role of microorganisms isolated from cows with mastitis in Moscow region in biofilm formation

Background and Aim

Mastitis is one of the most important diseases of cows and the most expensive pathology for the dairy industry. Therefore, this study was conducted to explore the role of microorganisms isolated from cows with mastitis in the formation of biofilms under the conditions of farm biogeocenosis in the Moscow region.

Materials and Methods

Periodic visits to 12 farms in the Moscow region were conducted to explore the microbial profile of the udder of cows with mastitis. During the visits, 103 milk samples from sick animals were collected and examined. Through microbiological analyses, 486 cultures of microorganisms were identified, which are assigned to 11 genera. Mastitis in cows is caused not only by a single pathogen but also by microbial associations, which included two to seven microbial isolates.

Results

It was observed that 309 isolates (63.6%) from the total number of isolated microorganisms could form a biofilm. The ability to form biofilms was most frequently observed in Staphylococcus aureus (18.8%), Escherichia coli (11.9%), and Staphylococcus uberis (11.7%) cultures from the total number of biofilm-forming microbial cultures. Low biofilm-forming ability among the isolated microorganisms was found in lactobacilli, wherein only 20 (22.5%) Lactobacillus strains had the ability to form biofilms. The isolated microorganisms exhibited different sensitivities to antimicrobial agents, which cause difficulty in selecting an antimicrobial agent that would act on all aspects of the parasitocenosis.

Conclusion

A high proportion of microorganisms isolated from cows with mastitis have the ability to form biofilms. The isolated microorganisms exhibited different and highly heterogeneous sensitivity to the action of antimicrobial drugs. This causes difficulty in using these tools for the effective control of mastitis in cows, which is frequently caused by pathogenic associations of microbial biofilms. Therefore, it is important to explore novel and more effective methods to combat this disease.