Chemical Composition, Antimicrobial Activity, and Withdrawal Period of Essential Oil-Based Pharmaceutical Formulation in Bovine Mastitis Treatment

Abstract

Due to the emergence of antibiotic-resistant bacteria, the risk it represents to public health, and the possible consequences for animal health and welfare, there is an increasing focus on reducing antimicrobial usage (AMU) in animal husbandry. Therefore, a great interest in developing alternatives to AMU in livestock production is present worldwide. Recently, essential oils (EOs) have gained great attention as promising possibilities for the replacement of antibiotics. The current study aimed to test the potential of using a novel EO-based pharmaceutical formulation (Phyto-Bomat) in bovine mastitis treatment. The antibacterial activity was performed using the microdilution technique. Lactating dairy cows were treated with 15 mL of Phyto-Bomat in the inflamed quarter for 5 consecutive days in order to analyze blood and milk samples for thymol and carvacrol residues using gas chromatography and mass spectrometry (GC–MS). Antimicrobial activity expressed as the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) indicates that this formulation has the highest activity against Gram-positive strains. The dominant compounds in Phyto-Bomat were thymol and carvacrol, at 12.58 ± 1.23 mg/mL and 23.11 ± 2.31 mg/mL, respectively. The quantification of these two compounds in evaluated biological samples showed that 24 h after administration the concentration of thymol and carvacrol in milk samples was at the same level as before application. On the other hand, thymol and carvacrol were detectable in plasma samples even after 24 h post-treatment, with values ranging from 0.15–0.38 and 0.21–0.66 µg/mL, respectively. The tested formulation showed encouraging results of antibacterial activity against bovine mastitis pathogens, as well as the withdrawal period of dominant compounds, which implies that further testing regarding the bacteriological and clinical cure rates in clinical settings is needed.

Intramammary Ethno-Veterinary Formulation in Bovine Mastitis Treatment for Optimization of Antibiotic Use

“…The antimicrobial activity of selected EOs was previously tested at the Laboratory of the Scientific Institute for Food Technologies (FINS), University of Novi Sad. In the next step, chemical composition and antimicrobial activity of final pharmaceutical formulation (Phyto-Bomat) were tested [ 31 ].…”

“…The effectiveness of the final formulation on microorganisms was determined according to the Clinical Laboratory Standards [ 32 ], described by Kovacevic, et al [ 31 ]. The minimum inhibitory concentration (MIC) was determined as the lowest concentration of the final preparation that prevented the transition of oxidated form to the reduced form of resazurin and was determined by cultivating 100 µL of solution from each well of the microtiter plate in Mueller–Hinton agar (MHA, HiMedia) [ 33 ].…”

“…strains. The MBCs determined for the EO-based formulation ranged from 45.4 mg/mL to 90.09 mg/mL [ 31 ].…”

“…Then, the tip of each teat was disinfected with 70% ethanol. The first streams of milk were discarded, after which 10 milliliters of milk were stored into sterile tubes marked with an ID number of the cow [ 31 ]. After the milk samples were collected, they were immediately transported to the Laboratory for testing biological material, food, and animal feed “In vitro LAB” DOO Šabac, Republic of Serbia, under the cold chain (4 °C) for bacteriological testing.…”

Alternatives to Antimicrobial Treatment in Bovine Mastitis Therapy: A Review

“…Moreover, the financial profitability of the antibiotic should be taken into account [ 21 ]. During intramammary treatment with antibiotics in lactation, milk has to be discarded and can only be used again after the withdrawal period has expired, which is quite expensive [ 48 , 52 ]. Some of frequently applied antibiotics are considered critically important for human healthcare, representing an additional global concern related to the protection of public health [ 15 ].…”