A comparative study of the antimicrobial efficacy of a herbal preparation to synthetic antibiotics for bovine mastitis treatment in Zambia.

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Ngwisha, Joshua
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The University of Zambia
Mastitis is a universal concern that accounts for reduced milk yield, loss from milk discarding due to antibiotic residues, increased veterinary costs and early culling of cows. This study aimed to compare the antimicrobial efficacy of locally available ethno veterinary herbal (Aloe genus and Curcuma longa) fresh formulations to synthetic antimicrobials on bovine mastitis causing bacteria in-vitro. Herbal formulations for the treatment of mastitis may not have any residual effects in the milk and blood of the treated cows. The plant materials of the genus Aloe and Curcuma longa were sourced within Zambia. The active compounds of these herbs were obtained as crude extracts using the water, ethanol and ethyl acetate solvents. The test microbes comprised of standard controls and field isolates. The agar dilution method was used to determine the antimicrobial activity by observing the susceptibility graded as Susceptible, intermediate or resistant. The synthetic anti-mastitis’ susceptibility was compared to that of the herbal preparations. The Minimum Inhibitory Concentrations (MIC) of the herbal formulation was also determined using two-fold serial dilutions. On average, the agar dilution trials revealed; 41.8% resistance , 13% intermediate and 45.3% susceptibility for the herbal formulation, while the synthetic antimicrobials produced 23.5% resistance, 5.2% intermediate and 71.3% susceptibility. The gram positive microbes (genera Staphylococcus, Streptococcus, Bacillus, Lactobacillus) when analysed alone for the agar dilution tests indicated; 18.8% resistance, 25.3% intermediate and 56% susceptibility on the herbal treatment, while the synthetic anti-mastitis formulation averaged; 16.8% resistance, 4.75% intermediate and 78.5% susceptibility. The gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa) were mostly resistant and were absent in the field isolates assessed and therefore did not warrant sole analysis. Mean MIC was 11.5mg/ml at the 5% serial dilution for herbal extract compared to the Cephalexin (semi-synthetic antimicrobial) MIC for S. aureus at 0.5mg/L or 0.0005mg/ml. The Aloe genus and Curcuma longa crude herbal formulation from Zambia has antimicrobial efficacy on bovine mastitis causing microbes in-vitro and may be used as an alternative to synthetic anti-mastitis preparations.
Thesis of Master of Science in Microbiology.