Abstract
Abstract. This study aimed at evaluating the antimicrobial potential of Usnea barbata lichen as a medicinal plant against selected Staphylococcus species isolated from raw milk of cows. In-vitro screening of methanol and ethyl-acetate extracts from Usnea barbata lichen were evaluated to determine their antimicrobial activity against thirteen different Staphylococcus species. The selected organisms were isolated from raw bovine milk and identified using several biochemical tests and confirmed with API staph kit. The antimicrobial activity of the extracts were evaluated using both the agar well diffusion method (at 5 mg/ml, 10 mg/ml and 20 mg/ml) and the broth micro-dilution technique to determine the mean zone of inhibition and the minimum inhibitory concentration (MIC), respectively. Both the methanol and ethyl-acetate extracts showed variable antimicrobial activity against the Staphylococcus species with mean zones of inhibition ranging from 0-34 mm in diameter at 5 mg/ml, 10 mg/ml and 20 mg/ml, respectively. Susceptibility by the Staphylococcus species tested in the methanol and the ethyl-acetate extract was 92.31 % and 53.85 %, respectively. The MIC result for the methanol extract ranged from 0.04 to 10 mg/ml, while that of the ethyl-acetate extract ranged from 0.16 to 5 mg/ml. Results from this study revealed the in vitro microbial activity of Usnea barbata extracts which indicate its potential as a medicinal plant.
Highlights
Mastitis, an inflammation of the mammary gland especially in dairy animals is known to be a huge threat due to the resistance of several causative organisms to antimicrobial agents, leading to considerable economic losses in farms (Halasa et al 2009)
The current study aimed to evaluate the in-vitro antimicrobial activity of methanol and ethylacetate extracts of Usnea barbata lichens on some selected Staphylococcus species isolated from raw milk of cows
The screening of the antimicrobial properties of Usnea barbata lichen in the current study indicated a significant activity with a range between 0 to 34 mm against all the Staphylococcus species that were tested
Summary
An inflammation of the mammary gland especially in dairy animals is known to be a huge threat due to the resistance of several causative organisms to antimicrobial agents, leading to considerable economic losses in farms (Halasa et al 2009). Staphylococcus species are among the several pathogenic organisms that cause mastitis and are known to be resistant to a wide range of antimicrobial agents in several parts of the world (Pyorala & Taponen 2009, Sampimon et al 2011). The continuous use of antimicrobials in the dairy sector has led to the emergence of resistant strains of several pathogens that are linked to the cause of mastitis disease in animals (Pitkala et al 2004). Mastitis disease causing organisms develop resistance to antimicrobials through a systematic process which make them able to withstand the effect of drugs used against them (Suleiman et al 2010).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
