In vitro antibacterial and antifungal activities of extracts and fractions of leaves of Ricinus communis Linn against selected pathogens.

INTRODUCTION: Infectious disease impacts are reduced due to the development of antimicrobial agents. However, the effectiveness of antimicrobial agents is reduced over time because of the emergence of antimicrobial resistance. To overcome these problems, scholars have been searching for alternative medicines. Ricinus communis is used as a traditional treatment for bovine mastitis, wound infection, and other medicinal purposes. OBJECTIVE: The objective of the present study was to further evaluate the antimicrobial activities of R. communis leaf extracts and fractions. METHODS: R. communis leaves were macerated in methanol and acetone. The methanol extract showed better antimicrobial activity and subjected to further fractionation via increasing polarity of solvents (n-hexane, chloroform, ethyl acetate, and aqueous). Test microorganisms included in the study were six laboratory reference bacteria (Escherichia coli, Staphylococcus aureus, Streptococcus agalactiae, Kleibsella pneumoniae, Pseudomonas aeruginosa and Streptococcus pyogenes), two clinical isolate bacteria (E. coli and S. aureus), and Candida albicans. The agar well diffusion method was employed to determine antimicrobial activity. The minimum inhibitory concentrations (MIC) and minimum bactericidal/fungicidal concentrations (MBC/MFC) were determined through broth microdilution. RESULTS: The results indicated that the best antimicrobial activity for ethyl acetate fraction ranged from 14.67 mm (clinical E. coli) to 20.33 mm (S. aureus) at 400 mg/ml, however, n-hexane exhibited the lowest antimicrobial activity. Among the tested fractions, ethyl acetate fraction showed the lowest MIC values ranged from 1.5625 mg/ml (S. aureus) to 16.67 mg/ml (Candida albicans). The ethyl acetate fraction showed bactericidal activity against all tested microorganisms. CONCLUSION: Hence, ethyl acetate fraction of crude methanol extract exhibited the best antimicrobial activity.

Prevalence, aetiology and risk factors of mastitis of dairy cows kept under extensive management system in west Wollega, western Oromia, Ethiopia.

INTRODUCTION: Mastitis is an inflammation of the mammary gland that could either be clinical or subclinical, and can be caused by infectious agents. It has different aetiological pathogens such as Staphylococcus aureus, Streptococcus agalactiae, Escherichia coli that pose different economic and health impacts. In Ethiopia, previous studies on mastitis have been focused on semi-intensive and intensive dairy production system. The objectives of this study were therefore to estimate prevalence, aetiology of causative pathogens and identify different risk factors of mastitis in extensive management systems. A total of 532 lactating cows were randomly selected for a cross-sectional study carried out in four districts of west Wollega, western Oromia, Ethiopia. RESULT: Based on the clinical examination and California mastitis test, 39.67% overall prevalence of mastitis on cow level was recorded. Of them, 16.70% and 22.70% were clinical and subclinical mastitis, respectively. Among 2,128 quarters examined 210 were blind teats. The associated risk factors age ≥8 years (16.35%), parity 1-3 calving (27.63%), milk yield 1-2 litres (21.98%), lactation stage <4 months (18.04%) and tick infestation (26.70%) were significantly associated in the occurrence of mastitis. Staphylococcus spp. (15.60%) were the dominant bacteria isolated from collected mastitic milk. CONCLUSION: Mastitis is an important disease for dairy cows kept under an extensive management system. Its occurrence is determined by risk factors like age, parity, milk yield, lactation stage and tick infestation. This study is indicated Staphylococcus species as the major bacteria isolated from mastitic milk. This study warrants further study on the prevalence, aetiology, economic impact and potential risk factors of mastitis in dairy cows kept in extensive production system.