In Vitro Antimicrobial Activity Evaluation of Selected Medicinal Plants Against Multidrug-Resistant Isolates of Clinical Bovine Mastitis

Abstract

Fikre Birhanu Balcha, Mishamo Sulayeman and Sultan Abda Neja

Mastitis is one of the challenges impairing the development of the dairy industry. Among mastitis-causing bacteria, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) represent the main causative agents that threaten the farmers not only due to the high incidence rate and zoonotic potential but also due to reports of multi-drug resistance. The study was conducted to assess the antimicrobial activity of selected medicinal plants against multidrug-resistant bacterial isolates from clinical bovine mastitis. Milk samples from mastitis cases were aseptically collected and S. aureus and E .coli isolates were identified, the antibiotic sensitivity test pattern of the isolate were confirmed. Four medicinal plants were collected; extracted and their in vitro effectiveness on multidrug-resistant S. aureus and E. coli isolates of bovine mastitis was validated compared to the conventionally used antimicrobial drugs. Extracts from the four plants were effective against the two isolates. Extract of Crotona macrostachis at 100mg/mL minimum inhibitory concentration (MIC) showed the highest mean zone of inhibition (20.2 ± 1.48) on E. coli while Prunes Africana at 50mg/mL MIC showed 12.9 ± 0.74. The highest mean zone of inhibition 13.8±0.84 for Datura Stamonium at a MIC of 100mg/mL and lowest mean zone of inhibition 11.64 ± 0.86 for Crotona macrostachis at 100mg/mL MIC was observed on S. aureus. Moreover, compared to S. aureus, better efficacy was observed for all tested plant extracts against E. coli. This study indicated that traditional medicinal plant preparations might be considered as an alternative option for the treatment of resistant isolates of clinical bovine mastitis.

PDF