Evaluation of antimicrobial activity of methanol crude extract, N-hexane, dichloromethane and ethyl acetate fractions of Anacardium occidentale leaves against multiple antibiotic resistant bacterial isolates associated with asymptomatic bacteriuria

Asymptomatic bacteriuria is a common clinical finding which does not present any clinical symptoms. The incidence of increased resistance to conventional antibiotics by associated organisms makes the search for more effective antimicrobials from plant source inevitable. This study aims to evaluate the antimicrobial activity of methanol crude extract, N-Hexane, Dichloromethane and Ethyl acetate fractions of Anacardium occidentale leaves against multiple antibiotic resistant bacterial isolates associated with asymptomatic bacteriuria. The minimum inhibitory concentrations of crude extract, N-Hexane, Dichloromethane and ethyl acetate fractions against fifty multiple antibiotic resistant bacterial isolates were determined using the micro broth dilution method. The bacteria used were made up of Escherichia coli (28%), Klebsiella pneumoniae (16%), Staphylococcus aureus (28%) and Enterobacter feacalis (28%). These revealed ethyl acetate fraction as the most effective with MIC range of 50–0.195 mg/mL and N-Hexane fraction as the least effective with MIC range of 100–25 mg/mL. However, Staphylococcus aureus was the most susceptible to ethyl acetate fraction with MIC range of 3.125–0.195 mg/mL. The study concluded that all the fractions tested were effective against all the bacterial isolates tested at varying concentrations and could be useful in the management of multiple antibiotic resistant asymptomatic bacteriuria.