Abstract
Objective: The present study aims to evaluate the antibacterial action of the extract of G. hirsutum L. against Escherichia coli and Klebsiella pneumoniae. Methods: For the evaluation of the antibacterial activity and determination of MIC, the 96-well plate microdilution technique is used. In a 96-well plate, Mueller Hinton broth and the crude ethanolic extract under study at different concentrations. The assay was performed in duplicate. The plates were incubated at 37 ° C for 24-48 hours. The Minimum Inhibitory Concentration (MIC) was determined as the lowest concentration of the extract that inhibited the visible growth of the microorganism. After reading the MIC, aliquots of 20 μL were withdrawn from each well that did not show bacterial growth, and transferred to wells of a new plaque, devoid of any antimicrobial. The inoculated plates were aseptically closed and incubated at 35 ° C, and the Minimum Bactericidal Concentrations (MBCs) were recorded after 48 h. MBC was defined as the lowest extract concentration that results in visible inhibition of microorganism growth. Results: It was observed that the extract under study had MIC of 1024 μg /mL and MBC50 greater than 1024 μg / mL. Conclusion: In view of the obtained results it can be affirmed that the extract has a moderate antibacterial effect against the strains of K. pneumoniae and E. coli.