The antimicrobial activity of the ethanolic and aqueous extract of Pontederia cordata against selected pathogens were investigated using the Disc Diffusion Assay. The Diameter of Zone of Inhibition, DZOI was used as an indicator of plant extract antimicrobial potency. For the ethanolic extract, the highest DZOI of 36.9 mm was recorded against E.coli with antimicrobial susceptibility following the sequence: E.coli > P.mirabilis > P.aeruginosa > S.aureus.

For the hexane extract, the highest DZOI of 26.5 ± 3.3mm was also obtained against E.coli. The order of antimicrobial susceptibility following the sequence: E.coli > P. mirabilis > P.aeruginosa. Thus, the ethanolic extract was found to be more antimicrobial than the hexane extract. Both the ethanolic and hexane extracts were microbial against C. albicans Compared to the positive control, Ciprofloxacin, the antimicrobial susceptibility for E.coli was registered at 87.86% and 63.1% for the ethanolic and hexane extract. Likewise, the antimicrobial susceptibility for P. mirabilis was registered at 84.5% and 66.71% respectively.

Thus, the ethanolic and hexane extract of Pontederia cordata can be used to treat topically E.coli and P. mirabilis infections.