Marine microalgal extracts were studied for their antibacterial activity against the multidrug resistant human pathogens. Twenty marine microalgae were cultured and extracts were screened against 10 human pathogens. Among them, Isochrysis galbana extract showed highest percentage of antibacterial activity. Among the 5 solvents used for the extraction of antimicrobials, n-butanol showed maximum extraction (41.3%) of antimicrobials. The percentage inhibition of bacterial pathogens by these microalgae showed the maximum inhibition of Escherichia coli.

KEYWORDS: Marine microalgal extracts, Multidrug resistant human pathogens,Antibacterial activity.