Background Some macrofungi have been studied and found to possess antimicrobial and nutritional properties. Mutation and hybridization of the wild types of different species have also been found to improve these qualities. Methods Spawn of Pleurotus pulmonarius and Pleurotus ostreatus were obtained and cultured on Potato Dextrose Agar and Malt Extract Agar. Mutants of P. pulmonarius and P. ostreatus were obtained by exposing the cultures to Ultra-violet ray at wavelength of 280nm for 30-60 minutes. The hybrid was obtained by culturing the wild types of both organisms on the same solid medium on plate at a distance of 8mm apart. The point of contact between both organisms was taken as the hybrid and used in submerged fermentation to obtain the mycelia mats and exopolysaccharides (EPS). The antibacterial activity was determined by testing the EPS against Staphylococcus aureus, Pseudomonas sp. Enterobacter sp, Escherichia coli, Salmonella sp, and Yersinia enterocolitica, obtained from environmental samples, using disc diffusion method. Results All the EPS produced by these organisms had antibacterial activity except those produced by two of the mutants (PPO2 and PO1). Acetone which was used as a control had very little antagonist effect on the isolates. The EPS were also found to contain phenolics. Mutants and hybrid of P. pulmonarius and P. ostreatus produced EPS which had better antibacterial activity against different pathogenic microbes compared with their wild type except PPO2 and PO1. Conclusions Since exopolysaccharides produced through submerged fermentation of P. pulmonarius and P. ostreatus, their hybrid as well as mutants of both organisms have antimicrobial activities with higher activities recorded from mutants derived from combinations of both organisms, large scale submerged fermentation of these organisms could be carried out to obtain antimicrobials that pathogenic bacteria are not likely to be resistant to, rather than depending solely on synthetic antimicrobial agents.