Crude Cell-free extract of eight(8) fungal isolates gained from a petroleum effluent contaminated soil in Calabar, Cross River State Nigeria, were tested for antimicrobial activity against the native hydrocarbon degrading bacteria (Bacillus species, micrococcus species) and some clinical isolates (pseudomonas aeroginosa, Escherichia coli and staphylococcus aureus) as well, using Agar well diffusion technique. The results indicated that three of the obtained isolates (Penicillium sp, Aspergillus sp., and Cladosporium) demonstrated anti-microbial activity against some of the microbes tested (80%), with the diameter of zones of inhibition ranging from 20mm-34mm. Crude cell-free extract of Penicillium sp (F2) exhibited activity against two of the native hydrocarbon utilizers (Bacillus sp., and micrococcus sp.), while that of Aspergillus sp. (F8) exhibited a broad spectrum activity on one of the hydrocarbon utilizing bacteria (Micrococcus sp) and two of the clinical isolates (Escherichia coli and pseudomonas aeruginosa) staphylococcus aureus was resistant to all cell free extracts. These results provided grounds for further work to investigate the repressive effects of these metabolites as it affects bioremediation involving organisms.
