DigitalCommons@PCOM

Utilization of Semi-Solid Agar Inoculation in Microbial Co-culture Yields a Bacteria with Antibiotic Properties Against MRSA

Suwanee, GA

Microbial co-culture has many important applications, not least of which being the identification of novel antibiotic factors. Semi-solid agar inoculation co-culture is an innovative technique that aims to increase the yield and biodiversity of cultured environmental samples and to physically separate bacteria to aid in the isolation process. Methicillin-resistant Staphylococcus aureus (MRSA) inoculated into semi-solid tryptic soy agar (TSA) with a 1% agar concentration was able to proliferate and disseminate throughout the entirety of the plate without difficulty. Bacteria isolated from soil obtained from Radium Springs, Georgia was cultured onto MRSA-inoculated agar using a point inoculation technique. Isolates of interest were identified by their ability to produce a zone of inhibition whereby inoculated MRSA had a decrease or absence of growth in the region containing the proliferating soil colony and 1-2 mm beyond its borders. Due to the ability of secreted factors to diffuse throughout the semi-solid agar, interactions between the microorganisms, or lack thereof, were readily seen. Results revealed a Gram-positive bacteria that demonstrated inhibitory effects in multiple co-culture experiments. Preliminary characterization showed the inhibitory bacteria to be bacillus shaped and non-spore-forming amongst other properties. Current findings suggest that this bacterium may be the source of a novel antibiotic with the potential to inhibit MRSA.