I was able to obtain an extract from the only isolate (LB #5) that I had. The extract appeared insoluble in methanol as I had a hard time resuspending it; the extract formed a large white clump that would not fully dissolve even after lengthy vortexing. However, I still carried out the following procedure of testing the extract with the obtained solution. I chose to test it against the Gram-negative #2 E. coli and #7 E. aerogenes as well as against the Gram-positive #4 E. raffinosus and #6 B. subtilis as my isolate was able to grow in those tester strains during the ESKAPE testing we performed before. 

In the end, my extract did display some antibiotic-producing ability (so the extract was somewhat successfully resuspended). Out of all test plates, my extract was able to show inhibition only against E. coli but not against the other Gram-negative bacterium nor the Gram-positive bacteria. This means that my extract has narrow-spectrum antibiotic activity. 

The picture below shows the zone of inhibition around my extract (it is a little bit hard to see but it is there) that is was able to produce against E. coli