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Identification and Characterization of Antimicrobial-Producing Bacterial Isolates from Soil Samples

Kyle Zurbuch

The diminishing supply of effective antibiotics and the growing number of multidrug-resistant bacteria have created a global problem in the healthcare community. To address this ever-growing issue, there have been many endeavors to seek out novel and natural forms of antibiotics. One of these sources is soil, home to many antibiotic-producing bacteria. With the guidance of the Small World Initiative, soil from the old OminSource metal recycling plant in Fort Wayne, Indiana, was obtained and screened for any antibiotic-producing bacteria. From this initial screen, eight bacterial strains were isolated and identified for having antimicrobial abilities against safe relatives of six common antibiotic-resistant bacterial pathogens. Two bacterial isolates had antimicrobial activity against Staphylococcus epidermidis. One isolate had activity against Klebsiella species, and all eight isolates had antimicrobial activity against Bacillus subtilis. Using the 16S rRNA sequence, the bacterial isolates were all identified as Bacillus species. Their motility, Gram reaction, endospore presence, morphology, and type of oxygen metabolism were also determined using various biochemical tests. The crude antimicrobial extract was extracted from each isolate using ethyl acetate. Each chemical extract was retested against their corresponding bacteria, still displaying antimicrobial activity. Thin-layer chromatography was used to separate the antimicrobial compound from the remaining compounds in the extract. After separation, the structure of the antimicrobial chemical compound will be determined using nuclear magnetic resonance spectroscopy. The structure will supply additional information on the possible functional groups giving the bacterial isolate its antimicrobial abilities against two common antibiotic-resistant bacteria.

2022

no embargo