SACAD: John Heinrichs Scholarly and Creative Activity Days


Antibiotic resistance is a detrimental worldwide challenge, producing bacterial infections that are progressively more difficult to treat and cure. To attempt to help alleviate this issue, we screened soil samples for the presence of antibiotic-producing microorganisms. Soil samples were collected and diluted to 1:100 and 1:1000 ratios of soil and distilled water. These soil mixtures were then streaked onto tryptic soy agar (TSA) plates and incubated at 30℃ until colonies developed. These colonies were then selected and plated on a lawn of Serratia marcescens, which was utilized as the target organism.

Serratia marcescens was selected due to its known resistance to many widely prescribed antibiotics such as penicillin and ampicillin. Colonies that produced clear zones on the Serratia marcescens lawns, indicating antibiotic production, were then isolated into pure cultures by sequential rounds of streaking. Isolated organisms were submitted for partial 16S rDNA sequencing and preliminary identification. Using

this approach, we isolated three bacterial strains with antibiotic activity. The results of sequencing verified that our organisms were Bacillus mojavensis and two individual strains of Bacillus amyloliquefaciens with 0.09%, 0.47%, and 0.28% genetic differences from known partial 16S rDNA sequences in the database, respectively. In the future, further characterization of each of these organisms and isolation of each compound of interest will be executed to further investigate each organism’s antibacterial properties.

Faculty Advisor

Dr. Eric Gillock



Submission Type

in-person poster




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