Secondary metabolites of Serratia marcescens as potential antimicrobials

The rise of antimicrobial resistance (AMR) has become a global health emergency. According to the CDC, nearly 1.27 million people worldwide are killed by antibiotic-resistant pathogens, costing $4.6 billion annually to treat. Many pathogens are developing resistance against commonly prescribed antibiotics at a pace far more rapid than pre-pandemic levels. Considering this observation, new antimicrobials need to be identified. Natural sources of antimicrobial substances represent potential sources of new and interesting antimicrobials. Serratia marcescens, a common soil bacterium, is one of these potential sources for new antimicrobials against both prokaryotic and eukaryotic pathogens and viruses. One of these compounds, prodigiosin, has been well documented for its potential as an antibacterial and antifungal agent. This exploratory study involves culturing S. marcescens in varying growth conditions, such as temperature. By altering the growth conditions of S. marcescens, it may be possible to modify the production of secondary metabolites for extraction and antibiotic efficacy testing. The primary goal of this experiment is to analyze the activity of crude cellular lysate of S. marcescens under different laboratory conditions and compare its antibiotic effects with first-generation antibiotics. In addition to culturing S. marcescens, we have screened our laboratory isolate using the Kirby-Bauer plate assay against eight different antibiotics to develop a basic antibiotic susceptibility profile. This will be an additional measure for possible changes of our S. marcescens isolate under different laboratory conditions. With these crude extracts, we will also screen for antimicrobial activity against other common prokaryotic microorganisms, eukaryotic pathogens, and viruses.