Effect of Oxygen Concentration on Neisseria gonorrhoeae Susceptibility to Resazomycins

Justin Rice,* Kailee Cunningham,* Deanna Schmitt
Department of Biological Sciences, West Liberty University, West Liberty, WV 26074

Presentation Category: Biological Sciences (Poster Presentation)

Student’s Major: Human Biology

As pathogenic bacterial species are becoming more resistant to commonly used antibiotics, it is essential for new antibiotics to be developed. A family of resazurin-based compounds, resazomycins, was discovered to be highly effective antimicrobials against Neisseria gonorrhoeae (Ng) in vitro. However, when these compounds were tested in a mouse model of gonorrhea, few resazomycins exhibited any therapeutic effect. These differences between in vitro and in vivo therapeutic efficacy may be due to differences in oxygen concentration. Most mammalian tissues exist at oxygen concentrations well below atmospheric levels, typically 2-5% instead of 20%. We hypothesized that decreased oxygen levels may confer resistance to resazomycins. To test this, we cultivated clinical isolates of Ng under different oxygen conditions and then determined the minimal inhibitory concentration (MIC) of various resazomycins. The resazomycin MICs for the different Ng isolates were up to 4-fold higher under 2% oxygen than 20% oxygen suggesting oxygen levels effect susceptibility to resazomycins. Further investigation is needed to determine how Ng is becoming resistant to resazomycins under low oxygen conditions.

Funding: NASA West Virginia Space Grant Consortium #80NSSC20M0055

Program/mechanism supporting research/creative efforts: a West Virginia SURE program