Faculty Presentations Faculty Presentations: Caterina M. Miraglia

Inhibitory effects of dimethyl sulfoxide on Gardnerella vaginalis biofilms

Full list of poster authors

• Caterina M. Miraglia, D.C., MLS(ASCP)CM*
• Grayson L. Baird, PhD**

*University of Massachusetts Dartmouth, Department of Medical Laboratory Science
**Department of Diagnostic Imaging, Brown University Health

Conference where poster was previously displayed

American Society for Microbiology- Rediscovering Microbiology Joint Meeting

Poster abstract 

Bacterial vaginosis (BV) is the most common cause of lower genital tract infection in women of childbearing age. In many cases, relapse occurs within 1 year of standard treatment. This may be caused by the establishment of biofilms within the vagina by Gardnerella vaginalis. G. vaginalis can be resistant to standard treatment antimicrobials, which necessitates the investigation of alternative compounds that could be effective in eradicating the biofilms that establish and allow the persistence of BV. Many alternative antimicrobials are hydrophobic, so they must be dissolved in solvents such as dimethyl sulfoxide (DMSO) to study their antibiofilm effects in vitro. DMSO has been shown to have antibiofilm effects in vitro against several types of bacteria. It is important to know the percentage of DMSO concentration that inhibits biofilm formation to ensure that the antibiofilm activity of the compound of interest is being accurately assessed and not interfered with by the final percentage of DMSO in solution. The effects of DMSO on G. vaginalis biofilm formation have not yet been reported. This study examines the inhibitory effects on biofilm formation of G. vaginalis by DMSO at different concentrations using two-fold serial dilutions (50% - 0.10%) in 96-well microplates. Assays were run 3 times on separate days with 8 technical replicates each. At DMSO concentrations of 1.60% to 50%, biofilm inhibition was statistically significant. At DMSO concentrations of 0.78%, 0.39%, and 0.10%, biofilm inhibitory effects were considerably less than the higher concentrations and were not statistically significant. Interestingly, DMSO concentration of 0.20% appeared to increase biofilm formation, although this finding was not statistically significant. It is therefore important when preparing stock solutions of hydrophobic antimicrobial compounds to study against G. vaginalis biofilms that the final concentration of DMSO in the microplate is less than 1.60%. DMSO positive controls containing the final concentration of DMSO must also always be used.