TitleThe safe, natural antimicrobial peptide subtilosin for control of bacterial vaginosis
NameNoll, Katia Sutyak (author), Chikindas, Michael (chair), Matthews, Karl R. (internal member), Woychik, Nancy (internal member), Dedova, Olga (outside member), Rutgers University, Graduate School - New Brunswick,
SubjectMicrobiology and Molecular Genetics,
DescriptionBacterial vaginosis (BV) is a condition characterized by an imbalance in the vaginal microflora where healthy lactobacilli are replaced by anaerobic microorganisms, especially Gardnerella vaginalis. It is estimated that 10-30% of North American women suffer from BV, frequently requiring medical attention. Proliferation of BV-associated organisms is known to have pathogenic effects, particularly in pregnant women. BV is associated with development of pelvic inflammatory disease, low fetal birth weight, preterm births with an elevated risk of infant death, intra-amniotic infections leading to fetal brain damage, and spontaneous abortion. Furthermore, BV (and G. vaginalis in particular) has been shown to increase the probability of contracting HIV and to stimulate viral replication. The antibiotics commonly prescribed to treat BV cause widespread inhibition of the healthy vaginal microflora, leading to a 20% recurrence rate of infection, often with newly developed antibiotic resistance(s). One promising alternative BV treatment is the bacteriocin, or antimicrobial peptide, subtilosin A. This dissertation describes the isolation, characterization, and purification of subtilosin from a fermented dairy product isolate of B. amyloliquefaciens. This is the first report of the intra-species horizontal gene transfer of subtilosin (from B. subtilis), and it is the first bacteriocin characterized from B. amyloliquefaciens. Via well diffusion assays, subtilosin was found to inhibit several human pathogens, including G. vaginalis, but has no effect on healthy vaginal lactobacilli. Motility and structure analyses of human spermatozoa revealed subtilosin possesses potent spermicidal activity. In vitro ectocervical tissue toxicity testing showed subtilosin is completely safe for human tissues. Elucidation of the molecular mechanism of action established that subtilosin specifically inhibits G. vaginalis by forming pores in the cell membrane, causing an efflux of ATP and dissipation of the delta pH portion of the proton motive force. Finally, microplate checkerboard assays confirmed that subtilosin acts synergistically with other antimicrobials of varying mechanisms of action, suggesting that lower concentrations of subtilosin could be used to effectively inhibit G. vaginalis, thereby decreasing the likelihood of developing resistance. Taken together, the data presented herein demonstrate that subtilosin is a safe, natural antimicrobial peptide that can easily be formulated into an effective prophylaxis or treatment for bacterial vaginosis.
NoteIncludes bibliographical references
Noteby Katia Sutyak Noll
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.