Complementary and conventional antimicrobials for integrative targeted control of bacterial vaginosis associated pathogens
Creators: name: Al-Gburi, Ammar
Publisher: name: No Publisher Supplied
Year: 2016

description: Bacterial vaginosis, the polymicrobial vaginal infection, occurs in women of an adolescent and childbearing age and associated with numerous gynecological and obstetric complications.This infection is characterized by the presence of thick-adherent vaginal biofilms, composed mainly of Gardnerella vaginalis, Atopobium vaginae, Mobiluncus curtisii, Prevotella bivia and Peptostreptococcus anaerobius. Gardnerella vaginalis is thought to be one of the primary etiological agent of the infection paving the way for various opportunists to colonize the ecological niche. The failure of conventional treatment with synthetic antibiotics is largely due to antibiotic tolerance of biofilm-associated cells and infection recurrence with antibiotic-resistant mutants. The dissertation-related articles include four major components of the study. First one is a review on importance of natural derived antimicrobials (alone and particularly in combination with antibiotic) as an effective strategies for combating the tolerance of biofilm-associated pathogens to antibiotic treatment. Second component is our study aimed at evaluation of antimicrobial activity of natural derived substances, subtilosin, Îµ-poly-L-lysine and lauramide arginine ethyl ester against established biofilms of G. vaginalis, using three commonly utilized methods (plate counts, ATP viability and resazurin assays) to assess cell viability in the antimicrobial-treated G. vaginalis biofilms. Subtilosin and lauramide arginine ethyl ester showed the strongest biofilm bactericidal effect in comparison to the other tested antimicrobials. The plate count was reported as the best method for estimating the bactericidal effect of the studied antimicrobials. The study's third component is a research article reporting on elucidation of antimicrobial activity of subtilosin and lauramide arginine ethyl ester in combination with commonly prescribed antibiotic clindamycin and metronidazole against bacterial vaginosis-associated pathogens. All tested antimicrobial combinations were inhibitory for BV-associated Mobiluncus curtisii and Peptostreptococcus anaerobius. LAE and subtilosin synergized ith clindamycin and metronidazole against biofilms of G. vaginalis but not biofilm-associated vaginal lactobacilli. Last but not least, the fourth component of our study is a report on safety and putative probiotic properties of Bacillus amyloliquefaciens B-1895 and subtilosin-producing Bacillus subtilis KATMIRA1933. The cell-free supernatants of both Bacillus strains were non-mutagenic and having antimicrobial properties against human pathogens Listeria monocytogenes, Streptococcus intermedius and Porphyromonas gingivalis. The two strains were strongly co-aggregating with pathogenic Escherichia coli and Pseudomonas aeruginosa. In addition, the endospores of B. amyloliquefaciens B-1895 and B. subtilis KATMIRA1933 were tolerant to 0.3% (w/v) bile salts and survived when incubated for 4 h in MRS broth at pH 2.0 to 3.0. The chapters are linked through the idea of using natural derived antimicrobial (particularly, subtliosin and LAE) alone (II) and in combination with the commonly prescribed antibiotics metronidazole and clindamycin (III) to counteract biofilm formation by BV-associated pathogens. Since LAE is already certified as GRAS for certain applications, we evaluated safety of  a putative probiotic Bacillus subtilis KATMIRA1933 (IV), the producer of subtilosin which was used as anti-biofilm agent.