Bacterial vaginosis (BV) is the most common genital tract infection in women during their reproductive years and it has been associated with serious health complications, such as preterm delivery and acquisition or transmission of several sexually transmitted agents. BV is characterized by a reduction of beneficial lactobacilli and a significant increase in number of anaerobic bacteria, including Gardnerella vaginalis, Atopobium vaginae, Mobiluncus spp., Bacteroides spp. and Prevotella spp.. Being polymicrobial in nature, BV etiology remains unclear. However, it is certain that BV involves the presence of a thick vaginal multi-species biofilm, where G. vaginalis is the predominant species. Similar to what happens in many other biofilm-related infections, standard antibiotics, like metronidazole, are unable to fully eradicate the vaginal biofilm, which can explain the high recurrence rates of BV. Furthermore, antibiotic therapy can also cause a negative impact on the healthy vaginal microflora. These issues sparked the interest in developing alternative therapeutic strategies. This review provides a quick synopsis of the currently approved and available antibiotics for BV treatment while presenting an overview of novel strategies that are being explored for the treatment of this disorder, with special focus on natural compounds that are able to overcome biofilm-associated antibiotic resistance.

We have previously documented that faecal indicator bacteria (Escherichia coli, faecal coliform, enterococci) recommended by the U.S. Environmental Protection Agency (USEPA) to establish recreational water quality standards are naturally found in high concentrations in the surface and subsurface of soils in Hawaii. Rain, the source of all streams in Hawaii, washes the soil sources of faecal bacteria into all the streams of Hawaii, at concentrations which consistently exceed the USEPA recreational water quality standards. The objective of this study was to test the hypothesis that faecal bacteria are able to establish themselves in the soil environments of tropical islands by conducting the same study in Guam, a tropical pacific island with warmer temperatures and higher humidity than Hawaii. The same methods and study design used in Hawaii was used in Guam. The results of the study conducted in Guam revealed that all streams contain consistently high concentrations of faecal coliform, E. coli, and enterocci which exceeded the old USEPA recreational water quality standard of 200 faecal coliform/100 ml as well as the new water quality standards of 126 E. coli/100 ml or 33 enterococci/100 ml. These same faecal indicator bacteria were recovered in high concentrations in surface and subsurface (18-36 cm depth) soil samples in Guam. Limited coastal water analysis showed that most coastal marine waters contain low concentrations of faecal bacteria but coastal waters impacted by stream run-off showed elevated levels of faecal bacteria. The results of this study support the hypothesis that environmental conditions in the tropical areas of the world can support the growth and establishment of populations of faecal bacteria in the soil. Thus, soil becomes an environmental, non-faecal source of faecal indicator bacteria. These results indicate that USEPA water quality standards may not be directly applicable to tropical island environments.

Bacterial vaginosis (BV) is characterized by a highly structured polymicrobial biofilm, which is strongly adhered to the vaginal epithelium and primarily consists of the bacterium Gardnerella vaginalis . However, despite the presence of other BV-associated bacteria, little is known regarding the impact of other species on BV development. To gain insight into BV progress, we analyzed the ecological interactions between G. vaginalis and 15 BV-associated microorganisms using a dual-species biofilm model. Bacterial populations were quantified using a validated peptide nucleic acid fluorescence in situ hybridization approach. Furthermore, biofilm structure was analyzed by confocal laser scanning microscopy. In addition, bacterial coaggregation ability was determined as well as the expression of key virulence genes. Remarkably, our results revealed distinct biofilm structures between each bacterial consortium, leading to at least three unique dual-species biofilm morphotypes. Furthermore, our transcriptomic findings seem to indicate that Enterococcus faecalis and Actinomyces neuii had a higher impact on the enhancement of G. vaginalis virulence, while the other tested species had a lower or no impact on G. vaginalis virulence. This study casts a new light on how BV-associated species can modulate the virulence aspects of G. vaginalis , contributing to a better understanding of the development of BV-associated biofilms.