Bacterial vaginosis pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sara Mehrsefat, M.D. [2]
Overview
Bacterial vaginosis is actually a syndrome resulting from an imbalance in the different types of bacteria in the vagina (also called vaginal "flora"). The healthy vaginal microflora has been described as being constituted mainly by Gram-positive bacilli of the genus Lactobacillus. Lactobacilli play an important role in maintaining the female genital tract health by keeping the vagina's pH at normal levels. When vagina's pH levels become unbalanced, certain microorganisms may overtake the normal flora leading to a low-grade infection that often produces an abnormal vaginal discharge.[1][2]
Pathophysiology
Bacterial vaginosis is resulting from replacement of the normal hydrogen peroxide producing Lactobacillus sp. in the vagina with high concentrations of anaerobic bacteria (e.g., Prevotella sp. and Mobiluncus sp.), Garderella vaginalis, Ureaplasma, Mycoplasma, and numerous fastidious or uncultivated anaerobes.[3]
The healthy vaginal microflora has been described as being constituted mainly by Gram-positive bacilli of the genus Lactobacillus including L. crispatus, L. iners, L. gasseri, and L. jensenii. However, other non-beneficial microbial species, including Gardnerella vaginalis, Enterococcus spp., and Prevotella spp., can be present in small numbers, not sufficient to cause disease. Lactobacilli play an important role in maintaining the female genital tract health by keeping the vagina's pH at normal levels.[1] When vagina's pH levels become unbalanced, certain microorganisms may overtake the normal flora leading to a low-grade infection that often produces an abnormal vaginal discharge.[2]
Pathogenesis
The exact pathogenesis of bacterial vaginosis is not fully understood, it is thought that bacterial vaginosis is a result of an imbalance in the different types of bacteria in the vagina by following mechanisms:
- Loss of lactobacilli result in PH rises and massive overgrowth of vaginal anaerobes
- pH rises results in decrease hydrogen peroxide production, also facilitates adherence of Gardnerella vaginalis to the exfoliating epithelial cells
- Decrease in hydrogen-peroxide production result in overgrowth of the anaerobes
- Anaerobes produce large amounts of proteolytic carboxylase enzymes
- Proteolytic carboxylase enzymes break down vaginal peptides into a variety of amines that are volatile, malodorous, and associated with increased vaginal transudation
Associated Conditions
Bacterial vaginosis is not considered a sexually transmitted disease. However sexual activity has been associated with development of this condition.
Bacterial vaginosis has been associated with serious health problems which include:[1][4][5][6]
- Preterm birth
- Spontaneous abortion
- Pelvic inflammatory disease
- Endometritis
- Acquisition and transmission of several sexually transmitted agents
References
- ↑ 1.0 1.1 1.2 Machado D, Castro J, Palmeira-de-Oliveira A, Martinez-de-Oliveira J, Cerca N (2015). "Bacterial Vaginosis Biofilms: Challenges to Current Therapies and Emerging Solutions". Front Microbiol. 6: 1528. doi:10.3389/fmicb.2015.01528. PMC 4718981. PMID 26834706.
- ↑ 2.0 2.1 Borges S, Silva J, Teixeira P (2014). "The role of lactobacilli and probiotics in maintaining vaginal health". Arch Gynecol Obstet. 289 (3): 479–89. doi:10.1007/s00404-013-3064-9. PMID 24170161.
- ↑ Koumans EH, Sternberg M, Bruce C, et al. The prevalence of bacterial vaginosis in the United States, 2001-2004: associations with symptoms, sexual behaviors, and reproductive health. Sex Transm Dis 2007;34:864–9.
- ↑ Guerra B, Ghi T, Quarta S, Morselli-Labate AM, Lazzarotto T, Pilu G; et al. (2006). "Pregnancy outcome after early detection of bacterial vaginosis". Eur J Obstet Gynecol Reprod Biol. 128 (1–2): 40–5. doi:10.1016/j.ejogrb.2005.12.024. PMID 16460868.
- ↑ Rothman KJ, Funch DP, Alfredson T, Brady J, Dreyer NA (2003). "Randomized field trial of vaginal douching, pelvic inflammatory disease and pregnancy". Epidemiology. 14 (3): 340–8. PMID 12859036.
- ↑ Jacobsson B, Pernevi P, Chidekel L, Jörgen Platz-Christensen J (2002). "Bacterial vaginosis in early pregnancy may predispose for preterm birth and postpartum endometritis". Acta Obstet Gynecol Scand. 81 (11): 1006–10. PMID 12421167.