Bacterial vaginosis is the most prevalent vaginal infection in females at their reproductive age. It may also affect females after menopause and after hysterectomy (Biswas, 1993; Marrazzo, 2006).
Patients who have bacterial vagionsis are more prone to upper genital tract infections with severe consequences on fertility and the outcome of pregnancy (Biswas, 1993).
The normal vaginal flora including lactobacilli and facultative aerobic gram- positive bacteria are believed to be an important protective factor against infection by genital pathogens (Hiller, 1998).
Normally lactobacilli constitute 95% of bacteria in the vagina. It is essential for maintaining an acidic PH of the vagina by producing lactic acid from glucose (Hiller, 1998;Koumans, 2001).
Bacterial vaginosis is characterized by increased vaginal PH and milky white discharge. It is also associated with massive reduction or even absence of normal H2O2 - producing lactobacilli and over growth of anaerobic bacteria, including Gardnerella vaginalis, Ureaplama urealyticum, Mycoplasma hominis, Mobiluncus species, Prevotella species, and other anaerobes (Koumans , et al., 2001; Aggarwal, et al., 2003; Swidsinki, et al ., 2005).
Although this shift in normal bacterial flora has no obvious explanation, Shrier, et al., (2003) in their study explained the role of immune system response; local and systemic responses to normal vaginal flora and to sexually transmitted pathogens.