This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genital Tract Infections (Too hot to handle!), Subject name: Gynaecology & Obstetrics
Which of the following conditions is most likely to be associated with a vaginal pH of 6? 
Select and explain. 
A. Atrophic vaginitis, B. Candidal vaginits, C. Doderlein's bacillus, D. Gardnella vaginitis
D: Gardnella vaginitis
Answer: D: Gardnella vaginitis 
Explanation: - Normal pH of vagina is 3.8 to 4.5. A pH of 6 is alkaline which ours Trichomoniasis Bacterial vaginosis. - Bacterial vaginosis is more common. It include Gardnella vaginalis, Ureaplasma urealyticum, Mobiluncus species, Mycoplasma hominis, and Prevotella species. - pH of vagina:- Before pubey - 7 At pubey - the pH becomes acidic (4-4.5) , it occurs due to Doderlein bacteria which conves glycogen (present in vaginal epithelium) into lactic acid under the influence of oestrogen. Post menopause > 7 ( Doderlein bacteria disappears after menopause )