A study done in 2001 found a 17-year-old female virgin constantly suffering bacterial vaginosis — even after treatment. Turns out she actually had something called Gardnerella vaginalis. You might want to talk to your doctor about this as it could be the solution to your problem.
Also, are you douching? If so, stop because it can also cause BV. Don’t flush out that good bacteria. It only causes problems.
