(NSFW?)Is gardnerella vaginitis a sexually transmitted disease? Does a man give this to a woman?

I’ve heard contradicting information on this. I heard that this is a bacteria always present and an infection is only caused by stress or something that upsets the balance. But I’ve read that this is sexually transmitted? Can a man pick this up from one woman and transmit it to another? (don’t know if I should mark this as NSFW…. perhaps just PG14?)