Hi My Girlfriend Has Autoimmune Disease And She Knows From

Hi my girlfriend has autoimmune disease and she knows from experience that because of this the bacteria from on a penis can make her very sick during and after sex and can make it hard for her to pee and can make things really hurt for her. She says out of all her partners that it hurts the most with me and I make her the sickest and she figures that naturally I just have a lot of bacteria on my penis and I was wondering what I could do to help with this? Is there some type of antibacterial cream or something I could use? She really loves sex and I really love sex with her and I don't want to make her sick every-time we have sex.