This is not medical advice but for oral health you might try a system that attempts to both target bad bacterial and support good bacteria, such as one that incorporates xylitol gum as described and documented here by Ellie Phillips DDS (you don’t need to buy her xylitol gum of course): https://drellie.com/complete-mouth-care-system/

She also recommends a colon health probiotic and eating a healthy diet with a wide variety of plants and vegetables to improve the health of your saliva. She writes “Oral probiotics may seem a good idea, but many contain artificial sweeteners like Splenda, that can damage gut health… If you want an oral probiotic, I recommend Garden of Life Probiotic Smile lozenges, which contain strains of Streptococcus uberis KJ2, S.oralis KJ3 and S.rattus JH145, plus xylitol to feed probiotic bacteria.”

That said, as far as I know these recommendations were made for general oral health and not specifically about Fusobacterium nucleatum animalis C2.

Foods rich in good probiotic bacteria, such as strains of lactobacillus and bifidobacterium are a good place to start. Anything cultured or fermented is usually a good bet. There are also probiotic supplements, if you want a particular strain.

My guess would be that certain bacteria or strains are better than others at outcompeting the undesirable colonies, but you'd have to look for specific research to say which ones. In lieu of that, though, it's not hard to experiment with probiotics and see which, if any, have a noticeable positive impact on you.

Eating Plants

Brush & floss your teeth. Eat healthy. Sleep enough. Exercise.