"Yoghurt is produced using a culture of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus bacteria"
This is transient bacteria that we dont "naturally" have in the gut. Even if you try the natural antifungals against "some" human source probiotics you will never know how many unknow bacteria in our gut will be killed because there are so many unknow species.