Not only do antibiotics NOT kill fungal & yeast infections, they can create or facilitate conditions which are perfectly suited to yeast & fungal infections. Antibiotics are notorious for setting up conditions which lead to fungi and/or yeast overgrowth. That's one of the numerous issues with random use or not clinically indicated use of antibiotics, and can occur even if antibiotics are used correctly.
Antifungal meds can be pretty hard on the system too -- best to know specifically what the problem is before throwing lots of different treatments at an unidentified illness.
Also some antibiotics contain fungi.