Sulfa antibiotics can be good for a number of infections. If you don’t see improvement from the sulfa, you can sometimes get Tylosin here at a dosage of 1 tsp per gallon of water for 5 days:
https://jedds.com/products/tylosin-powder?_pos=1&_sid=b35ecc06d&_ss=r
https://jedds.com/products/tylosin-powder?_pos=1&_sid=b35ecc06d&_ss=r