I've read that antibiotic creams may help. Fred Coleman Dr. Fred Coleman is a perinatologist, or maternal-fetal medicine subspecialist.
Infection is fairly rare from a cerclage.
You don't have to do much of anything to avoid it. I would not suggest creams. You may get a discharge from the cerclage, which is not an infection, but rather a consequence from the presence of the foreign body. Frequently we give antibiotics if there is an unusual amount of discharge, pain or contractions. We also tend to give them at the time of surgery.