At this stage, some people do culture and sensitivity. Step 4 and culture and sensitivity. In many cases, daily cleansing is all that is necessary. Marbofloxin or Baytril systemically for at least 45-60 days. Clean with TrizEDTA twice daily.
Some people use aminoglycosides even though they are ototoxic.
The rationale is to decrease the inflammation, mucous secretion from the mucoperiosteum, pain and viscosity of the exudate in the tympanic cavity. If OM is diagnosed, I would anesthetize and, with visualization, flush the ear with TrizEDTA and directly instill Baytril and NaDex phosphate into the tympanic bulla. If the tympanum is present and OM is suspected then I would do a myringotomy. The location of the myringotomy should be ventral. Maintenance therapy would include biweekly TrizEDTA cleansing longterm.