Aloha! You're speaking with Dr. Michael SalkinYes, I do. If Nacho's X-rays revealed no lower respiratory involvement (no evidence of pneumonia), then Nacho's stertor - those sounds you're hearing - are likely to be originating from Nacho's nasal and sinus cavities. It's difficult to clear the many bacterial agents responsible for infection in those areas. Pasteurella multocida is often implicated as a cause of respiratory disease but we also find Bordetella bronchiceptica, Pseudomonas species, and Staphylococcus species. Pasteurella is commonly associated with rhinitis and sinusitis in rabbits and, unfortunately, high rates of recurrence are seen after discontinuation of drug therapy. Here are some guidelines for you derived from scholarly studies:1) Infection was eliminated in 7 of 8 rabbits treated with enrofloxacin (5mg/kg SC every 12 hours for 14 days). (SC = subcutaneous injections)2) Enrofloxacin given in the drinking water (50-100mg/L) before and continuing for 48 hours after inoculation with a virulent strain of P. multocida protected rabbits against bacteremia provided that daily intake of the drug was greater than 5mg/kg.3) Ciprofloxacin (20mg/kg PO every 24 hours) for 5 days eliminated P. multocida infection in a group of diseased rabbits. (PO = by mouth)4) One researcher reported success in control of chronic cases of confirmed pasteurellosis using enrofloxacin (5-10mg/kg PO every 12 hours) or chloramphenicol (50mg/kg PO every 12 hours) for up to 2-3 months. Please note that oral antibiotic therapy may be unrewarding in some cases of respiratory disease in rabbits. Treatment failure can be a result of misidentification of the underlying etiology or bacterial disease in the form of nasal cavity or pulmonary granuloma or abscesses, where oral medications are often only partially to poorly effective. In some cases, treatment is enhanced with the addition of antibiotic therapy in the form of nebulization. The addition of mucolytic agents can be helpful as well. Flushing of the nasolacrimal ducts and instillation of antibiotics into the ducts is also useful. Please feel free to share our conversation with your vet and please respond with further questions or concerns if you wish.