Trouble with hognose RI not responding to antibiotics

[SeaPancake]

Apologies in advance for the long post; I’m losing hope with trying to treat my hognose’s respiratory infection and I don’t want to leave any details out in case I’m missing something. I got my boy Boops 2 years ago from somebody who didn’t want him anymore. I don’t know much about his history, only that he’s likely in the range of 10-17 years old. He was slightly underweight when I got him (72g and is now 101g) and only ever had a heat mat without a thermostat so he probably wasn’t getting proper heating. He eats a fuzzy mouse every 10 days.

Current Enclosure:

• 50W CHE, 83°-79° ambient for 12 hours during the day with 93° basking spot, 75° ambient for 12 hours at night
• Humidity varies throughout the year, usually 30%-55%
• Resin hide on warm and cool side, plastic leaves, sandstone rock for shedding, water bowl (emptied and sanitized every 3 days)
• 3 inches of Oxbow Blend Pure Comfort paper bedding
• Once a month I replace the bedding and deep clean the enclosure and all decorations with diluted chlorhexidine (I rinse very well so no residue is left)

Symptoms:

• He has sneezing fits that come and go in frequency, I’ve heard them multiple times a day and sometimes maybe only once or twice a week
• Just the other day I witnessed him sneeze out a bunch of white stuff and got it on video (see pictures below)
• Writhing and repeatedly opening his mouth like he has something stuck in his throat
• Mucous-y and occasionally dark green poops
• Occasional bubbles at mouth but not often
• I’ve fortunately never seen him open mouth breathing while he’s just chilling, only when he’s having these fits

Vet history:
May 2022:

• Noticed he was sneezing, vet said he was healthy but that the aspen bedding was likely too dusty so I switched him to a paper bedding which they recommended

November 2022

• Sneezing did not resolve, saw a different vet (same practice) who said that he had a little bit of excess saliva and was a little gassy
• Prescribed 8 doses (can’t remember amount per dose) of Ceftazidime

December 2022

• He seemed to get mildly better but still sneezing, vet prescribed 2 additional doses of Ceftazidime

January 2023

• Got a culture done via swab to hopefully diagnose illness, no bacteria was detected that shouldn’t have already been there
• Did a fecal float, did not find any parasites

July 2023

• Same symptoms persisted so I took him in again
• Vet prescribed 4 doses (0.01mL each) of Meloxicam and 9 doses (0.02 mL each) of Ceftiofur (wound up giving him an extra dose that I was given as good measure), once again mildly improved but did not last
• Redid fecal float and added a direct since it was a fresh sample, did not find parasites in either

Since July I’ve just been trying to be more diligent than ever about sanitization and proper temperatures in the hopes that he can finally overcome whatever this is but no such luck.

The vet seemed out of ideas so I wanted to see what others thought. If this was your snake what would your next course of action be? I don’t want to just keep giving him more shots and making him suffer if it isn’t going to solve the problem.

My biggest concern right now is the white stuff he sneezed out. He was going through sneezing motions with no sound (which has never happened before) and then there was finally a sneezing noise when he shot the white stuff out which makes me think it was blocking his airway. This is the first time I’ve seen this happen.

Most of the time he seems perfectly fine – he’s never refused a meal, never regurgitated, he’s active, alert, and he’s been steadily gaining weight. It just breaks my heart every time I hear him sneeze knowing that I don’t know how to fix him. I love him so much and I feel hopeless about ever getting him healthy. I plan to take him back to the vet soon so I wanted to see if there's anything in particular that I should discuss with them that might have been overlooked before.

Any advice would be greatly appreciated