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Bad luck or am I missing something? Sinus infection from hell

Seeking the collective wisdom here on my horse who I just have a nagging feeling there’s another layer of the big stinky onion I haven’t gotten to. 5 year old gelding. Timeline: he showed in Florida in April and had a mile respiratory virus that progressed to a fever and nasal discharge. Started on SMZs, no improvement, Vet didn’t like his breathing, put him on naxcel and genticin for a week, fever came down for about a week, then he had a mild cough for a few days which we were advised was probably just post respiratory infection irritation. Couple days later 104.5 fever, not eating, wouldn’t hold his head up, sent him to the hospital.

Culture there came back with strep zoo, and they determined that they wanted to try a longer course of SMZs. Ultrasound of the lungs showed mild irritation but nothing that they said couldn’t be incidental to just being in a trailer, throat and guttural pouches scoped clean, X-rays showed fluid in the sinus. We initially thought dental but no tooth issues on X-ray per the surgeons, so they treated it as a primary infection. After 5 days he still had a lot of discharge so I sent for a CT which showed what I am told is a remarkable quantity of sinus infection that affected all 8 sinuses. Vet who did the imaging said take him straight to the vet school, so off to UF he went for surgery. (By the way, saw some old COTH threads with bad experiences there and wanted to voice that I thought the surgical team there wa fabulous and the bill was about 40% less than I expected)

Surgeon there cancels the first surgery slot after he looks at imaging and decides to consult with the guy who invented the sinus flap technique and a couple other surgeons since he had not seen a horse with so many parts of the sinus infected in his career. They do two procedures, one to go in with laser to flush lower sinuses from inside the nostril and a long one the next day where they put in 4 holes and one flap across the middle of his forehead to access and clean out the other sinuses. They put tubes into the 4 holes and he stayed there for a week so they could flush the tubes daily, goes home on SMZs.

He finishes those up, gets his staples out, everything looks incredible and I bring him home to VA and in less than 2 weeks off the antibiotics he starts getting some swelling at the flap site and a wart looking thing. I was told that can happen where they get a big bony callous but had the vet out and good thing I did since between when I called and when she came the goose egg had about doubled in size and was painful. She swabs at the scab on the wart thing to get a culture and a bunch of blood and pus comes out and the Q tip goes all the way down to the bone in a tract. Oh joy. Films show a sequestrum forming which I knew was a possibility with the extent of his surgery. Going to our more local surgical referral center for surgery number 3 to get that bone cleaned up.

So I guess my question is what the F? I feel like we haven’t really kicked this infection at this point, and I’m just worried there’s something else I need to be doing here. Culture is preliminarily back with strep, not full sensitivity yet. He is back on SMZs because I said I wasn’t comfortable with him not having something in his system through the weekend given how fast he went from a little icky to a very sick dude. Also on preventative dose of gastrogard in the event he needs heavier antibiotics (I think chloramphenicol or rifampin were mentioned but not doing either without full culture), panalog ointment, and equioxx for pain. I can tell he doesn’t feel great, and it’s painful to the touch. Has anyone in the group experience dealt with a piece of this that they learned something I might find helpful? Can strep zoo just be this difficult to kick even without having some kind of antibiotic resistance, or at this point should I be asking if that’s just incidental and we should consider if whatever we are dealing with is just not growing on culture? Is this just bad luck he had the most extensive sinus infection the surgeon had seen or should I be considering whether something is causing his immune system to not be able to handle?

Pics are: X-ray showing the problem area, photo from right after staples came out, current photos showing swelling and wound


Yikes! Poor guy.

No experience, but as someone who majored in medical microbiology, I think it is a good idea to look at the sensitivity and hit it with guns that will work. Did the fist culture that showed Strep zoo include sensitivity that showed the strain was susceptible to SMZs? (Or more to the point, did they share those results with you?) [ETA: the reason I ask is because while the below study showed relatively low resistance to SMZs in S. zoo strains, it doesn’t sound like a first line choice and a lot of vets throw SMZs at just about anything, especially sinus infections, in my experience.]

This article is about specifically Strep zoo as a cause of endometritis in mares, but looked at isolates and studied their susceptibility and resistance to Abx. They also discuss general Streptococcus spp. susceptibility. Might help, if only to give you talking points and questions to ask vet when sensitivity comes back.

Hope that helps.


No personal knowledge just wanted to send jingles for your boy. Hang in there.


Oh, poor baby! That cute face! Unfortunately, I have no more help other than more jingles.


Strep zoo imho is a giant asshole. My horse had similar but not nearly as dramatic symptoms to yours. We ended up having to treat every few months. My vet was hesitant to put her on a long course of abx. Last fall I finally called in a bunch of favours from a bunch of friends and with their donations plus what I could squeeze out of my vet I put her on a nearly 3-month course of Uniprim. Fwiw, for my horse Uniprim seemed about the best choice of everything we tried (other SMZs and Excenel), but we did not try the “big guns” because vets were not that concerned about her labs. Meanwhile, I was thinking they could throw around “ubiquitous” all they liked, but I could see my damn horse was still sick and having nasty flare ups every few months.

Knock on wood, she’s better. Is she 100%? I dunno and we have the complications of mild asthma, allergies, and undiagnosible noisy breathing. I’m always looking for zebras. “Is she louder today?” “Is there dirt in her nose because she’s been rummaging in dirt or is this the start of mild discharge that’s getting field dust stuck to it?”

Will she never need abx again for the same issue? I’m doubtful. All I can do at this time is monitor, give her every damn supplement under the sun that someone may have once thought was good for respiratory health and keep all digits crossed.

I wish you good luck and hope you are able to get to the point I’m at at the very least!


The first course we only did a few days of SMZ and then vet thought we might have a pneumonia type thing and didn’t want to put him through the process of getting that culture, just got a PCR to rule out anything that would need to be reported to health authorities and quarantined etc. The hospital got a culture from nasal swab at first and then during surgery got a culture from inside the sinus and to my knowledge both showed SMZ susceptibility and the thinking was that it wasn’t the wrong antibiotic, it was just an area that meds don’t get to very well so needed that physical cleaning. The culture was also sensitive to naxcel which he had just been on and it came back, but they felt that was inappropriate for a longer course.

And no, of course no one sent me the culture and sensitivity and you know I asked :laughing:

We will see what this third culture comes back with but we he fact that so far they have all showed sensitivity to antibiotics that previously didn’t clear it is making me think I’m missing something here. I actually saw that article on round one and should review again, thank you!


Thank you! Yep, that’s about where I am. “OK so if this stuff is everywhere all the time why is MY horse so sick?” It’s sure stressful. Did your girl need any kind of probiotic or anything from being on antibiotics that long?

Your horse has such a beautiful, sweet face.

As a human who dealt with horrible sinus infections and numerous surgeries that eventually led to a bone infection in my skull and facial bones: Has the idea of IV antibiotics, at least a few rounds, been brought up? That’s what finally helped me turn the corner on my problem. Oral stuff just wasn’t maintaining a consistent blood level.

Sorry for comparing humans to horses, but I feel so sorry for your poor horse and for you, too. Hope things turn around for the better soon.


I understand! Yes we did a week of IV antibiotics at the start. It worked briefly but then he was sicker than before. The vets felt that you can’t do that for longer than a week or so.

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Yee birds and little fishes! as my grandmother would say. You have both certainly been through the ringer! It sounds like you have proceeded very responsibly and systematically. Yes, such infections can be incredibly difficult to eradicate. It is also possible that his current issue is “just” the sequestrum and not a continuation of the previous sinus infection. I assume he has had basic bloodwork as part of his treatment, one does wonder about his immune system. I had a horse years ago that seemed to spend half his life sick with something. Hopefully with the sequestrum dealt with he will finally feel better. This will be a great story in ten years! Meanwhile sending healing vibes!

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Oh, she’s a special cupcake (ulcers repeat offender) so she’s been on probiotics for pretty much the entire 10 years I’ve owned her. She did not have any gut symptoms from being on ABX so long.

And I totally hear you on the WHY IS MY HORSE THE ONLY HORSE? And in my case, very open barn (bars between stalls, not solid walls), turned out with her buddies every day, etc. Nobody else got sick. Nobody. There were a few days where I was panicked that we were going to be “patient zero” for some sort of outbreak, but nothing ever happened.


I don’t have any suggestions for you, but I’m jingling for your and your horse. I had a very much loved Hackney pony that had a sinus infection from hell. We’d do antibiotics, he’d seem better, then it would start all over again. My vet offered to scope him, thinking it was probably a sinus tumor, but the pony was 29 and already not doing great, so I chose to euthanize instead of putting my sweet boy through any more poking and prodding.

I know this doesn’t help you since your horse was already scoped. I sure hope you can get to the bottom of this.



Interesting point.

Underlying my years of chronic sinus and facial bone infections was a funky, weak immune system. So truth be told, what finally cured me was surgery to remove the necrotic bone + IV antibiotics + gamma globulin type stuff to bolster my immune system.

Do they give horses with chronic infections some sort of immune booster like gamma globulin? Even if just to get them over the hump so they start to heal?


They don’t but the thought occurs to me to see if there’s some kind of woo woo something I can do to make myself feel better in that department. I’m sure there’s some kind of something I can purchase to feel productive, and maybe it will even work.

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Lots of jingles!



More dead bone that they had to take out today than anticipated but he’s home. An interesting thing I learned today while talking to the vet, who says if we have this come back after this that he would think we are dealing with something not growing on culture:

I believe it’s expensive and wasn’t brought up until after the surgery or I would have just gone for it regardless, but he says it’s much more accurate than a culture and sometimes proves useful in situations where the clinical picture and the cultures aren’t matching up. I wanted to share in the event someone else is searching later because they’re in the same shoes. Still waiting on last week’s culture results so no word there yet but at least they got down to clean live tissue. Tech called what they took out “spongy”


So glad he’s home, so sorry you’re dealing with this!

(Goes without saying that I am jingling!)


I’m glad he’s home and hopefully feeling well. Jingles for him and you.

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Thanks for sharing the info about cultures. It’s so thoughtful of you to think about helping others while you’re going through such a stressful ordeal. Continued jingles for you and your handsome boy.:kissing_heart:

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Culture back with a significant amount of strep zoo showing sensitivity to SMZ, and a moderate amount of Pantoea agglomerans with a fair amount of resistance. My understanding is that bacteria is rarely found and no one thus far has any kind of experience with it, so we are just going to see how another two weeks of antibiotics treats us and if we have more problems then moving to the microgen.

Leave it up to one of my creatures, I swear.