Using Antibiotic Beads to Treat Bone Infection in Trumpeter Swan
This young Trumpeter Swan was found on the ice, weak and unable to fly. Admitted on December 20, 2020, it tested positive for lead toxicity. It also had several fractured toes, likely damaged as the swan struggled to ambulate on the ice.
The boots it is wearing in this photo are designed to immobilize the toes, allowing the bones to knit. More details are in a future slide.
We noticed the feet becoming more tender and the bones looked swollen, so we took additional radiographs a few days after admission.
In this radiograph you can see the infection setting into the bone (the haze surrounding the fractures). This is a grave concern. Bony infections are difficult to treat, especially in an animal already compromised with lead toxicity. Amputation of these bones is not an option since they are the swan's load-bearing bones.
Our medical team conferred and decided to do a "digit deletion." This surgical process removes the infected bone pieces with the hope that the body will lay down new bony callous in the small gap that is created. It is challenging and precise: We need to remove all the infection, but leave enough bone material that the bony callous will form across the newly-created gap.
A week after the digit deletion surgery (you can see the gap created by the removal of infected bone), the medical team is dismayed to see this persistent infection is still present and spreading to what was healthy bone. (the haze around the bone ends)
Fortunately, during the surgery, the medical team took swabs to culture the bacteria. Doing in-house cultures has greatly improved our ability to successfully treat our patients.
After many meetings it was decided to try antibiotic beads.
The beads are created by mixing the antibiotics which have proven successful in the culture process. They are poured into a mold, left to cure for a short while, then surgically inserted into the infected site. They will slowly dissolve and absorb into the swan's system over time.
This is only done when results are not being achieved using systemic antibiotics - either oral or intravenously. We need to place the antibiotics exactly where they need to be to best treat the infection.
We reached out to the leading veterinary antibiotic bead company Kerrier, and asked for their assistance. We are fortunate that they donated this first kit to us so we could test and see how successful something like this might be for our patients.
The swan was prepped for another surgery and we inserted the antibiotic beads.
After the beads have cured, they are removed from the mold and inserted into the infected site.
Note the placement of the beads in both feet. Having the antibiotics directly on the infection site and slowly absorbing is an extremely effective way of treating persistent infections. It is also much less stressful for the patient. In this case, the swan is receiving daily meds and other treatments but with some patients this type of treatment may result in less handling - always a benefit to them.
While some of what you see is swelling, this gives you an idea of the area affected by the beads and what it looks like after the beads were inserted.
During all these surgeries, the swan's treatment for lead toxicity continues and it receives different therapies to encourage healing of the bones. In this photo Dr. Leslie Reed, our director of veterinary education programs, performs laser therapy on the swan's feet while Jordyn Maas, one of our vet techs, holds the swan.
We've been using low level laser therapy as a treatment for several years and found it helpful. It decreases inflammation and swelling, which speeds the healing process.
(If you've ever wondered what we do with all those donated pillowcases...note the cover on the swan's head. We cover patients' heads during treatments to help reduce stress and keep the animal calm.)
Those protective boots that you saw earlier? They need to be re-applied on a regular basis to keep them as clean as possible.
Professionals in wildlife medicine often need to be creative in sourcing materials. It's not like you can simply purchase swan booties online... In this instance we're cutting appropriately sized boots (or platform shoes if you will) from a foam kneeling pad. Yes, the same ones that you use when gardening.
As Dr. Reed puts on new boots she is assisted by Steph Grieb, who not only is one of our year-round Animal Care Crew volunteers but also helps train volunteers and is now working with our med staff as a medications assistant. Congratulations, Steph!
Swim time is an important physical therapy for all our waterfowl. The patient has to be healthy enough to hold its head up and not have any open wounds in order to qualify for daily swims.
Once the swan's boots are removed and the infection is greatly reduced, the swan will be given free roam in a room with swim pools so it can bathe as often as it wants. For now, the daily PT means wrangling the swan into a large pool then re-capturing it to return it to its pen.
We've talked a bit about stress in this case study and others. Our goal is to try to reduce stress for all our patients. Handling the swan like this on a regular basis is very stressful and can negatively impact its recovery. It's yet another condition that we must balance when we create our patient treatment plans.
Finally. What we've been waiting to see: Bony callous is forming around the beads. After two months of treatment and three weeks following the bead surgery, we're starting to have hope for the swan's recovery.
As the beads continue to absorb into the swan's system, the bony callous will fill in the spaces left by the beads. (the callous is the solid white material indicated by the arrows)
With continued treatment focused on managing stress while treating the lead toxicity and the bone infection, we are hopeful for the swan's eventual release this spring.
Many thanks to Kerrier for working with us to treat this beautiful swan.
Other Case Studies
Case Study 1 - Healing a Heron
Case Study 2 - Kingfisher with a Luxation
Case Study 3 - Rehabilitating a Gunshot Swan
Case Study 4 - An Injured Sandhill Crane
Case Study 5 - One Lucky Duck
Case Study 6 - Treating a Blanding's Turtle
Case Study 7 - A Surprising Find in a Juvenile Herring Gull
Case Study 8 - Hook, Line and Sinker - Spiny Softshell Turtle
Case Study 9 - Coyote caught in a Trap
Using Antibiotic Beads to Treat Bone Infection in Trumpeter Swan