Any animal can develop a bacterial infection for a variety of reasons. Chances are, you have experienced some kind of bacterial infection in your lifetime. Should you worry about your dog getting a bacterial infection? Well, there’s no reason to become alarmed. However, it’s a good idea to become familiar with actinomycosis and other bacterial infections. This way, you can help prevent it in your dog or detect it early if one does occur.
What is Actinomycosis in Dogs?
Actinomycosis is an infection that can occur in dogs when microbes from the Actinomyces bacteria group penetrate the skin or body. The Actinomyces bacterium is naturally occurring in the mouth of dogs. However, when the bacteria penetrate the skin or enter the airways or body cavities, it can lead to a serious infection. Actinomycosis is usually accompanied by a combination of different bacteria types, like E. coli, Pasteurella, Staphylococcus aureus, Streptococcus, and more. The severity of actinomycosis or any other kind of bacterial infection depends on the type of wound or injury, the location, how long it has been left untreated, and the dog’s own immune system.
Actinomycosis can occur in cats and other animals. It is very rare in humans.
Causes of Actinomycosis and Bacterial Infections in Dogs
Actinomycosis is most commonly caused by a penetrating wound like a dog bite or from a penetrating foreign body that migrates, like foxtails and cheatgrass (grass awns) or similar types of plant material. The foreign body is often inhaled by the dog. Or, the plant material gets lodged in the fur, then pierces the skin. A dog may also ingest plant material while self-grooming. Either way, the object can burrow and migrate to different parts of the body.
Hunting dogs and large breed dogs tend to be more commonly affected than other breeds, but actinomycosis can occur in any breed of dog.
Although actinomycosis is not extremely common all over the US, it can happen to your dog anywhere. Actinomycosis from foreign bodies occurs more commonly in western (and some mid-west) regions of the US where foxtail and similar grasses are prevalent.
Signs of Bacterial Infections in Dogs
The signs of bacterial infections typically depend on the location of the infection. Visible infections are often subcutaneous (under the skin) but may also involve the surface of the skin. These can look like wounds or areas of swelling. They may appear as firm or soft swelling. They may or may not be ulcerated on the surface. A discharge may be present. Discharge consistency and color can vary from watery and pinkish or red (serosanguinous) to thick and yellow or green in color (pus). The discharge may have a foul odor, especially if it looks like pus.
Actinomycosis may also occur in the face, head, mouth, or airway of a dog. You may notice signs like coughing, sneezing, or abnormal breathing. A discharge may be present from the nose or mouth or eye area. Your dog may even have trouble eating or swallowing.
If actinomycosis is present inside the body where it cannot be seen by the naked eye, your dog may show various signs of illness, like lethargy, loss of appetite, and weight loss. Pneumonia may occur secondary to actinomycosis.
Because actinomycosis is a bacterial infection, many dogs will develop a fever at some point. Some or all of your dog’s lymph nodes may become enlarged (called lymphadenopathy). Lymph nodes are located all one your dog’s body, but the easiest ones to find when swollen are the submandibular (right and left side of the head near where the back of the jaws meets the neck), axillary (armpits), and popliteal (back of the knees) lymph nodes.
Be sure to contact your veterinarian right away if you notice any wounds, swelling, or signs of illness in your dog.
Diagnosing Actinomycosis and Other Bacterial Infections
If you suspect your dog has a bacterial infection (or any kind of illness for that matter) be sure to contact your veterinarian as soon as possible. Your vet will need to see your dog in person in order to make an accurate diagnosis and begin the appropriate treatment.
During the visit to your veterinarian’s office, a technician or assistant will ask you questions about your dog’s recent history and activities. The veterinarian will perform a complete physical examination. Depending on your vet’s findings, the next step may be to do some laboratory tests. Blood chemistry and complete blood count will likely be recommended to assess your dog’s organ function, blood cell counts, and overall health. If your vet notes or suspects any internal abnormalities, radiographs (x-rays) may also be recommended.
If the site of suspected infection is accessible, your vet will likely recommend culture and sensitivity testing. The vet or tech will collect a sample from the wound. This sample will be prepared in a way that stimulates the growth of any bacteria present. If anything grows, they will microscopically determine the types of bacteria present. Then, they will test different types of antibiotics to see which ones eliminate the bacteria. Performing a culture and sensitivity is the most accurate way to find out which bacteria are present and determine which antibiotic medication is most likely going to eradicate the infection.
Bacterial Infection Treatments for Dogs
Treatment of a bacterial infection depends on the type of bacteria present and the severity of the infection. For mild to moderate infections, antibiotics may be the only treatment necessary. Penicillin is the antibiotic of choice for actinomycosis. However, your veterinarian may prescribe a different antibiotic depending on culture results, the nature of the infection, and your dog's medical history. The necessary course of antibiotic treatment typically lasts several weeks.
For more serious or invasive infections, surgical intervention may be necessary. Surgical treatments vary depending on the location and severity of the infection. For severe skin infections, the vet typically needs to clear away the dying tissue to promote new tissue growth (this process is called debridement). If tissue damage has caused pockets under the skin, a surgical drain may also be placed. Some wounds will be partially sutured closed while others must be left open to heal.
If the bacterial infection is present inside a body cavity, like the abdomen, then the veterinarian may need to go in surgically to remove it. This type of surgery may also require a surgical drain.
For some major infections, your primary care veterinarian may recommend referral to a veterinary surgeon. These specialists are board-certified in veterinary surgery and know how to handle the most serious surgical procedures.
Recovery from actinomycosis and other bacterial infections can take weeks to months. Your dog will need to be on a long course of antibiotics. Other medications may be prescribed for pain management. Your dog will need to be hospitalized for several days if surgical treatment was done. Expect to return to the vet frequently for follow-up exams and treatments. It is essential that you comply with your vet’s instructions if you want your dog to recover. Communicate about any difficulties you are having so your vet’s office can help you make adjustments.
How to Prevent Bacterial Inceptions in Dogs
The best way to prevent actinomycosis and any other type of bacterial infection in your dog is to detect problems early. If your dog is bitten by another animal, seek immediate veterinary attention. Animal bites can turn serious very quickly. Even if you are able to administer first aid on the scene, you should still follow up with a veterinarian.
Inspect and groom your dog well after spending time outdoors, especially if your dog has been in an area with tall grasses or similar plants. Most penetrating foreign bodies are difficult to see with the naked eye, but you may be able to brush or comb them off. This process can also help you detect parasites like fleas or ticks.