What to Know About Pasteurella

Medically Reviewed by Dany Paul Baby, MD on November 02, 2022
Written by Sarah Vallie
4 min read

Both humans and animals carry a variety of bacteria within our bodies. This bacteria can be spread to others through bodily fluids like saliva or mucus. Many of these bacteria are harmless, but some can cause illness or infection. The Pasteurella bacteria often infects humans through an animal bite or scratch and can cause mild infection to severe illness.

Pasteurella is a genus of bacteria that often causes illness in animals. Pasteurella are zoonotic bacteria, meaning that they can be transmitted from animals to humans. The most common species of Pasteurella in humans is Pasteurella multocida, which is usually passed to humans through a bite or scratch from domestic pets.

Dogs and cats carry the Pasteurella multocida bacteria in their saliva and mucus. This is normal for them and does not make them sick. But other animals can become extremely ill when infected with Pasteurella multocida. It can cause illnesses like:

  • Atrophic rhinitis. This condition damages the bones and causes lesions in the snouts of pigs.
  • Fowl cholera. This highly infectious and deadly disease affects wild and domestic birds, most commonly chickens, turkeys, and waterfowl.
  • Hemorrhagic septicemia. This disease causes internal bleeding and leads to death within 24 hours of the start of symptoms. Pasteurella multocida causes hemorrhagic septicemia in hooved animals like antelope, buffalo, cattle, deer, goats, and sheep.

Other species of Pasteurella include:

  • Pasteurella aerogenes, a strain often found in hamsters and pigs that can cause infection and illness in humans.
  • Pasteurella canis, a bacteria that’s part of the normal flora of animals, especially dogs, but can cause soft tissue infection in humans.
  • Pasteurella dagmatis, another bacteria that’s part of the normal flora of animals like dogs but can cause severe infection in humans.
  • Pasteurella haemolytica, which causes respiratory infections in cattle and horses.
  • Pasteurella pneumotropica, a strain that causes disease and death in rodents.

The most common symptom of pasteurella infection is a soft tissue infection at the site of the bite or scratch. Within 24 hours of the bite or scratch, you may experience swelling, tenderness, and pus drainage. Sometimes, Pasteurella can cause a more severe soft tissue infection.

Cellulitis. If the Pasteurella bacteria get deeper into the tissue, it can lead to an infection called cellulitis. In a cellulitis infection, the injured area may become red, swollen, painful, and warm to the touch. Sometimes the skin will blister. Some people with a cellulitis infection may have a fever and chills.

Necrotizing fasciitis. Commonly called the “flesh-eating disease,” necrotizing fasciitis is a severe infection that causes the soft tissue to die. It spreads quickly and can lead to organ failure, sepsis, and shock. Up to 20% of patients with necrotizing fasciitis have died over the last five years.

In patients who are elderly, have compromised immune systems, or are very young, Pasteurella infections may cause illness beyond a soft tissue infection. Complications of Pasteurella infections can include:

  • Arthritis. Bacteria can cause infection within the joints. Symptoms include a joint that’s red, swollen, and warm; a fever; and difficulty using the joint.
  • Eye infections. Eye infections, like conjunctivitis, can cause red, painful, itchy eyes and eye discharge.
  • Meningitis. Meningitis happens when the membranes around the brain and spinal cord become inflamed. Symptoms include fever, headache, nausea, sensitivity to light, stiff neck, and vomiting. Bacterial meningitis can be very serious.
  • Pneumonia. Pneumonia is an infection within the air sacs in the lungs. Symptoms include chest pain, chills, cough, diarrhea, fatigue, fever, nausea, shortness of breath, and vomiting.
  • Osteomyelitis. Osteomyelitis happens when infection gets into bone and causes pain and swelling. Symptoms include feeling ill, fever, pain, redness, swelling, tenderness, warmth, and difficulty bearing weight or moving the joints near the affected area. 
  • Septicemia. Septicemia is when an infection gets into the blood and causes blood poisoning. Symptoms of sepsis include anxiety, confusion, feeling cold, fever, high heart rate, lethargy, light sensitivity, loss of interest, pain, nausea, and vomiting. Severe cases can lead to coma and death.  
  • Tenosynovitis. Tenosynovitis is an infection of the membranes surrounding your tendons, the tissues that connect muscles to bones. Symptoms include pain, swelling, and difficulty moving that part of the body.
  • Urinary tract infections. Urinary tract infections (UTIs) are infections within the urinary system. Symptoms include cloudy urine; pain when urinating; strong-smelling urine; a constant urge to urinate; and urine that’s colored red, pink, or brown. Women may experience pelvic pain.

Your doctor or medical provider can run a blood test to check for infection. In some cases, they may request an imaging test, like an X-ray. X-rays use radiation to create images of the body. Denser material, like bone, doesn't absorb the radiation as well as material like tissue. This allows bones to show up white on the X-ray image. By taking an X-ray, your doctor will be able to check for fractures caused by an animal bite as well as look for signs of osteomyelitis and necrotizing fasciitis.

Treatment for Pasteurella infection will depend on the severity of the infection. The first line of treatment for Pasteurella is antibiotics. Pasteurella bacteria are able to be treated with a few different antibiotics, like amoxicillin and penicillin. A typical course of antibiotics is 7-10 days, but severe infection may need a longer course.

In cases of severe, deeper Pasteurella infection into the soft tissue, such as necrotizing fasciitis, surgery may be necessary. Your doctor may need to remove all affected tissue.

If your infection is due to an animal bite or scratch, your doctor may recommend a tetanus and/or rabies vaccine as a precautionary measure.

The best way to avoid a Pasteurella infection is to avoid bites or scratches from household pets. If you have an open wound, be cautious not to let your pets lick the area or expose the area to their saliva. If you are bitten or scratched by an animal, be sure to thoroughly flush and clean the injury right away. Follow up with your healthcare provider as needed.