Treating Clostridium in Dogs with Amoxicillin

Clostridium is gram positive bacteria, and species of these bacteria that are capable of causing diarrhea and other digestive problems in dogs.

These bacteria are anaerobic and can thrive in environments with no oxygen. Since they produce endospores, they’re difficult to clear, as endospores are dormant structures that enable the bacteria to survive in harsh conditions. In the endospore form, these bacteria are resistant to starvation, ultraviolet and gamma radiation, adverse temperatures, stomach acids and most chemical disinfectants. However, the bacteria can’t reproduce in the endospore form. 

Development of Disease

Clostridium bacteria can survive the passage through the stomach when ingested by the dog. Once it reaches the colon, it changes from the dormant form to the active form and reproduces, thus making it capable of causing disease. The disease can vary from being mild to severe depending on the type of clostridium that’s infected the pet.

Types of Clostridium:

  • Clostridium perfringens is the most common form of clostridium bacteria. There’s normally some amount of these bacteria in the large intestine of the dog. However, if their numbers increase, disease can occur.
  • Clostridium difficile can also be transmitted like clostridium perfringens. Additionally, it can be transmitted through food. Its presence is relatively common in puppies and not so common in adult dogs.
  • Clostridium botulinum produces the toxin botulism that can be damaging to pets. If the dog eats improperly stored food, he’s most likely to contract this disease.
  • Clostridium tetani produces the toxin tetanus. Tetanus usually occurs when a wound becomes infected with C. Tetani and toxins from the bacterium cause the disease.

Symptoms Exhibited by Dogs Infected with Clostridium:

  • Mild to extremely severe diarrhea
  • Cramps
  • Vomiting
  • Fever
  • Lethargy
  • Dehydration
  • Bloating
  • Pain in abdomen
  • Blood in stools


Amoxicillin, a semi-synthetic penicillin derivative, is a moderate spectrum antibiotic that effectively treats clostridium in dogs. It works to prevent the synthesis of bacterial cell wall and thus inhibits bacterial growth. It shouldn’t be used for viral or parasitic infections. Amoxicillin has a wide coverage as it spreads to all bodily tissues and fluids except the brain and the spinal fluid. The response to amoxicillin treatment can be seen within few days and the full course of treatment typically lasts for several weeks. The dog should be administered antibiotics only in cases of persistent diarrhea as excessive administration of antibiotics will result in antibiotic resistant bacterial growth.

Recommended Dosage

The recommended dosage is 5 to 10 mg per pound of body weight, every 12 to 24 hours. Since its stable in gastric conditions, it can be administered with or without food. Care should be taken to not overdose the pet as this might cause adverse reactions or symptoms such as vomiting, nausea, diarrhea, abdominal pain, renal failure and hematuria (blood in urine).

Amoxicillin shouldn’t be given to animals, hypersensitive to penicillin and to those that are on drugs like erythromycin. Pet owners should also adopt preventive measures to ensure that pet’s don’t consume contaminated food or feces.