Bacterial infections can strike your dog internally and externally. If your dog appears sick or suffers from an infected wound, take him to the vet for diagnosis and treatment. Your vet might or might not prescribe antibiotics, depending on the type of infection and its location. Don't try treating your dog yourself with leftover human or pet antibiotics you have on hand.
Internal Canine Bacterial Diseases
Diarrhea and vomiting can result from various canine complaints, including bacterial infection. If your dog's fecal sample tests positive for salmonella, your vet probably won't prescribe antibiotics unless your dog is severely ill, because these bacteria has become antibiotic-resistant. Puppies might experience campylobacteriosis, which causes severe diarrhea. Affected dogs require intravenous fluids, but only the seriously ill usually receive antibiotics.
Canine Skin Infections
If your dog suffers from flea, food or environmental allergies, he's likely to scratch incessantly. The lesions created by the itching present perfect opportunities for bacteria to invade and cause secondary skin infections. While your vet might prescribe oral and topical antibiotics for the infection, these do little good unless the underlying allergy is diagnosed and treated. Depending on the extent and depth of the infection, antibiotic treatment can last for weeks. Folliculitis, among the most common types of canine bacterial skin infections, can cause hair loss, acne, abscesses, crusting, redness, inflammation and draining pus.
Canine Respiratory Infections
If your dog starts honking, you might think he sounds like he's dying. If that's his only symptom, and his other behavior is normal, he's likely come down with kennel cough, the extremely contagious Bordetella bronchiseptica. Dogs usually develop kennel cough after exposure to other dogs at a boarding facility, dog park, doggie day care or similar place where lots of dogs congregate. Your vet probably won't prescribe antibiotics, as kennel cough is much like a human cold and runs its course within a couple of weeks. If your dog exhibits more serious symptoms along with coughing, that's another story. Fever, breathing difficulties, appetite loss and nasal discharge are signs of pneumonia, possibly bacterial in origin. If your dog is diagnosed with bacterial pneumonia, he'll almost certainly require antibiotic therapy.
Canine Eye, Ear and Mouth Infections
While you can't see what's going on inside your dog, you can catch an infection brewing on his outside. Take your dog to the vet if his eye, ears or mouth swell up or produce a discharge, or if he appears in pain. If your dog experiences an eye injury, your vet might prescribe topical antibiotics to keep bacteria away. Otherwise, your dog might develop bacterial keratitis, or corneal infection, which could require referral to a veterinary ophthalmologist to treat the condition and save your dog's vision. Ear infections might be treated with a thorough cleaning by your vet, along with topical or oral antibiotics. Your dog's mouth and gums can be a breeding ground for anaerobic bacterial infections, or germs that can grow without the presence of free oxygen. Combating anaerobic infections means a long-term course of antibiotics for your pet.