10 Common Bacterial Infections in Dogs: Signs, Causes & Treatment
As a dog owner, keeping your pup healthy is a top priority—but bacterial infections can sometimes sneak up unexpectedly. These infections range from mild skin irritations to serious internal illnesses, and knowing the early warning signs can make all the difference in your dog’s recovery.
Bacterial infections occur when harmful bacteria overwhelm your dog’s natural defenses. Without prompt treatment, even minor infections can escalate into bigger health problems. The good news? Many bacterial infections are treatable with veterinary care, especially when caught early.
In this guide, we’ll cover the 10 most common bacterial infections in dogs, including:
- Key symptoms to watch for
- How dogs get infected
- Treatment options to help your pet recover
Whether you’re a new pet parent or a seasoned dog owner, understanding these infections can help you act fast and keep your pup happy and healthy.
1. Skin Infections (Pyoderma)
What is Pyoderma?
Pyoderma is one of the most common bacterial skin infections in dogs, often caused by Staphylococcus bacteria. It occurs when harmful bacteria overgrow due to underlying issues like allergies, parasites, or a weakened immune system.
Symptoms to Watch For:
- Red, inflamed skin
- Itching and discomfort
- Pustules (pus-filled bumps) or crusty lesions
- Hair loss in affected areas
- Foul odor (in severe cases)
Diagnosis & Treatment:
Your vet may perform skin scrapings, bacterial cultures, or biopsies to confirm pyoderma. Treatment typically includes:
- Antibiotics (oral or topical)
- Medicated shampoos or sprays
- Addressing underlying causes (e.g., flea control, allergy management)
Prevention Tips:
- Maintain regular grooming and bathing (with dog-safe products)
- Keep your dog’s skin dry, especially in skin folds
- Treat allergies or parasites promptly
- Schedule routine vet check-ups
Early treatment prevents worsening infections and keeps your pup comfortable!
2. Urinary Tract Infections (UTIs)
What Causes UTIs in Dogs?
Urinary tract infections occur when bacteria (often E. coli) invade the bladder or urethra. Risk factors include weakened immunity, diabetes, kidney disease, or poor hygiene. Female dogs and seniors are more prone to UTIs.
Symptoms to Watch For:
- Frequent urination or straining to pee
- Blood or cloudy urine
- Accidents indoors (in house-trained dogs)
- Licking the genital area excessively
- Whining or discomfort while urinating
Diagnosis & Treatment:
Your vet will likely perform:
- Urinalysis to check for bacteria/inflammation
- Urine culture to identify the specific bacteria
- Blood tests (if kidney involvement is suspected)
Treatment includes:
- Antibiotics (prescribed based on lab results)
- Increased water intake (to flush bacteria)
- Probiotics (to support urinary tract health)
- Diet changes (e.g., urinary-health formulas)
Prevention Tips:
- Provide fresh, clean water daily
- Encourage regular bathroom breaks
- Wipe your dog’s genital area after outdoor play (for prone breeds)
- Schedule annual vet check-ups, especially for senior dogs
Act fast! Untreated UTIs can lead to kidney infections or bladder stones.
3. Lyme Disease
What Is Lyme Disease?
Lyme disease is a bacterial infection caused by Borrelia burgdorferi, transmitted through the bite of infected black-legged ticks (deer ticks). Dogs in wooded or grassy areas are at higher risk, especially during warm months.
Symptoms to Watch For:
- Lameness (shifting legs or stiffness)
- Fever and lethargy
- Loss of appetite
- Swollen lymph nodes or joints
- Rare but serious: Kidney, heart, or nervous system complications
Note: Symptoms can appear weeks after infection, and some dogs show no signs at all.
Diagnosis & Treatment:
Your vet may recommend:
- Blood tests (e.g., SNAP 4Dx® to detect antibodies)
- Joint fluid analysis (if lameness is present)
- Urinalysis (to check for kidney involvement)
Treatment includes:
- Antibiotics (e.g., doxycycline for 4+ weeks)
- Pain relievers (for joint discomfort)
- Supportive care (hydration, rest)
Prevention Tips:
- Use vet-approved tick preventatives (topical, oral, or collars)
- Check for ticks daily (especially after hikes or grassy play)
- Remove ticks promptly (with tweezers, grasping the head)
- Ask your vet about the Lyme vaccine (for high-risk areas)
Early action saves lives! Untreated Lyme disease can lead to chronic pain or kidney failure.
4. Leptospirosis
What Is Leptospirosis?
Leptospirosis is a zoonotic bacterial disease (can spread to humans) caused by Leptospira bacteria. These spiral-shaped bacteria thrive in stagnant water, mud, or soil contaminated by urine from infected wildlife (rats, raccoons, livestock). Dogs contract it through skin wounds or by drinking contaminated water.
Symptoms to Watch For:
- Sudden fever and shivering
- Severe lethargy or depression
- Increased thirst and urination (kidney involvement)
- Jaundice (yellow gums/eyes from liver damage)
- Vomiting, diarrhea (sometimes bloody)
- Muscle pain or reluctance to move
Note: Some infected dogs show no symptoms but can still spread bacteria!
Diagnosis & Treatment:
Your vet will:
- Perform blood tests (checking liver/kidney values)
- Run urine tests or PCR for Leptospira DNA
- Possibly recommend antibody testing
Treatment includes:
- IV fluids (to support kidney function)
- Antibiotics (penicillins followed by doxycycline)
- Hospitalization for severe cases (organ failure risk)
Prevention Tips:
- Vaccinate annually (core vaccine in high-risk areas)
- Avoid stagnant water (puddles, ponds, flood zones)
- Control rodent populations near your home
- Wear gloves when handling a sick dog’s urine
- Disinfect surfaces with bleach solutions
Act fast! Leptospirosis can cause fatal kidney/liver damage within days. Early treatment boosts survival chances.
5. Kennel Cough (Bordetellosis)
What Is Kennel Cough?
Kennel cough is a highly contagious upper respiratory infection, primarily caused by Bordetella bronchiseptica bacteria. It spreads rapidly in places where dogs congregate (boarding facilities, dog parks, or shelters) through airborne droplets or shared surfaces.
Symptoms to Watch For:
- Persistent dry, hacking cough (often sounds like a “honk”)
- Gagging or retching (may produce white foam)
- Mild fever or lethargy in some cases
- Runny nose or sneezing (if combined with viral infections)
Note: Symptoms typically appear 2–10 days after exposure.
Diagnosis & Treatment:
Your vet will:
- Perform a physical exam (listening to cough characteristics)
- Rule out other conditions (e.g., canine flu, collapsing trachea)
- In severe cases: X-rays or nasal swabs
Treatment includes:
- Antibiotics (if bacterial infection is confirmed)
- Cough suppressants (for comfort, if no pneumonia is present)
- Rest and hydration (avoid irritants like smoke or cold air)
- Humidifiers (to ease airway inflammation)
Prevention Tips:
- Vaccinate (oral, nasal, or injectable Bordetella vaccine)
- Limit exposure in high-risk settings (boarding, daycare)
- Disinfect shared items (bowls, toys, crates)
- Boost immunity with a balanced diet and regular exercise
Contain the cough! Isolate sick dogs for 7–14 days to prevent outbreaks.
6. Staphylococcal Infections (Staph Infections)
6. Staphylococcal Infections (Staph Infections)
What Are Staph Infections?
Staph infections in dogs are caused by Staphylococcus bacteria, which commonly live on the skin but can cause problems when they overgrow due to wounds, allergies, or weakened immunity. These infections often lead to secondary skin issues and can spread if untreated.
Symptoms to Watch For:
- Red, inflamed skin or hot spots
- Pus-filled bumps or crusty sores
- Excessive itching or licking
- Hair loss in affected areas
- Odor from infected skin
Note: Staph infections often occur alongside allergies or flea infestations.
Diagnosis & Treatment:
Your vet will:
- Perform a skin cytology (microscopic exam of skin cells)
- Conduct a bacterial culture to identify the strain
- Recommend blood tests if infection has spread
Treatment includes:
- Oral antibiotics (e.g., cephalexin) for 2–4 weeks
- Antibacterial shampoos or sprays (e.g., chlorhexidine)
- Topical ointments for mild cases
- Addressing underlying causes (allergies, parasites)
Prevention Tips:
- Bathe your dog regularly with medicated shampoos
- Treat allergies promptly (food/environmental)
- Keep wounds clean and covered
- Boost immunity with a healthy diet and probiotics
Don’t delay! Staph infections can worsen quickly and become resistant to antibiotics if improperly treated.
7. Ear Infections (Otitis Externa)
What Are Canine Ear Infections?
Ear infections (otitis externa) are common in dogs, often caused by bacterial overgrowth (Staphylococcus or Pseudomonas). They frequently occur due to moisture buildup, allergies, or foreign bodies in the ear canal. Breeds with floppy ears (like Cocker Spaniels) are especially prone.
Symptoms to Watch For:
- Head shaking or tilting
- Pawing at ears or rubbing against furniture
- Foul odor from ears
- Redness, swelling, or discharge (yellow/brown)
- Crusts or scabs inside the ear
Note: Chronic infections may lead to hearing loss or deeper ear canal damage.
Diagnosis & Treatment:
Your vet will:
- Examine the ear canal with an otoscope
- Take a ear swab to identify bacteria/yeast
- Check for underlying causes (allergies, mites)
Treatment includes:
- Prescription ear cleansers (to remove debris)
- Antibiotic/antifungal drops (e.g., Baytril, Mometamax)
- Oral antibiotics for severe cases
- Anti-inflammatory meds to reduce pain/swelling
Prevention Tips:
- Clean ears weekly with vet-approved solutions
- Dry ears thoroughly after swimming/bathing
- Treat allergies promptly (a major trigger)
- Avoid cotton swabs—they can push debris deeper
Early care is critical! Untreated ear infections can lead to ruptured eardrums or permanent damage.
8. Other Tick-Borne Diseases
What Are Tick-Borne Diseases?
Beyond Lyme disease, ticks transmit multiple dangerous bacterial infections to dogs, including ehrlichiosis, anaplasmosis, and Rocky Mountain spotted fever. These illnesses are caused by different bacteria (Ehrlichia, Anaplasma, and Rickettsia rickettsii) and can lead to severe, sometimes fatal complications if untreated.
Symptoms to Watch For:
- High fever (often cyclical)
- Lethargy behavior or depression
- Loss of appetite and weight loss
- Swollen lymph nodes
- Nosebleeds or bruising (ehrlichiosis)
- Joint pain and lameness (anaplasmosis)
- Red spots on gums/skin (Rocky Mountain spotted fever)
Note: Symptoms may appear 7–21 days after a tick bite and can overlap between diseases.
Diagnosis & Treatment:
Your vet will:
- Run SNAP 4Dx® or PCR tests to identify specific pathogens
- Check blood smears for parasites (e.g., Ehrlichia morulae)
- Perform complete blood work to assess organ damage
Treatment includes:
- Antibiotics (doxycycline is most common)
- IV fluids for dehydrated dogs
- Pain relief for joint/body aches
- Blood transfusions in severe cases (e.g., anemia from ehrlichiosis)
Prevention Tips:
- Use vet-approved tick preventatives year-round (topicals, collars, orals)
- Check for ticks daily—focus on ears, paws, and groin
- Remove ticks properly with tweezers (grasp the head)
- Avoid tall grass/wooded areas in peak tick season
- Ask about vaccination (where available)
Time matters! Delayed treatment can cause kidney failure, neurological issues, or death.
9. Salmonella (Salmonellosis)
What Is Salmonellosis in Dogs?
Salmonellosis is a bacterial infection caused by Salmonella species, affecting a dog’s gastrointestinal tract. While less common than in humans, dogs can contract it through contaminated raw food, infected feces, or polluted water. Puppies, seniors, and immunocompromised dogs are at higher risk.
Symptoms to Watch For:
- Acute diarrhea (may contain blood or mucus)
- Vomiting and loss of appetite
- Fever or lethargy
- Dehydration (sunken eyes, dry gums)
- Septicemia (in severe cases—swift vet care needed!)
Note: Some dogs show no symptoms but can still shed bacteria, posing risks to humans and other pets.
Diagnosis & Treatment:
Your vet will:
- Test fecal samples (culture/PCR for Salmonella)
- Run blood work to check for sepsis or dehydration
- Possibly recommend X-rays to rule out blockages
Treatment includes:
- Fluid therapy (IV or subcutaneous for dehydration)
- Antibiotics (reserved for severe cases to avoid resistance)
- Probiotics to restore gut balance
- Bland diet (boiled chicken + rice) during recovery
Prevention Tips:
- Avoid raw diets unless properly handled/vetted
- Wash bowls daily with hot, soapy water
- Pick up feces promptly in yards/public spaces
- Practice hygiene—wash hands after handling pets/raw meat
- Store pet food safely (sealed containers, no cross-contamination)
Zoonotic alert! Salmonella can spread to humans—clean up accidents with disinfectants (bleach solutions).
10. Campylobacteriosis
What Is Campylobacteriosis?
Campylobacteriosis is a bacterial intestinal infection caused by Campylobacter jejuni or Campylobacter coli. These spiral-shaped bacteria spread through contaminated feces, water, or undercooked meat—posing risks at dog parks, kennels, or multi-pet households.
Symptoms to Watch For:
- Watery or bloody diarrhea
- Vomiting (sometimes with bile)
- Fever and lethargy
- Abdominal pain (whining, hunched posture)
- Loss of appetite
Note: Puppies, seniors, and immunocompromised dogs may develop severe dehydration or sepsis.
Diagnosis & Treatment:
Your vet will:
- Test a fresh fecal sample (PCR or culture)
- Check for dehydration (skin tent test, blood work)
- Rule out parasites (e.g., giardia) or other infections
Treatment includes:
- Antibiotics (e.g., erythromycin or azithromycin)
- Electrolyte fluids (oral or IV)
- Probiotics to restore gut flora
- Bland diet (pumpkin, plain chicken)
Prevention Tips:
- Pick up poop immediately in yards/walks
- Disinfect surfaces with bleach (bacteria survive weeks in soil!)
- Avoid raw poultry or unpasteurized dairy
- Wash hands after handling pets or cleaning accidents
- Quarantine sick dogs until diarrhea resolves
Zoonotic warning! Humans can catch it too—wear gloves when cleaning up.
Final Thoughts: Protecting Your Dog From Bacterial Infections
Bacterial infections can threaten your dog’s health—but armed with knowledge, you’re their first line of defense. From skin infections to tick-borne diseases, early recognition and veterinary care are critical to preventing complications.
Remember:
✔ Watch for symptoms (lethargy, fever, unusual discharge)
✔ Act fast—delayed treatment risks organ damage or chronic illness
✔ Prevent proactively with hygiene, vaccines, and parasite control
✔ Partner with your vet for regular check-ups and tailored advice
Your vigilance ensures your pup stays happy, healthy, and by your side for years to come. When in doubt? Always consult your vet—they’re your best ally in your dog’s well-being.
