Bacterial Infection of the Breast in Dogs

Mastitis in Dogs

Mastitis is a bacterial infection of one or more lactating (milk producing) glands in the breasts. It is often the result of an ascending infection, trauma to the lactating gland, or an infection that has been spread through the blood stream.

Escherichia coli (E. coli), Staphylococci, and β-hemolytic Streptococci are some of the main bacteria that are found to be most commonly involved. It is a potentially life-threatening infection, in some cases leading to septic shock, the direct effect of the mammary glands with systemic involvement.

This condition mainly affects postpartum bitches, but it rarely occurs in pseudopregnant lactating bitches too.

Symptoms and Types

• Loss of appetite
• Lethargy
• Firm, swollen, warm, and painful mammary gland(s) from which purulent (pus-like) or hemorrhagic fluid can be expressed
• Neglect of puppies (due to pain when attempting to nurse)
• Failure of puppies to thrive
• Fever, dehydration, and septic shock with systemic involvement
• Abscesses or gangrene of gland(s), if left untreated

Causes

• Ascending infection via teat canals
• Trauma inflicted on the mammary glands by a puppy’s toenails or teeth
• Poor hygiene
• Systemic infection originating elsewhere in the body

Diagnosis

You will need to give a thorough history of your dog’s health, onset of symptoms, and possible incidents that might have led to this condition. A complete blood profile is then typically recommended, including a chemical blood profile, a complete blood count, and a urinalysis.

If the is present, the milk is normally slightly more acidic than the serum is; it may also have increased alkalinity with infection. Neutrophils, macrophages, and other mononuclear cells can be normally observed in high numbers in normal milk; however, the presence of large numbers of free bacteria and degenerative neutrophils are noted with the presence of septic disease.

Meanwhile, if there is cancer present in the breast, the affected glands will not produce milk. Differentiation between malignant and benign condition will be achieved with an examination and culture of the mother’s milk.