Cause One: Bacteria
The most common cause of bladder infections is bacteria. There are lots of bacteria near the moist opening of your dog's urinary tract, but since urine is sterile, most of the bacteria are killed with frequent urination. However, they sometimes migrate up the urethra inside the dog's bladder, especially if your dog doesn't get the chance to urinate at least every six hours.
There are several types of bacteria that can cause bladder infections, such as E-coli and Streptococcus.
Cause Two: Diet
Diet can lead to increased instances of bladder infections because many types of commercial dog food contain bacteria. In addition, people often store foods out in the open where bacteria can accumulate. If you add water or milk to your dog's food and leave it sitting out, bacteria are given the opportunity to rapidly multiply.
Dogs with a Vitamin A deficiency may not be able to fight off bacteria in the bladder as well, causing an increased likelihood for bladder infections.
Avoid this by feeding a high quality diet, which is less likely to have lower quality ingredients. If your dog is prone to bladder infections, give them cranberries. They work for dogs just as they do for humans!
Cause Three: Fungus
Because bacteria are usually responsible for bladder infections, many veterinarians do not check for fungus. If antibiotics aren't helping, a fungus called Candida albicans may be the cause.
Fungus enters the bladder the same way as bacteria and is often more common in colder weather because dogs drink less and thus urinate less.
Cause Four: Other Illnesses
Bladder infections may appear as a side effect of a weakened immune system or drugs associated with other illnesses. Many dogs with diabetes or kidney stones also suffer from bladder infections. Diabetes adds sugar to the bladder, which provides a good environment for bacteria, and kidney stones block parts of the bladder where bacteria can hide.
Any illnesses that causes urine retention can also cause bladder infections since the urine isn't cleaning out the urethra as frequently. Damage to the spinal cord can cause nerve damage that causes discomfort when urinating as can defects in the bladder caused by genetic disorders or trauma. Tumors, either malignant or benign, near or in the bladder, can also cause bladder problems.
If your dog is frequently urinating or seems to be straining to urinate or if you notice a strange odor or color in your dog's urine, don't wait for this problem to develop. Bladder infections can lead to much more serious kidney problems if left untreated.