Bacterial infections are the cause of many disease conditions affecting the urinary system of dogs. The bacteria usually gain entry into urinary system via the urethral opening. From there they reach the urinary bladder and cause infection there. Infections of the kidney, referred to as pyelonephritis, may also result if the bacteria travel from the urinary bladder to the kidneys via the ureters.
Several problems with the urinary system, as well as certain other factor such as diabetes and immune deficiencies, predispose dogs to urinary tract infections. Reduced flow of urine, incomplete emptying of the bladder while voiding, and urine that is too dilute, may also increase the chances of bacterial infections setting in. Compared to male dogs, females have much higher incidence of urinary tract infections, but in older males, especially in those that are not castrated, infections affecting the prostate gland are common. These bacterial diseases affecting the dogs are not transferable to humans, however.
Prompt treatment and complete elimination of bacterial infections are of great importance as these pathogenic bacteria may develop resistance to the antibiotic drugs unless they are wiped out from the body. Drug resistance may result in stubborn infections that refuse to go away. If the infections of the bladder and the prostate gland are not resolved completely, they may spread to the kidneys, leading to potentially fatal disease conditions such as kidney failure. Unresolved infections are also known to cause struvite stones in the urinary tract of dogs.
Bacterial Cystitis in Dogs
Infection of the bladder caused by bacteria, and the associated inflammatory condition, is referred to as bacterial cystitis. It is caused by pathogenic bacteria that reach the bladder via the urethra. Urinating frequently, and with pain, difficulty to pass the urine, and urinating in unusual places are the common symptoms of bacterial cystitis. The urine may have traces of blood in it. In some cases, the dog may remain completely asymptomatic, and the disease gets diagnosed only when a urine sample is tested for some other reason, or when it is routinely analyzed.
Dogs which have been taking steroids for a long time may have this kind of asymptomatic bladder infections. Those having a hormonal disorder called hyperadrenocorticism, characterized by the overproduction of adrenal gland hormones, also may not have any perceptible symptoms.
Bacterial cystitis is usually diagnosed by testing a sample of the urine.
Besides a routine urinalysis, the veterinarian may want the urine to be cultured to identify the pathogen causing the bacterial infection and the drugs that are most effective against those microbes. A two-week course of oral antibiotics may clear up mild infections, but for severe infections, the drug therapy is continued for longer periods. Urine samples are tested periodically to check whether the drugs have effectively eliminated the infection. This may continue for several months after recovery too, to ensure that there has been no recurrence.
Chronic infections and frequent recurrence may indicate an underlying disorder or defect that needs to be corrected. The veterinarian must be informed about all the medications the dog is taking, as well as the ones that were taken previously, as some drugs are known to increase the chances of acquiring bacterial infections. X-rays, ultrasound scans, and cystoscopy may be done to detect structural defects and other disorders such as abnormal growths, cysts, kidney and ureter stones, cancers etc. Blood tests are also done to identify certain other factors that make the dog more susceptible to these infections.
In some dogs, bacterial cystitis may recur without any apparent reason. In such cases, the veterinarian may put the dog on a low-dose, long-term, maintenance course of antibiotics. This treatment may help avoid the recurrence of urinary tract infections. It may also prevent the bacteria from spreading to the kidneys and causing infections there. Dogs on this long-term antibiotic therapy are tested regularly by culturing their urine sample in addition to conducting routine urinalysis. Frequent voiding of the bladder may go a long way in preventing the recurrence of bladder infections.