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Animal Skin and Allergy Clinic Blog

The Good, the Bad, the Ugly: Bacteria in Veterinary Medicine

bacteriaThe world around you is teeming with life. You know about a lot of it, be it your trusty canine companion curled at your feet or the blooming pot of flowers on your windowsill. Most of it, however, is not visible to the naked eye. Like it or not, bacteria and other microscopic life are a huge part of the world.

In our world, these tiny life forms can make you or break you. Bacteria in veterinary medicine can be some of our biggest foes, but most of them are our greatest allies. Animal Skin and Allergy Clinic spends a large part of our day not only fighting off bad bacteria but helping to protect the good bacteria.

The Biology of a Bug

Bacteria are single-celled microorganisms in our environment. Although they are tiny, they make up a huge proportion of our world. A milliliter of water can hold around one million bacteria. They are everywhere – in the soil, in the water, on our skin, and on the skin of our pets.

There are many different types of bacteria. We classify them by a few distinguishing factors:

Oxygen requirements – Bacteria that need oxygen to survive are aerobic, while those that live in the absence of oxygen are called anaerobes.

Shape – The microscopic shape of a bacteria is also an identifying factor. A bacterium may be round (a cocci), elongated (a rod), or spiral shaped (a spirochete).

The bacterial population in a specific body area, such as in the digestive tract or on the surface of our skin, is referred to as the normal flora. In general, these organisms do a good job of keeping one another in check and working together to maintain a normal balanced world.

When Good Bacteria Go Bad

Sometimes, however, bacteria that cause disease, known as pathogens, will begin to grow out of check by the other beneficial microbes and the host immune system. This may occur to a disruption in the normal flora, resulting in an overgrowth. It can also occur when a non-normal bacteria is introduced into an area. It can also occur because of a failure of the hosts immune function.

At Animal Skin and Allergy Clinic we see these circumstances occur regularly. The disruption in the skin’s normal bacterial population can result in skin or ear rashes, hair loss, scaling, itchiness, odor, and even infection. Some common reasons for a bacterial imbalance may be caused by:

  • An abnormal immune system
  • Inflammation in the skin (often secondary to something like an allergy)
  • A hormonal or endocrine imbalance (such as hypothyroidism)
  • Abnormal anatomy (excess skin folds for example)
  • A wound or disruption in the skin’s barrier

A bacterial imbalance is no fun for either you or your pet. Luckily, we are here to help.

Fighting Bacteria in Veterinary Medicine

Bacteria in veterinary medicine can often be controlled when needed by the judicious use of systemic (oral or injectable) antibiotics. If a bacterial population is causing a problem, we first need to diagnose the underlying cause so that the problem does not recur. After this issue has been addressed, we can then move on to treating the bacterial imbalance when appropriate.

Topical therapy, such as antimicrobial shampoos and other topicals, are always needed. This type of therapy is extremely useful for targeting selected areas and helps to break down the biofilm where pathogenic bacteria hide from systemic antibiotics. These topicals also help to replenish the defects in the skin barrier.

When we select a systemic antibiotic sometimes we obtain a culture, which is a sample of a given area. This helps us determine which antibiotic is most likely to be successful in clearing the pathogens completely from the skin.

If your pet is prescribed an antibiotic, it is very important that you finish giving the entire prescribed course of medication, even if your pet seems better sooner. This is essential to completely getting rid of the issue and preventing relapse. Finishing the antibiotic course as prescribed is also important in preventing antibiotic resistance.

What’s in a Treatment Plan?

When your pet has a bacterial skin infection it is important to have the right treatment plan in place. Depending on the severity of the infection, topical treatment should be used between once a week and up to daily for bad infections. When also treating with systemic antibiotics the following criteria must be met:

  • The bacteria must be sensitive to the antibiotic prescribed
  • The right amount of antibiotics must be given
  • The correct length of treatment time is needed

With skin infections too low of a dose and too short of a treatment time will leave resistant bacteria behind. Then the next time that particular antibiotic is used it will not work. Skin infections require a minimum treatment time of 21 days for systemic antibiotics. We have seen a number of pets in our clinic who were treated elsewhere first on a 7 to 10 day course of low dose antibiotics, which inevitably leads to treatment failure. Because of these two very common errors we are seeing a large increase in multi-drug resistant bacterial skin infections.

Bacteria in veterinary medicine often get a bad rap, but our goal is to restore normal bacterial flora, not to eliminate bacteria entirely. It is important to remember that these tiny organisms rule the world, and can just as often be our friends rather than our enemies.