Dr Liesel van der Merwe is a small animal medicine specialist. Send her your questions: This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Dr Liesel van der Merwe

It has been ingrained in us always to “make sure you finish the course of antibiotic treatment, even if you feel better”.

Yet antibiotic resistance is a major health crisis throughout the world. A reference from 2017 states that deaths due to antibiotic resistant organisms were 700 000 and increasing. Fleming, who discovered penicillin, said in 1945, that the development of resistance was a major threat to this antibiotic, and indeed to all antibiotics.

Bacteria and viruses “learn” and develop different mechanisms to evade these treatments. These adaptations can be passed on to the next generation. The author of that article describes antibiotics as a nonrenewable precious resource.

I was bitten by a cat recently, an occupational hazard. Cat bites are always sore and often deep – they have sharp teeth. I disinfected the wound but within six hours my thumb was the size of a sausage. Two days after treatment with antibiotics all was again normal – swelling down, redness gone and no longer painful. So, now the question: Should I stop treatment or should I finish the course?

Most medical and veterinary doctors will prescribe a standard course of antibiotics for simple common infections. The more complicated common infections, and those affecting certain regions of the body, will have a longer course of treatment – sometimes several weeks to months.

These complicated chronic infections are monitored with tests to determine if the infection is under control, if the antibiotics can be stopped and also to check for relapses. This is ideally how antibiotic treatment should be used: Tailored to the specific infection and the specific patient. Examples of this in pets are bone infections, prostatic infections and kidneys infections.

More and more information is becoming available on how long our antibiotic courses actually need to be. These types of studies are part of a strategy to try to reduce antibacterial resistance and “save our antibiotics”.

Data has shown that shorter courses of antibiotics are just as effective in treating common uncomplicated infections as some of the previously accepted “standard” antibiotic courses. In fact, effective treatment course were, generally, only half as long as previously. Emphasis is being placed on gauging patient response to the treatment even for these common conditions.

Unnecessarily prolonged exposure to antibiotics causes the selective pressure to push for antimicrobial resistance. The longer bacteria are exposed to an antibiotic, the more they can “learn” about it.

Remember that antibiotics do not only affect the “target” causing the infection, but all the bacteria present in our bodies. These “bystander” bacteria are also exposed each time antibiotics are prescribed. The biome of our bodies (all the bacteria contained in our bodies) can also be thrown out of balance, resulting in overgrowth of more dangerous bacteria as a side effect.

Antibiotics are not always necessary. Simple skin wounds, grazes and infections can often be managed with surface treatments and shampoos using disinfectants. Sniffles and airway irritations are often viral or allergic. Antibiotics should not take the place of good practice.

A bite wound in a patient (dog) will not heal properly just because the patient is placed on antibiotics. The wound needs to be cleaned and flushed; damaged, dead tissue removed and good drainage provided. No amount of antibiotic treatment will work if these first principles are not adhered to, and many wounds will heal without any antibiotics if they are cleaned and flushed and managed correctly.

It is time that everybody takes responsibility for making good decisions about antibiotics.

Fleming A. Nobel lecture: penicillin. 1945. Available: www.nobelprize.org/nobel_prizes/medicine/laureates/1945/fleming-lecture.html 
Can Pharm J (Ott). 2017 Nov-Dec; 150(6): 349–350