Antibiotic Prescribing
Welcome
Over-prescription of antimicrobials is creating resistant organisms. According to the CGDent, UK dentists prescribe 8% of all antibiotic prescriptions in NHS primary care. That's to people. But 73% of antibiotics world-wide actually go to farm animals as a feed additive - it makes them produce more meat.
Antibiotic stewardship is an attempt by healthcare professionals to limit antimicrobial prescription by doctors, dentists, vets and nurses, through education about the dangers of resistance. However, the drug companies ("big pharma") rely on excessive use of antibiotics for profit, and use their large advertising, "education" and lobbying budgets to ensure change will be very difficult.
More of this later, but let's start with learning what the words mean - there are so many of them!
An antimicrobial is an agent that kills microorganisms, or stops their growth. Household bleach is an antimicrobial, one that is used externally to kill microorganisms (e.g. on kitchen surfaces). There are even antimicrobial paints that are used on ship hulls to specifically kill bacteria.
Penicillin is also an antimicrobial. When used on people, it is usually used as a medicine, cream or injection.
There are 4 main types of microorganisms that cause harm to humans. Can you list them?
As well as being listed by what type of microorganism they act against, antimicrobials can also be classified according to their function.
Agents that kill microbes are called microbicidal, while those that merely inhibit their growth are called biostatic, or in the case of bacteria, bacteriostatic.
Biostatic agents
This includes disinfectants like Sodium Hypochlorite (bleach), antiseptics like Carbolic Acid (phenol), and preservatives like Sorbic Acid (used in cheese and wine). None are guaranteed to kill all the microbes, but they either kill most of them (leaving behind the more “harmless” ones), or prevent the microbes from growing.
Biostatic antibiotics, like Tetracycline, don't kill bacteria, but they prevent bacteria from dividing. They effectively put an infection on hold, stopping it from getting worse. This gives time for the body’s natural defences (like the immune system) to destroy them and clear the infection. Clearly you wouldn't normally use these drugs on a person with a damaged immune system.
The use of antimicrobial medicines to treat infection is known as antimicrobial chemotherapy, while the use of antimicrobial medicines to prevent infection is known as antimicrobial prophylaxis.
What does “prophylaxis” mean?
Prophylactic antibiotics may be administered to patients with disorders of immune system function to prevent bacterial infections (particularly hospital-acquired infection).
Prophylactic antibiotics may also be administered to healthy individuals to limit the spread of an epidemic, or to patients who have frequent repeated infections (such as urinary tract infections) to prevent recurrence.
Many dental procedures release oral bacteria into the blood stream. Antibiotic prophylaxis used to be common in dentistry, to prevent infection of (already damaged) hearts, or artificial joints.