Home' Southern Health News : October 2015 Contents Antibiotic Awareness Week
BY JACQUIE VAN SANTEN
Antibiotics were introduced in the 1940s and have saved millions of lives since then. But what are they, and how do they
work? And why are we developing resistance to them? Southern Health News spoke with Rebecca Larcombe, a Specialist
Pharmacist in Infectious Diseases, Immunology and Antimicrobial Stewardship, based at Flinders Medical Centre, to coincide
with Antibiotic Awareness Week, held 16 to 22 November.
What are antibiotics?
Antibiotics are medicines that fight bacterial
infections. They work by either killing the bacteria
outright or preventing their reproduction. Once
the antibiotic has done its job, the body’s immune
system can kick in and do its work continuing to
fight the bacteria.
What is a bacterial infection?
Bacteria are tiny single-celled organisms, thought
by some researchers to be related to plants. They
are among the most successful life forms on the
planet, and range in habitat from ice slopes to
Bacteria can be beneficial – for instance, gut
bacteria help us to digest food – but some are
responsible for a range of infections. These
disease-causing varieties are called pathogenic
bacteria. Many bacterial infections can be
treated successfully with appropriate antibiotics,
although antibiotic-resistant strains are beginning
to emerge. Immunisation is available to prevent
many important bacterial diseases.
What is antibiotic resistance?
This is when an antibiotic no longer works against
bacteria that it was originally effective against. In
fact, they can survive – and even multiply - in the
presence of an antibiotic. It is an increasing serious
threat to global public health and the World Health
Organisation has stated that ‘A post-antibiotic era—
in which common infections and minor injuries can
kill—is a very real possibility for the 21st century’.
Most infection-causing bacteria can become
resistant to at least some antibiotics. Bacteria
that are resistant to many antibiotics are known
as multi-resistant organisms. Unfortunately
drug companies have minimal new drugs in
development to fix this problem, therefore we have
to preserve the effectiveness of the antibiotics we
have available now.
There are high proportions of antibiotic resistance
in bacteria that cause common infections such
as urinary tract infections, pneumonia and blood
Antibiotic resistant bacteria such as Methicillin-
resistant Staphylococcus aureus (MRSA or golden
staph), Vancomycin-Resistant Enterococcus
(VRE) and multi-drug-resistant Mycobacterium
tuberculosis (MDR-TB) are serious public health
problems. Patients with multi-drug resistance
infections are generally at increased risk of worse
clinical outcomes. They often fail to respond to
standard treatment, have prolonged illness, higher
costs to health care and a greater risk of death.
The most important ways you can prevent
antibiotic resistance are:
• Only use antibiotics in the appropriate
circumstances – and only when you absolutely
need them. Often, people expect doctors to
prescribe antibiotics for a viral illness – but
remember, antibiotics do not work against viruses.
• If your doctor prescribes antibiotics, complete the
course. This gives the medication a better chance
of being fully effective, so that bacteria do not
• Practise good hygiene, and use appropriate
infection control procedures.
• Remain up-to-date with vaccinations.
Source: Rebecca Larcombe and Better Health
Flinders Medical Centre
How do antibiotics work?
Different types of antibiotics work in different
ways. For example, penicillin destroys bacterial
cell walls, while other antibiotics can affect the
way the bacterial cell works.
Doctors choose an antibiotic according to the
bacteria that usually cause a particular infection.
Sometimes they do a test to identify the exact
type of bacteria causing your infection and its
sensitivity to particular antibiotics, however there
is a delay in results due to having to grow the
bacteria in the laboratory.
Do antibiotics work on viruses as well?
No. Antibiotics are useless against viral
infections. A virus is an even smaller micro-
organism than bacteria and they can only
reproduce inside a host’s living cell. It is very
difficult to kill a virus since they use their host
cells to perform their activities for them. That’s
why some of the most serious communicable
diseases known to medical science are viral in
origin, such as hepatitis. Special antiviral drugs
are available to treat some viruses.
Antibiotics do not fight infections
caused by viruses, such as:
• Most coughs and bronchitis
• Sore throats (unless caused by streptococcus
12 / OCTOBER 2015 / SOUTHERN HEALTH NEWS
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