Transcript Bacterial Resistance to Antibiotics

Antibiotics &
Bacterial Resistance
Antibiotics
Are natural substances that stops or
destroys microorganisms by attacking
metabolic pathways in the bacteria
Example
penicillin which works by preventing bacteria
from constructing a normal cell membrane
Streptomycin works by preventing bacteria
from manufacturing proteins
The first antibiotic
1928 – discovered by accident Alexander Fleming in
St. Mary's Hospital, London (UK)
He received the Nobel Prize in Medicine in 1945 along
with his two colleagues
The first antibiotic
 Fleming noticed that the mould
was releasing a substance that
was inhibiting bacterial growth
and lysing (killing) the bacteria.
 Grew a pure culture of the
mould and discovered that it
was a Penicillium mould, now
known to be Penicillium
chrysogenum.
‘Age of Antibiotics’
 Since the 1940s researchers have
identified more then 2500 naturally
occurring antibiotics that can be used
to treat infections
 However, over the 50 years since,
many disease-causing bacteria have
become slowly resistant to the
antibiotics
Antibiotic resistance
Initially when a antibiotic is introduced into
a system… it kills off the weaker strains of
bacteria
This leaves behind the strong strains
These strong strains have slight variations
within their genetic material which
allow then to survive the antibiotic
These strong bacteria reproduce to pass on
their strong fighting ability
Antibiotic use in animals
 A large percentage of antibiotics
produced are used in livestock
production in 3 ways…
Therapeutic doses to treat disease
Preventative doses to reduce risk of
disease or death during production
Low dose added to feed to promote
growth
Non-therapeutic use of
antibiotics in farm animals is a
good or bad thing?
Take 5 minutes and
discuss with the person
beside you whether it’s
a good or bad thing to
add antibiotic to
livestock feed
Think about… production rates, consumer thoughts, price of meat
at the store, health of animals
YouTube
“Super Bugs – Bacterial Drug Resistance”
“Thom and the Super Bugs” - funny
What do you guys think?