Download Alexandre Apfel and Tudor Gradinariu with additions by Ms. S. Smith

Antibacterials
By: Alexandre Apfel and Tudor
Gradinariu with additions by Ms. S.
Smith
Overview: Bio-agents
 Two main types

Bacteria
 Living
microorganisms that invade the body
and cause infection.

Viruses
 Non-cellular
infectious particles that
reproduce within a host cell.
Pictures of disease-causing
bacteria!
Tuberculosis
Tetanus
Cholera
Basic Penicillin Facts
 Over 50 types of penicillin
 Either natural or semisynthetic
Penicillin G – Natural
Ampicillin – Semisynthetic
• Semisynthetics tend to kill bacteria more
efficiently than naturals
Development of Penicillin
(D.6.1)
 1890s – noticed some fungi killed
bacteria
 Alexander Fleming – 1928
 Working with staphylococcus aureus
 Found mold, but no bacteria
 Concluded penicillium notatum, inhibited
growth of bacteria, but abandoned
further experimentation because it was
hard to isolate the mold.
Development of Penicillin
(D.6.1) cont’d
 Florey and Chain – 1940
 Injected mice with deadly bacteria
 Mouse + penicillin = still alive
 1941a policeman with a shaving
infection treated favorably
 1945 sufficient supply for anyone who
needed it
 Fleming, Florey & Chain received a
Nobel Prize in 1945
How Penicillin Works (D.6.2)
 Bacteria cell walls mainly composed of
polysaccharides
 Cross-links connect the various layers
 Penicillin interferes with cross-link
creation and maintenance
 Penicillin + Bacteria =
How Penicillin Works (D.6.2)
cont’d
 Animals do not have cell walls, so
penicillin is not harmful to humans/other
animals
 Thus, bactericidal drug
Structure of Penicillins (D.6.2)
 Common structure in
all penicillins –
6-aminopenicillanic
acid
 deactivated by
stomach acid
 add a side chain to
make it acid-resistant
6-aminopenicillanic acid
Side Chain
Penicillin G
Modifying the Side Chain (D.6.2)
 Bacteria can produce
penicillinase, enzyme
which deactivates
the penicillin\
 Modifying the side
chain increases
resistance to enzyme
The Possibilities Are Endless!
 Cefamandole nafate
 Cefazolin sodium salt
 Ceftriaxone disodium salt
hemi(heptahydrate)
Broad Spectrum Antibiotics
(D.6.2)
 Effective against many kinds of bacteria
 Examples:


Ampicillin
Tetracyclines (Aureomycin & Terramycin)
 Often kill harmless as well as harmful
bacteria, including stomach
 Used in treatment to relieve any
significant discomfort
Narrow Spectrum Antibiotics
(D.6.2)
 Effective against specific types of
bacteria
 Examples:

Most penicillins
 May be applied after broad spectrum
antibiotics to target the particular
bacterium
Penicillin Overprescription
(D.6.3)
 Penicillin is usually safe
 10% of population is allergic - side effects
include fever … rash… shock… death…
 allergy may develop over time
 can wipe out harmless/helpful bacteria in
digestive tracts, which can be replaced by
harmful bacteria
 can lead to resistances in bacteria from
originally vulnerable strains (i.e. gonorrhoea,
TB, typhoid)
Penicillin Patient Compliance
(D.6.3)
 Important to take antibiotics as directed… a full
course… so as to not have ‘wasted’ the use of
the antibiotic
 If at all possible, avoid taking antibiotics –
unless it is the only course of action
 What might be a problem with overuse of
antibacterial soaps?
Penicillin in Animal Feed (D.6.3)
 Used to reduce disease and promote
growth in livestock
 Again, drug-resistant strains develop,
which transfer from animals to humans
 Increased concerns have created a
growing “Green” movement for animal
products using fewer to no anti-biotics