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! Tetanus Tuberculosis 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 Penicillin G Side Chain

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