Antibacterials

1. Antibacterials By: AlexandreApfel and Tudor Gradinariu with additions by Ms. S. Smith

2. 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.

3. Pictures of disease-causing bacteria! Tuberculosis Tetanus Cholera

4. 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

5. 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 penicilliumnotatum, inhibited growth of bacteria, but abandoned further experimentation because it was hardto isolate the mold.

6. 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

7. 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 =

8. POP~!

9. 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

10. 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

11. Modifying the Side Chain (D.6.2) • Bacteria can produce penicillinase, enzyme which deactivates the penicillin\ • Modifying the side chain increases resistance to enzyme

12. The Possibilities Are Endless! • Cefamandole nafate • Cefazolin sodium salt • Ceftriaxone disodium salt hemi(heptahydrate)

13. 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

14. 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

15. 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)

16. 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?

17. 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