{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

antibiotics - A a Keyplayers 2 PaulErlich a . nothumans B a...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Antibiotics and Resistance a. Key players 2. Paul Erlich- a. Wanted to find a “magic bullet”.  – Wanted to find something that would kill microbes and  not humans. B. a. Salvarsan-first microbial agent  – an arsenical containing compound which was effective  against syphilis. First chemotherapeutic agent 2. Alexander Fleming-discovered the first antibiotic (penicillin) in 1928. Naturally  occurring substance produced by fungus or other microbes  ( http://microblogology.com/blog/?p=13 ) a. Chain and Florey-followed through on Fleming’s findings to isolate and produce penicillin. a. Terms 3. Selective toxicity  – antibiotics cause greater harm to microorganisms than to human  host – Generally by interfering with biological structures or biochemical processes  common to bacteria but not to humans 4. Theraputic index-  Toxicity of drug is expressed as therapeutic index – lowest dose  toxic to patient divided by dose typically used for treatment – High therapeutic index  = less toxic to patient 5. Half-life  – rate of elimination of drug from body expressed in half-life – time it takes  for the body to eliminate one half the original dose in serum – Half-life dictates  frequency of dosage 6. Drug combinations can result in: a. Antagonistic effects b. Synergistic effects c. Additive effects
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
7. Innate or intrinsic resistance a. Mechanisms of action(Fig. 21.2) Differing antibiotics target different  components of microbes.  1.  Cell wall synthesis:  All of these antibiotics act by disrupting peptidoglycan synthesis in bacterial cell wall, therefore weakening cell wall. a. β lactam drugs (Table 21.1, Fig. 21.3, Fig.21.5, Fig. 21.6)- active against growing/dividing microorganisms . They bind and inactivate the transpeptidases used to create the peptidoglycan wall – The functional structure in penicillin that causes it to work. (transpeptidases are also called penicillin binding proteins) b. All have a β lactam ring structure ( Fig. 21.4).
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}