Chapter 20: Antimicrobial Agents Flashcards
What is the cell wall made up of
peptidoglycan (meurin)
what is the peptide portion of the cell wall made up of
- polypeptide
- tetra peptide (4 amino acid chains attached to NAH)
tetrapeptide
4 amino acid chain attatched to NAH
what makes up the backbone of the cell wall
glucose
- alternating NAM and NAG molecules
What are the antimicrobial agents that attack the bacteria cells wall
- Penicillin
- Cephaloporins
spectrum
how much bacteria you can attack
what are the two types of penicillin
- natural
- semisynthethic
How is Pen G natural penicilin administed
injection
Pen v penecillinis administered
orally
how does penicillin destroy bacteria
attacked the PG peptide in the cell wall, causing osmomtic lysis
adverse effects of penicillin
- development of allergies
- resistance
what is the nucleus in penicillin called
the B lactam ring
organsims that produces enzyme B lactamases
S aures
Cephalopsprins destroys bacteria by
attacking PG peptide in the cell wall causing osmotic lysis
Cephaloporins is used to treat
menigitis
what are the semi forms of cephalosporins
gen 1 –> gen 5
Cephalosporins disadvantages
- resistant to enzymes
- more expensive
Semisynthetic penicillin is used to treat
- methicillin (MRSA)
what are four examples of antimicrobial agents that attack protein synthesis
- Chloromphenicol
- Erythromycin
- Streptomycin
- Tetracycline
Chloramphemicol
- attacks protein synthesis of bacteria
-least expensive - penetrates tissues wall (BBB)
Chloraphenicol is the old treatment for
menigitis
Chloramphenicol can be made
- natural
- lab prep
Adverse effects of Chloramphenicol
- Aplamsic Anemia (supresses immune system)
- Causes “grey baby syndrome”
- attatched to the 50s unit of ribosomes (inhibits peptide bonds)
Erythromycin attaches to
the 50s subunit of ribosomes
- stops translations (inhibits movement of RNA; unable to read codon)
what is the alternate drug used for people with penicillin allergies
Erythromycin
what form does erythromyecin take
syrup form (easy to administer)
Erythromyicin is used to treat
Gram positive bacteria
Adverse effects of erythromyecin
- mild Gi sysmptoms (2-3%)
- broad spectrum
Streptomycin was discovered in
1944
Streptomycin was used to treat
TB
adverse effects of streptomycin
-resistance
- can cause deafness
- causes kidney failure
How does streptomycin destroy bacteria
Protein synthesis
- attaches to the 30s subunit (change shape of mRNA; mRNA is misread (abberent protein))
forms of tetracycline
- natural
- modified (deoxycycline (semi form))
tetracycline
- natural or modified
- broadest spectrum of activity
- Treats: STD
tetracycline applications
- given to animals in feed –> comes into the food chain –> resistance in human population
- trests: STD’s
Tetracycline Adverse Effects
- destroys the normal flora of the GI tract (causes sever diarrhea and superinfections from fungal agents)
- Dangerous in pregnancy
- mother: liver / kidney failure
- fetus: damage to bone structure of the skull (permanent) - damage to enamal (binds to ca)
- blocks docking site (attatches to 30s subunit)
Sulfa drugs
- inhibit follic acid synthesis (no DNA or RNA –> cell dies)
- competitive inhibitors
Adverse effects of Sulfa drugs
- used in the thrid trimester of pregnancy can cause server neurological damage
- causes juandice
- anemia
- allergies
Sulfa drugs and Trimethopin can be combined to treat
cytitis (UTI)
Trimethopin
- inhibit follic acid synthesis (no DNA or RNA –> cell dies)
trimethopin adverse effects
- juandice
- allergies
What antimicrobial agent attack the plasma membrane
Polmyxin B
What is polymyxin used to treat
Pseudomonanas
how does Polymyxin attack bacteria
cellular content leak out
Adverse effects / limitation of Polymyxin
- has to be applied topically (to the skin)
- used systemically ( toxin to the kidneys)
how do antiviral drugs destroy viruses
minic nucleotides
- form false neucleotides
what are false nucleotides made up of
nucleoside analog + P
what are the 5 antiviral drugs
- acycliovir
- lamivudine
- Ganciclour
- azzidothymine
- riboviron
Acyclovir
- glutamate
- treats hepres 2
- shuts down DNA synthesis
Lamivudine
Thymine
- treats Hep B, HIV
Ganciclour
Glutamate
- herepes 5 / CMV retinal (HIV)
Azzidothymine
- thymine
- HIV
Ribovirin
- Glutamate
- Influenza
