Antimicrobials Flashcards
What are antimicrobials
Drugs that kill or inhibit the growth of micro-organisms
What are examples of antimicrobials
Antibiotics Antiviral drugs Anti fungal drugs Anti protozoa Anti parasitc drugs
What are sites to where of groups of antibiotics can work
Bacterial cell wall and membrane
Nucleic acid synthesis
Protein synthesis
What types of antibiotics target the bacterial cell wall and and membrane
Penicillins Cephalosporins Carbapenems Monobactams Glycopeptides Polymxins
Which type of antibiotics target nucleic acid synthesis
Folate antagonists
Dna gyrase: Quinolones
Rna polymerase: rifmycins
Which type of antibiotics target protein synthesis
50s subunit:
- macrolides
- lincomycins
- oxozolidiones
- chroamphenicol
30s subunit:
- tetracylines
- aminoglycosides
Which type of bacteria lack a membrane
Gram positive bacteria
Which type of bacteria have a membrane
Gram negative
How do antibiotics inhibit the cell wall synthesis i.e target the cell wall and membrane
By creating beta lactam rings
Which antibitoics are beta lactam antibiotics
Penicillin
Chephalosporins
Carpanenems
Monobactams
What does glycopeptide target
target gram positive organism
What are examples of folate synthesis inhibitors
Sulfonamides
Trimethoprim
What do sulfonamide target in folate synthesis
PABA (structural analogues) so they compete
What are trimethoprim
Strucutrual analogues of folate so they compete with it
Is trimethoprim and sulfonamide safe in pregnancy
No because babies require folate
How can we measure the effectiveness of antibiotics
In vitro
In vivo
What is the minimum inhibitory concentration
The minimum in vitro concentration which an antibiotic can inhibit growth
What is the minum bactericidal concentration
The minimum in vitro concentration which an antibiotic can kill bacteria
How can we measure in vitro antibiotic effectiveness
By looking at:
Minimum inhibitory concentration
Minimum bactericidal concentration
How can we detect resistance mutation
By PCR
What do we need to consider in invivo effectiveness
Pharmacokinetics Pharmacodynamics Drug interaction Foreign material Source control Host immune response
What are the factors in pharmokinetics
Absorption
Distribution
Metabolism
Excretion
(ADME)
What is distribution
The volume of distribution that relates to the concentration of drug in blood relative to the dose given
Where does metabolism of drugs occur
in the liver
Where are the sites of excretion
Renal excretion
Biliary or gut
What is a small volume of distribution due to
Durg being plasma bound
What is a large volume of distribution due to
Fat soluble drug
What is antimicrobial resistance
The ability of the microbe to resist the effects of medication that once could successfully treat the microbe
What are the mechanism of antimicrobial resistance
- Production of enzymes
- Changes to target sites or metabolic pathways
- Efflux pumps
What are the 3 main pathogens restant
MRSA
VRE
ESBL
What are examples of production of enzymes for antimicrobial resistance
Beta lactam enzymes can be produced which hydrolyse beta lactam molcule so the antibiotics cant work
How can we stop production of beta lactam enzyme
Give decoy substrates that bind to the enzyme
What are the ways in having changes to target sites of metbolic pathways
Mutation to stop binding of beta lactams Methylation of rRNA Mutations in the gene for DNA gyrase Mutation in porin channles Use of exogenous thymidine or thymidine for DNA synthesis
How do efflux pumps cause antimicrobial resistance
Efflux pumps pump out the antibiotic from the bacterial cell via porins
What are the 4 main drug immune mediated reactions
Type 1
Type 2
Type 3
Type 4
What is type 1 immune mediated reactions
Ige mediated response
What is type 2 immune mediated reactions
Cytotoxic production resulting in drug induced haemolysis
What are type 3 immune mediated reactions
Immune complexes resultsin in serum sickness like (fever, rash, arthralgia) reactions after several days
What is type 4 immune mediated reaction
Delayed hypersensitivity
What does type 1 immune mediated response cause
Urticaria, angioedema, or anaphalyaxis reaction
Which antibiotics are safe in pregnancy
Penicillins Cephalosporins Clindamycin Glycopeptides Metronidazole
