Antibiotics Flashcards
(49 cards)
Difference between Antimicrobials and Antibiotics
Antimicrobials are drugs that act on microorganisms
Antibiotics are Antimicrobials derived from micro organisms
What/where are the microbacterial sites of action
Cell wall- Beta lactams, Glycopeptides
DNA synthesis- Quinolone, Rifampicin, Sulphonamides (via folate)
Protein synthesis- Microlides, Aminoglycopeptides, Tetracyclines
Mechanisms of Antimicrobial Resistance
-Bacterium or the species has always been resistance to the antimicrobial so it can’t get in e.g. gram negative bacilli such as Pseudomonas
-Antimicrobials are degraded by enzyme produced by the micro organisms as soon as they enter eg beta lactams, aminoglycoside enzymes
-Mutation in the target site of antimicrobial(drug gets in by can’t bind to its receptor because it’s altered) eg Quinolones, Macrolides, Penicillin binding proteins)
How does Resistance arise
Intrinsic eg Enterococci and cephalosporins
Mutation resipulting in altered binding side
Transferable DNA (usually due to exposure to antimmicrobials) plasmids and transposons
Which organism or micro bacteria is resistant to every antibiotic in South Africa
Ace inhibitor Baxter
Which antimicrobials are concentration dependent
Aminoglycosides
Quinolones
Which antimicrobials are time dependant
Beta Lactams
Glycopeptides
Indications for antimicrobial infections
Reduce infection in those immunocompromised
Prevent surgical infections
Prevent disease in close contact (meningococcal)
Prevent endocarditis in valvular heart disease
Prevent recurrent of rheumatic fever
4 different classes of Beta lactams
Penicillin
Cephalosporins
Lavlanic acid
Carbapenem
Explain the Mechanism of action of beta lactams
Inhibit formation of peptidoglycan crosslinks, hindering bacterial cell wall synthesis
Which classes of drugs have hypersensitivity type 1 as main adverse effect
Beta lactams
How long does long acting injectable benzathine penicillin last for
21 days
What can benzathine penicillin be used to treat ? (3)
Strep tonsillar pharyngitis
rheumatic fever
syphilis
Which penicillin is only useful in IV
Ampicillin
Which penicillin is well absorbed when taken orally
Amoxicillin
2 types of aminopenicillins and how are they administered
Ampicillin - IV
Amoxicillin- orally
Which penicillins are for gram positive bacteria
Penicillin 1 : benzathine penicillin
Drugs for staph aureus, syphilis, enterococci, Listeria, Actinomyces
Which penicillins are for gram negative bacteria
Penicillins 2 : Aminopenicillins: ampicillin and amoxicillin
Penicillin 3 : Cloxacillin, flucloxacillin(orally)
What is the commonest cause of resistance in beta lactams
Production of enzyme beta lactamases by bacteria
Beta lactamases inhibitors (developed to assist beta lactams by inhibiting the enzyme that acts against them) are beta lactam drugs that bind covalently to the active site of beta lactamases rendering the enzyme inactive
Irreversible inhibitors of beta lactamases by:
Clavulanate
Tazobactam
Combined with beta lactams, can reverse resistance,
Amoxicillin-clavulanate (coamoxiclav)
Which class of drugs is ceftriaxone
3rd generation cephalosporins
( good CSF penetration)
Which class of drug is cefazolin and how is it administered
1st generation cephalosporins, IV
Where is cefazolin used
Used at Induction for surgical prophylaxis
Which drug to prescribe for bacterial meningitis
Ceftriaxone IV/IMI
Drug of choice for gonorrhoea
Ceftriaxone
