16. Bactericidal Antibiotics Flashcards
Which are the bactericide antibiotics? (4)
- BETALACTAMS
- AMINOGLYCOSIDES
- QUINOLONES
- GLYCOPEPTIDES
What defines betalactams?
beta lactam ring
What is the therapuetic index of beta lactams?
wide: very safe
What is the toxicity of beta lactams?
low
What are the side effects of beta lactams? (4)
digestive system (most common orally):
- nausea
- vomiting
- ab pain
- dyspepsia
Teratogenicity with beta lactams?
none
MOA of beta lactams? (2)
inhibit bacterial cell wall synthesis:
-inhibit transpeptidase activity of penicilin binding protiends (PBP)
What drugs are betalactams?
- penicillins
- cephalosporins
- monobactams
- carbapenems
- clavulanic acid
What is PBP? (2)
penicilin binding protein
-enz involved in synthesis of bacterial wall
What is the mechanism of action for resistence for bacteria against betalactams? (3)
- INACTIVATION of the ANTIBIOTIC: producing BETA-LACTAMASES to bind to beta- lactams
- REDUCE UPTAKE INTO THE CELL: loss/modification of porins and pumps of influx or active efflux from the cells
- ALTERATION OF THE TARGET ENZYME: they produce enzymes (mutated PBP) with less affinity for beta-lactams
What can you do to a bacteria that starts producing beta lactamase inhibitors?
Prescribe beta lactamase inhibitors so that the antibiotic will work again
ex. clavulanic acid
How are betalactams administered? (2)
orally
parenterally
Do betalactams cross BBB?
yes
Distribution of betalactams?
good/wide distribution
Betalactams cross placenta?
yes but still safe
Betalactam metabolism?
remain active until eliminated
Beta lactam elimination?
renal
Betalactam short term adverse effects?
- hypersensitivity reactions (urticaria, angioedema)
- anaphylactic shock: bronchospasm, severe dyspneoa
- GI intolerance: oral candida, diarrhea, nausea, vomit
Betalactam long term adverse effects?
Less frequent
- Hematologic: fever, eosinophilia, haemolytic anaemia
- Renal toxicity: Renal failure
What is angioedema?
swelling (usually localized) of the subcutaneous tissues due to increased vascular permeability and extravasation of intravascular fluid.
What mediates angioedema? (2)
Mast cell derived mediators (eg, histamine, leukotrienes, prostaglandins)
Bradykinin and complement-derived mediators
Who discovered pencilin?
Alexander fleming
The most commonly used betalactam antibiotics?
penicillins
What did alexander fleming find?
- penicilin
- substance released by Penicillum fungi inhibits S.aureus
How do bacteria defend themselves against penicillin?
penicillinase production (betalactamase)
What are the types of penicillins? (5)
- natural penicillins
- resistant to penicilinases
- aminopenicillins
- antipseduomonas (broad spectrum parenteral )
- betalactamase inhibitors
What are the natural penicillins? (4)
PENICILLIN G (IM, IV) PENICILLIN G PROCAINE (IM) ---long effect 4-5 days. PENICILLIN G BENZATHINE (IM)---long effect 26 days. PENICILLIN V (ORAL)---Resistant to acid degradation.
Natural penicillins work against which bacteria? (3)
- gram + cocci (EXCEPT S. aureus)
- gram + bacillus
What are the penicillinase resistant drugs? (2)
- CLOXACILLIN (ORAL, PARENTERAL)
- METHICILLIN
Penicillinase resistant drugs work against which bacteria?
staphylococcus
What are the aminopenicillins drugs?
- amoxicillin
- ampicillin
aminopenicillins drugs work against which bacteria? (@)
- GRAM + COCCI ( EXCEPT S. aureus)
- GRAM BACILLUS (EXCEPT Pseudomona)
What are the antipseudomonas drugs also called?
Broad spectrum penicillins
What are the antipseudomonas drugs? (2)
- piperacillin
- ticarillin
Antipseudomonal drugs work again which types of bacteria?
Gram negative bacillus
What are the betalactamase inhibitor drugs? (3)
- Clavulanic aicd
- Sulbactam
- tazobactam
Indications of penicillin? (8)
Respiratory infections:
- pharyngitis
- otitis
- bronchitis in COPD
Skin and Soft tissue infections:
- cellulitis
- erysipelas
Bone and joint infections
STDs
Endocarditis
What bacteria causes pharyngitis?
Streptococcus pyogenes
How do you treat pharyngitis? (2)
Penicillin G or amoxicillin
What bacteria causes otitis?
- Streptococcus pneumoniae
- H. influenzae
- produce betalactamases
How do you treat otitis?
amoxicillin-clavulanic acid
What bacteria causes bronchitis in COPD? (2)
- Streptococcus pneumoniae
- H. influenzae
- produce betalactamases
How do you treat bronchitis in COPD?
amoxicillin-clavulanic acid
What bacteria causes cellulitis?
Streptococcus pyogenes
What bacterial causes erysipelas?
S. aureus
How do you treat cellulitis?
amoxicillin
How do you treat erysipelas? (2)
- amoxicillin-clavulanic
- cloxacillin
What bacteria causes bone and joint inflammation?
S. aureus
What bacteria causes STDs? (2)
gonorrhea and syphilis
What bacteria causes causes endocarditis? (3)
-Streptococcus viridans
-Staphylococcus
aureus
-Enterococcus
How do you treat bone and joint infections? (2)
Cloxacillin+ Gentamicin
How do you treat STDs?
penicillin G
How do you treat endocarditis? (4)
-Streptococcus viridans = amoxicillin
-Staphylococcus
aureus = cloxacillin
-Enterococcus = Ampicillin+Gentamicin
Which specific bacteria is rsponsible for more than 50% of endocarditis?
streptococcus viridans
