Cell Wall Synthesis Inhibitors Flashcards
Which Beta lactam drug has extended coverage of gram negative microbes and is often reserved for treating systemic klebsiella infections? A. penicillin G B. amoxicillin C. vancomycin D. piperacillin E. daptomycin
D?
Cell wall synthesis are (which is false) A. bactericidal B. Orally administered C. Cleared by the Kidneys D. Narrow or extended spectrum E. Inhibit mostly gram negative bacteria
E.
Fosfomycin
Non Beta lactam drug, works as a structural analog. SINGLE DOSE oral treatment for UTI (multiple doses cause resistance)
D-cycloserine
structural analog non-beta-lactam drug. Toxicity: serious CNS effects; dose related
Bacitracin
Topical application ONLY, poorly absorbed
Uses: skin and ophthalmologic infections. Good in combination with polymyxin B (membrane inhibitor) and aminoglycoside
Vancomycin
Blocks elongation and cross linking of Peptidoglycan. Bind to terminus.
Rapidly bactericidal for dividing bacterial cultures (exception: static in enterococci)
T or F: vacomycin is administered by IV only and used for gram positive microbes including most MRSA
True
T or F: Vancomycin causes Gray baby syndrome
F. vancomycin causes Red Man syndrome. Also causes ototoxicity and nephrotoxicity
T or F: Vancomycin is used for serious gram positive infections such as MRSA and penicillin resistant strep and is additive with aminoglycosides
F. they are synergistic with aminoglycosides.
What are the 4 classes of Beta-lactam antibiotics?
penicillins, cephalosporins, carbapenems, and monobactams
Beta lactams are bactericidal, are structural analogs, and are mostly used for gram positive aerobes. T or F?
True
What Beta lactams are metabolized? aka the exceptions:
nafcillin, imipenem. Both are metabolized in the kidneys
What is the primary resistance to B-lactam drugs?
microbes produce Beta Lactamases.
What is the main adverse effect of Beta lactam drugs?
Allergies; mostly delayed (as opposed to acute-anaphylactic shock or accelerated) and cause a mild, reversible rash
which is acid stable and given orally? Pen G or Pen A
Pen V. But Pen G achieves higher levels in the blood through IM injection. pen V needs 4 doses a day
What is the main target and Adverse effects for Penicillins (G and V)
Gram positive bacteria. Stevens-Johnson syndrome - rash, finger swelling, sores in the mouth, pain in the abdomen
what is the main use for penicillin?
non penicillinase producing microbes (strep pneumo, staph, Neisseria men., etc)
Penicillinase resistant Penicillin… Name one drug and the main uses.
Oxacillin and methicillin. Penicillinase producing staphylococci and streptococci (MRSA is resistant)
What destroys extended spectrum penicillins?. whats one way around this?
Beta lactamases. combine with beta-lactamase inhibitors.
what group does amoxicillin belong to? (in the extended spectrum penicillins)
Aminopenicillins. Uses include non lactamase gram negative bacilli including E. coli, H. influenza, Salmonell, Shigella and mixed infections
name the members of the extended spectrum penicillin groups carboxypenicillins and ureidopenicillins
carbenicillin and peperacillin. have same gram+ activity plus enhanced Gram - activity for Psudomonas and Klebsiella. Often combined with aminoglycoside and used for HIV and burn patients inected with pseuidomonas or Klebsiella
What drugs do you use for pseudomonas and klebsiella infections?
carbenicillin or piperacillin
Clavulanic acid is a…
B-lactamase inhibitor. Used with extended spectrum penicillins (synergistic) amoxicillin or piperacillin,and clavulanic acid.
These are structurally related to penicillins (have beta lactam rings) and as analogs of the penicillins they just soak up the beta lactamases.
Cephalosporins
inhibit cell synthesis. 4 generations based on spectra of activity. newer generations are better for gram negatives but have less gram+ microbes. Better penetration and more resistant to beta lactamases
Which is false for cephalosporins?
a. 2nd, 3rd, and 4th generation drugs are given IV or IM
b. Must be given carefully due to toxicity
c. cause Disulfiram-like reaction (antabuse effect)
d. can induce Amp C
B. They are actually very safe.
Antabuse effect-2nd and 3rd generations, headache, nausea, vomiting, vertigo, headache.
antibacterial resistance is caused by Amp C (induces own resistance)
2nd generation Cephalosporins
only group with significant activity against anaerobes
3rd generation cephalosporins
most widely used treatment in children and infants with moderate to severe infections
4th generation cephalosporins
high resistance to Beta Lactamases. useful for enterobacter and penicillin-resistant strep
What group has the broadest activity of all beta lactam drugs?
Carbapenems. Imipenem is usual drugs. NOT for MRSA or VRE
Imipenem
carbapenem that has renal metabolism and is inactivated. Must be used with cilastatin
cilastatin usage
used with imipenem to inhibit metabolism and inactivation by the kidney
Monobactam
aztronam. NO cross reactivity with penicillins (use in patients with penicillin allergies)
Aztreonam is limited to Gram negative aerobes ( perfect for pseudomonas)
true or false, aztreonam is used for gram negative aerobes as well as gram positive anaerobes
False. Aztreonam ( a monobactam beta lactam drug) is limited to gram negative aerobes like PSEUDOMONAS
Daptomycin
Cell membrane agent. causes transmembrane channels and membrane depolarization. Similar use to vancomycin but treats VREnterococcus and MRSA
