Pharm - Penicillins & cell wall synth gen concepts Flashcards by amanda kastel

name 3 glycopeptide antibiotics

are they beta lactams?

not beta lactams

vancomycin
telavancin
dalbavancin

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name 4 “miscellaneous” AB’s

daptomycin
fosfomycin
bacitracin
polymyxin

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name 3 “classes” of penicillins

G and V

B-lactamase resistant penicillins

extended spectrum penicillins

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name 3 “extended spectrum” penicillins

amino, carboxy, ureido

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name 5 beta lactam classes

penicillins
cephalosporins
monobactams
carbapenems
B-lactamase inhibitors

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differentiate between gram positive and gram negative cell walls as far as peptidoglycan

gram positive has MANY more layers of peptidoglycan than gram negative

in gram negative, peptidoglycan layer is very thin

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in gram positive cell walls, what binds the many layers of peptidoglycan together?

lipoteichoic acid

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where is the penicillin binding protein located in bacteria?
is it in gram positive, gram negaitve, both?

on the cell membrane

in both gram pos and neg

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which has porin channels and what do these do?
(gram pos or neg)

gram neg

controls entry into the bacteria

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which can antibiotics enter more easily and why - gram positive or gram negative bacteria?

gram positive is easier to enter

it’s more porous

gram negative has a DOUBLE phospholipid membrane (outer and inner)

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which has LPS - gram positive or negative

gram negative

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compare the location of beta lactamases between gram pos vs gram neg

gram pos - outside the peptidoglycan layers

gram neg - most in the periplasmic space (btwn the 2 membranes) and some also in periplasmic space but trapped within the lipoproteins. –NOT outside the bacteria like in gram positive

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peptidoglycan is composed of….

sugar + amino acids (peptides)

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what enzyme do beta lactams like penicillins and cephalosporins block

transpeptidase - AKA PBP (penicillin binding protein)

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explain what transpeptidase does
explain specific for staph aureus

enzyme involved in synthesizing cell wall peptidoglycan

forms a peptide cross bridge between 2 glycopeptide polymers via amino acid side chains. Specifically, in staph aureus, the bridge is (Gly)5-D-Ala between lysines. removes the last (5th) alanine and fuses the 4th onto the glycine of the other glycopeptide monomer

this reaction happens millions of times to form the cell wall

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what is NAM

N-acetylmuramic acid

single sugar monomer (glycopeptide) that, along with NAG (N-acetyl glucosamine) forms the backbone for peptidoglycan

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NAG + NAM are attached to….

a penta peptide (5 amino acids)

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what are the terminal 2 amino acids in the glycopeptide polymer

D-ala D-ala

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for cell wall synthesis to occur, it’s very important for PBP to bind…..

D-ala D-ala

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explain the 3 “stages” of peptidoglycan/cell wall synthesis

Make everything within the bacteria. racemierize and condense L-Ala to D-Ala with D-alanyl-D-alanine synthase
Tranport outside of the membrane to start forming crossbridge
Transglycosylation (fuse sugars) and transpeptidation (fuse amino acids) by PBP

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what does D-alanyl-D-alanine synthase do and what inhibits it

racemerizes and condenses L-Ala into D-ala

inhibited by D-cycloserine (a medication)

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Name 2 rings within penicillin

name 2 enzymes and their sites that can break down penicillin - RESISTANCE

4-membered beta lactam ring is fused to a thiazoline ring

beta lactam ring broken down by penicillinase/b lactamase

amidase is an enzyme that can destroy amide bond (O=C-N)
CN bond broken

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penicillins and other beta lactams structurally resemble what?

D-alanyl D-alanine

(D-ala D-ala)

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explain the MOA of penicillin

IRREVERSIBLY binds and inhibits PBP (transpeptidase enzyme) which forms a highly unstable penicilloyl-enzyme intermediate

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true or false penicillin reversibly binds PBP

FALSE irreversibly with covalent bond

what does penicillin compete with

D-ala D-ala for PBP

true or false all the beta lactams have the same MOA as penicillin

true

What penicillins CANNOT be hydrolyzed by staph beta lactamases? are they active against MRSA?

antistaphylococcal penicillins like methicillin, nafcillin, oxacillin, and cloxacillin NOT active against MRSA still

Penicillin V vs Penicillin G

Penicillin V given orally Penicillin G given IV

name 2 things that penicillins (ie: pen g) are NOT active against

gram negative rods and staph aureus (resistance!! - b lactamases)

name what regular penicillins (like pen g) are active against

gram positives and gram negative cocci NON-b-lactamase producing anaerobes

name 3 things that antistaphylococcal penicllins are active against

staphylococci (NOT MRSA) streptococci s. epidermis

true or false penicillin G is active against staph

FALSE - staph is resistant through B-lactamases only the antistaphylococcal penicillins are active against staph - BUT STILL NOT MRSA

name some things that antistaphylococcal penicillins are NOT active against

MRSA enterococci anaerobic gram negatives

what are extended spectrum penicillins

like penicillin, but better against gram negatives - wider spectrum

true or false extended spectrum penicillins are NOT active against staph

true get hydrolyzed by beta lactamases

name 2 extended spectrum penicillins

aminopenicillins antipseudomonal penicillins

4 mechanisms of penicillin resistance what are the 2 main?

2 main: -inactivation by B lactamases -modification of target PBP's other 2: -impaired penetration of the drug to target BPB (only gram - through porin channels) -antibiotic efflux

name 2 ways that PBP is modified to give resistance

major - staph aureus modifies to PBP2a so penicillin can't bind other - pneumococcal and enterococci do same

**penicillinase acts on....

B lactam ring - breaks it

the penicillins differ in their ___ and ____

acid stability and protein binding

which 4 penicillins are acid-stable? what does this say about their route of administration?

Penicillin V dicloxacillin ampicillin amoxicillin given orally and relatively well absorbed

oral penicillins should be administered how in regard to food?

1-2 hours before or after a meal

which penicillin is usually given IV

Pen G could also be given IM but it's irritating and painful

true or false penicillins are highly plasma protein (albumin) bound

TRUE can displace other things

explain the distribution of penicillins

not well distributed to eyes and prostate and CNS

how is penicillin mainly excreted and why is this important

UNCHANGED (not lot of metabolism) in the kidneys therefore, renal function is important consideration

route nafcillin and class

IV anti-staphylococcal

route oxacillin and class

IV anti-staphylococcal

route and class cloxacillin

PO anti-staphylococcal

route and class dicloxacin

PO anti-staphylococcal

route penV

oral

route and class amoxicillin

PO extended-spectrum penicillin (same as augmentin)

route and class pipercillin

IV extended spectrum penicillin

route and class ticarcillin

IV extended spectrum penicillin

as mentioned, penicillins are weakly distributed to the CNS. Therefore, can they be used for meningitis

they actually can - bc in meningitis the meninges are kind of "leaky" so they can still get in

name 2 IM penicillin injections and rationalize the ingredients

benzathine penicillin - benzathine is a stabilizer for IM injection procaine penicillin G - procaine is anesthetic for IM injection to help with the pain DEPOT

benzathine penicillin and procaine penicillin G is effective treatment for....

B-hemolytic streptococcal pharyngitis (STREP THROAT)

penicillin is synergistic with which 2 drugs

gentamicin and tobramycin

_______ is really only indicated for minor infections (like simple respiratory inf or minor SSTI) because of relatively poor bioavailability

penicillin V

name 3 anti-staphylococcal penicillins which strain are they specifically used to treat

nafcillin cloxacillin dicloxicillin ONLY MSSA penicillinase-producing staphylococci - they are resistant to the B lactamase they produce and can survive

as mentioned, nafcillin, cloxacillin, and dicloxacillin can be used to treat MSSA and penicillinase producing staphylococci name their routes of administration as a recap

nafcillin - IV cloxacillin and dicloxacillin - PO

name the aminopenicillins and their general common feature which is better absorbed? how do their spectrums of activity differ?

ampicillin and amoxicillin they are stable orally!!!! amox is better orally absorbed both have similar spectrum

explain what kind of infections amox/ampicillin can and CANT be used for

can - UTI, lowerrespiratory tract, sinusitis, otitis, meningitis, speticemia NOT - for common nosocomial infections like pseudomonas, enterobacter, and klebsiella

what is calvulanic acid

beta lactamase inhibitor often combined with amoxicillin

chemical name for the "extended spectrum" penicillins

carboxypenicillins AND ureidopenicillins

example of ureidopenicillin and route administration

pipercillin IM/IV

what can pipercillin be combined with

a beta lactamase inhibitor to increase activity ie- TAZOBACTAM, sulbactam, clavulanic acid

explain what pipercillin is active against

lot of gram negatives MAINLY - PSEUDOMONAS (NOSOCOMIAL) and klebesiella

anti-pseudomonial penicillins

extended spectrum carboxy penicillins - like ticarcillin ureido penicillins - like pipercillin

name a carboxypencillin as well as route administration

ticercillin IV/IM

ticarcillin is given in combo with.....

clavulanate

briefly explain what ticarcillin can be used for

more serious infections - like bacteremia, pseudomonas, bone and joint infections, SSTI, UTI, gynecologic infections, intra-abdominal infections, lower resp

carboxypenicillins are NOT used for ___ and ___

gram positive cocci and listeria

can ampicillin be combined with a beta lactamase inhibitor

YES

side effects penicillin

well tolerated generally obviously - risk of hypersensitivity and anaphylaxis (less than 1%) which could progress to shock SEIZURES in renal failure pts -- only for high doses -- we must lower the dose for them!!!

HOW does penicillin cause hypersensitivity in some patients

the degradation products of penicillin like penicilloic acid and products of alkaline hydrolysis bind the host protein

which penicillin can cause neutropenia

nafcillin

which penicillin can cause interstitial nephritis

methicillin

which penicillin can cause hepatitis

oxacillin

NVD from penicillins is most common when

either broad spectrum or high doses -- killing all the good

_____- can cause pseudomembranous colitis and vaginal candidiasis

ampicillin

3 DDIS of PEN G and PEN V

decrease effectiveness oral contraceptives probenecid increases plasma levels colestipol decreases PEN V (oral) absorption

are penicillins bactericidal or static

CIDAL

Pharm - Penicillins & cell wall synth gen concepts Flashcards

(85 cards)