Antibiotics Flashcards Preview

Tom > Antibiotics > Flashcards

Flashcards in Antibiotics Deck (34):
1

Beta-Lactams

Inhibits cell wall CROSSLINKING (synthesis): Penicillins, Cephalosporins, Monobactams, Carbapenems

DOES THIS BY IRREVERSIBLY BINDING TRANSPEPIDASES (Penicillin Binding Proteins) PREVENTING CROSSLINKING

Restance occurs via beta-lactamases (degrades lactams) and by mutating Penicllin binding proteins so drugs no longer have affinity to PCPs

Vanco (glycopeptide) actually binds the D-ALA D-ALA parts of the cell.

2

Penicillin, Methicillin, Oxacillin

When do you use Naficillin?

D-ala-D-ala peptidoglycan side chain, inhibiting transpeptidase from forming crosslinks

Resistance develops vai lactamase expression.  Counter with lactamase inhibitor

"Use Naf for staph" aures (not MRSA tho)

3

Ampicillin kills?

"HELPSS" kill enterococci

H Flu, E coli, Listeria monocytogenes, Proteus, Salmonella, Shigella

4

Piperacillin

Combo with Tazobactam (b-lactamase)

Used specifically for Psuedomonas A.

Efficacy against G+, G-, and Anaerobes (psuedo is an aerobe than can also be a faculative anaerobe--grows very well in low/no O2)

5

Clavulanic Acid

Beta Lactmase Inhibitor.  Given with Beta lactams to increase their half lives as well to be used in bacteria expressing beta-lactamases.

6

Monobactams

Beta-lactams that only have one ring.  Less likely to act as haptens thus they are good to use in G- infections in ppl w/ Pencillin allergies.

Aztreonam

7

Cephalosporins

Cef's cover?

Cef's don't cover?

Beta Lactams: Prefix: Cefs;

Increased resistance to beta-lactamases

Cover (2nd gen): HEN PEcKS (H flu, Enterobacter, Neisseria, Proteus, E coli, Kleb, Serratia)

Don't Cover: "LAME" Listeria, Atypicals (chlamy, Mycoplasma), MRSA, Enterococci

Worsen Nephrotoxicity of Aminoglycocides

4th Generation best for Psuedomonas (Cefepime)

8

Carbapenems (Imipenem)

Beta-lactam, Big Gun used in ICUs

ALWAYS ADMINISTERED WITH Cilastatin**** (decreases renal tubular inactivation by inhibiting renal dehydropeptidase I)

Binds PBP's like cillins.

Last Resort used for highly resistant organisms (klebseilla, serratia (red ring on toilet), enterobacter) because of GI/Seizure SEs

9

Vancomycin

Glycopeptides, G+: Inhibits elongation via D-ala D-ala binding.

Enterococci have resistance by switching to D-ala-D-lactose, which can be horizontally transfered to Staph Aur via VRE plasmid

"GlycoPeptide works like Penicillin"

 

10

Bacitracin

Glycopeptide, G+,  inhibits NAG-NAM tranpsort to outer wall

11

Protein Synthesis Inhbitors

  • Aminoglycosides--Targets 30s portion of Ribosome
  • Tetracycline/Doxycycline--
  • Chloramphenicol
  • Macrolides
  • Lincosamides
  • Mupriocin

12

Aminoglycosides

Strepomycin, Gentamycin, Tobramycin, Amikacin, Neomycin (GANTS)

Anti-30s subunit of Ribo; post-antibiotic effect (activity persists beyond detectable amounts)

"Aminoglycosides=small protein sugars used to inhibit the smaller part of the ribo"

ACUTE RENAL FAILURE** (made worse by Cephalosporins)

"GANTS caNNOT kill anaerobes"

N-ephrotox, N-euromuscular blockade, O-totox, T-eratogen

13

Tetracycline/Doxycycline

Competes with tRNA for A site on 30s ("with tetracyclines the ribosome never has a chance to start cycling"--prevents initiation)

 

Active against G+/- and protozoa

Not for children dt deposition in teeth (grey) or bone (deformation)

"Vacum the bedroom" Vibrio, Acne, chlamydia, Ureaplasma, Mycoplasma, Tuleramia, H Pylori, Borrellia, Rickettsia"

14

Chloramphenicol

Binds 50s inhibiting translocation of ribosome

Protein synth inhibitor

15

Macrolides

Erythromycin, Azithromycin (Z-pak)

Binds 50s subunit inhibiting translocation "macrolides stop the ribo slide"

Risk of Prolonged QT**** ("z prolongs the qt")

Erythro: also has GI/Liver (p450) issues

"MACRO": Motility (GI) issues, Arrthymias (Qt), Cholestatic hepatitis, Rash, eOsinophillia

"Atypical PUS: Atyipical Pneumonia (myco and legionella), URI, STDs"

16

Clindamycin

Protien synth inhibitor; binds to 23s portion of the 50s ribo subunit, causing premature tRNA dissociation

Lincosamide class: Used for skin and soft tissue infections: SE-->pseudomembranous colitis

"Clinda causes premature ejac" of the ribosome

ANAEROBIC INFECTIONS (aspiration pneumonia, lung abscesses, MRSA)

CAUSES C. DIFF INFECTION

17

Mupirocin

Protein Synth Inhibitor

Blocking protein synth via Inhibits isoleucyl tRNA synthase

Used for S. Aureus skin infections

18

Purine Synthesis Inhibitors

  • DHF reductase inhibitors
  • Suflonamides

19

Trimethoprim

DHF Reductase Inhibitors (methotrexate also hits DHFR)

Synergizes: TMP-SMZ

"TMP" Treats Marrow Poorly (megaloblastic anemia, leukopenia, granulocytopenia)

20

Sulfonamides

Analog of PABA blocking PABA-->Dihydropteroate synthase inhibitors (bacteria need to make folate since they cannot absorb it)

Synergizes: TMP-SMZ (Bactrim)

Hypersensitivity reactions, Hemolysis (G6PD def), nephrotox, photosensitivity, Kernicertus (thus dont use in Preggers), Stevens Johnson Syndrome

21

Flouoroquinolones

-floxacins (cipro, gemi, levo)

inhbitis DNA topoisomerase II (DNA GYRASE) "cipro-circular-gyrase"

UTIs from pseudomonas; prophylaxis for anthrax

Associated with ruptured tendons (damages cartilage), tendonitis (particularly achilles tendon) "Fluoroquinolones hurt attachments to your bones"

22

Metronidazole

Nitro group is released by bacterial metabolism and reacts with DNA

Flagyl, used for anaerobic bacteria nd protozoa

GET GAP on the Metro: Giardia, Entamoeba, Trichomona, Gardnerella, Anaerobic bacteria, h Pylori

DISULFIRAM LIKE REACTION W/ ETOH

23

Inhibitors of Cyp P450's

"PICK EGS"

Protease Inhibitors, Isoniazid, Cimetidine/Cipro, Ketonacozle, Erythromycin, Grape Fruit Juice, Sulfonamides

Acute ETOH is inhibitor (Chronic is inducer)

24

Inducers of Cyp P450's

BCG PQRS

Barbiturates, Carbamazepine, Grisesofluvin, Phenytoin, Quinidine, Rifampin, St. Johns Wort

Chronic ETOH=Inudcer (acute is inhibitor)

 

25

Daptomycin

Lipopeptide Antiobiotic.  Disrupts bacterial cell membrane leading to loss of membrane potential.  Also inhibits macromolecule synthesis

Good to use for very drug resistant bacteria.

Causes myopathy.

26

Linezolid

Inhibits the 23s portion of the 50s ribosomal subunit.

"draws a line btwn the 50s and 30s subunits"

Can be used in MRSA  VRE resistant infections

SEs: Optic Neuritis, and Thrombocytopenia; Weak MAO increasing risk for Serotonin syndrome

27

Isoniazid

Decreases synth of mycolic acids.

Bacterial catalase-peroxidase needed to activate INH.

Competes with Pyridoxine (B6) causing:

1) Neurotoxicity (decreased NT/GABA synth)

2) Hepatotoxicity (needed for transaminase Rxns)

"INH=Injures Neurons and Hepatocytes"

"B6 is RIPES" for TB

28

Rifampin

Inhibits DNA-dependent RNA polymerase ("crab claw")

Used for Tb and for menignococcal and H. Influ type B** prophylaxis

Minor Hepatotox and drug interactions ("AMPs P450"---Rifabutin does not), orange body fluids.

4R's of Rifampin: 1) RNA poly inhibtior 2) Ramps up P450, 3) Red/Orange body fluids, 4) Rapid resistance if used alone.

 

29

Pyrazinamide

SEs?

Hyperuricemia, hepatotoxicity

WORKS BEST AT LOW pH*** P-yrazinamide at low p-H (works intracellularly)

Increases Acidity of Macrophage phagolysosome increasing their killing.

"PyraziMIDE causes Tb to DIE INSIDE the macros"

30

Ethambutol

Inhibits Arabinosyltransferase decreasing carb polymerization of Mycobacterium. (resistance via increased arabinosyltransferase translation)

SEs: Optic neuropathy (red-green blindness) requiring periodic testing.

Etham hurts Eyes***

31

Vancomycin

Inhibits Cell wall peptidoglycan formation by binding D-ala D-ala.

SEs: "NOT" trouble free: N-ephrotoxicity, O-totoxicity, T-hrombophlebitits.

RED MAN SYNDROME: release of antihistiamines causing rapid flushing when administered (treat by slowling infusion and giving antihistamine)

Restance: D-ala D-ala to D-ala D-lac

Given as IV cuz of poor absorption unless you want to target C diff (then give orally)

32

Amphotericin B

Binds Ergosterol forming pores.
"Amphotericin tears holes in fungi, RBCs, heart, and kidneys"

Need to supplement AND MONITOR K and Na because of altered renal tubule permeability.  Risk for arrthymia (again Na/K issue).  Anemia

33

Tx for Anaerobic bacteria?

Metronidazole and Clindamycin

Aminoglycosides cannot kill anaerobes

34

As you increase in Cephalosporins what you do you do to the spectrum?

First gens good for which bacteria?

As you increase generation of cephalo's you INCREASE G- coverage and DECREASE G+ coverage.

PEcK: Proteus, Ecoli, Kleb