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Antibiotics
Drugs
30
Microbiology
Post-Graduate
12/03/2014

Additional Microbiology Flashcards

 


 

Cards

Term
Types of Cell Wall Synthesis Inhibitors
Definition

ß-Lactams

                                      - Penicillin

                                      - Cephalosporin

                                      - Carbapenem

                                      - ß-Lactamase Inhibitors

Vancomycin

Bacitracin

Cycloserine

Isonziad

Ethionamide

Ethambutol

Term

ß-Lactams

MOA

Definition

Interfere w/ Cell Wall Synthesis by inhibiting Penicillin Binding Proteins: Transpeptidase, Transglycosylase and Carboxypeptidase. Peptidoglycan Monomers will build up and trigger Autolytic Enzymes to kill the bacteria

 

 

EXCEPT: B-Lactamase Inhibitors

Term
Naturally Occuring Penicillins
Definition

ß-Lactam + Thiazolidine

Bacteriocidal

 

Active against: Gram(+) Cocci and Bacilli

                                   Gram(-) Cocci and Spirochetes

Inactive against: Gram(-) Rods                

 

 

Penicillin G = Acid Labile, Narrow Spectrum

Penicillin V = Acid Stable, Narrow Spectrum

Term

Semi-Synthetic Penicillins

 

Definition

ß-Lactam + Thiazolidine

Bacteriocidal 

 

Methicillin             Ampicillin

  Nafcillin                Amoxicillin

Oxacillin  

                          

Similar to Natural Penicillin except it has better activity against Gram(-) Rods

Resistant to ß-Lactamase

Increased Stability in Stomach Acid

Term
Cephalosporin
Definition

ß-Lactam + Dihydrothiazine

Bacteriocidal

 

1st Gen: Cefazolin= Gram(+), Narrow Spectrum

2nd Gen: Cefuoxime= Expanded Spectrum w/  Gram(-)

3rd Gen: Cefriaxone= Broader Spectrum w/ more Gram(-)

4th Gen: Piperocillin= Extended Spectrum against Pseudomonas Aeroginosa

Term
Carbapenems
Definition

Pharmacology: Bacteriocidal

Broadest Spectrum in comparison to other ß-Lactams

 

Active against: Gram(-), Gram(+), Strict Anaerobes and most ß-Lactamases

 

Resistance: occurs by enzymatic inactivation by Carbapenemase

Resitant Gram(-) rods are increasing

Term
ß–Lactamase Inhibitors
Definition

MOA: Bind strongly to ß-Lactamase to protect ß-Lactams

 

Has very little antibacterial properties but it is used in combo w/ other ß-Lactams to protect it from degradation

 

Augmentin= Clavulenic Acid+Amoxycillin

Unasym= Sulbactam+Ampicillin

Zosyn= Tazobactam+Piperacillin

Term

ß-Lactam

Drug Resistance Mechanisms

Definition

Intrinsic Resistance = Bacteria lacking a cell wall

(Chlamydia, Ureaplasma, Mycoplasma, Anaplasma)

 

Mutation of Porins = decreased permeability against Gram(-)

 

Inactivating Enzymes on Plasmids = inactivates components of the drug (ß-Lactamase)

 

Mutation of PBPs = MRSA

Term

Vancomyocin

 

Definition

MOA: Inhibits Peptidoglycan cross-linking by binding to the terminal D-Alanine

 

Pharmacology: Bacteriocidal, Narrow Spectrum

 

Active against: Gram(+)

 

Resistance: VanA and VanB replace the terminal D-Alanine with Lactic Acid via MDR on Plasmids or Transposons

 

Term
Bacitracin
Definition

MOA: Binds to Bacteroprenol and inhibits transfer of Peptidoglycan monomers

 

Pharmacology: Bacteriocidal, Narrow Spectrum, Topical

 

Active Against: Gram(+)

 

Resitance: occurs by decreasing penetrance of the drug

Term
Cycloserine
Definition

MOA: Analog to D-Alanine leading inhibition of cross-linking

 

Active against: Mycobacterial Infections (Acid Fast)

Term

Isonziad

(INH)

Definition

MOA: Inhibits Mycolic Acid

 

Active against: Mycobacterial Infections (Acid Fast)

Term
Ethionamide
Definition

MOA: Inhibits Mycolic Acid (derivative of INH)

 

Active against: Mycobacterial Infections (Acid Fast)

Term
Ethambutol
Definition

MOA: Inhibits Arabagalactan synthesis which is part of the cell wall in Acid Fast bacteria

 

Active against: Mycobacterial Infections (Acid Fast)

Term

Cell Membrane Dysfunction


Polymyxin B and Polymyxin E (Colistin)

Definition

MOA: Cationic Detergent that disrupts the cell membrane

 

Pharmacology: Bacteriocidal, Narrow Spectrum

 

Active against: Gram(-)

 

Term
Types of Protein Synthesis Inhibitors
Definition

30S: Aminoglycosides and Tetracyclines

 

50S: Macrolides, Chloramphenicol, Oxazolidinone, Streptogramin and Lincosamides

Term

Aminoglycosides

(30S)

Definition

MOA: Inhibits the initiation complex at 30S resulting in misreading mRNA. Its uptake depends on oxygen

 

Pharmacology: Bacteriocidal, Narrow Spectrum, Poor GI absorption. Neurotoxic to CN 8

 

Active against: Aerobic, Gram (-)

Inactive against: Anaerobic, Gram (+)

 

Natural Derivatives: Tobramyocin, Neomyocin, Kanamyocin, Gentamyocin, Amikacin and Streptomycin (for Mycobacterium)

 

Synthetic Derivatives: Netilmycin and Amikacin

 

Resistance: 

Enzymatic Modification

Transport Interference

Mutation of binding sites

Accelerated Export of Drug

Term

Tetracycline

(30S)

Definition

MOA: Binds to 30S to prevent binding of tRNA to mRNA

 

Pharmacology: Bacteriostatic, Broad Spectrum 

(w/ Chlamydia, Mycoplasma, Rickettsia)

 

Derivatives: Minocycline, Doxycyclin, Tetracycline

 

Side Effects: Photosensitivity, Calcium and Iron Chelator, Discoloration of Teeth

 

Resistance: Decreased Permeability, Active Efflux, Acetylation and Altered Binding Sites

Term

Macrolides

(50S)

Definition

MOA: Binds to 50S and prevents tRNA release AFTER peptide bond formation

 

Pharmacology: Bacteriostatic, Used when theres Penicillin Allergy,  Broad Spectrum

(w/ Gram(+), Gram(-), Chlamydia and Mycoplasma)

 

Derivatives: Azithromycin, Erythromycin and Clarithromycin

 

Resistance: Alteration of 50S and Enzymatic Modification

 

Term

Chloramphenicol

(50S)

Definition

MOA: Binds to 50S and inhibits the elongation phase by inhibiting Peptidyl Transferase (mitochondrial)

 

Pharmacology: Bacteriostatic, Broad Spectrum including Anaerobes

Term

Lincosamides

(50S)


Definition

MOA: Prevents peptide bond formation

 

Pharmacology: Bacteriostatic

 

Active against: Gram(+) and Anaerobes

Inactive against: Gram(-)

 

Derivatives: Clindamycin and Lincomycin

 

Resistance: Methylation of 23S rRNA

Term

Streptogramins

(50S)

Definition

Derivative and MOA: 

Quinupristin - Prematurely releases Peptides

Dalfopristin - Binds to 50S and prevents Elongation

 

Pharmacology: Bacteriocidal, Good for Vanco resistance with Staph and Enterococcus

 

Active against: Gram(+) 

Term

Oxazolidinones/Linezolid

(50S)

Definition

MOA: Binds to 50S and interferes with the formation of an Initiation Complex

 

Pharmacology: Bacteriostatic, Gram(+), Reserved for VREF and MRSA

Term
Types of Folic Acid Synthesis Inhibitors
Definition

Sulfanomides and Trimethoprim

Para-aminosalicyclic Acid and Dapsone

 

Term
Sulfonamides and Trimethoprim
Definition

MOA: 

Sulfonamides - Inhibits Dihydropteroate Synthase

Trimethoprim - Inhibits DHF Reductase

These enzymes are utilized in DNA synthesis in bacteria

 

Pharmacology: Bacteriostatic, Broad Spectrum, Usually used together

 

Active against: UTIs, GIT Infections and Respiratory Infections

 

Resistance: Overproduction of PABA or DHF, Folic Acid Dependency

Term
Para-aminosalicyclic Acid and Dapsone
Definition

SIMILAR TO SULFONAMIDES AND TRIMETHOPRIM

EXCEPT:



Narrow Spectrum --> Mycobacterium

Term
Types of Nucleic Acid Synthesis Inhibitors
Definition

Metronidazole/Flagyl

Quinolones/Fluroquinolones

Rifamycin

Term
Metronidazole (Flagyl)
Definition

MOA: Reduced to its active form in vivo and disrupts DNA under Anaerobic conditions

 

Pharmacology: Bacteriocidal, Narrow Spectrum, active form of the drug disrupts DNA under anaerobic conditions

 

Active against: Anaerobic Bacteria, Anti-Protozoa

Term
Quinolones/Fluoroquinolones
Definition

MOA: Inhibits DNA Topoisomeriase II/Gyrase and DNA Topoisomerase IV which is needed for DNA Replication, Recombination and Repair

 

Pharmacology: Bacteriocidal, Broad Spectrum, Affects bone and cartilage

 

Derivatives: Ciprofloxacin, Ofloxacin and Norfloxacin

Term
Rifamycin
Definition

MOA: Inhibits DNA-dependent RNA Polymerase needed for Transcription

 

Pharmacology: Bacteriocidal, Broad Spectrum

 

Active against:  Mycobacterium Tub. Gram(+)

Inactive Against:  Gram(-)

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