Penicillin G

Penicillin V

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- β-lactam; natural penicillin

Mechanism:

- D-ala-D-ala analogue binding to PBPs (transpeptidase) preventing cross-bridge formation

Spectrum:

- Gram (+) aerobes (Streptococcus spp)

- Neisseria meningitis

- Syphillis

- Actinomyces

- Fusobacterium

Notes:

- cleaved by β-lactamases

Ampicillin

Amoxicillin

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- β-lactam; aminopenicillin

Mechanism:

- binds PCPs like PCN except it has polar group allowing passage through porins

Spectrum:

- Gram (+) aerobes (Streptococcus spp)

- Neisseria meningitis

- Syphillis

- Actinomyces

- Fusobacterium

- H. influenzae, E. coli

Methicillin

Oxacillin (iv)

Nafcillin (iv)

Dicloxacillin (oral)

- class

- type

- mechanism

- spectrum

Class and Type:

- β-lactam; penicillinase-resistant PCNs

Mechanism:

- same as PCN, bulky group prevents access of penicillinases to cleavage site

Spectrum:

- Staphylococci making penicillinases (but not MRSA or MRSE) i.e. MSSA and MSSE

Piperacillin

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- ureidopenicillins; β-lactams

Mechamism:

- same as PCN; polar group allows entry through porin

Spectrum:

- PCN coverage +

- H. influenzae

- Enterobacteriaceae

    ~ 70% of Klebsiella

- Pseudomonas aeruginosa

- Neisseria gonorrhoeae

- NOT Staphylococci!!

Notes:

-ampicillin derivative

Tazobactam

Clavulanate

Sulbactam

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- β-lactam; β-lactamase inhibitors

Mechanism:

- minimal antibiotic activity itself

- binds penicillinases allowing attached β-lactam to work

Spectrum:

- aerobic Gram (-) rods (Pseudomonas)

- aerobic Gram (+) cocci (not MRSA or MRSE)

- anaerobes

Notes:

- Pseudomonas activity

   ~ ticarcillin/clavulanate

   ~ pipercillin/tazobactam

- No Pseudomonas activity

   ~ amoxicillin/clavulanate

   ~ ampicillin/sulbactam

Cefazolin

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- β-lactam; 1st generation cephalosporin

Mechanism:

- same as PCN but better pharmacokinetics and antibiotic properties

Spectrum:

- Same as PCN-G plus

- Klebsiella

- MSSA, MSSE

- E. coli

- Proteus mirabilis

- no/minor anaerobes, no Enterococcus, no Haemophilus

Ceftriaxone

Cefotaxime

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- β-lactams; advanced cephalosporins

Mechanism:

- oxime stabilizes β-lactam ring while aminothiazolyl group allows porin entry

Spectrum:

- Gram (+) bacteria (not Enterococcus)

- Enterbacteriaceae

- Haemophilus

- Neisseria spp

- not Pseudomonas

Notes:

- ceftriaxone has longer serum 1/2 life and covers more Gram (-) rods

Ceftazidime

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- β-lactam; advanced cephalosporin

Mechanism:

- 2 side chains stabilize each other against Pseudomonas defenses

Spectrum:

- Pseudomonas

- Haemophilus

- Enterobacteriaceae

- poor Gram (+) activity

Notes:

- use for infects due to resistant organisms and Pseudomonas

Cefepime

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- β-lactam; advanced cephalosporin

Mechanism:

- side chain for Pseudomonas activity; zwitterion for easier porin access

Spectrum:

- Pseudomonas

- Haemophilus

- Enterobacteriaceae

- good Gram (+) activity

Notes:

- serious Pseudomonal infections

- nosocomial, Gram (-) Bacillus infections

Imipenem

Meropenem

Doripenem

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- β-lactams; carbapenems

Mechanism:

- β-lactam stability, binds avidly to high MW PBPs (esp PBP2)

Spectrum: (very broad)

- Staphylococcus

- Streptococcus

- Enterococcus

- Pseudomonas

- anaerobes

Notes:

- use for resistant, polymicrobial, or life-threatening infections

- Doripenem is the most broad spectrum antibiotic

Aztreonam

- class

- type

- mechanism

- spectrum

- notes

Class:

- Monobactams

Mechanism:

- monocyclic β-lactam ring has groups allowing porin entry and stabilization vs Pseudomonas

Spectrum:

- aerobic Gram (-) rods (inc. Pseudomonas)

- no anaerobic, no Gram (+) activity

Notes:

- can give in place of PCN because there is no cross-reactivity

- resistant to most penicillinases

Vancomycin

- class

- type

- mechanism

- spectrum

- notes

Class:

- Glycopeptides

Mechanism:

- binds D-ala-D-ala thus blocking transpeptidase binding

- inhibits RNA synthesis

Spectrum:

- Gram (+) only; too large for porin protein

- MRSA

Notes:

- toxicity = red man syndrome, hearing loss at high doses, nephrotoxicity when given with aminoglycosides and loop diuretics

Ticarillin

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- β-lactam; carboxypenicillin

Mechanism:

- same as PCN

- polar group allows entry through porin

Spectrum:

- broad spectrum except Klebsiella

Daptomycin

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- Acid lipopeptide

Mechanism:

- alteration of cell membrane

- binds membrane in calcium-dependent manner, forming oligomers that create cation channels leading to depolarization of bacterial cell membrane

Spectrum:

- Gram (+) only

- useful for resistant organisms, MRSA

Notes:

- IV use only

- best MRSA agent at the moment

- does not work in lungs

- toxicity = myopathy

Colistin

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- Acid lipopeptide

Mechanism:

- alteration of cell membrane

- detergent-like action on outer membrane

- displaces Mg and Ca from LPS, depolarizing outer membrane and causing its loss of function

Spectrum:

- Gram (-), except Neisseria

Notes:

- nephrotoxic, neurotoxic

- used for really bad Gram (-) infections when carbapenems don't work

Gentamycin

Tobramycin

Amikacin

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- aminoglycosides; acts on 30S subunit

Mechanism:

- acts on 30S subunit blocking initiation and cause misreading of mRNA transcript

Spectrum:

- Gram (-) aerobic bacilli

- Staphylococcus

- Enterococcus

Notes:

- nephrotoxicity

- ototoxicity

- weakness of respiratory muscles

- flaccid paralysis

- use only for serious infections e.g. Pseudomonas, enterococcal endocarditis

Tetracycline

Doxycycline

Minocycline

Tigecycline

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- Tetracyclines; acts on 30S subunit

Mechanism:

- prevents binding of tRNA to 30S 

Spectrum: broad spectrum

- intracellular organisms

  ~ mycoplasma

  ~ rickettsiae

  ~ chlamydia

- MRSA

Notes:

- contraindicated for pregnancy and kids due to brown/yellowish discoloration of developing teeth and depression of skeletal growth

Erythromycin

Clarithromycin

Azithromycin

- class

- type

- mechanism

- spectrum

- notes

Class and type:

- E & C = macrolides, A= azilide

Mechanism:

- act on 50S subunit by binding 23S subunit and interfering with translocation of AA onto peptide chain

- becomes inserted into peptide chain

Spectrum:

- Gram (+) and (-) (not Enterobacteriaceae)

- anaerobes

- protozoa

- spirochetes

- good vs intracellular organisms

  ~ rickettsiae

  ~ mycoplasma

  ~ chlamydiae

Notes:

- toxicity: transient hearing loss, prolongation of QT interval

- A and C have longer 1/2 life and broader spectrum

Clindamycin

- class

- type

- mechanism

- spectrum

- notes

Class and type:

- aminosugar; acts on 50S subunit

Mechanism:

- acts on 50S subunit blocking peptide bond formation and elongation

Spectrum:

- anaerobes (+/-)

- Gram (+) cocci

- NOT C. difficile

Notes:

- commonly causes antibiotc colitis due to C. difficile overgrowth

- workhorse for dentists (anaerobic dental infections)

Linozolid

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- oxazolidinones; 50S subunit inhibition

Mechanism:

- binds 50S unit near 30S interface preventing formation of initiation complex

Spectrum:

- Gram (+)  esp resistant organisms, MRSA

Notes:

- can cause bone marrow suppression and severe lactic acidosis due to mitochondrial inhibition

Rifampin

Rifabutin

Rifaximin

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- Rifamycins; inhibit enzymes

Mechanism:

- blocks mRNA synthesis by inhibiting RNA polymerase -- prevents initiation but not elongation

Spectrum:

- mycobacterial infections

- meningitis prophylaxis

- endocarditis

- MRSA

- osteomyelitis

- Rifabutin good vs resistant M. tuberculosis 

- Rifaxamin is good for C. difficile colitis b/c not absorbed well

Notes:

- do not give alone! resistance develops quickly

- orange-red discoloration of urine and contacts

Levofloxacin

Ciprofloxacin

Moxifloxacin

Gemifloxacin

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- Fluoroquinolones; inhibit enzymes

Mechanism:

- inhibits topoisomerases

- stabilizes DNA-enzyme complex after strand breakage and before repair

Spectrum: broad spectrum

- Gram (-) bacilli

   ~ Enterobacteriaceae

   ~ Pseudomonas aeruginosa

   ~ Haemophilus influenzae

   ~ others

- S. pneumoniae (not cipro)

- S. aureus (not cipro)

- intracellular pathogens

  ~ Legionella

  ~ Mycoplasma

  ~ Chlamydia

  ~ Chlamydophila

- Mycobacterium

Notes:

- can cause abnormal glucose homeostasis

- may cause arthropathy

- hallucinations possible

- photosensitivity

Metronidazole

Tinidazole

- class

- type

- mechanism

- spectrum

- notes

Class and Type:

- nitroimidazoles

Mechanism:

- acts as electron sink depriving organism of reducing power

- gives off cytotoxic intermediate which damages DNA

Spectrum:

- anaerobes (except actinomycetes)

- Clostridium difficile

- Trichomonas and amebiasis

Notes:

- do not mix with alcohol = disulfiram reaction

- seizures, encephalopathy, ataxia, peripheral neuropathy are major side effects

Trimethoprim

Sulfamethoxazole

- class

- type

- mechanism

- spectrum

- notes

Class and type:

- Trimethoprim/ sulfonamides

Mechanism:

- inhibit DNA synthesis

- Trimethoprim inhibits DHF reductase

- Sulfamethoxazole acts as PABA analogue

Spectrum: very broad

- Gram (+)

- Gram (-)

- Mycobacteria

- Parasites

  ~ Toxoplasma gondii

  ~ Isospora belli 

- Fungi

  ~ Pneumocystis jiroveci

Notes:

- hypersensitivity reactions = Steven's-Johnson syndrome ("body-wide 3rd degree burns")

β-lactams except:

  - aztreonam (no activity)

  - ceftazidime

macrolides

  - variably susceptible

clindamycin

fluoroquinolones

  - ciprofloxacin (variable)

daptomycin

linezolid

TMP/SMX

fusidic acid

fosfomycin

Staphylococcus aureus (MSSA) antibiotic susceptibility

β-lactams except

  - aztreonam (NA)

  - ceftazidime (poor)

  - penicillin

  - ampicillin/amoxicillin

macrolides

  - variably susceptible

clindamycin

fluoroquinolones

  - ciprofloxacin (variable)

glycolipopeptides

daptomycin

linezolid

TMP/SMX

fusidic acid

fosfomycin

ceftaroline

  - only active β-lactam

glycolipopeptides

daptomycin

linezolid

TMP/SMX

fusidic acid

fosfomycin

Enterobacteriaceae antibiotic susceptibility

- E. coli

- K. pneumoniae

- P. mirabilis etc

β-lactams except:

  - PCN G & V

  - nafcillin, oxacillin, dicloxacillin

fluoroquinolones

aminoglycosides

tetracyclines

nitrofurantoin

fosfomycin

colistin

These β-lactams only:

  - piperacillin/tazobactam

  - ticarcilliin/clavulanate

  - ceftazidime

  - cefepime

  - carbapenems (not ertapenem)

fluoroquinolones

aminoglycosides

fosfomycin

colistin

Anaerobes

- Bacteroides spp

- Fusobacteria spp

- Veillonella spp

- Peptostreptococcus

- Prevotella spp

β-lactams except:

  - aztreonam

  - nafcillin, oxacillin, dicloxacillin

  - cephalosporins

       ~ cefoxitin & cefotetan active

clindamycin

metronidazole

tetracyclines

fluoroquinolones except

  - ciprofloxacin

  - levofloxacin