Antibacterials Flashcards Preview

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Flashcards in Antibacterials Deck (27):
1

Natural Penicillins:

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Inhibitors of cell wall synthesis

Streptococcus
#Enterococcus (esp E. faecalis)

#Minimal

Treponema pallidum
(Syphilis)
#Mouth anaerobes

#Hypersensitivity
#Seizures (high doses)

-Have lost utility against
Staphylococci (due to β-lactamase)
-Only cidal against Enterococcus when combined with aminoglycoside
- Streptococcus spp. are uniformly susceptible, with exception of some S pneumoniae isolates

2

Aminopenicillins:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Ampicillin/Amoxicillin

Inhibitors of cell wall synthesis

Streptococcus
Enterococcus (espE. faecalis)
Listeria monocytogenes

Escherichia.coli, Proteus mirabilis, Haemophilus influenzae (but resistance is common due to B-lactamase)

Treponema pallidum
(Syphilis)
#Lyme

#Hypersensitivity
#Seizures (high doses)

3

Aminopenicillins + Beta-lactamase Inhibitors:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Ampicillin+ Sulbactam
Amoxicillin+Clavulanate

Inhibitors of cell wall synthesis

Streptococcus
Enterococcus (espE. faecalis)
methicillin-sensitive Staphylococcus
aureus (MSSA)

Escherichia.coli, Proteus mirabilis, Haemophilus influenzae (but resistance is common due to B-lactamase)
B-lactamase producing strains of H. influenzae, some strains of Klebsiella spp., E coli.

Treponema pallidum
(Syphilis)
#Lyme
Excellent anaerobic activity (including Bacteroides fragilis)

#Hypersensitivity
#Seizures (high doses)
#Diarrhea

4

Penicillinase Resistant Penicillins:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Nafcillin/Oxacillin
Dicloxacillin

Inhibitors of cell wall synthesis

EXCELLENT MSSA (drugs of
choice)
Streptococcus

#None

#None

#Hypersensitivity
#Seizures (high doses)
Hepatotoxicity (oxacillin) and interstitial nephritis (nafcillin)

- “Penicillinase” is β-lactamase that hydroyzes penicillins but not these agents
- Unique due to hepatic elimination, so no dosing adjustments necessary in renal insufficiency

5

Extended Spectrum Penicillin + Beta-lactamase Inhibitor:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Ticarcillin+Clavulanate
Piperacillin+Tazobactam

Inhibitors of cell wall synthesis

EXCELLENT MSSA (drugs of
choice)
Streptococcus
Enterococcus (esp E. faecalis)

Broad-spectrum activity, including Pseudomonas

Treponema pallidum
(Syphilis)
Mouth anaerobes
Excellent anaerobic activity (including Bacteroides fragilis)

#Hypersensitivity
#Seizures (high doses)
#Diarrhea

6

1st Generation Cephalosporins:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Cefazolin
Cephalexin
Cefadroxil

Inhibitors of cell wall synthesis

MSSA
Streptococcus

E. coli, Klebsiella

#oral anaerobes

#Hypersensitivity
#Seizures (high doses)

Uses: skin and soft tissue infections

7

2nd Generation Cephalosporins:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Cefuroxime
Cefaclor
Cefprozil
*Cefoxitin

Inhibitors of cell wall synthesis

MSSA, Streptococci
*Poor MSSA
*Streptococcus

E. coli, Klebsiella
H. influenzae

#oral anaerobes
*Moderate B. fragilis

#Hypersensitivity
#Seizures (high doses)

8

3rd Generation Cephalosporins:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Ceftibuten
Cefdinir
Cefpodoxime
Ceftriaxone
Cefotaxime
Cefixime
*Ceftazidime
**Ceftaroline

Inhibitors of cell wall synthesis

MSSA
Streptococcus
*Poor MSSA, Streptococcus
**Only β-lactam with activity against MRSA, excellent against Streptococcus

Broad, not Pseudomonas
*Broad, including Pseudomonas
**Broad, not Pseudomonas

#oral anaerobes

#Hypersensitivity
#Seizures (high doses)

#Ceftriaxone unique for non-renal elimination
#Ceftriaxone/cefotaxime gold- standard for community-acquired meningitis, N. gonorrhea, neuro Lyme

9

4th Generation Cephalosporins:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Cefepime

Inhibitors of cell wall synthesis

MSSA
Streptococcus

Broad activity , including Pseudomonas

#None

#Hypersensitivity
#Seizures (high doses)

10

Monobactams:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Aztreonam

Inhibitors of cell wall synthesis

None

Good, including Pseudomonas

#None

#Hypersensitivity
#Seizures (high doses)

Safe to use in patients with severe allergic reactions to other beta- lactams (like penicillin)

11

Carbapenems:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Imipenem/Cilastatin
Meropenem
Doripenem
*Ertapenem

Inhibitors of cell wall synthesis

Streptococcus
MSSA
Enterococcus faecalis
*No Enterococcus

Excellent, including Pseudomonas
*Doesn't cover Pseudomonas

Anaerobes, including excellent B. fragilis

#Hypersensitivity
#Seizures (high doses)
Imipenem- ↑ incidence of seizures in pts with ↓ renal function & or hx of seizures

12

Glycopeptide:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Vancomycin

Inhibitors of cell wall synthesis

Streptococcus
MRSA/MRSE
Enterococcus
Not VRE

#None

C. difficile

Rash and hypotension with rapid IV administration (Red Man’s syndrome)
Nephrotoxicity (mostly with high doses or in combination with aminoglycosides)
Neutropenia, allergy (rare)

Used exclusively for gram- positive infections (IV) and C. difficile-associated diarrhea (PO)
-Old drug, but resistance amongst staph/strep is rare
-At UPMC, ~80% of Enterococcus faecium is VRE (vancomycin- resistant), as is ~20% of E. faecalis

13

Fosfomycin:

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Inhibitors of cell wall synthesis

Streptococcus
Staphylococcus
Enterococcus

E. coli & others
Not pseudomonas

#None

#Well tolerated

-Only available in USA as single- dose oral regimen for acute cystitis in females
-First line option due to increasing E coli resistance to other agents (TMP/SMX, quinolones)

14

TMP/SXM:

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Inhibitors of DNA & RNA synthesis

S. aureus
S. epi
Most MRSA & MRSE
Poor streptococcus

Most gram- including Stenotrophomonas maltophilia
EXCEPT
Pseudomonas

Nocardia
Pneumocystis jiroveci (PCP) (fungus)
Toxoplasma gondii (protozoa) NOT
B. fragilis or other anaerobes

- Skin rash (3-4%): from mild reactions that resolve with continuation to Stevens-Johnson (rare)
- Renal: TMP inhibits secretion of creatinine and may lead to mild (~10%) elevations of serum creatinine
- Hyperkalemia
- Acute tubular necrosis
- Acute interstitial nephritis
- Hematological: neutropenia, thrombocytopenia (rare)

- Many uses, including urinary tract, gastrointestinal, skin, pneumocystis (both treatment and prophylaxis), toxoplasmosis, nocardiosis
- Monitor for increase in INR when used concomitantly with warfarin (drug interaction)
- Dosing based on Trimethoprim component

15

Rifampin:

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Inhibitors of DNA & RNA synthesis

Staph/Strep
No enterococcus
Not used as monotherapy

N. meningitidis (prophylaxis only)

M. tuberculosis

- Orange-red discoloration of tears, sweat, urine, etc
- Gastrointestinal
- Hepatotoxicity: from mild, transient elevations in bilirubin to fulminant hepatitis (rare)

- MANY drug-drug interactions
- Utilized almost exclusively in combination due to rapid emergence of resistance when utilized alone
- Uses: Tuberculosis, staphylococcal endocarditis, infections of prosthetic materials

16

Fidaxomicin:

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Inhibitors of DNA & RNA synthesis

Streptococcus
Staphylococcus
Enterococcus

#None

Gram-positive anaerobes (especially C. difficile)

#Non-toxic

Only use is for C. difficile infection

17

Quinolones:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Ciprofloxacin
Levofloxacin
*Moxifloxacin

Inhibitors of DNA & RNA synthesis

Streptococcus
S. pneumo (Moxi > Levo > Cipro)
Poor enterococcus
No Staph

Cipro/Levo: Excellent activity against most (incl Pseudomonas)
Moxi: Moderate activity, poor activity vs. Pseudomonas

- Most have poor anaerobic activity
- Moxi- has ↑ activity,
including Bacteroides fragilis
- Good activity atypicals: Chlamydia spp. Mycoplasma
Legionella spp

- CNS: headache, dizziness, insomnia, mood alterations, seizures
- Tendinitis with rupture (especially achilles tendon in elderly patients corticosteroids) - Prolonged QTc
- C difficile: although possible with all antibiotics, FQ portend especially high risk

Cipro & Levo adjusted for renal pts, Moxi not adjusted

18

Aminoglycosides:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Gentamicin
Tobramycin
Amikacin

Inhibitors of protein synthesis

Enterococcus
Streptococcus
Staphylococcus

Broad, including Pseudomonas (ami > tobra > genta)

#None

- Nephrotoxicity- via proximal tubular cell accumulation. Usually reversible
- Ototoxicity (rare)- Usually irreversible

- Almost always used in combination:
--> With cell-wall active agents for staph/strep/enterococcal endocarditis
--> As “double-coverage” for severe gram-negative infections until susceptibility known
- Pharmacokinetic monitoring necessary to maximize efficacy (high peaks) and minimize toxicity (low troughs)

19

Macrolides:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Azithromycin
Clarithromycin

Inhibitors of protein synthesis

Strep pneumoniae & other strep
MSSA

H. influenzae
N. gonorrhea
M. catarrhalis
Campylobacter
H. pylori

- Atypicals: Legionella, Mycoplasma, Chlamydia
- Anaerobic activity but NOT B. fragilis
- Mycobacterium avium complex (MAC)

- Erythromycin utilized for pro- kinetic gastrointestinal effects. Clarithro/Azithro have fewer GI side effects.
- Torsades de pointes (ventricular tachycardia) associated with clarithromycin, mostly when utilized in combination with interacting agents (via CYP3A4 hepatic enzymes; azithromycin is not metabolized via this process)

- Utilized for coverage of atypical pathogens in community-acquired pneumonia
- Also utilized for otitis, sinusitis, pneumonia
- Clarithromycin: More prone to
drug-drug interactions
- Clarithromycin: non-buterculous mycobacterial infections, combination therapy for H. pylori
- Azithromycin: chlamydial infections, traveler’s diarrhea, MAC prophylaxis in AIDS

20

Tetracyclines:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Tetracycline
Doxycycline
Minocycline

Inhibitors of protein synthesis

Strep pneumoniae
Staphlococcus (incluidng MRSA)
Enterococcus
Strep pyogenes

H. influenzae
N. gonorrhea
M. catarrhalis
Campylobacter

Anaerobes, atypicals, Rickettsial infections, Lyme disease

- GI, esophageal ulceration (take
with fluid and remain upright) - Gray-brown to yellow
discoloration of teeth in children
- Photosensitivity

- Appropriate for a wide variety of infections, although use in the hospital is generally limited due to alternative agents with more potent gram-negative activity
- May still be options for COPD exacerbations, outpatient treatment of upper respiratory tract infections

21

Glycylcyclines:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Tigecycline

Inhibitors of protein synthesis

Extensive, including MRSA, VRE

Extensive, although no Pseudomonas

Extensive anaerobic coverage, including Bacteroides fragilis

- GI, esophageal ulceration (take
with fluid and remain upright) - Gray-brown to yellow
discoloration of teeth in children
- Photosensitivity
- Nausea & vomiting

Not appropriate for treatment of bacteremia due to low serum levels

22

Lincosamides:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Clindamycin

Inhibitors of protein synthesis

S. aureus (including MRSA)
S. epi
Streptococcus
Not enterococcus

#None

Good anaerobic activity, but resistance common with Bacteroides

- Nausea/vomiting/diarrhea
- C. difficile colitis (Can occur with any antibiotic, but most
commonly associated with clindamycin)

Due to risk for C. difficile, should
be rarely utilized:
- oral infections and skin and soft
tissue infections in patients with penicillin allergy
- As part of combination therapy in necrotizing fasciitis (Gp A Strep)

23

Oxazolidinone:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Linezolid

Inhibitors of protein synthesis

Vast activity, even against MRSA and most VRE (vancomycin- resistant Enterococcus)

#Negligible

#Investigational

- Myelosuppression, mostly thrombocytopenia, common with treatment courses >2 weeks
- Reversible MAO-I and can cause serotonin syndrome when given in combination with other serotonergic agents

Mainly reserved for patients with resistant gram-positive infections (esp VRE & MRSA) with few other options

24

Nitrofurantoin:

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

DNA damaging agents

Most gram+ including VRE

Most E. coli, Klebsiella, Enterobacter (Proteus and Pseudomonas almost always resistant)

#None


- Gastrointestinal (lower with
macrocrystalline formulation- due to slower dissolution)
- Pulmonary: wide range, from acute cough and dyspnea to fibrosis with chronic use

Only utilized for treatment of urinary tract infections but NOT pyelonephritis

25

Metronidazole:

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

DNA damaging agents

None

None

Extensive against anaerobes,
including B fragilis Trichomonas ( protozoa) Giardia (protozoa) Helicobacter pylori
C difficile

- Gastrointestinal, metallic taste
- Peripheral neuropathy

- Drug of choice for initial treatment of mild-moderate severity C. difficile disease
- Otherwise extensively utilized for treatment/coverage of anaerobic infections

26

Lipopeptides:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Daptomycin

Cell membrane damaging agents

Extensive activity, including MSSA, MRSA, MRSE, drug-resistant Streptococcus, most Enterococcus (including VRE)

#None

#None

- Muscle pain/weakness (creatinine phosphokinase elevations)
- Rash

27

Polymyxins:

Drug(s)

Mechanism of Action

Gram+

Gram-

Other

Adverse Effects

Comments

Polymyxin B
Colistin

Cell membrane damaging agents

#None

Extensive activity, including
Pseudomonas.

#None

- Dose-related, reversible nephrotoxicity
- Neurotoxicity (neuromuscular blockade) and paresthesias

Often drug of last resort for multi- drug resistant gram – infections.