Review Of Anti-mircobial Mechanisms Flashcards

1
Q

Infections of the upper respiratory tract induce

A

Acute Ottis media (middle ear)

Acute bacterial rhinosinusitis ( sinus infections)

Bacterial pharyngitis (strep throat)

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2
Q

Infections of the lower respiratory tract include

A

Chronic bronchitis

Community-acquired pneumonia

Hospital acquired pneumonia

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3
Q

What is the general treatment sequence for bacterial infections?

A

Treated empirically until a definitive treatment for the specific agent is present

  • empirically tx is implemented based on most likely causative organisms

Patient history and factors play a critical role in this

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4
Q

Antimicrobial activity to take into consideration when choosing anti-microbial

A

Gram (+) vs Gram (-) vs mycobacterium

Aerobic vs anaerobic

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5
Q

Inhibtors of cell wall synthesis includes what?

A

B-lactam drugs:
penicillins (gram (+) only)
cephalosporins (gram (+/-)
carbapenems

Glycopeptides
- vancomycin (pretty much only used in MRSA)

MOA:

  • act by preventing synthesis of the peptidoglycan cell wall
  • B-lactams act by inhibiting transpeptidase
  • glycopeptides act by inhibiting D-alanine residues needed for peptidoglycan cross-linking
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6
Q

Protein synthesis inhibtors include what?

A

Lincosamides (gram (+) only, disrupts 50s ribosome)
- Clindamycin

Macrolides (broad spectrum, disrupt 50s ribosome)

  • clarithromycin
  • azithromycin
  • erythromycin

Aminoglycosides (broad spectrum, disrupt everything pretty much)

  • gentamicin
  • tobramycin

Tetracyclines (broad spectrum, disrupts 30s ribosome)

  • tetracycline
  • doxycycline
  • minocycline
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7
Q

DNA/RNA synthesis inhibitors include what?

A

Fluroquinolones

  • direct inhibtors that disrupt topoisomerases in microbes
  • causes destability and inability to prevent supercoiling
  • levofloxacin (causes destability of tendons in patients)
  • moxifloxacin
  • ciprofloxacin

Folate synthesis inhibtors

  • indirectly prevent DNA synthesis due to competitively inhibiting folic acid synthesis
  • sulfonamides (inhibts dihydropteroate synthase)
  • trimethoprim (inhibts dihydrofolate reductase)
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8
Q

Generations of cephalosporins

A

1st generation

  • cefadroxil
  • pretty much only gram (+) activity

2nd generation

  • cefuroxime
  • mix of gram (+/-)

3rd generation

  • cefdinir
  • ceftriaxone
  • cefotaxime
  • cefpodoxime
  • more gram (-) activity w/ very mild (+)

4th generation

  • cefepime
  • only gram (-) activity
  • Anti-MRSA = ceftaroline*
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9
Q

Treatment of acute otitis media

A

Overall Goal is:

  • reduce pain
  • deliver antibiotics once diagnosis is confirmed

common agents that cause this are:
- streptococcus pneumonia
- haemophilus influenza
- moraxella catarrhalis
(all often possess B-lactam resistance)

specific treatment

1) high dose amoxicillin (S. Pneumoniae is most effective for this treatment)
- lasts 10 days
2) use clindamycin if amoxicillin did not kill all

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10
Q

Treatment of acute bacterial rhinosinusitis

A

Overall Goal is:

  • reduce sings/symptoms
  • limit antibiotic therapy unless you can confirm it is a microbe (must distinguish viral from bacterial)
  • eradicate infection completely (prevent complications/chronic disease)

common agents that cause this are:
- streptococcus pneumonia
- haemophilus influenza
- moraxella catarrhalis
- also viral infections
(all often possess B-lactam resistance)

Specific TX:
- non-bacterial = OTC decongestants and saline/steam inhalation
- bacterial = amoxicillin-clavulanate is first line
(must have clavulanate to counteract amoxicillin resistance)
can also use tetracyclines but only in adults not children (stunts bone growth)

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11
Q

Treatment of acute bacterial pharyngitis

A

Overall Goal is:

  • improve signs/symptoms
  • limit ADRs
  • prevent tranmission
  • prevent complications (rheumatic fever/abscesses)
  • common agents that cause this are:*
  • streptococcus pneumonia
  • GAS bacteria (is strep throat at this point)

Specific treatment

  • only give antibiotics if you know what GAS it is
  • supportive care = antipyretic/analgesics and NSAIDS
  • 1st line = penicillin or amoxicillin
  • 2nd line = cephalosporins and macrolides
  • can use rifampin as a synergist in carriers of strep throat*
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12
Q

Treatment of acute exacerbation of chronic bronchitis

A

Treatment goals

  • reduce severity of chronic symptoms
  • stop current acute exacerbation
  • prolong intervals between future exacerbation
  • most common infectious agents*
  • H. Influenza
  • M. Catarrhalis
  • S. Pneumoniae
  • E. Coli
  • note: these may not be present*

Specific treatment:

  • if bacterial: ampicillin or/and amoxicillin/clavulanate therapies
  • can also throw in Fluroquinolones*
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13
Q

Treatment of bacterial pneumonia

A

Treatment goals

  • eradication of organisms
  • minimized morbidity
  • cost-effective treatment

Need to determine hospital or environmental acquired

Atypical pneumonia includes

  • mycoplasma
  • legionella
  • cant use B-lactams or glycopeptides since they have no wall*
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