Intro to Antimicrobial Therapy Part 2 Flashcards
Three primary schemes are used for classification of antimicrobial drugs. WHat are they?
- Classification by Susceptible Organism
- Classification by Mechanism of Action
- Classification on whether drugs inhibit bacterial growth or are lethal to bacterial cells
What are the classifications of susceptible organisms?
5
Antibacterial Drugs—active against bacteria
Antifungals —active against fungi
Antivirals —active against viruses
Antiprotozoal
Antihelminthic
What are the types of antibacterial classifications for susceptible organisms?
2
Narrow-spectrum—drugs active against only a few microorganisms.
Broad-spectrum—active against a wide variety of microorganisms
How is selective toxicity achieved?
6
Inhibition of cell wall synthesis
Protein synthesis inhibitors
DNA synthesis inhibitors
RNA synthesis inhibitors
Mycolic acid synthesis inhibitors
Folic acid synthesis inhibitors
Protein Synthesis inhibitors: Inhibit 30s Subunit
are what classes and what drugs?
2 with three each
Aminoglycosides
Gentamicin
Tobramycin
Amikacin
Tetracyclines
Tetracycline
Doxycycline
Minocycline
Protein synthesis inhibitors: 50s Subunit
are what classes and what drugs?
2 with three and four drugs
Macrolides
Erythromycin
Clarithromycin
Azithromycin
Others: Chloramphenicol Clindamycin Linezolid Streptogramins
DNA synthesis inhibitors?
Two classes
and 6 drugs
Fluoroquinolones Ciprofloxacin Oflaxacin Norfloxacin Levofloxacin Gatiflocacin Moxifloxacin
Metronidazole
RNA synthesis inhibitors
Rifampin
TB drug
Folic acid synthesis inhibitors
2
Sulfonamides
Trimethoprim
What locations in the body are normally free of florA?
3
The blood, brain, muscle and cerebrospinal fluid are normally free of flora
Endocarditis Patient history of- Native valve: 2 and 4 IV drug user: 2 and 1 Prosthetic valve: 3 and 3 What will be the causitive agent and what antibiotic will we use?
- Strep viridans (30-40%), “other Strep”(15-25%)
- Pen G or
Amp + Nafcillin or oxacillin + gentamicin - Staph aureus (MSSA and MRSA) All others rare
- vancomycin
- S. epidermidis, S. aureus, S. viridans and others
- vancomycin + rifampin + gentamicin
Intraabdominal infections
Diverticulitis, perirectal abscess, peritonitis: 4 and 3
What will be the causitive agent and what antibiotic will we use?
- E Coli
- occasionally P. aeruginosa
- (Anerobes) Bacteroides sp.
- Enterococci
TMP-SMX-DS (Bactrim) or Cipro or
Levofloxacin
+
Metronidazole
Skin and Soft Tissue Infections Generalized cellulitis: 2 and 4 Diabetic ulcer: 3 and 3 Animal bites: 1 and 1 Necrotizing fasciitis: 2 and 5 What will be the causitive agent and what antibiotic will we use?
1. Staph aureus Strep 2. Staph: MSSA: Cephalexin Staph: MRSA: TMP-SMX-DS or Clindamycin Strep: Cephalexin
1. Staph (assume MRSA) Strep (Group B) or pyogenes 2. Doxy or TMP-SMX-DS Or Clinda
- Pasturella multocida (cat)
- Amox-clav (Augementin)
- GABS, C. perfringens
- PCN G, cefoxitin, chloramphenicol, clindamycin, metronidazole
Urinary tract
What will be the causitive agent and what antibiotic will we use?
4 and 6
1. E. Coli Gram (-) aerobic bacilli Enterococcus Staph Saprophyticus
- TMP-SMX-DS
Nitrofurantoin
Fosfomycin
If > 20% resistance to TMP-SMX-DS then can use
Cipro, Levo, Moxi
Respiratory tract special considerations:
What will be the causitive agent and what antibiotic will we use?
Aspiration pneumonia: 2 and 3
Lower/hospital acquired: 2 and 4
History of HIV: 2 and 2
- Anaerobic and aerobic mouth flora
- Clindamycin or Ampicillin-Sulbactam or A carbapenem
- Pseudomonas aeruginosa
Gram(-) aerobic bacilli - Imipenem-cilastatin or meropenem add Ciprofloxacin or Tobramycin if suspect pseudomonas
- Pneumocystis carinii
S pneumoniae - Trimethoprim-sulfamethoxazole (Bactrim, Septra)
Pentamadine
Respiratory Tract
What will be the causitive agent and what antibiotic will we use?
Sinusitis: 7 and 6
CAP: 3 and 4
1. S. Pneumoniae 33% H. Influenzae 32% M. Catarrhalis 9% Anarobes 6% Grp A Strep 2% Viruses 15-18% S. Aureus 10%
2. Peds: Amox or Amox-Clav PCN allergy: Clinda Adult: Amox-Clav PCN allergy: Levo or Doxy
1. All of the above plus the atypicals Klebsiella pneum. Mycoplasma pneum. Chlamydia pneum.
2. Azithromycin, Clarithromycin, Doxycycline, or Respiratory FQ (if comorbidities)
Meningitis in children
What will be the causitive agent and what antibiotic will we use?
Child
1. E coli Enterococcus spp. GBS Listeria monocytogenes anerobes (bacteroides fragilis) Gram(-) aerobic bacilli
- Ampicillin + gentamicin
- Strep pneumoniae
Neisseria meningitis
Haemophilus influenzae - Vancomycin + cefriaxone or cefotaxime
neonates are susceptible to normal vaginal flora becoming pathogenic
Meningitis
Age 1 mo to 50 years: 2 and 3
Age
- S. Pneumoniae
Meninogococci - Cefotaxime or Ceftriaxone + vancomycin
1. Group B Strep 49% E Coli 18% Misc Gm + 10% Misc Gm – 10%
- Ampicillin + Cefotaxime or Gentamycin
What antibiotic should be administered before the surgery begins via IV
Often used to irrigate the surgical site as well?
DOC and Alt?
Cefazolin (Ancef) 1-2 gram IV (30 minutes before skin incision)
For penicillin allergic patients can use vancomycin 1-1.5g (1 hour infusion)
Certain individuals are susceptible to developing bacterial endocarditis
?
2
Prosthetic heart valves
Congenital heart disease
Bacterial endocarditis prophylaxis?
30-60 min prior to dental procedures using what?
Whats the alternative? 3
Amoxicillin 2 grams PO
For penicillin allergy
Clindamycin 600 mg
Azithromycin 500 mg
Clarithromycin 500 mg
Here are a few of MANY complications from antibiotic therapy?
5
- Toxicity
- C. difficile diarrhea
- Alteration of gut flora and change in vitamin K levels leading to difficulty managing warfarin therapy
- Candida overgrowth
- Serious side effects
C. Difficile diarrhea and colitis is a major complication of antibiotic therapy.
Frequent: 4
Infrequent: 4
Rare: 3
Ampicillin/amoxicillin
Cephalosporins
Clindamycin
Quniolones
Chloramphenicol
Macrolides
Sufonamides/Trimethoprim
Tetracycline
Metronidazole
Aminoglycosides
Vancomycin