Term
| When is the ideal time to give pre/peri-operative prophylaxis in a surgical procedure? |
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Definition
1 h before incision is 0.5%
2 h before is 0.7%
Give Before! |
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Term
| Why might prophylaxis be given during procedures that induce bacteremia? |
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Definition
| Endocarditis- prevent heart valve infection. |
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Term
| Why might you give Prophylaxis to immunocompromised patients? |
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Definition
| Prevent opportunistic fungal infections like Pneumocystis jjiroveci (Carinii) |
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Term
| How does one make the decision to go ahead with Pre-emptive therapy? |
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Definition
You have the labs, but not symptoms yet
Ex) Valganciclovir in transplant patient with evidence of CMV reactivation by increased viral load per PCR. |
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Term
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Definition
Broad-spectrum antibiotic treatment before precise etiology is known.
Ex) CA-pneumonia, Ventilator-associated pneumonia, Neutropenic patients and Meningitis |
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Term
| What is Pathogen-directed therapy? |
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Definition
| Organism is known but Antibiotic susceptibility is not. |
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Term
| When are NO antibiotics required? |
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Definition
1) Viral (i.e. rhinitis)
2) Contamination of sample
3) Colonization without infection (find resistant Enterococcus, but without infection)
4) Treatment has no known resolution (bronchitis) |
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Term
| What are 5 methods of susceptibility testing utilized by laboratories? |
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Definition
1) Disk diffusion (zone of inhibition)
2) Broth macrodilution, microdilution and agar dilution (MIC determination)
3) E-test (antibiotic gradient strip placed on agar to determine MIC)
4) Semi-automated (small wells of antibiotic to determine "break point" b/w susceptible and resistant.
5) Genetic testing |
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Term
| Which methods of susceptibility testing can determine MIC? |
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Definition
**need relationship b/w antibiotic amount of amount of inhibition**
1) Broth dilution/agar dilution
2) E-test |
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Term
| What pharmacodynamic considerations need to be made in prescribing antibiotics? |
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Definition
1) Concentration-dependent antibiotics (single, high dose)
- Knowledge of MIC is key- the ratio of peak concentration to MIC is predictor of efficacy of Aminoglycosides (potent gram-negative with NO bioavailability and both nephro and ototoxicity concerns) and Flouroquinolones.
2) Time-dependent Beta-lactams (lower doses more often) |
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Term
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Definition
- GI system failure or extreme illness (incapable of swallowing).
- Blood-borne infections |
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Term
| Why might you give Combination Therapy in a case of Bacterial Meningitis, TB, or Enterococcal endocarditis? |
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Definition
1) Bacterial Meningitis- wide range of organisms suspected
2) Prevent emergence of resistance (RIPE therapy)
3) Enterococcal endocarditis- Synergy of action b/w aminoglycoside (gentamycin ect.) and beta-lactam |
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Term
Explain what you would prescribe in each situation for Strep. Pneumoniae.
1) PCN MIC <=2ug/ml and PCN susceptible (87% and PUH)
2) PCN MIC= 4ug/ml and intermediate PCN susceptible (11% PUH)
3) PCN MIC >=8ug/ml and PCN resistant (2%PUH) |
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Definition
1) Treat IV PCN 18mil units/24 hours
2) Treat IV PCN 24mil units/24 hours or Ceftriaxone
Higher dose of beta-lactams overcome resistance mediated by PCn binding proteins (PBPs)
3) Treat with Vancomycin
Even high doses of beta-lactams cannot overcome PBP mediated resistance. This is the "break point" |
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Term
| What features define a "clean wound"? |
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Definition
No inflammation encountered with no entrance of GI, GU or Resp. tracts.
Anibiotics reduce infection rate from 5% to 0.8% |
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Term
| What might you prescribe for a UTI? |
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Definition
Nitrofurantoin b/e of high levels in the urine.
Example of matching drug with disease distribution. |
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Term
| What does the Cmax:MIC ratio have to do with efficacy? |
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Definition
| Maximize it to improve efficacy |
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Term
| Why are the resistance "break points" for PCN treatment of strep. pneumonia different Meningitis? |
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Definition
Because Meningitis requires CSF access, it takes more drug in order to have an effect.
The MIC break-point for meningitis resistance to PCN is lower because you just won't be able to get enough of it to the CSF! |
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Term
| Why would you give PCN prophylactically during surgery in kids with a history of Rhuematic fever? |
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Definition
| Strep infection can be fatal for the heart valves. |
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