Class 13 Deck 1 Flashcards by Charles Grant

What is the difference between bacteriocidal and bacteriostatic?

Bacteriosidal = Kill bacteria

- Bacteriostatic = Inhibit bacteria growth

How well did you know this?

Not at all

Perfectly

What is the Minimum Inhibitory Concentration (MIC)?

-Lowest concentration of antibiotic required to inhibit growth

How well did you know this?

Not at all

Perfectly

What is the Maximum Bactericidal Concentration (MBC)?

-Concentration required to kill 99.99% of the inoculum

How well did you know this?

Not at all

Perfectly

What is concentration dependent killing?

-Antibiotics that increase extent of killing with increased concentrations (aminoglycosides)

How well did you know this?

Not at all

Perfectly

What is time dependent killing?

-Clinical effectiveness is related to duration of exposure not greater concentrations.

How well did you know this?

Not at all

Perfectly

What is the post antibiotic effect?

-Antibiotics continue to suppress bacteria growth after drug is no longer detectable

How well did you know this?

Not at all

Perfectly

Post antibiotic effect (PAE) can be decreased in what type of environment?

-Acidic (infected)

How well did you know this?

Not at all

Perfectly

During the PAE phase, bacteria are more susceptible to killing by ______.

Leukocytes (body doing the work)

How well did you know this?

Not at all

Perfectly

Antibiotics with concentration-dependent killing and significant PAEs, it is more important to have very _____ _____ and allow the ______ to decrease to less than MIC (Let PAE do the work) this is the basis daily dosing of what drug?

High Peak
Trough
Amoniglycosides

How well did you know this?

Not at all

Perfectly

Sometimes the presence of an ______ may allow a drug to ______ when it otherwise wouldn’t. What is an example?

Infection, penetrate

- Meningitis

How well did you know this?

Not at all

Perfectly

What local factors may modify the efficacy of the drug?

Poorly drained infection (Low ph/O2 tension/ pus)
Mixed infection
Infected hematoma
Foreign body

How well did you know this?

Not at all

Perfectly

Food or substances containing what can alter GI absorption?

-Divalent metal ions

How well did you know this?

Not at all

Perfectly

What are the mechanisms for acquired resistance?

Decreased permeability
Increased effux pumps
Inactivation
Modification of antimicrobial target
Development of pathways that bypass target

How well did you know this?

Not at all

Perfectly

What is increased effux?

-Drug gets into cell but bacteria pumps it out.

How well did you know this?

Not at all

Perfectly

What drugs are effected by effux?

Macrolides
Fluroquinolones
Beta Lactams

How well did you know this?

Not at all

Perfectly

What is the predominant mechanism of acquired resistance of antimicrobials?

-Inactivation

How well did you know this?

Not at all

Perfectly

Beta lactams are inactivated by what?

-Beta lactamases

How well did you know this?

Not at all

Perfectly

Modification in the penicillin binding proteins account for methicillin resistance in _______ and penicillin resistance in _______ and _______

staphylococcus

- pneumococci and enterococci

How well did you know this?

Not at all

Perfectly

What are the three reasons to use multidrug therapy?

Polymicrobial infections
Emergence of resistance
Synergy

How well did you know this?

Not at all

Perfectly

What broad spectrum antibiotics can cover multiple organism infections?

Ampicillin-sublactam

- Imipenen-cilastin

How well did you know this?

Not at all

Perfectly

How should resistance be inhibited? What is an example of this?

Administration of 2 antibiotics w/ different MOAs

- TB

How well did you know this?

Not at all

Perfectly

What are the synergy combination responses?

Antagonism (1+1=0.5)
Indifferent (1+1=1)
Inbetween (1+1=1.5)
Additive (1+1=2)
Synergistic (1+1=3)

How well did you know this?

Not at all

Perfectly

Treatment of infection with antimicrobial use can be narrowed down to what three things?

Delivery of drug to infection
High enough concentration
Sufficient time to inhibit/kill bacteria

How well did you know this?

Not at all

Perfectly

What 5 infections require bactericidial therapy?

CV infection (endocarditis)
Meningitis/Cerebral abscess
Neutropenic patients
Osteomylitis
Prothesis/vascular access infection w/o removing device

How well did you know this?

Not at all

Perfectly

What 3 things should be known to make proper therapy choices?

- Patient - Invading microbe - Antimicrobial agents

What information should be known about the patient?

- Where exposed | - Previous antibiotic treatments

What are some examples of impaired host defenses against SPECIFIC INFECTION types?

- Anatomical (ulcerations) | - Secondary (Neutropenia, aspleenia, Malignancy, HIV, immunosupressant therapy)

What can increase a patients risk for infection complications? and what should you consider?

- Prothesis or foreign bodies (Heart valves, grafts) | - front loading antibiotic therapy

How are preggos at risk for infection complications?

- Pharmacokinetics are altered - Increased VD and GFR - Little or not safety data on ABX

What ABX is OK for preggos?

- PCN, Cephalosporins and erythomycin | - except ticarcillin

What ABX should be used only if necessary in preggos?

- Aminoglycosides (cranial nerve dysfunction) | - Isoniazid (Retardation, myoclonus, seizures)

What 6 drugs should be avoided in preggos?

- Metranidazol - Ticarcillin - Tetracyclines - Trimethoporin - Rifampin - Fluroquinolones

What does tetracyclines do to fetus?

- Fatty necrosis of liver - Panreatitis - renal innjury

What can increase risk of taking a specific ABX drugs?

- Previous reaction to the ABX | - Decreased renal/hepatic function

Decreased renal function can have what effect with aminoglycosides? PCN/Imipenem? Ticarcillin/Mezlocillin/Pipercillin?

- 8th cranial nerve (ototoxicity) - Seizures - Bleeding (platelet dysfunction)

80% of all nosocomial infections occur where?

- Resp system (24%) from vents - Blood (17%) from IV catheters - Urniary tract (36%) From foleys

IV catheters are a common cause of what?

- Bactermia | - Fungemia

How is catheter infection defined?

- 1 positive blood culture from cath and perpherial site - Clinical manifestation of infection - No other apparent source

What central line sites are at greatest risk for infection?

Femoral > I.J. > Subclavian

What is the initial therapy for catheter related infections? and why?

- Vancomycin | - High prevalence of MRSA and staph epidermidis in noscomial infections

When would gram negative rod coverage w/ catheter related infections be appropriate?

- infection at other body site | - CV instability

How should staph epidermidisa and enterocococcus be treated?

Remove catheter and short course of ABX

Staph aureus often disseminates and can cause what destructive infections?

- Osteomylitis | - Endocarditis

How should staph aureus be treated?

- Prolonged ABX therapy | - Look for metaststic lesions

Candida fungemia requires what?

- Looking for metastatic infections | - If non found remove cath and use fluconazole

What drug is usually used for surgical prophylaxis? and why?

-1st gen cephalosporin (cefazolin)

What are the 4 would classes?

- Class I: Clean - Class II: Clean-Contaminated (surgery in area known to have bacteria) - Class III: Contaminated (Break in sterile technique) - Class IV: Dirty-Infected (infection before surgery)

What is the most common infection from clean wounds? and what should be administered?

- Staphylococcal | - Some do not require prophalyxis

Clean-Contaminated and contaminated requires what? (including hyst and urinary tract procedures)

Prophylactic ABX

Patients w/ UTI's should have what ABX?

-ABX against gram negative bacilli (Fluorquinolones, aminoglycosides, 3rd gen cephlasporins)

Biliary tract and urinary tract should have what type of ABX?

- Ampicillin-sublactam | - Piperacillin-tazobactam

What is the SCIP mandate for prophylactic ABX?

-All patients 18 and up have parenteral ABX -Must be administered w/i one hour prior to incision (fluroquinolone & Vanco w/i 2 hours)

Bacteremia resulting from ______ is much more likely to cause IE than from bacteremia associated with a dental, GI, or GU procedure.

-Daily activities

What are the new guidelines for infective endocarditis?

-ABX Prophylaxis for those with the highest risk of adverse outcomes should they develop IE, rather than those at highest risk of developing IE.

What 4 cardiac conditions are at greatest risk for adverse outcomes with IE?

- Prosthetic cardiac valve - Previous IE - Congentital heart disease - Cardiac transplant who develop valvulopathy

What procedures have increased risk for developing bacteremia subsequent IE?

- Dental | - Respiratory tract procedures

What bacteria is the most common cause of endocarditis?

-Streptococcus viridans

What is the preferred prophylaxis for dental or respiratory procedures?

- PO amoxicillin - IV ampicillin/cefazolin in unable to take PO - PO cephalexin/Clindamycin/Azithromycin if allergic to PCN

Post op pneumonia is NOT community acquired and usually needs what ABX?

-Clindamycin (similar to erythromycin but more active against anaerobes)

What is the leading cause of noscomial GI infection?

-C-Diff

What causes C-Diff?

- ABX by altering normal bowel flora | - Enterotoxin A and Cytotoxin B

What is the ABX of choice in C-Diff?

- Metronidazole | - Vanc if not responsive to metronidazole

Class 13 Deck 1 Flashcards

(62 cards)