Anti-microbial General Principles Flashcards

1
Q

Which type typically attack the cell wall- bacteriocidal or bacteriostatic?

A

Bacteriocidal attack the cell wall to kill the organism

Bacteriostatic stop growth, work on proteins and ribosomal subunits

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2
Q

What is the minimum inhibitory concentration (MIC)?

A

Lowest concentration of ABX required to prevent growth

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3
Q

Can you compare the potency different ABX based on their MIC for a given organism?

A

No

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4
Q

What is minimum bactericidal concentration (MBC)?

A

Lowest concentration required to kill bacteria

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5
Q

MIC or MBC: Reported on the culture and sensitivity report?

A

MIC

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6
Q

What is concentration-dependent killing?

A

Want to get a high peak concentration and then allow concentration to drift down over time. Examples aminoglycosides and fluoroquinolones

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7
Q

What is time-dependent killing?

A

Want the MIC to be longer period of time. Trough values are typically important for ABX the are time dependent killing.
Example is beta lactams, monobactams, macrolides

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8
Q

Is post-antibiotic effect demonstrated in all antimicrobials?

A

Yes; demonstrated in virtually all antimicrobials

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9
Q

What is Post-antibiotic effect (PAE)?

A

ABX continue to suppress the growth of bacteria even after the ABX is no longer detectable

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10
Q

PAE decreased or increased in acidic environments?

A

Decreased in acidic (infected) media

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11
Q

T/F: Post-antibiotic effect is especially present in concentration dependent ABX?

A

True

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12
Q

What four things contribute to antimicrobial resistance?

A
  1. Overuse for inappropriate indications
  2. Broad Spectrum
  3. Poor infection control
  4. Inappropriate dose or duration
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13
Q

T/F: All gram positive bacteria have intrinsic resistance to vancomycin?

A

False, all gram negative bacteria

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14
Q

Intrinsic or Acquired resistance definition: reflects a genetic alteration in the bacteria that renders a once effective antimicrobial ineffective?

A

Acquired

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15
Q

What are the four mechanisms through which acquired resistance is achieved?

A
  1. Decreased permeability (Stops the ABX from entering the organism)
  2. Increased efflux pumps (form pumps to “kick out” ABX)
  3. Inactivation (ex. beta lactamase)
  4. Modification of antimicrobial target
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16
Q

T/F

The more board the spectrum, the greater chance of resistance

A

True

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17
Q

T/F

Continuous infusion has been shown to be more effective than intermittent boluses

A

FALSE

has not been shown

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18
Q

Should 2 ABX with different MOA be used?

A

Yes to inhibit emergence of resistant strains of an organism. Creates synergistic effect

Ex. beta lactam and aminoglycoside (BL breaks down bacterial cell wall and allows easier entry for aminoglycoside)

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19
Q

Treatment of an established infection with an effective therapy of ABX agents is based upon what three things?

A
  1. Delivery of a concentration of drug to the site of infection
  2. Concentration sufficient to kill or inhibit growth of the offending organism
  3. Sufficient period of time to eradicate the infection
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20
Q

What 5 clinical situations is bactericidal therapy considered necessary for clinical cure?

A
  1. CV infection (particularly endocarditis or prosthetic valves)
  2. Meningitis and cerebral abscess.
  3. Severe neutropenia
  4. Osteomyelitis
  5. Tx of prosthesis or vascular access related infections w/o removing the device
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21
Q

Vascular access devices typically grow what type of bacteria?

A

Gram Positive

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22
Q

Lung infections typically grow what type of bacteria?

A

Gram Negative

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23
Q

What is an antibiogram?

A

A chart demonstrating the resistance patterns in your specific hospital/facility/region and compares bacterial strains and how susceptible they are to each ABX available

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24
Q

What are examples of impaired host defense?

A
  1. Anatomical (ulceration)
  2. Neutropenia
  3. Aspleenia
  4. Malignancy
  5. HIV
  6. Immunosuppresant therapy
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25
Q

How are the pharmacokinetics of pregnant patients changed?

A

Increased volume of distribution and increased GFR

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26
Q

T/F: Penicillins, Tetracyline, Cephalosporins, and Erythromycin are all considered safe for pregnant patients?

A

False; Tetracycline should always be avoided

27
Q

What medications are to be avoided in pregnant patients?

A
  1. Metranidazole
  2. Ticarcillin
  3. Rifampin
  4. Trimethoprim
  5. Fluoroquinolones
  6. Tetracyclines
28
Q

Canadian Population Study determined which three ABX had no increased risk to fetus or mother?

A

Amoxil, Cephalosporins, Macrobid

29
Q

Why is tetracycline contraindicated in pregnant patients?

A

Associated with acute fatty necrosis of liver, pancreatitis, and possible renal injury

30
Q

If patient contracted itchy red areas with previous ABX treatment, should that medication be used again?

A

Yes; as long as not raised rash

31
Q

Per 2018 CDC data, ____in____ hospitalized patients will develop an infection?

A

1 in 31

32
Q

Rank central line location sites from most likely to least likely to get infected

A

Femoral>I.J.>Subclavian

Risk increase the further the site is from the heart

33
Q

What is the disease associated with altered bowel flora?

A

Pseudomembranous enterocolitis caused from Clostridium difficile over growth

34
Q

What two toxins mediate C.Diff pathogenesis?

A
  1. Enterotoxin A

2. Cytotoxin B

35
Q

How is C Diff diagnosis confirmed?

A

With detection of one of the toxins

36
Q

What percent of successfully treated C Diff patients have relapse infection?

A

10%

37
Q

What is treatment for C.Diff?

A
  1. Oral Vanco (1st line treatment for mild, mod, sever)
  2. Dificid (fidaxomicin) (1st line treatment for mild, mod,severe)
  3. Fecal Transplant

Don’t use Flagyl anymore d/t SE’s (more than 2 rounds and get neuro damage)

38
Q

Which ABX has the highest risk of developing C Diff?
Second Highest risk?
Rarely?

A

1st Cleocin
2nd Cephalosporins
Rarely- Vancomycin and Flagyl

39
Q

T/F: PPI and H2 Antagonist therapy does not increase risk of developing C Diff?

A

False; while PPI is associated with higher risk, both increase risk of developing C Diff infection

40
Q

What is the “best way” (per emily) to cure C Diff?

A

Fecal Transplant (99% cure rate)

41
Q

What happens if an obese patient donates feces for fecal transplant?

A

The recipients have been shown to increase weight

42
Q

What percentage of Surgical Site Infections (SSI) are considered preventable?

A

50%

43
Q

Why is cefazolin chosen so frequently for SSI?

A
  1. Low cost
  2. Broad spectrum
  3. Low incidence of allergic reaction
44
Q

Gross GI spillage is an example of what wound class?

A

Class III

45
Q

Perforated viscera or old wound with devitalized tissus is an example of what wound class?

A

Class IV

46
Q

Surgery in areas known to harbor bacteria is an example of what wound class?

A

Class II

47
Q

Surgery on traumatic wounds is an example of what wound class?

A

Class III

48
Q

T/F: Class IV wound is the only wound class that REQUIRE ABX?

A

False; Class III and Class IV are required, while Class II should be considered

49
Q

Which organism is most common species on clean wounds?

A

Staphylococcal

50
Q

What are recommendations for patients at high or moderate risk undergoing procedures involving infected tissues or receiving prosthetic cardiac valves?

A
  1. Include anti-staphylococcal ABX for cellulites and osteomyelitis
  2. Coverage for active infections
    (i dont even know wtf this slide means)
51
Q

What are recommendations for fungal infection prophylaxis?

A

Little data to support it
Difficult to prove fungal infection
Issue complicated by fluconazole resistant C Albicans emerging and other changing resistant fungal species

52
Q

(Per Emily) When should ancef be given for SSI?

A

60 mins prior to incision

53
Q

(Per Emily) when should vanco be given for SSI?

A

120 mins prior to incision

54
Q

What is typical dose of vancomycin?

A

15mg/kg on Actual Body Weight up to around 2.5g

55
Q

Elderly and morbidly obese patients have a volume of distribution close to __, so if we are using .7 to dose them with Vanco we are ____ them

A

1

underdosing

56
Q

What two ABX’s should be given to pregnant patients only if necessary?

A

Aminoglycosides

Isoniazid

57
Q

What reactions are considered “true allergic reactions” to ABX?

A

Anaphylaxis
Steven-Johnson syndrome
Allergic interstitial nephritis

58
Q

3 most common types of nosocomial infections

A

Urinary
Respiratory
Blood

59
Q

T/F

Antibiotic impregnated catheters will always decrease risk of bactermia

A

FALSE

may decrease the risk….proven to be not that great

60
Q

What percentage of the population are natural carriers of c.diff?

A

10%

they are at a higher risk of infection

61
Q

T/F

You can get c.diff infection with a single dose on Ancef

A

True

62
Q

What surgical wound class is atraumatic, has no break in sterile technique and no entry into the respiratory, GI, GU tracts?

A

Class I

63
Q

If a procedure is long, you want to redose your prophylactic ABX after __ half-lives

A

2

So,
Ancef (t= 2hrs) after 4 hours
Cleocin (t =3hrs) after 6 hours
Vanco (t = 8hrs) after 16 hours