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Flashcards in Pogue: Clinical Treatments Deck (56):
1

JP is a 31 y/o male with blood cultures positive
for P.aeruginosa. Which of these agents would
not be appropriate empirically?
– A) cefepime
– B) tigecycline
– C) piperacillin
– D) meropenem

B) tigecycline
Will get a question like this

2

LL is started on ampicillin for an urinary tract
infection with e.faecalis which of the following
adverse events is most likely
– A) nephrotoxicity
– B) increased LFT
– C) allergic reaction
– D) Infusion site reaction

C) allergic reaction
Beta Lactams and allergic rxns

3

Linezolid’s therapy limiting side effect is
– A) a high rate of nephrotoxicity
– B) allergic reactions
– C) thrombocytopenia
– D) drug interactions, lots of ‘em!
– E) hepatotoxicity

C) thrombocytopenia
Will get a question like this

4

Which of the following lacks activity against
VRE
– A) tigecycline
– B) doripenem
– C) daptomycin
– D) linezolid

B) doripenem

5

Skin and Soft Tissue Infections
Most common agents

S.aureus

S.pyogenes (Group A Strep)

6

Skin and Soft Tissue Infections
Common disease states (3):

o Impetigo
o Erysipelas (Strep)
o Cellulitis (Staph, Group B Strep)

7

Streptococcus Pyogenes Infections:
DOC:
What type of resistance is increasing?

Penicillin (only if it is strep pyogenes alone!)

Erythromycin resistance increasing

8

Staphylococcus Aureus Infections:

Empiric coverage:
Recently need to cover:

EMPIRIC COVERAGE WILL USUALLY NEED TO COVER STAPH!!

Increase in CA-MRSA over the past few years requires that we routinely cover for MRSA as well

9

Oral MSSA Agents (3):

Amoxicillin/clavulanic acid

Dicloxacillin (Negative- needs to be dosed 4x per day)

Cephalexin (Negative- needs to be dosed 4x per day)

10

Oral MRSA Agents (5):

Doxycyline
TMP/SMX
Linezolid
Clindamycin (remember to do D test if erythromycin resistant and clindamycin susceptible)
Quinolones?

11

Why are Quinolones last line against MRSA?

Quinolones (maybe respiratory quinolones, which have good activity; BUT really last line!!)

Why? One-step, rapid mutation against staphylococcus resulting in resistance

12

Worried about Staph and Strep Together?

TMP/SMX and doxycycline?
All other MSSA/MRSA agents?

TMP/SMX and doxycycline are NOT RELIABLE against GAS

All other oral MSSA/MRSA agents could be used

13

Skin and Soft Tissue Infections
Treatment Basics:

Use agent with most narrow spectrum

Follow-up at 24-48 hours is crucial: assess success of regimen

14

Use agent with most narrow spectrum:

MSSA:
MRSA:

TMP/SMX?

MSSA: beta-lactam

MRSA: doxycycline, clindamycin are good options; ED physicians often use TMP/SMX if they are sure it is MRSA

Remember: TMP/SMX will NOT cover GAS

15

Severe Cellulitis

MSSA:
MRSA:

Severe Cellulitis: IV therapy is indicated

o MSSA: nafcillin is DOC
o MRSA: vancomycin is DOC (Note: empiric coverage often for MRSA due to increasing prevalence)

16

Cellulitis
Duration of Therapy:

Uncomplicated vs. severe

Duration of Therapy:

Tailored to clinical scenario: this is why follow up assessment is necessary

Uncomplicated Cellulitis: 5 days

Severe Cellulitis: up to 14 days (IV therapy; can step down to oral treatment)

17

Necrotizing Faciitis

Causative Agent:
Polymicrobial Infections:

Causative Agent: S.pyogenes (most commonly); can also be Vibrio, aeromonas and MRSA (more recently)

Polymicrobial Infections: can be seen in at risk populations (PVD, DM, decubitis ulcers)

18

Gas Gangrene
Causative Agent:

Clostridium spp. (most commonly C.perfringens)

19

Necrotizing Infections
Treatment:

Group A Strep and Clostridial Infections:

Clindamycin?

PROMPT SURGICAL DEBRIDEMENT

Group A Strep and Clostridial Infections: penicillin + clindamycin

Clindamycin: although it has decent activity against these agents, really given to suppress toxins (via inhibition of protein synthesis); hypothetically, other ribosomal Abx would work as well

20

Animal Bites

Empirical treatment:
Skin bugs:
Mouth bugs:

Animal Bites:
• Need to cover Pasturella multocida empirically!!
- Also staph and strep (because these are on the skin)
- Also anaerobes (because these are in the mouth)

21

Animal Bites
Treatment:

PO:
IV:

Pasturellla often has a beta-lactamase: therefore, B-lactam/B-lactamase inhibitors are the mainstay of therapy

Amoxicillin/Clavulanic Acid: PO

Ampicillin/Sulbactam: IV

Alternatives: doxycycline, moxifloxacin (especially in penicillin allergies)

22

Treatment of human bites:

Human bites (and fists to the mouth) should be treated the same way (minus the need for Pasturella coverage)

23

Diabetic Foot Ulcers
Causative Agents:

G(+) cocci, predominantly S.aureus; as time goes on, GNR and anaerobes as well

24

Diabetic Foot Ulcers
Treatment of uninfected ulcers:

Treatment: UNINFECTED ULCERS SHOULD NOT BE TREATED; ONLY TREAT UNTIL INFECTION RESOLVES Empiric

25

Diabetic Foot Ulcers
Therapy:

Therapy:
o IV therapy initially
o Commonly with vanomycin + amp/sulbactam (however, a wide variety of regimens can be used to cover the likely pathogens)

26

Diabetic Foot Ulcers
Duration:
Mild
Moderate to severe
osteomyelitis

Duration: only treat until infection is gone (not until ulcer heals)
o Mild Infections: 1-2 weeks
o Moderate to Severe Infections: 2-4 weeks
o Osteomyelitis: 4-6 weeks

27

BONE AND JOINT INFECTIONS
Basics:
The most common agents:

Most common causative agents: staphylococcus spp. (MSSA, MRSA, coagulase-negative staph); in certain scenarios, anything can play a role.

28

BONE AND JOINT INFECTIONS
Duration of Therapy:

o At least 3 weeks of therapy for joint infections (4+ weeks for S.aureus or pseudomonas)
o At least 4-6 weeks of therapy for bone infections (possibly followed by suppressive therapy)

29

BONE AND JOINT INFECTIONS
Therapy Basics:

o Long duration
o Maximum doses (IV)
o Bactericidal drugs

30

BONE AND JOINT INFECTIONS
Staphylococcus Aureus Infections
Therapy:
IV

IV therapy to start:
o MSSA: nafcillin is the DOC
o MRSA: vancomycin is the DOC

31

BONE AND JOINT INFECTIONS
Staphylococcus Aureus Infections
Therapy:
Oral

Oral Therapy:

Linezolid: option for patients with limited IV access (not first line)

32

BONE AND JOINT INFECTIONS
Staphylococcus Aureus Infections

Suppressive Therapy:

Commonly used drugs:

Often used for staph infections

Commonly used drugs:
- Doxycycline
- TMP/SMX
- Clindamycin

33

BONE AND JOINT INFECTIONS
Staphylococcus Aureus Infections

Note About Rifampin:
Monotherapy:

However, commonly used when hardware is involved (prosthetic valves, hips etc.) Why?
What is used in these scenarios?

Not good as monotherapy (due to easy mutation)

Staph aureus produces a biofilm on foreign material
Rifampin has excellent biofilm penetration

Nafcillin/Vancomycin + Rifampin used in these scenarios

34

BONE AND JOINT INFECTIONS
Staphylococcus Aureus Infections

What is given to manage pain?

Anti-inflammatory drugs given to relieve pain

Standard antibiotic treatment often effective

35

Gram Negative Infections:

First line therapy:
Oral Step Down:

First line therapy: IV B-lactam against causative agent

Oral Step Down: FQ (due to good oral availability; also good for penicillin allergy)

36

JJ is a 32 y/o with uncomplicated cellulitis. He
has a history of anaphylaxis with penicillin.
Cultures show s.aureus susceptible to all of
the following antibiotics. Which treatment
should be chosen? Why?
– A) cephalexin
– B) linezolid
– C) vancomycin
– D) doxycycline

D) doxycycline

It is less expensive.
Cephalexin-penicillin
linezoild - more narrow

37

Rifampin‐ remember the pearls
• Drug interactions‐ Why?
• Your patient is crying blood?
• Watch alcohol intake‐ why?

CYP inhibitor

Colorizes urine and tears

Hepatotoxicity

38

PSEUDOMONAS:

G+/-?
What do some physicians do?

Gram negative that clinicians worry about because it is virulent and develops resistance easily

Some physicians try to use 2 agents to double cover pseudomonal infections- there is no clinical evidence that this is effective in vivo

39

Pseudomonal Treatment:

IV B-lactam for 4-6 weeks
- Joint: 4 weeks
- Bone: 6 weeks

Can also add anti-pseudomonal Aminoglycoside (gentamicin, tobramycin, amikacin) or FQ (cipro, levo) for 2 weeks

40

Review: antipseudomonal agents

• Piperacillin, Piperacillin/tazobactam
• Cefepime, Ceftazadime
• Aztreonam
• Imipenem, Meropenem, Doripenem
• Gentamicin, Tobramycin, Amikacin
• Ciprofloxacin, Levofloxacin
• Polymyxins

41

Disseminated Infections Attacking Joints:
DOC:

Neisseria Gonorrhea: Cetriaxone is the DOC.

42

BACTERIEMIAS
Basics:
Source Control:

Skin/bone/joint:
Catheter-related:
Pulmonary:
Urosepsis:

Source Control: the appropriate therapy differs based on the source of the infection; if you can manage the source you can manage the bacteremia

o Skin/Bone/Joint: Gram (+)
o Catheter-Related: Gram (+), Gram (-), candida spp.
o Pulmonary: organisms associated with pneumonia
o Urosepsis: urinary pathogens

43

Catheter-Related Bloodstream Infections:
Basics:

Therapy:

Basics:
o The longer the line is in, the higher the chance (don’t leave it in longer than it has to be)
o If you can, remove infected catheter (not always possible)

Therapy: antibiotic lock therapy (high concentrations of Abx placed directly in the catheter)
- Almost never works

44

Catheter-Related Bloodstream Infections

Duration:
Coagulase-Negative Staph:
Most bacteria and fungi:
S.aureus (seeding):

Duration:
o Coagulase-Negative Staph: 5-7 days
o Most bacteria and fungi: 14 days
o S.aureus (seeding): at least 14 days

45

Catheter-Related Bloodstream Infections

Candida in the Blood:
Empiric therapy: depends on:
Risks:
No/Low-Risk for C.glabrata:
C.glabrata:

Empiric therapy depends on risk for fluconazole-resistant organisms (C.glabrata)

Risks: recent azole exposure, known carrier of C.glabrata

No/Low-Risk for C.glabrata: use fluconazole
C.glabrata: use an echinocandin

46

ENDOCARDITIS
Basics:
Causative Agents:

Basics:
- Difficult to treat (often needs surgical intervention)

Causative Agents:
o G (+) organisms: most common
o Gram (-), including pseudomonas
o Candida spp.
o HACEK organisms

47

ENDOCARDITIS
Duration:
Regimen:

o Duration: usually 4-6 weeks
o Regimen: IV antibiotics (max dose, bactericidal); occasionally, highly bioavailable oral drugs may be used (as step down therapy)

48

Strep Endocarditis

Causative Agents:
Duration of Treatment:

Causative Agents: Viridans strep and S.bovis

Duration of Treatment:
Standard: 4 weeks; Prosthetic Valve: 6 weeks

49

Strep Endocarditis

Treatment:
What is preferred?
Second-line?
What can be added? Why for resistant and sensitive strains?

Treatment: depends on susceptibility pattern

B-Lactams Preferred: penicillin (if susceptible) or cetriaxone

Vancoycin: if penicillin allergy exists

Gentamicin can be added:
- Resistant strains: for synergy (entire course of treatment)
- Sensitive strains: to shorten duration of therapy (only 2 weeks)

50

Staph Endocarditis:

Causative Agents:

Treatment:
MSSA/MSSE:
What if they have an allergy to penicillin? Severe? Non-severe?

Causative Agents: S.aureus and coagulase-negative staph (most commonly S.epidermidis)

Treatment:
MSSA/MSSE:
- Nafcillin for 6 weeks
- Gentamicin for 3-5 days (synergy; shortens duration of bacteremia)

Penicillin Allergy:
Cefazolin (non-severe)
Vancomycin (severe)

51

Staph Endocarditis:

Treatment
MRSA:
Prosthetic Valve:

MRSA:
Vancomycin (high dose)

Prosthetic Valve:
May require more than 6 weeks of nafcillin therapy
Add rifampin (penetration of biofilm)
Gentamicin for 2 weeks

52

Enterococcal Endocarditis:
Treatment:
DOC:
If VRE (3):
What should be added to cell wall agent for synergy?

Ampicillin is the DOC (if sensitive); if not, vancomycin is next in line

If VRE:
- Daptomycin
- Quinupristin/Dalfopristin
- Linezolid

Gentamicin should be added to cell wall agent for synergy

53

Enterococcal Endocarditis:

Duration:
Ampicillin susceptible
Vancomycin
VRE

Duration:
o Ampicillin susceptible: 4-6 weeks
o Vancomycin: 6 weeks
o VRE: at least 8 weeks

54

Miscellaneous Endocarditis Bugs

G-:
Use what if possible:
Some use:

Candida:
What is notable?
Use?

HACEK:
Common in what type of pts?
Commonly used drugs (2):

Gram (-):
o Use B-lactam if possible (high doses)
o Some use 2 drugs for pseudomonas

Candida:
o HIGH MORTALITY RATE
o Therefore, will always use amphotericin B + flucytosine (synergy)

HACEK Organisms:
o Gram negatives common in patients in the community who are not IV drug users
o Commonly Used:
- Ceftriaxone (4 weeks)
- Ampicillin/Sulbactam (4 weeks)

55

What is the duration of each infection:

Prosthetic valve strep endocarditis

Coag (‐) staph (Catheter-related bloodstream infection) CRBSI

Severe cellulitis

Candida bacteremia

Pseudomonal joint infection

Prosthetic Valve Strep Endocarditis: 6 weeks

Coag (‐) Staph CRBSI: 5-7 weeks

Severe Cellulitis: 14 days

Candida Bacteremia: 14 days

Pseudomonal Joint Infection: 4 weeks

56

Major side effects:
Doxycycline
TMP/SMX
Clindamycin

– Doxycycline – photosensitivity and chelation
– TMP/SMX – rash/allergic reactions
– Clindamycin – diarrhea