Pogue: Clinical Treatments Flashcards
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
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
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
Which of the following lacks activity against VRE – A) tigecycline – B) doripenem – C) daptomycin – D) linezolid
B) doripenem
Skin and Soft Tissue Infections
Most common agents
S.aureus
S.pyogenes (Group A Strep)
Skin and Soft Tissue Infections
Common disease states (3):
o Impetigo o Erysipelas (Strep) o Cellulitis (Staph, Group B Strep)
Streptococcus Pyogenes Infections:
DOC:
What type of resistance is increasing?
Penicillin (only if it is strep pyogenes alone!)
Erythromycin resistance increasing
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
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)
Oral MRSA Agents (5):
Doxycyline TMP/SMX Linezolid Clindamycin (remember to do D test if erythromycin resistant and clindamycin susceptible) Quinolones?
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
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
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
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
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)
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)
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)
Gas Gangrene
Causative Agent:
Clostridium spp. (most commonly C.perfringens)
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
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)
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)
Treatment of human bites:
Human bites (and fists to the mouth) should be treated the same way (minus the need for Pasturella coverage)
Diabetic Foot Ulcers
Causative Agents:
G(+) cocci, predominantly S.aureus; as time goes on, GNR and anaerobes as well
Diabetic Foot Ulcers
Treatment of uninfected ulcers:
Treatment: UNINFECTED ULCERS SHOULD NOT BE TREATED; ONLY TREAT UNTIL INFECTION RESOLVES Empiric
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)
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
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.
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)
BONE AND JOINT INFECTIONS
Therapy Basics:
o Long duration
o Maximum doses (IV)
o Bactericidal drugs
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
BONE AND JOINT INFECTIONS
Staphylococcus Aureus Infections
Therapy:
Oral
Oral Therapy:
Linezolid: option for patients with limited IV access (not first line)
BONE AND JOINT INFECTIONS
Staphylococcus Aureus Infections
Suppressive Therapy:
Commonly used drugs:
Often used for staph infections
Commonly used drugs:
- Doxycycline
- TMP/SMX
- Clindamycin
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
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
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)
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
Rifampin‐ remember the pearls
• Drug interactions‐ Why?
• Your patient is crying blood?
• Watch alcohol intake‐ why?
CYP inhibitor
Colorizes urine and tears
Hepatotoxicity
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
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
Review: antipseudomonal agents
- Piperacillin, Piperacillin/tazobactam
- Cefepime, Ceftazadime
- Aztreonam
- Imipenem, Meropenem, Doripenem
- Gentamicin, Tobramycin, Amikacin
- Ciprofloxacin, Levofloxacin
- Polymyxins
Disseminated Infections Attacking Joints:
DOC:
Neisseria Gonorrhea: Cetriaxone is the DOC.
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
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
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
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
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
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)
Strep Endocarditis
Causative Agents:
Duration of Treatment:
Causative Agents: Viridans strep and S.bovis
Duration of Treatment:
Standard: 4 weeks; Prosthetic Valve: 6 weeks
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)
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)
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
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
Enterococcal Endocarditis:
Duration:
Ampicillin susceptible
Vancomycin
VRE
Duration:
o Ampicillin susceptible: 4-6 weeks
o Vancomycin: 6 weeks
o VRE: at least 8 weeks
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)
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
Major side effects:
Doxycycline
TMP/SMX
Clindamycin
– Doxycycline – photosensitivity and chelation
– TMP/SMX – rash/allergic reactions
– Clindamycin – diarrhea
