Bone & Joint, Bloodstream & Line

Bone & Joint infxns comprised of 2 disease processes —>

1. osteomyelitis

2. septic arthritis

Osteomyelitis Diagnosis: LABS

1. + (3)

2. Presence of _____ in chronic cases

3. Cultures → 2

4. -

1. +WBC, CRP, ESR

2. anemia

3. blood, deep tissue

4. bone biopsy

Best option to rule in/rule out osteomyelitis?

MRI

Typical pathogen for osteo/periprosthetic joint infxns

staph aureus 

Ostoe/Joint DEFINITIVE THERAPY

IV therapy may be converted to PO if there is a clear clinical response after ______

*Patients must have good adherence and outpatient follow-up!!!

7-10 days

OSTEO/JOINT INFXNS definitive therapy

Preferred tx options

1. MSSA →

2. MRSA →

3. Streptococcus →

4. Enterococcus →

5. Enterobacteria (GNR) →

6. Pseudomonas →

7. Anaerobes →

1. oxacillin, nafcillin, cefazolin

2. vanco

3. PCN or cephalo 

4. pen G, ampicillin

5. ceftriaxone

6. ceftazidime, cefepime, zosyn

7. metronidazole, clindamycin

________ can cause rhabdomyolysis!!!

daptomycin

OSTEOMYELITIS DURATION OF THERAPY

1. Acute

2. Chronic

1. 6 weeks

2. 6 weeks IV → 3-12m PO (if indicated)

SEPTIC ARTHRITIS EMPIRIC THERAPY

1. If culture yields MSSA →

2. Gram stain negative →

3. Duration: IV antibiotics _______ follow by PO therapy for a minimum of ______

4. Longer courses of IV ______ may be needed to treat difficult pathogens such as Pseudomonas

5. *_______ course recommended for bacteremia and secondary S. aureus arthririts

1. anti-staph PCN (oxacillin, nafcillin), or 1st gen cephalo (cefazolin)

2. vanco + GNR agent

3. 2 weeks → +1-2 weeks

4. 3-4 weeks

5. 4 week

PROSTHETIC JOINT INFXN

1. empiric therapy 

2. If staph is suspected or confirmed …

1. rifampin 

2. NEVER use ^ as monotherapy

BLOODSTREAM INFECTIONS

1. Community-acquired → BSI occurring ____ after hosp admission

2. Hospital-acquired

1. <48h

2. >/= 48h

BSI PATHOGENS

1. Important clinical pathogens → 4

2. USUAL CONTAMINANT

1. coag + staph AUREUS, enterobacteria, pseudomonas, candida

2. coag - staph EPI

BSI Contaminants

When potential contaminant is seen in 1 of 2 blood cultures

We assume it is a pathogen and TREAT it IF:

1. Same organism in ½ blood cultures and ALSO in _________ (urine, wound, etc)

2. Presence of organism in ½ blood cultures in the setting of ____________ (infective endocarditis)

3. Same organism is observed in ________ (2/2)

1. another culture source

2. prosthetic heart valves/devices

3. multiple blood culture

Which is a probable contaminant with 1 of 2 blood cultures being positive?
A. Coagulase positive Staphylococcus
B. Coagulase negative Staphylococcus
C. Candida
D. Pseudomonas

B

Which could be a pathogen and should be treated empirically?
A. 1 of 2 blood cultures AND urine both growing Staphylococcus epidermidis
B. 1 of 2 blood cultures growing coagulase negative Staphylococcus AND PSH includes heart valve replacement
C. 2 of 2 blood cultures growing Streptococcus anginosus
D. All of the above
E. None of the above

D

Management of S. aureus Bacteremia (SAB)

1. All patients should be treated with ____ antibiotics

2. Control the ________

3. Document clearance → __________ after initial + cultures

4. EMPIRIC coverage → preferred + alt

5. MSSA (definitive) → 

6. MRSA (definitive) →

1. IV

2. source of infxn

3. repeat blood cultures 48h

4. vanco AUC/MIC 400-600 → daptomycin 

5. nafcillin, oxacillin → cefazolin (non sev PCN allergy)

6. same as empiric

DAPTOMYCIN monitoring

CK levels baseline + weekly

SAB SYNERGISTIC Therapy Considerations

1. currently recommends AGAINST addition of ________

2. currently recommends AGAINST addition of ________ in the absence of prosthetic devices (can use when present) → NEVER USE AS MONOTHERAPY!

1. gentamicin

2. rifampin

SAB DURATION OF THERAPY uncomplicated

14 days from 1st set of - blood cultures

SAB DURATION OF THERAPY complicated

28-42 days from 1st set of - blood cultures

OTHER GRAM + BSI ANTIMICROBIAL THERAPIES

1. Enterococcus →

2. Vancomycin-resistant enterococci VRE →

3. Streptococcus →

1. ampicillin, vanco, combo +gentamicin or amp+ceftriaxone

2. daptomycin

3. IV PCN or cep

h

Which is the most appropriate therapy for a MSSA BSI?
A. Vancomycin
B. Linezolid
C. Daptomycin
D. Nafcillin

D

Which is most appropriate therapy for a MSSA BSI in a patient with a non-SEVERE PCN allergy?
A. Nafcillin
B. Vancomycin
C. Cefazolin
D. Gentamicin

C

Which is the most appropriate initial therapy for a MRSA BSI?
A. Vancomycin
B. Linezolid
C. Daptomycin
D. Nafcillin

A

Which is the most appropriate therapy for a VRE BSI?
A. Vancomycin
B. Linezolid
C. Daptomycin
D. Nafcillin

C

Which is day #1 of therapy for a Staph aureus BSI?
A. 1st day antibiotic administered
B. 1st day clear blood culture collected

B

Which is TRUE regarding antibiotic monitoring parameters?
A. Daptomycin → platelets
B. Linezolid → creatine kinase
C. Ceftriaxone → serum creatinine
D. Vancomycin → AUC/MIC

D

10/16

1. gram NEGATIVE BSIs - empiric therapy is based on …

2. ESBL + BSI tx →

3. Duration of therapy

1. source of infxn

2. carbapenem

3. 7-14d

BSIs: Empiric Pseudomonas coverage is needed WHEN → 4

1. sepsis w unknown source of infxn

2. immunocomp

3. IV abx in prev 90d

4. hospital-acquired