Cellulitis, Osteomyelitis

Question 1

Non MRSA Cellulitis treatment

Answer 1

Penicillin G (if definitively streptococcal)
Cefazolin/cephalexin
Ceftriaxone
Clindamycin

Question 2

Empiric MRSA coverage needed for cellulitis with these factors

Answer 2

Penetrating trauma
IVDU
Purulent drainage
Nasal colonization with MRSA
Evidence of MRSA elsewhere or SIRS w/ nonpurulent cellulitis

Question 3

Outpatient empiric MRSA therapy for cellulitis

Answer 3

Clindamycin
Bactrim (+ B lactam to cover streptococcus)
Doxycycline (+ B lactam to cover streptococcus)

Question 4

Inpatient empiric MRSA therapy cellulitis

Answer 4

Vancomycin
Linezolid
Daptomycin
Telavancin

Question 5

Treatment duration for celluitis

Answer 5

5-10 days

Question 6

Erysipelas

Answer 6

Skin infection that spreads through lymphatic system in skin
Usually occurs in infants, older adults
Warmth, erythema, pain
Edge of infection is elevated and sharply demarcated
Systemic signs common but blood culture rarely positive (5%)

Question 7

Erysipelas common organism

Answer 7

Group A Streptococcus (G, C, B also seen)

Question 8

Erysipelas treatment

Answer 8

Penicillin G
Cefazolin
Clindamycin

5 days

Question 9

Necrotizing fasciitis

Answer 9

Involves subcutaneous fat and superficial fascia
Severely alters surrounding tissue, leads to gangrene or cuteanous anesthesia

Question 10

Streptococcol nec fasc

Answer 10

Streptococcus pyogenes (type 2)

Spontaneous
Varicella
Minor trauma (cuts, burns splinters)
Surgical procedure

Question 11

Mixed infection nec fasc

Answer 11

Facultative and anaerobic bacteria (type 1)

Secondary infection to:
Perianal abscess
Abdominal surgery
Trauma
Decubitus ulcer
IVDU

Question 12

Most important part of nec fasc treatment

Answer 12

Surgical debridement

Question 13

Empiric ABX therapy for nec fasc

Answer 13

Vancomycin or linezolid
PLUS
Zosyn or carbapenem or ceftraixone + metronidazole

If GAS, S. aureus, or Clostridium spp suspected:
Add Clindamycin or linezolid

Question 14

Clindamycin and LInzeolid in nec fasc

Answer 14

Suppress toxin and cytokine production

Question 15

Streptococcal nec fasc treatment

Answer 15

High dose IV penicillin
PLUS
Clindamycin or linezolid

Question 16

Varicella cellulitis

Answer 16

Maculopapules, vesicles, scabs with clear fluid. On trunk/face then spread elsewhere

1. Acyclovir 800mg PO 4-5 times daily x5 days
2. Valacyclovir 1g PO TID x5-7 days

Question 17

Diabetic Foot Infection organisms

Answer 17

Polymicrobial

S. aureus, GAS, GBS, Enterococcus, Proteus, E. coli, Klebsiella, Enterobacter, P aeruginosa, Bacteroides, Peptostreptococcus

Question 18

Mild Diabetic Foot Infection

Answer 18

Local infection involving only the skin and subcutaneous tissue. No SIRS criteria. Erythema of 2cm or less

No antibiotics in the past month

Question 19

Mild DFI treatment, no MRSA risk factors

Answer 19

Dicloxacillin
Nafcillin
Oxacillin
Cephalexin
Cefazolin
Levofloxacin
Doxycycline
Bactrim (if sulfa allergy)
Moxifloxacin
Clindamycin

Question 20

Mild DFI treatment, high risk for MRSA

Answer 20

Previous MRSA infection or colonized

Linezolid
Cilndamycin
Doxycyline
Bactrim

Question 21

Moderate to severe DFI definition

Answer 21

Local infection with erythema > 2cm OR
involves structures deeper than skin & subcutaneous tissue w/ or w/o SIRS criteria

Question 22

Moderate to severe DFI treatment

Answer 22

Unasyn
2nd or 3rd generation cephalosporins (cefuroxime, cefotaxime, ceftriaxone)

Question 23

Moderate to severe DFI treatment if recent antibiotics

Answer 23

Zosyn
2nd or 3rd generation cephalosporins
Ertapenem

Question 24

Moderate to severe DFI treatment if macerated ulcer or warm climate

Answer 24

Zosyn
Dicloxacillin or nafcillin or oxacillin PLUS ceftazidime or ciprofloxacin
Meropenem
Imipenem

Question 25

Moderate to severe DFI if ischemic limb/necrosis/gas forming

Answer 25

Augmentin Unasyn Zosyn

Question 26

Moderate to severe DFI if risk for gram-negative organisms

Answer 26

Ertapenem Meropenem Imipenem Ciprofloxacin Aminoglycoside Polymyxin

Question 27

Moderate to severe DFI if risk of MRSA

Answer 27

Risks: prolonged hospitalization, ICU admit, recent hospitalization, recent ABX use, invasive procedure, HIV, nursing home, open wound, hemodialysis, discharge w/ long-term central venous access Vancomycin Linezolid Doxycycline Bactrim Daptomycin

Question 28

DFI treatment duration

Answer 28

1-2 weeks, can prolong 3-4 weeks if slow response, severe PAD 6 weeks if osteomyelitis

Question 29

DFI treatment duration if amputation needed

Answer 29

2-5 days post op if no remaining infected tissue/bone 1-2 weeks if residual infected tissue 3 weeks if residual infected bone

Question 30

Empiric osteomyelitis treatment for children

Answer 30

Cefazolin Nafcillin/oxacillin If MRSA community prevalence is >10%: Clindamycin Vancomycin (if high resistance to clindamycin)

Question 31

Empiric osteomyelitis treatment for adults

Answer 31

Gram - coverage (cefazolin, ceftriaxone, cefepime, meropenem) + Anti-staph agent (clindamycin, doxycycline, vancomycin, linezolid, daptomycin)

Question 32

Empiric osteomyelitis treatment for sickle cell patients

Answer 32

High risk for Salmonella Ceftriaxone/cefotaxime OR ciprofloxacin/levofloxacin

Question 33

Osteomyelitis with prosthetic joint & retention of prosthesis or one-stage exchange

Answer 33

Staph: staph coverage + rifampin 300-450mg BID x2-6 weeks THEN rifampin + cipro/levo for 3-6 months If no staph, then IV or PO tx for 4-6 weeks, followed by indefinite oral suppression therapy

Question 34

Osteomyelitis with prosthetic joint and removal of prosthesis

Answer 34

IV or PO therapy x4-6 weeks

Question 35

Osteomyelitis treatment duration if amputation

Answer 35

If all infected tissue removed: 24-48 hours

Question 36

Acute osteomyelitis treatment duration

Answer 36

3-6 weeks

Question 37

Chronic osteomyelitis treatment duration

Answer 37

6-8 weeks IV or PO abx May extend if high risk of failure (MRSA, extensive infection)

Question 38

Osteomyelitis criteria to switch to PO

Answer 38

1. Highly bioavailable PO abx available 2. PT can be adherent 3. Identified organism is highly susceptible to PO abx 4. C-reactive protein <2.0 5. Adequate surgical debridement 6. Resolving clinical course

Question 39

Impetigo mild treatment

Answer 39

Topical mupirocin or retapamulin ointment for 5 days Mild = focal and few lesions

Question 40

Impetigo oral treatment

Answer 40

If ecthyma or multiple lesions, outbreak MSSA: dicloxacillin, cephalexin MRSA: bactrim, doxycycline, clindamycin Strep: penicillin

Question 41

Risk factor for MRSA surgical SSTI infection

Answer 41

Prior MRSA infection Nasal carrier MRSA Recent hospitalization Recent antibiotic admin

Question 42

Gram neg/anaerobe coverage needed if surgical SSTI involve these areas

Answer 42

Axilla GI tract Perineum Female GU tract Use zosyn, carbapenem, or ceftriaxone + metronidazole

Question 43

Animal bite treatment

Answer 43

First line: Augmentin If immunocompromised, mod-severe injury, penetrated into joint, treat preemptively for 3-5 days