Clinical Treatment: Skin, Soft Tissue, Bone, and Bloodstream Infections

Question 1

What would be some risk factors for expecting MRSA over MSSA?

Answer 1

Recent hospitalization, previous Abx exposure, indwelling lines, hemodialysis, nursing homes, etc

Question 2

Since the rise of community-acquired MRSA, in what type of infections is MRSA coverage always warrented?

Answer 2

Purulent cellulitis, or abscesses

Question 3

What are some oral options for MSSA?

Answer 3

Amoxicillin/clavulanic acid
Dicloxacillin (second generation pen)
Cephalexin (1st generation cephalo)

Question 4

What are some oral options for MRSA?

Answer 4

Doxycycline / minocycline
TMP / SMX
Linezolid
Clindamycin -> but remember inducible resistance

Question 5

Why might TMP / SMX not be able to be given alone for skin infections?

Answer 5

Poor S. pyogenes coverage, although MRSA is covered. Need to give with cephalexin

Question 6

What is the most important thing to do when giving a patient an antibiotic therapy?

Answer 6

The 48 hour call to assess their condition, to see if their Abx regimen needs to be changed

Question 7

What is the standard of care for MSSA or MRSA in severe cellulitis? What is meant by severe?

Answer 7

MSSA: Nafcillin or cefazolin
MRSA: Vancomycin, cover empirically

severe: oral abx failed, irrigation and debridement is necessary, or systemic symptoms are present

Question 8

What is necrotizing fasciitis commonly associated with? What is another necrotizing infection?

Answer 8

S. pyogenes
Recently MRSA, Vibrio and aeromonas

Gas gangrene is considered necrotizing

Question 9

What is vital for treatment of necrotizing infections?

Answer 9

Prompt surgical intervention

Question 10

What is the treatment for severe GAS or clostridial infections? Why?

Answer 10

IV penicillin + clindamycin (due to toxin suppression activities) -> inhibits protein synthesis

Penicillin will cover GAS + clostridium

Clinda: staph, strept, and anaerobes

Question 11

What bug must be empirically covered in animal bites?

Answer 11

Pasteurella

Also comes with staph, strep, and anaerobes

Question 12

What is the mainstay of therapy for animal bites (and human bites)? Alternatives?

Answer 12

B-lactam / B-lactamase inhibitors

I.e. amoxicillin/clavulanic acid

Alternately: Doxycycline, moxifloxacin, or ceftriaxone

Question 13

What is the empiric therapy for infected diabetic foot ulcers?

Answer 13

Initially IV therapy with vancomycin +/- ceftriaxone to cover gram negative in case of deep tissue infiltration

DONT WAIT FOR ULCER TO FULLY HEAL TO STOP

Question 14

When is Rifampin used for bone infections?

Answer 14

When complicated by prostheses which could have biofilm

Question 15

What is suppressive therapy for bone infection?

Answer 15

Long-term doxycyclline, TMP/SMX, or clindamycin use when the infection cannot be fully cleared

Question 16

What are common antibiotic therapy durations?

Answer 16

Mild: 1-2 weeks
Moderate to severe: 2-4 weeks
Osteomyelitis / prosthetic implant infection: 4-6 weeks

Question 17

When are fluoroquinolones best used?

Answer 17

As an oral stepdown therapy following IV beta-lactam therapy

Question 18

What is the pseudomonal treatment for joint vs bone?

Answer 18

IV beta-lactam for 4-6 weeks
4 weeks for joint
6 weeks for bone

Some add antipseudomonal aminoglycoside (gentamicin, tobramycin, amikacin) or fluoroquinolone (ciprofloaxacin, levofloxacin)

Question 19

What is the drug of choice for gonorrhea?

Answer 19

Ceftriaxone or azithromycin

Question 20

What is antibiotic lock therapy?

Answer 20

Soaking your catheter in antibiotics to stop bloodstream infections (bacteremia), associated with both gram +, gram -, and candida spp.

Question 21

What is the treatment for streptococcal endocarditis?

Answer 21

4 weeks penicillin or ceftriaxone, or vancomycin if penicillin allergy

6 weeks with prosthetic valve

Add gentamicin for synergistic action, especially among resistant strains (2-6 weeks)

Question 22

What is used in treatment of staphylococcal endocarditis? What if prosthetic valve?

Answer 22

MSSA:
Nafcillin x 6 weeks
Cefazolin if non-severe penicillin allergy
Vancomycin if severe penicillin allergy

MRSA: High dose vancomycin

Add rifampin if prosthetic valve?

Question 23

What is the drug of choice for enterococccal endocarditis?

Answer 23

Ampicillin 4 weeks, gentamacin can be added

If amp-resistant, 6 weeks Vanco

Do at least 8 weeks if VRE (use daptomycin)

Question 24

What is a common saying for Clindamycin / Metronidazole?

Answer 24

Clindamycin above the diaphragm, metronidazole below

Clindamycin is good at treating Bacteriodetes and anaerobic species from mouth anaerobes leading to aspiration pneumonia

Metronidazole is good at treating anaerobic species in the gut and pelvis (C. difficile, Trichomonas)