Skin and Soft Tissue Infections (SSTI)

Question 1

When would wound cultures be obtained for skin and soft tissue infections?

Answer 1

• purulent infections
• necrotizing infections

Question 2

When would blood cultures be obtained for skin and soft tissue infections?

Answer 2

• severe infections
• intravenous drug use (IVDA)

Question 3

When would imaging be obtained for skin and soft tissue infections?

Answer 3

necrotizing (deep) infections= CT scans

Question 4

What is a purulent infection?

Answer 4

• cutaneous abscesses, collection of pus within the dermis and deeper skin tissue
• furuncles and carbuncles
• folliculitis

Question 5

What is the presentation of a purulent infection?

Answer 5

• tender, red nodules
• signs of erythema
• systemic signs (fever, chills, malaise)- carbuncles and abscesses only

Question 6

What pathogens are respondsible for purulent infections?

Answer 6

• staphylococcus aureus (MRSA)
• if patient has significant water exposure, pseudomonas aeruginosa

Question 7

What is the empiric treatment for severe purulent infections?

Answer 7

• vancomycin
• daptomycin
• linezolid
• televancin
• ceftaroline

Question 8

What is the empiric treatment for moderate purulent infection?

Answer 8

• trimethoprim/sulfamethoxole
• doxycline

Question 9

What is the duration of therapy for purulent infections?

Answer 9

5 days (minimum)

Question 10

What is a non-purulent infection?

Answer 10

involves epidermis and dermis, history of wound from minor trauma, abrasion, ulcer, or surgery
- cellulitis
- erysipelas

Question 11

What is the presentation of non-purulent infections?

Answer 11

• fevers, chill, malaise
• hot and painful to the touch
• systemic symptoms common
• non-elevated lesions with poorly defined margins
• involvement of regional lymphatic system

Question 12

What pathogens are respondsible for non-purulent infections?

Answer 12

• group A strep (streptococcus pyogenes)
• staphylococcus aureus (MRSA coverage for penetrating trauma, IV drug use, purulent drainage, MRSA infection elsewhere)

Question 13

When should MRSA be empirically covered for non-purulent infections?

Answer 13

• penetrating trauma
• IV drug use
• purulent drainage
• MRSA infection elsewhere

Question 14

When would a purulent infection be classified as severe?

Answer 14

• failed inscision & drainage and failed PO antibiotics
• immunocompromised
• SIRS or sepsis (2/4 of the following: temp >38C or 36C, HR > 90bpm, RR > 24bpm, WBC > 12K or <4K)

Question 15

When would a non-purulent infection be classified as severe?

Answer 15

• failed PO antibiotics
• immunocompromised
• SIRS or sepsis (2/4 of the following: temp >38C or 36C, HR > 90bpm, RR > 24bpm, WBC > 12K or <4K)

Question 16

What is the treatment for necrotizing infections?

Answer 16

aggressive surgical intervention and antibiotics

medical emergency!

Question 17

What is the presentation of necrotizing infections?

Answer 17

• marked systemic toxicity
• change in skin color to maroon or purple/black as progresses
• bullae
• crepitus
• cutaneous anesthesia
• edema beyond the margins of erythema

Question 18

What pathogens are respondsible for necrotizing infections?

Answer 18

• group A streptococcus (S. pyogenes)
• staphylococcus aureus (MRSA)
• clostridium perfringens

Question 19

What is the treatment of necrotizing infections?

Answer 19

• extended spectrum beta lactam= piperacillin/tazobactam, cefepime, carbapenem
• clindamycin
• vancomycin

Question 20

What is the purpose of using clindamycin in the treatment of necrotizing infections?

Answer 20

INOCULUM EFFECT
necrotizing soft tissue infections have large bacterial burden and clindamycin efficacy is not affected by the size of bacterial burden unlike beta lactams which has decreased efficacy when bacteria is rapidly dividing. clindamycin also inhibits streptococcus toxin production

Question 21

What is the treatment for osteomyelitis?

Answer 21

same as necrotizing infections, but longer duration of therapy to 4-6 weeks