ID-SSTI

Question 1

Two most common microbes causing SSTI

Answer 1

S. aureus and group A beta hemolytic strep

Question 2

Erisypelis–describe it

Answer 2

Occurs on face and legs
It is superficial and involves the dermis
Caused by group A strep
More indurated then cellulitis

Question 3

Skin layers involved in cellulitis

Answer 3

Diffuse and involves the dermis and subcutaneous tissues

Question 4

Match the organism causing cellulitis and the how it is contracted:

-Aeromonas hydrophila

Answer 4

• Aeromonas hydrophila: fresh water lakes, streams, or rivers; medicinal leeches
• nonspecific cellulitis

Question 5

SSTI: Vibrio sp.

Organism, clinical features

Answer 5

• Vibrio sp.: salt water, brackish water; or contact with drippings from raw seafood
• Direct inoculation, or ingested leading to bacteremia and secondary skin infection; hemorrhagic bull in area of cellulitis; LIVER FAILURE is a risk factor for V. vulnificus

Question 6

SSTI: Erysipelothrix rhusiopathiae

Organism, clinical features

Answer 6

-Erysipelothrix rhusiopathiae: contact with saltwater marine life (also associated with freshwater fish); contact with infected animals such as swine and poultry

cellulitis involves hand an fingers in those handling fish, shellfish, or occasionally poultry, meat contaminated with bacterium

Question 7

SSTI: Pasteurella multocida

organism, clinical features

Answer 7

-Pasteurella multocida: cats

cellulitis at cat bite or scratch mark

Question 8

SSTI: Capnocytophaga canimorsus

organism, clinical features

Answer 8

-Capnocytophaga canimorsus: dogs

Cellulitis and sepsis particularly in patients with functional or anatomic asplenia

Question 9

SSTI: Bacillus anthracis

organism, clinical features

• Mycobacterium marinum
• Mycobacterium foruitum

Answer 9

Edematous pruritic lesion with central eschar; spore-forming organism

-Bacillus anthracis: infected animals or animal products’ bioterrorism

Question 10

SSTI-Francisella tularensis

organism, clinical features

Answer 10

-Francisella tularensis: contact with or bite from infected animal (cats) or ticks

Ulceroglandular syndrome characterized by ulcerative lesion with central eschar and localized tender LAD; constitutional symptoms are often present

Question 11

SSTI:
-Mycobacterium marinum

organism, clinical features

Answer 11

-Mycobacterium marinum: fresh water or salt water, fish tanks, swimming pools

Clinical: often trauma associated; papular lesions become ulcerative at site of inoculation, ascending lymphatic spread and can be seen “sporotrichoid”; absence of systemic toxicity

Question 12

SSTI:
-Mycobacterium fortuitum

organism, clinical features

Answer 12

Mycobacterium foruitum: exposure to freshwater footpaths/pedicures at nail salons; infection following breast augmentation and open heart surgery, shaving with razors; Clinical: multiple boils, razor shaving strongly associated with it

Question 13

Primary way to treat CA-MRSA abscess

Answer 13

I&D

Question 14

When is antibiotic therapy recommended for CA-MRSA

Answer 14

• If I&D does not make it go away
• disease is extensive or has rapid progression
• immunodeficiency and multiple comorbidities
• very young or very old
• signs of systemic illness
• septic phlebitis is known

Question 15

what is Type I Nec fasciitis

Answer 15

polymicrobial with aerobic and anaerobic gram positive and gram negative organisms

Question 16

What is Type II Nec fasciitis

Answer 16

monomicrobial

most commonly strep pyogenes
also can be caused by S. aureus, vibrio vulnificus, streptococcus agalactiae

Question 17

What is Type III Nec Fasciitis

Answer 17

gas gangrene, clostridial myonecrosis; most commonly caused by Clostridium perfringens

Question 18

Diagnosis and Txt of Nec Fasciitis

Answer 18

X ray can show subQ gas
MRI very useful
Gold standard for treatment and diagnosis is surgery

Abx: vancomycin plus zosyn/imipenem/meropenem
-Add clindamycin if evidence of group A strep

Question 19

Antibiotic for vibrio vulnificus necrotizing fasciitis

Answer 19

doxycycline plus ceftazidime

Question 20

Antibiotic for Aeromonas hydrophila-associated NF

Answer 20

doxycycline plus cipro

Question 21

Diagnostic Criteria for Staphylococcal Toxic Shock Syndrome

Answer 21

Fever >38.9

Systolic BP <90

Diffuse macular rash with subsequent desquamation, especially on palms and soles

Involvement of 3 organ systems

Negative results on serologic testing for RMSF, leptospirosis, measles, negative CSF

pg12

Question 22

Common causes of staphylococcal toxic shock

Answer 22

tampon use, wounds, history of injection drug use, burns, nasal packings, catheters

Question 23

Abx therapy for:

MSSA toxic shock syndrome
MRSA TSS
S. pyogenes TSS

Answer 23

MSSA: oxacillin or nafcillin +clindamycin
MRSA: oxacillin or nafcillin+clindamycin
Strep: penicillin +clindamycin

Question 24

Contact precautions for suspected group A strep in necrotizing fasciitis or TSS. What about for household contacts?

Answer 24

Droplet precautions and contact precautions
household contacts with comorbidities, immunocompromised, or elderly: benzathine penicillin G plus rifampin, clindamycin, or azithromycin

Question 25

How to manage an animal bite?

Answer 25

Prompt wound irrigation with normal saline, removal of any foreign bodies and debridement of ketotic tissue

Give rabies and tetanus shots

Augmentin prophylaxis ONLY in those who are immunosuppressed, have moderate to severe wounds, wound on face or hands, wounds near a joint or bone, wound with significant crush injury

Question 26

how to manage a human bite?

Answer 26

always give prophylactic augmentin

Question 27

Antibiotic coverage for diabetic foot ulcer

Answer 27

MRSA coverage, Pseudomonas, and anaerobes