Bacterial infections of skin and soft tissue I Flashcards Preview

Year 1 Microbiology > Bacterial infections of skin and soft tissue I > Flashcards

Flashcards in Bacterial infections of skin and soft tissue I Deck (37):
1

Which pathogens are associated with diabetes?

S. aureus and GBS

2

Which pathogen is associated with neutropenia and hot tub use?

Pseudomonas aeruginosa

3

Which pathogens are associated with IV drug use?

MRSA, pseudomonas aeruginosa

4

Which pathogen is associated with impetigo?

Strep pyogenes

5

Impetigo is characterized by what type of skin lesion?

Honey crusted lesions and erosions often around mouth

6

Which organism is associated with bullous impetigo?

Staph aureus

7

What is responsible for the blisters seen in bullous impetigo?

Exfoliative toxin from staph aureus

8

Which organism is responsible for ecthyma?

Strep pyogenes

9

What type of lesion is characteristic of ecthyma?

Punched-out ulcerative lesions

10

Which organism is most commonly responsible for a furuncle?

Staph aureus

11

What is a furuncle?

Essentially a staph aureus abscess on a hair follicle

12

What is a carbuncle?

Multiple furuncles coalescing and extending deeper into subcutaneous tissues

13

What is the defining feature of a carbuncle?

Chills and fevers (sometimes systemic spread)

14

Which organism is typically responsible for erysipelas?

Strep pyogenes (recent respiratory or skin infection)

15

Cellulitis is most often caused by what organism?

GAS or staph aureus

16

What is paronychia?

Localized, superficial infection or abscess of the nailfolds, lasting longer than 6 weeks and usually secondary to candida albicans infection

17

What is the most common organism associated with paronychia?

Staph aureus

18

What is the most common cause of necrotizing fasciitis?

Strep pyogenes

19

What are the hallmarks of necrotizing fasciitis?

Toxicity, multi organ failure, death

20

What is the gram stain for pseudomonas?

Gram negative

21

What is the shape of pseudomonas?

Rod

22

What is the coagulase test for staph aureus?

Positive

23

What is the hemolysis pattern for staph aureus?

Beta

24

What are the structural virulence factors for staph aureus?

Capsule, peptidoglycan, teichoic acid, protein A

25

What is the role of the staph aureus virulence factor Protein A?

Turns Ab around so it can no longer link to a phagocyte (non-functional presentation, soaks up Abs)

26

What virulence factor mediates staphylococcal scalded skin syndrome?

Exfoliative toxins

27

Which enzymes serve as virulence factors in staph soft tissue infections?

Coagulase, hyaluronidase, fibrinolysin, lipases, nucleases

28

Why is staph not culturable from the skin of a SSSS patient?

Toxin mediated disease

29

Why are leukocytes not seen on the skin of a SSSS patient?

No inflammation involved - only blistering

30

What kind of toxins are exfoliative toxins?

Serine proteases

31

What is the function of exfoliative toxins?

Split desmoglein-1 and form intercellular bridges in the stratum granulosum epidermis

32

What is Nikolsky sign?

In SSSS - lateral pressure on fingertips leads to sloughing off of skin

33

Which antibiotics are resistant to beta lactamase hydrolysis?

Methicillin, oxacillin, nafcillin

34

What gene confers resistance of staphylococcus to methcillin?

MecA

35

Most is the most likely bacterial cause of ostetomyelitis?

Staph aureus

36

What is the most likely cause of septic arthritis in children and adults receiving intraarticular injections?

Staph aureus

37

What is the most likely cause of septic arthritis in sexually active adults?

Neisseria gonorrhea