Msk 14

Question 1

The orgaism responsible for:

Impetigo

Answer 1

Streptococci, staphylococci

Question 2

The orgaism responsible for:

Erysipelas

Answer 2

Streptococci

Question 3

The orgaism responsible for:

Folliculitis

Answer 3

Staphylococci, Psudomonas sp (hot tub)

Question 4

The orgaism responsible for:

Carbuncles, furuncles

Answer 4

Staphylococci

Question 5

The orgaism responsible for:

Cellulitis

Answer 5

Streptococci

Staphylococci

Haemophilus influenzae (unimmunized)

Question 6

What conditions favor high dose growth (i.e. conditions that allow for large accumulation/innoculation of the pathogen)?

Answer 6

Dirty or moist

Question 7

What conditions reduce the minimal dose threshold (number of organisms needed to produce infection)?

Answer 7

Compromised blood supply

Decreased immunity

Question 8

Risk group: diabetes mellitus and/or severe peripheral vascular disease

Pathogenesis: infection begins at site of surgical incision, mucosal tear, or site of skin breakdown

Etiology: mixed aerobic and anaerobic bacteria

Answer 8

Type I Necrotizing Fasciitis

Question 9

Caused by Group A streptococci (streptococcal gangrene)

Any age group, any patients

Pathogenisis: penetration injury, hematogenous translocation to sites of blunt trauma or muscle strain

Answer 9

Type II Necrotizing Fasciitis

Question 10

Fast progressing, life-threatening due to septic shock

Etiology:

Clostridium sp. (gas gangrene)

 - World War I epidemics to intradermal "skin popping" (drug usage)

Streptococcus pyogenes (flesh-eating)

Enteric bacteria (e.g. E. coli)

Answer 10

Myonecrosis/Necrotizing myositis

Question 11

Pt presents with hemorrhagic bullae, palpable crepitus (gas) felt, discoloration, and a foul smell from the gluteus maximus. This pt is diabetic, old, and recently fell hard on his butt. What’s the diagnosis? How do we treat?

Answer 11

Clostridial myonecrosis

Debridement; hyperbaric oxygen therapy, antibiotics

Question 12

What is the primary etiology of pyomyositis?

Answer 12

Staphylococcus aureus (70-90%), 25% MRSA

Question 13

Pt presents with pus filled abscess in large muscle group. He is immunodeficient due to IV drug use. Laboratory tests reveal high count of staphylococcus aureus. What is the diagnosis?

Answer 13

Pyomyositis

Question 14

What is the etiology for this disease:

Myonecrosis (gas gangrene)

Answer 14

Clostridia

Question 15

What is the etiology for this disease:

Synergistic myositis (gangrene)

Answer 15

Mixed infections with anaerobic bacteria and enteric bacteria

Question 16

What is the etiology for this disease:

Pyomyositis (muscle abscesses)

Answer 16

Staphylococcus aureus (group A strep)

Question 17

What is the etiology for this disease:

Miscellaneous chronic infections

Answer 17

Actinomyces

Nocardia

Mycobacterium

Fungi

Question 18

What is the etiology for this disease:

Viral myositis

Answer 18

Influenza virus A & B

Question 19

Animal bites tend to be _______, including aerobes/facultative anaerobes and anaerobes.

Answer 19

Polymicrobial

Question 20

Animal bites play a role in the transmission of _________.

Answer 20

Pasteurella (multi-drug resistant)

Pasteurella canis = dog

Pasteurella multocida = cat and dog

Question 21

What arethe common aerobic isolates from a human bite?

Answer 21

Eikenella corroden (G-)

Staphylococci (S. aureus most important)

Streptococci

Corynebacteria

Question 22

What are the most common anerobic isolates from a human bite?

Answer 22

Bacteroides

Peptostreptococci

Question 23

What is the most concerning multidrug-resistant organism in US military wounds?

Answer 23

Acinetobacter calcoaceticus-baumannii complex

also S. aureua, K. pneumonia, P. aeruginosa

Question 24

Where is acute osteomyelitis found?

Answer 24

Long bones of children

onset 1-2 days

chills, fever, malaise, pain, swelling, redness

Question 25

Where is chronic osteomyelitis typically found?

Answer 25

Vertebral bodies in elderly

Onset weeks-months

localized low back pain & tenderness, may be fever

Question 26

Whats the difference between arthralgia/reactive arthritis and septic (suppurative) arthritis?

Answer 26

Arthralgia/reactive arthritis: no bacterial invasion locally, often an immune response to bacteria in another area fo the body

Suppurative: bacterial invasion locally

Question 27

Is septic arthritis usually monoarticular or polyarticular?

Answer 27

Monoarticular - local infection

Question 28

Is arthralgia or reactive arthritis usually monoarticular or polyarticular?

Answer 28

Polyarticular

Question 29

What is the primary etiology of infection due to general/trauma?

Answer 29

S. aureus, including MRSA

Question 30

What are some primary risk factors for rheumatologic diseases?

Answer 30

IV dug abusers

Diabetes

Question 31

A young, sexually active male presents with native joint pain. What type of organism should you suspect is the cause until proven otherwise?

Answer 31

Gonococcus

Question 32

A patient develops a prosthetic infection < 3 months after surgery. How was this acquired?

What organism would you suspect is responsible?

Answer 32

Acquired during implantation

Relatively virulent - S. aureus

Question 33

A patient develops a prosthetic infection 3 to 12 months after surgery. How was this acquired?

What organism would you suspect?

Answer 33

Acquired during implantation

Less virulent - S. epidermis or enterococci

Question 34

What is the challenge of biofilms on prosthetic implants?

Answer 34

Susceptibility of bacteria to antimicrobials often declines on a time-dependent logarithmic decline

Question 35

A pt has his prosthetic hip replaced due to a prosthetic infection. In order to culture the biofilm to determine the best antimicrobial to use, what process should the pathologist use?

Answer 35

Sonification