export_ssti bacteria iii

Question 1

Clostridium features

Answer 1

Gram-positive
Spore forming

Anaerobic

Question 2

Clostridium virulence factors

Answer 2

Hemolysin
Neurotoxin

Enterotoxin

Question 3

Four major species of Clostridium

Answer 3

C. perfringens (gangrene, diarrhea)
C. difficile (diarrhea, colitis)

C. tetani (tetanus)

C. botulinum (botulism)

Question 4

C. perfringens features

Answer 4

Produces hydrogen and CO2 gas

Question 5

C. perfringens alpha-toxin

Answer 5

Phospholipase that hydrolyzes lecithin and sphingomyelin

Question 6

C. perfringens diseases

Answer 6

SSTIs
Suppurative myositis

Myonecrosis

Question 7

Suppurative myositis

Answer 7

Inflammation of muscle

Question 8

Myonecrosis

Answer 8

Destruction of muscle

Gas gangrene most notably with P. perfringens

Question 9

Gas gangrene disease progression

Answer 9

Begins as cellulitis, progresses to suppurative myositis, then myonecrosis, then dissemination

Question 10

Diagnose and treat C. perfringens

Answer 10

Gram-positive rods WITHOUT leukocytes
Treatment must be immediate, as fatality is high

Surgical debridement, clindamycin

Question 11

C. tetani features

Answer 11

Strict anaerobe

“Drumstick” appearance

Question 12

C. tetani entry

Answer 12

Small, local infection provides source for tetinospasmin to travel to CNS

Question 13

Tetanospasmin

Answer 13

Heat liable neurotoxin
Inactivates inhibitory neurotransmitters, causing spastic paralysis

Rapidly degraded in GI, unlike botulinum

Question 14

Three major presentation of C. tetani infection

Answer 14

Generalized
Localized

Neonatal

Question 15

Generalized tetanus

Answer 15

Lock jaw
Back spasms

Autonomic involvement is most severe

Question 16

Localized tetanus

Answer 16

Confined to muscles at site of inoculation

Question 17

Neonatal tetanus

Answer 17

Infected umbilical stump

Question 18

Risus sardonicus

Answer 18

Sustained contraction of fascial muscles

Caused by tetanospasmin

Question 19

Opisthotonic posturing

Answer 19

Spinal muscles affected by tetanospasmin

Question 20

Treat C. tetani

Answer 20

Debridement of primary wound

Human tetanus Ig

Question 21

Prevent C. tetani infection

Answer 21

Immunize with boosters

Question 22

Mycobacterium features

Answer 22

Gram-positive, ACID-FAST, aerobic
Lipid-rich cell wall

Non-spore forming, non-motile

Slow growing

Question 23

Mycobacterial cell wall components

Answer 23

Mycolic acids

LAM

Question 24

LAM

Answer 24

Structurally and functionally related to LPS

Question 25

Mycobacterium diseases

Answer 25

TB (M. tuberculosis, M. bovis, M. kansasii) | Leprosy (M. leprae)

Question 26

Pott's disease

Answer 26

Skeletal muscle TB | Upper lumbar and lower thoracic vertebrae most affected

Question 27

Diagnose Pott's disease

Answer 27

Immunocompromised, developing countries "Gibbus" deformity Positive PPD test Granulomas

Question 28

TB host response

Answer 28

Th1 produce IFN-gamma, which stimulate macrophages to kill | Mycobacterium resists macrophages, and is walled off in granuloma

Question 29

Treat Mycobacterium

Answer 29

Combination of four antibiotics over several months

Question 30

M. leprae features

Answer 30

Targets macrophages and Schwann cells | Only reservoirs are humans and armadillos

Question 31

Two diseases of M. leprae

Answer 31

Tuberculoid | Lepromatous

Question 32

Tuberculoid leprosy host response

Answer 32

Th1

Question 33

Lepromatous leprosy host response

Answer 33

Th2 response | Abs ineffective, results in Hansen's disease

Question 34

Diagnose leprosy

Answer 34

Lepromin test | Culture is IMPOSSIBLE - biopsy can be done

Question 35

Treat leprosy

Answer 35

Prolonged treatment with uncommon antibiotics

Question 36

Nocardia features

Answer 36

Aerobic, Gram-positive rod (but doesn't take up stain well) Weakly acid fast Filamentous (resembles hyphae) Aerial hyphae

Question 37

Mycetoma

Answer 37

SSTI caused by nocardia Slow progression, painless Foot is the most common site

Question 38

Other diseases caused by nocardia

Answer 38

Lymphocutaneous disease | Cellulitis and subQ abscesses

Question 39

Diagnose and treat nocardiosis

Answer 39

Hx involving exposure from environment | Treat with TMP-SMX

Question 40

Actinomyces israellii

Answer 40

Filamentous bacteria Strict anaerobe Opportunistic pathogen Abscesses contain sulfur granules Associated with dental work Control with penicillin

Question 41

Diagnose and treat Actinomyces

Answer 41

Filamentous biopsy Differentiate from nocardia based on acid-fast stain Penicillin

Question 42

Acne vulgaris infection

Answer 42

Pilosebaceous unit affected

Question 43

Four elements of acne vulgaris pathogenesis

Answer 43

Follicular epidermal hyperproliferation Excess sebum production Inflammation Presence and activity of Propionibacterium acnes

Question 44

Propionibacterium acnes features

Answer 44

Gram-positive rod Anaerobic Stimulates inflammation

Question 45

Treat acne vulgaris

Answer 45

``` Topical first Oral antibiotics (doxycycline) ``` Isotrenoid (Accutane)

Question 46

Gingivitis

Answer 46

Inflammation of gingiva | Reversible

Question 47

Periodontitis

Answer 47

Chronic inflammatory disease Includes gingivitis along with loss of CT ad bone support for teeth Irreversible

Question 48

Gingivits and periodontitis causes

Answer 48

Bacteria in the dental plaques | Create inflammatory response in gingival tissue

Question 49

Dental caries causative agent

Answer 49

Streptococcus mutans (Viridans strep.) is dominant cause - acid products is the underlying causes