export_ssti bacteria iii

Question 1

Clostridium features

Answer 1

Gram-positive
Spore forming

Anaerobic

Question 2

Four major species of Clostridium

Answer 2

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

C. tetani (tetanus)

C. botulinum (botulism)

Question 3

C. perfringens features

Answer 3

Produces hydrogen and CO2 gas

Question 4

C. perfringens alpha-toxin

Answer 4

Phospholipase that hydrolyzes lecithin and sphingomyelin

Question 5

Suppurative myositis

Answer 5

Inflammation of muscle

Question 6

Myonecrosis

Answer 6

Destruction of muscle

Gas gangrene most notably with P. perfringens

Question 7

Gas gangrene disease progression

Answer 7

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

Question 8

Diagnose and treat C. perfringens

Answer 8

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

Surgical debridement, clindamycin

Question 9

C. tetani features

Answer 9

Strict anaerobe

“Drumstick” appearance

Question 10

C. tetani entry

Answer 10

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

Question 11

Tetanospasmin

Answer 11

Heat liable neurotoxin
Inactivates inhibitory neurotransmitters, causing spastic paralysis

Rapidly degraded in GI, unlike botulinum

Question 12

Three major presentation of C. tetani infection

Answer 12

Generalized
Localized

Neonatal

Question 13

Generalized tetanus

Answer 13

Lock jaw
Back spasms

Autonomic involvement is most severe

Question 14

Localized tetanus

Answer 14

Confined to muscles at site of inoculation

Question 15

Neonatal tetanus

Answer 15

Infected umbilical stump

Question 16

Risus sardonicus

Answer 16

Sustained contraction of fascial muscles

Caused by tetanospasmin

Question 17

Opisthotonic posturing

Answer 17

Spinal muscles affected by tetanospasmin

Question 18

Treat C. tetani

Answer 18

Debridement of primary wound

Human tetanus Ig

Question 19

Prevent C. tetani infection

Answer 19

Immunize with boosters

Question 20

Mycobacterium features

Answer 20

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

Non-spore forming, non-motile

Slow growing

Question 21

Mycobacterial cell wall components

Answer 21

Mycolic acids

LAM

Question 22

LAM

Answer 22

Structurally and functionally related to LPS

Question 23

Mycobacterium diseases

Answer 23

TB (M. tuberculosis, M. bovis, M. kansasii)

Leprosy (M. leprae)

Question 24

Pott’s disease

Answer 24

Skeletal muscle TB

Upper lumbar and lower thoracic vertebrae most affected

Question 25

Diagnose Pott's disease

Answer 25

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

Question 26

TB host response

Answer 26

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

Question 27

Treat Mycobacterium

Answer 27

Combination of four antibiotics over several months

Question 28

M. leprae features

Answer 28

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

Question 29

Two diseases of M. leprae

Answer 29

Tuberculoid | Lepromatous

Question 30

Tuberculoid leprosy host response

Answer 30

Th1

Question 31

Lepromatous leprosy host response

Answer 31

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

Question 32

Diagnose leprosy

Answer 32

Lepromin test | Culture is IMPOSSIBLE - biopsy can be done

Question 33

Treat leprosy

Answer 33

Prolonged treatment with uncommon antibiotics

Question 34

Nocardia features

Answer 34

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

Question 35

Mycetoma

Answer 35

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

Question 36

Other diseases caused by nocardia

Answer 36

Lymphocutaneous disease | Cellulitis and subQ abscesses

Question 37

Diagnose and treat nocardiosis

Answer 37

Hx involving exposure from environment | Treat with TMP-SMX

Question 38

Actinomyces israellii

Answer 38

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

Question 39

Diagnose and treat Actinomyces

Answer 39

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

Question 40

Acne vulgaris infection

Answer 40

Pilosebaceous unit affected

Question 41

Four elements of acne vulgaris pathogenesis

Answer 41

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

Question 42

Propionibacterium acnes features

Answer 42

Gram-positive rod Anaerobic Stimulates inflammation

Question 43

Treat acne vulgaris

Answer 43

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

Question 44

Gingivitis

Answer 44

Inflammation of gingiva | Reversible

Question 45

Periodontitis

Answer 45

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

Question 46

Gingivits and periodontitis causes

Answer 46

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

Question 47

Dental caries causative agent

Answer 47

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