Bacterial Skin infections I

Question 1

Streptococcus pyogenes General

Answer 1

• Causes Decubitus ulcers,Pressure/Bed Sore

- Gram positive cocci, chains, Catalase negative,M & T proteins, Group A

Question 2

Streptococcus pyogenes Virulence factors

Answer 2

-Exotoxin, Streptolysins/Streptokinase, Deoxyribonuclease, Hyaluronidase
-antiphagocytic capsule,adherence,M‐protein
• immune system evasion (SEP B)

Question 3

Streptococcus pyogenes Clinical Manifestations

Answer 3

-Impetigo, Pharyngitis, ERYSIPELAS, Cellulitis, Necrotizing fasciitis, SCARLET FEVER

Question 4

Staph Epidermis found on what items

Answer 4

Prosthetic devices, catheters

Question 5

Staph Epidermis Pathogenesis

Answer 5

Slime production, Biofilm,

Question 6

Pseudomonas aeruginosa General

Answer 6

-skin and BURN infections
-Gram‐negative rod, Motile, Oxidase positive, nosocomial, strict aerobe, nonfermenting, aquatic environments,lactose negative
• fruity aroma
• Multi‐drug resistance
-Green pigment

Question 7

Pseudomonas aeruginosa Transmission/epidemiology

Answer 7

-soil, water, food, on plants
–survives many disinfectants
• Transmission: invasive device (Foley catheter), destruction of protective structure (ie. skin)

Question 8

Pseudomonas aeruginosa Virulence factors

Answer 8

biofilm (alginate), quorum sensing, enzymes & toxins, degradative enzymes,type III secretion system, proteases, hemolysins

Question 9

Enterobacteriaceae General

Answer 9

Gram neg rod, normal gut flora, rarely cause cellulitis

Question 10

Haemophilus influenzae General

Answer 10

Gram negative rods/coccobacilli, X and V factor –

• Disease Associations: Meningitis,Osteomyelitis,Epiglottitis,Otitis media, RARE CAUSE OF CELLULITIS

Question 11

What bacteria causes Decubitus ulcers Pressure/Bed Sore

Answer 11

-MIXED FLORA 
• Pseudomonas
• Staphylococcus sp.
• Streptococcus sp.
• Corynebacterium sp.

Question 12

Causes of Chronic Ulcers

Answer 12

Mycobacterium tuberculosis
• M. fortuitum complex
• M. marinum
• M. ulcerans
• M. leprae
• Nocardia brasiliensis
• Corynebacterium diphtheriae

Question 13

Mycobacterium General

Answer 13

Gram positive cell wall, Acid fast, Slow growth

Question 14

Mycobacterium fortuitum complex -what type of people

Answer 14

Injecting drug users

Question 15

Mycobacterium MARINUM-where contracted

Answer 15

swimming pool granuloma
– “aquarium or fish tank
Mycobacteria

Question 16

Mycobacterium leprae General

Answer 16

-obligate intracellular: peripheral nerves,skin, nasal mucosa
-slow incubation period:3–5 years
-no in vitro growth: mouse foot pads,
armadillos

Question 17

Mycobacterium leprae Virulence factors

Answer 17

-cell wall, mycolic acids & wax D, acid fast positive
-obligate intracellular
–inhibition of phagosome‐lysosome fusion
– drug resistance

Question 18

Mycobacterium leprae Diagnosis

Answer 18

PCR, clinical, NO CULTURE

Question 19

Mycobacterium leprae Clinical manifestations

Answer 19

HANSENS DISEASE-tuberculoid, lepromatous

Question 20

Nocardia brasiliensis General

Answer 20

branching, intracellular, opportunist, partial acid‐fast, beaded Gram (+) bacilli

Question 21

Nocardia brasiliensis Clinical Manifestations

Answer 21

Chronic ulcer

Question 22

Corynebacterium diphtheriae General

Answer 22

pleomorphic Gram (+) bacilli
-cutaneous diptheria:
– unimmunized population
– over‐crowding conditions
• chronic ulcer

Question 23

Corynebacterium diphtheriae Virulence

Answer 23

• diphtheria toxin
– inhibits protein synthesis
• cutaneous diphtheria
– rare
– unimmunized population
– over‐crowding conditions

Question 24

Propionibacterium acnes General

Answer 24

Gram (+) bacilli (related to Corynebacterium)
• slow‐growing, non‐spore forming, anaerobic
• produce lactic acid, propionic acid, acetic acid
from glucose
• Normal skin flora

Question 25

Propionibacterium acnes Clinical Manifestations

Answer 25

-mostly on face, upper thorax
• cause acne
– produces inflammatory mediators resulting in papules, pustules, lesions typical of inflammatory acne
– usually self‐limiting

Question 26

Diabetic foot Infection caused by what bacteria?

Answer 26

Polymicrobial:
– S. aureus
– Enterococcus sp.
– Enterobacteriaceae
– Group B Streptococci
        -Streptococcus agalactiae
– anaerobic bacilli

Question 27

Fasciitis caused by what bacteria?

Answer 27

• Clostridium perfringens

- S. pyogenes