Pyogenic Garm + Cocci

Question 1

Staphylococcus aureus

Answer 1

Suppurative infections
Coagulase +
**Leading cause of infectious endocarditis
Furuncles (hair follicles), Carbuncles, osteomyelitis,infections of wounds, Respiratory tract infections (infants, children), bacterial arthritis, septicemia, food poisoning (preformed toxin)
TSS- Sun burn like rash
Scalded Skin Syndrome- sun burn like rash affecting infants and younger children

Question 2

Coagulase (-) Staphylococci

Answer 2

**Major cause of infections involving medical devices.
Normal flora-
Staph epidermidis- medical devices
Staph sapophyticus- UTIs
Usually do not produce extensive local tissue necrosis or large quantities of pus. Usually are subclinical presentations. Can be fatal in immunocompromised.

Question 3

Streptococcus pyogenes

Answer 3

Group A strep
**One of the most common human pathogens
Suppurative, toxin related & Immunologic reactions
Flora of skin, oropharynx
Exotoxins- streptolysins S & O

Question 4

Streptococcal Pharyngitis “Strep throat”

Answer 4

S. pyogenes attaches to epithelial cells by binding to fibronectin on their surface.
Produces hemolysins, DNAase, hyaluronidase and streptokinase which allow it to damage ad invade human tissue.
M Protein- cell wall component that prevents complement deposition, protecting from phagocytosis
***Can lead to rheumatic fever or acute poststreptococcal glomerulonephritis

Question 5

Scarlett Fever (scarlatina)

Answer 5

S. pyogenes
Punctate red rash on skin and mucous membranes.
usually begins on the chest and spreads to the extremities.
Caused by erythrogenic toxin

Question 6

Erysipela

Answer 6

Erythematous swelling of the skin caused by S. pyogenes
Diffuse edematous, acute inflammatory reaction in the epidermis and dermis extends into SubQ tissue.
Neutrophils!

Question 7

Impetigo (pyoderma)

Answer 7

S, pyogenes or S.aureus
localized,intraepidermal infection
***Antigenically and epidemiologically distinct from strain of S. pyogenes that causes pharyngitis
Person to person contact
Skin colonization, intraepidermal pustule, which ruptures and leaks a purulent exudate.
**Poststreptococcal glomerulonephritis

Question 8

Streptococcal Cellulitis

Answer 8

S. pyogenes

Infection of the loose CT of the deeper layers of the dermis. Results from traumatic inoculation of the skin

Question 9

Puerperal Sepsis

Answer 9

S. pyogenes

Post partum infection in the uterine cavity

Question 10

Streptococcus pneumoniae

Answer 10

Pneumonia, otitis media, sinusitis, meningitis
Most strains that cause clinical disease have a **Piolysaccharide capsule prevents activation of alternative pathway of complement
Flora or oropharynx
Spreads rapidly to involve an entire lobe or several lobes (lobar pneumonia). Alveloi are filled with proteinaceous fluid, neutrophils and bacteria.
**Asplenic patients are at risk of rapid fulminant septic shock and death

Question 11

Group B Streptococci

Answer 11

**Leading cause of neonatal pneumonia, meningitis and sepsis
Risk factors: premature delivery, low levels of maternally derived IgG
May cause pyogenic infections in adults infrequently