Pathology of Infectious Diseases Week 2

What are the most common human forms of staphylococcus?

Staph Aureus

Staph Epidermidis

Where is staph epidermidis found as natural flora?

Skin and Vaginal flora

T or F: Staph epidermidis only causes opportunistic infections

True

What % of the population are staph aureus carriers?

15%

Where can staph aureus exist as natural flora?

Nasal cavities and skin

What can be used to differentiate staph aureus from streptococcus?

Catalase

What can be used to differentiate staph aureus from staph epidermidis?

Coagulase

T or F: Staph Aureus can only be transferred directly, not indirectly

False (transfer can be direct or indirect)

T or F: Staph aureus can perform intergeneric conjugation

False

What is the function of Vitronectin?

Collagen binding protein

T or F: The capsule of staph aureus is non-immunogenic

False (it is immunogenic)

What is the function of Protein A (a virulence factor of Staph Aureus)

inactivates IgG

What is the function of Fibronectin?

Binding protein

What is the function of Coagulase?

disrupts blood plasma levels

What is the function of clumping factor?

Clumps the bacteria together

What is the function of leukocidin

Lipid disruption and leukocyte destruction

What allows Staph Aureus to trigger arthritis?

Gamma Toxin

What allows Staph Aureus to lyse neutrophils and allows for beta hemolysis?

Alpha Toxin

What allows staph aureus to disrupt cellular connections?

Exfoliate toxin

What type of bacteria causes Osteomyelitis?

Staph Aureus

What is a late sign of staph aureus infection?

Deep Concaved access

What are early signs of staph aureus infection?

Swollen

Painful

Redness

Warm to touch

Resembles spider bites

Fills with pus

Mounds up (breaks skin at top of mound)

What is the hematogenous source of osteomyelitis infection?

Skin infection

What are secondary sources of osteomyelitis infection?

Trauma and surgery

What are the symptoms of osteomyelitis?

Fever

Irritability or lethargy (children)

Pain in affected area

Swelling in affected area

Warmth and redness in affected area

What is Brodie sign?

Fluid-filled area in the bone seen on x-ray

Why is osteomyelitis only associated with a positive blood test half of the time?

it is sometimes only in the bones, and sometimes in the bones and blood

Where is Brodie sign more common in children?

Long bones

Where is Brodie sign more common in adults?

Vertebrae

What age group are respiratory staph infections typical in?

Children under the age of 2 yo

What infection precedes respiratory staph infections in 2/3 cases?

influenza

What are Osler's nodes?

red, tender spots under the skin of the fingers

T or F: petechiae may be associated with staph aureus endocarditis

True

How long do staph aureus food poisoning symptoms take to manifest?

30 minutes to 6 hours (faster if the toxin is ingested)

T or F: Staph Aureus is heat resistant and its toxin is salt resistant

False (the organism is salt resistant and the toxin is heat resistant)

What drugs are used to treat Methicillin-resistant staph aureus (MRSA)?

Bactrim and vancomycin

T or F: streptococcus is gram +

True

T or F: Streptococcus pyogenes can only be transmitted indirectly

False (only direct contact

What are the attachment structures of streptococcus pyogenes?

F-protein and Fimbria

T or F: the capsule of streptococcus pyogenes is non-immunogenic

True

What is the anti-phagocytic protein on streptococcus pyogenes?

M-protein

What toxins produced by streptococcus pyogenes causes rash and toxic shock?

Exotoxin A and C

What toxin produced by streptococcus pyogenes causes breakdown / prevention of clots?

Streptokinase (Fibrinolysin)

What toxin produced by streptococcus pyogenes breaks down hyaluronic acid?

Hyaluronidase

What toxin produced by streptococcus pyogenes prevents neutrophil and extracellular traps?

Streptodornase

What toxin produced by streptococcus pyogenes cleaves chemotactic neutrophil components?

C5A peptidase

What toxin produced by streptococcus pyogenes prevents migration of neutrophils?

Chemokine protease

What toxin produced by streptococcus pyogenes allows it to perform beta hemolysis?

Streptomycin S and O

What is an AKA for Pharyngitis?

Strep throat

What is an antibody cross-reaction of streptococcus pyogenes that damages heart valves?

Rheumatic Fever

What is a phage-mediated toxin reaction caused by streptococcus pyogenes, ending in strawberry tongue?

Scarlet Fever

What demographic is most affected by rheumatic fever?

children with specific genes

What demographic is most affected by scarlet fever?

children aged 3-15

What disease has the characteristic butterfly rash?

Erysipelas

What type of climate is erysipelas most commonly found in?

warm climates

What demographic is most commonly affected by erysipelas?

individuals over 20

What demographic is most commonly affected by impetigo?

children 2-5 yo

What condition is marked by hemhorrhagic pustules that evolve into necrotic ulcers?

Ecythma gangrenosum

What condition is usually preceded by by an injury, resulting in an infection of the dermal region?

Cellulitis

What condition was once a common postpartum infection of the uterine cavity?

Sepsis

What condition typically follows skin strep infections and is triggered by antibody-antigen complexes running through the kidneys?

Glomerulonephritis

Which bacteria has an immunogenic capsule as its only virulence factor?

Streptococcus pneumoniae

T or F: Streptococcus pneumonia can only be transmitted directly

True

What is the most common demographic affected by otitis media?

children under 2 yo

What is the acute phase of sinusitis?

2-4 weeks

What is the chronic phase of sinusitis?

12 weeks or longer

How long does it take for bacterial infection to develop in pneumonia?

24-48 hours

How long does red hepatization take in pneumonia?

2-4 days

How long does grey hepatization take in pneumonia?

4-8 days

How long does it take for normal lung response to be restored in pneumonia?

8-10 days

What is the most severe form of meningitis?

bacterial

What antibiotics are used to treat bacterial meningitis?

cephalosporin and vancomycin

What are the most prominent strains of Neisseria meningitidis worldwide?

A, B, and C

What are the most prominent strains of Neisseria meningitidis in the U.S.?

B and C

What type of virulence factors does Neisseria meningititis have?

Capsule (immunogenic)

IgA protease

LPS (common pyrogenic component)

Type IV pili

CD46 attachment

What is the primary sign of Meningococcemia?

Petechial skin rash

What is an uncommon downstream manifestation of Neisseria meningitis?

Waterhouse Friderichsen syndrome

How is Klebsiella pneumoniae transmitted?

Fecal contamination (not airborne)

T or F: Klebsiella pneumoniae can cause pneumonia

True

What are two primary symptoms of Klebsiella pneumoniae?

Thick gelatinous sputum and difficulty expectorating