Staphylococcus

What type of bacteria is staphylococcus?

Gram + cocci

What oxygen level does staphylococcus grow?

Facultative anaerobic (prefers oxygen)

Alpha hemolysis is ______ (color) and represents _______ hemolysis.

brown; partial

Beta Hemolysis is ______ (color) and represents ____ hemolysis.

yellow; complete

Gamma hemolysis is ______ (color) and represents ______ hemolysis

Transparent; no

Which staphylococcus species is a catalase-positive bacterium? What does this mean?

S. Aureus

• can degrade hydrogen peroxide into water and oxygen which creates bubbles

• Allows bacteria to survive unharmed in a host

What type of media is mannitol salt agar (MSA)?

• differential - mannitol fermenters

• Selective - for staphylococci due to NaCl levels

Why would a bacterium appear as yellow colonies on MSA?

if it can ferment mannitol

Where is staphylococcus common in a host?

NORMAL ON SKIN

• nares of humans and animals

What patients are most susceptible to Staphylococcus infections?

Infants and debilitated adults

True or False: Staphylococcus are resistant to dry and hot conditions and can survive well.

TRUE

Coagulase

clotting of blood plasma

Kinase

dissolving clot and releasing bacteria

What is Staphylokinase and what does it do?

potent thrombolytic agent that also degrades fibrin

• help material escape from localized host defense

What does leucocidin do?

kill WBC - IMMUNE INVASION

What does staphylococci have that causes shedding of skin to better penetrate the host?

Exfoliative toxins A and B

Exfoliative toxins cause what diseases?

Scalded skin syndrome and greasy pig syndrome

What does hyaluronidase do?

catalyze degradation of the hyaluronic acid in the CT and epithelium

What happens in toxic shock syndrome with superantigen?

Non-soecific activation of T cells which results in a MASSIVE cytokine release

S. Aureus affects which species?

• ruminants

• Poultry

• Dogs

What species does S hyicus affect?

Pigs

What species does S. Intermedium affect?

Rabbits

What is bumblefoot?

localized lesion on the foot with a secondary infection by S. Aureus

What is exudative epidermitis (greasy pig disease)?

S. Hyicus that produce exfoliative toxin secondary to skin trauma

Botryomycosis

rare chronic bacterial granulomatous disease that happens after castration in horses from an infection of the spermatic cord

How can you diagnose staphylococcus?

• direct smear microscopy

• Culture

• Antibiotic sensitivity test (AST)

• DNA based test

How can you treat staphylococcus?

Penicillin G (drug of choice

• Tetracyclines

• Bacitracin

• Nitrofuranes

• Macrolides

• Lincomycin

• Enrofloxacin

Which staphylococcus species can infect humans?

S. Aureus and S. Hyicus

Which species of staphylococcus causes MRSA?

S. Aureus