Gram positive cocci

Question 1

Staphylococcus aureus

Attack

• lungs
• CVS
• CNS = Bacteraemia = sepsiaemia
• bones

Answer 1

Morphology

• Catalase pos
• Anaerobic
• caugulase pos
• non-spore forming

Virulence

• protein A; binds to IgG preventing opsonization and preventing phagocytosis
• Hemolysis
• penicillinase
• hyaluronidase: breaks down connective tissue

Clinically

• Gastroenteritis ( food poisoning )
• Toxic shock syndrome
• Pneumonia
• meningitis
• bacteraemia
• osteomyeitis
• skin infection
• urinary infection

Treatment
*resistant to penecillin
Treat with vancomycin
*Clindamycin

Question 2

Staphylococcus epidermidis

Nosocomial infection

Answer 2

Metabolism

• catalase pos
• anaerobic
• coagulase neg

Virulence

• Polysaccharide: Adhere to prosthetic devices
• resistant to antibodies

Clinical

• Prosthetic joints
• Prosthetic heart valves
• Urinary tract infection

Treatment
vancomycin

Question 3

Staphylococcus saprophyticus

Answer 3

Metabolism
coagulase-positive
faculatative anaerobe
coagulase neg

Clinical
*urinary infection in sexually active females

Treatment
Penicillin