Staphylococci

• What type of bacteria are Firmicutes?

  Low GC gram-positive bacteria
• Are Firmicutes spore-forming or non-spore forming bacteria?

  Non-spore forming bacteria
• What are examples of lactic acid bacteria?

  • Streptococcus
  • Lactobacillus
  • Staphylococcus
  • Listeria
  • Mycoplasma
• What are examples of spore-forming bacteria in the Firmicutes phylum?

  Clostridium and Bacillus
• What type of bacteria are Actinobacteria?

  High GC gram-positive bacteria
• What are examples of Actinobacteria?

  • Streptomyces
  • Nocardia
  • Corynebacteria
  • Mycobacteria
• What are Staphylococci?

  Gram+ non-motile cocci
• What is the oxygen requirement for Staphylococci?

  Facultative anaerobe capable of both fermentation and respiration
• What is a major product formed when Staphylococci ferment sugars?

  Lactic acid
• What is the G + C content of Staphylococci?

  30 - 40%
• What does the term "staphyle" refer to in Greek?

  Bunch of grapes
• What distinguishes Staphylococci from Streptococcus?

  Catalase positive
• What is the significance of coagulase in Staphylococcus aureus?

  It causes plasma to clot by converting fibrinogen to fibrin
• What type of hemolysis does Staphylococcus aureus exhibit on blood agar?

  Beta-hemolysis
• How is coagulase testing for Staphylococcus aureus typically performed?

  Using latex bead agglutination
• What diseases are associated with Staphylococcus aureus?

  Pneumonia and septicaemia in newborns
• How does Staphylococcus aureus invade subcutaneous tissue during skin infections?

  With the aid of lipases
• What is a furuncle?

  A painful skin abscess caused by Staphylococcus aureus
• What is a carbuncle?

  A cluster of furuncles
• What is the primary cause of nosocomial infections related to Staphylococcus aureus?

  Common hospital-acquired infections
• How does septic arthritis occur in children?

  Through bacteria gaining access via the bloodstream or injury
• What is hematogenous osteomyelitis?

  Bacteria introduced during trauma or surgery
• What is scalded skin syndrome (SSSS)?

  A toxin produced by Staphylococcus aureus leading to skin desquamation
• What is the initial site of infection for SSSS?

  In the mouth, nasal cavities, throat, or umbilicus
• What is the typical recovery time for SSSS?

  It heals up in a matter of weeks
• What are the pathogenicity factors of Staphylococcus aureus?

  • Hemolysins: lyse erythrocytes
  • Leukocidin: acts on leukocytes
  • Exfoliatin: skin toxin causing peeling
  • Enterotoxins A, B & D: cause food poisoning
  • TSST-1: superantigen causing shock
  • Lipases: invade tissues
  • Fibrolysin: dissolves fibrin clots
  • Extracellular coagulase: forms fibrin wall of abscess
• How does food poisoning occur with Staphylococcus aureus?

  By ingestion of preformed toxin from contaminated food
• What are the symptoms of food poisoning caused by Staphylococcus aureus?

  Severe diarrhea and vomiting
• What is the treatment for Staphylococcus aureus infections?

  Usually sensitive to synthetic penicillins like oxacillin
• What is MRSA?

  Methicillin-resistant Staphylococcus aureus
• What has contributed to the rise of MRSA in hospitals?

  Production of altered penicillin binding proteins and penicillinase
• When were the first MRSA strains isolated?

  In the 1960s
• What is community-acquired MRSA (C-MRSA)?

  MRSA occurring in healthy individuals not recently hospitalized
• What are common risk factors for C-MRSA?

  Injecting drug use and close-contact sports
• How can Staphylococcus epidermidis infections occur?

  Through opportunistic infections in catheters and prosthetic devices
• What type of Staphylococcus is non-hemolytic and coagulase negative?

  Staphylococcus epidermidis