Healthcare Associated Infections

• What does HAI stand for?

  Healthcare-acquired infection
• What is a nosocomial infection?

  An infection originating in the hospital
• How long after admission does a hospital-acquired infection typically occur?

  72 hours after admission
• Why is the rate of infection lower in the community compared to healthcare settings?

  Healthcare environments have compromised patients and higher pathogen exposure
• What factors contribute to healthcare-acquired infections?

  Compromised patients, movement of healthcare workers, and immunosuppressive drug use
• What are the predominant pathogens associated with urinary tract infections (UTIs)?

  • E. coli
  • Other Gram-negative bacilli
  • Enterococci
  • Staphylococci
  • Candida
• What are the predominant pathogens associated with surgical wound infections?

  • Staphylococci (S. aureus and CNS)
  • Enterococci
  • E. coli
  • Pseudomonas aeruginosa
• What are the predominant pathogens associated with lower respiratory infections?

  • Pseudomonas aeruginosa
  • Other Gram-negative bacilli
  • S. aureus
• What are the predominant pathogens associated with bacteraemia?

  • Staphylococci (S. aureus and CNS)
  • Enterococci
  • Candida
  • E. coli
  • Other Gram-negative bacilli
• What are the two sources of nosocomial infections?

  Endogenous and exogenous sources
• What is the characteristic arrangement of staphylococci?

  Irregular clusters
• What is the approximate diameter of staphylococci?

  1 µm
• What type of anaerobe are staphylococci?

  Facultative anaerobe
• What is the coagulase test used for?

  To determine the ability to coagulate citrated plasma
• What are the infections caused by S. aureus?

  • Superficial infections: Boils, Sties, Impetigo
  • Serious infections: Septicaemia, Endocarditis, Osteomyelitis
• What is the significance of coagulase-negative staphylococci (CNS)?

  They are prevalent commensals of the skin
• What is the role of biofilm in S. aureus infections?

  It helps in bacterial attachment and protects against antibiotics
• How does S. aureus develop antibiotic resistance?

  Through mutations and acquisition of resistance genes
• What are the treatment options for MSSA and MRSA infections?

  • MSSA: Flucloxacillin, Erythromycin, Clindamycin, Vancomycin (if allergic)
  • MRSA: Vancomycin, Linezolid, Daptomycin, Ceftobiprole
• What is the role of PBP2a in MRSA?

  It confers resistance to most beta-lactams
• What is the significance of the mecA gene in MRSA?

  It encodes for PBP2a, which provides resistance to methicillin
• What are the signs of infection related to intravascular devices?

  • Exit site infection: Inflammation, tenderness, swelling, cellulitis, purulent exudate
  • Catheter-related bloodstream infection: Bacteraemia, septicaemia, endocarditis, septic shock
• What are typical exogenous pathogens associated with infections?

  MRSA, extended-spectrum beta-lactamase producing Gram-negative bacilli, Clostridium difficile
• What is Clostridium difficile known for?

  Causing antibiotic-associated diarrhoea and pseudomembranous colitis
• What are the diagnostic methods for Clostridium difficile infections?

  • Enrichment and selective isolation
  • Detection of GDH and toxin
  • Use of Braziers CCEY agar
• What are the signs of infection at the exit site of a catheter?

  Tenderness, swelling, cellulitis, and purulent exudate
• What is a catheter-related blood stream infection associated with?

  Bacteraemia, septicaemia, endocarditis, and septic shock
• What are some causative organisms of intravascular device-related infections?

  1. epidermidis, S. aureus, E. coli, and other Gram-negative bacilli
• How is the diagnosis of intravascular device-related infections typically made?

  Through exit site swab, Maki roll plate, and blood culture
• What are typical exogenous pathogens associated with infections?

  MRSA and extended spectrum beta-lactamase producing Gram-negative bacilli
• What is Clostridium difficile classified as?

  A Gram-positive, oval, sub-terminal spore-forming anaerobe
• What happens when normal gut flora is lost due to antibiotic therapy?

  1. difficile can grow to high numbers and produce toxins
• What are the symptoms of C. difficile infection?

  Diarrhoea, ulcerations of the colon, and potential death
• What is the treatment for severe C. difficile infections?

  Metronidazole or oral vancomycin
• What is fidaxomicin used for?

  It is a narrow-spectrum oral antibiotic for C. difficile infections
• What are some alternative treatment options for C. difficile infections?

  Probiotics, faecal transplants/enemas, and immunotherapy
• What is a key prevention strategy for healthcare-associated infections (HAIs)?

  Screening patients on admission
• How can endogenous infections be prevented in healthcare settings?

  By limiting the time between admission and surgery and using antibacterial treated dressings
• What is a common method to prevent exogenous infections?

  Hand washing and using sterile equipment
• What are the potential outcomes of healthcare-associated infections?

  Serious illness, death, increased hospital stay, and increased costs