In-Depth Notes on Hospital-Acquired Infections and Infection Control

Definition of Hospital-Acquired Infections (HAIs)

• HAIs are infections that were not present at the time of a patient's admission to a hospital.
• Occurs in up to 25% of hospitalized patients.
• Common types of HAIs include:
  • Urinary tract infections (UTIs)
  • Respiratory infections
  • Wound infections
  • Skin infections
  • Soft tissue infections
  • Septicaemia

Preventable vs Non-Preventable HAIs

• Preventable HAIs:
  • Caused by medical, nursing, or surgical errors (e.g., poor hand hygiene, surgical instruments left inside patients).
• Non-Preventable HAIs:
  • Due to uncontrollable factors (e.g., immune-compromised patients, severe injuries).

Sources of HAIs

• Various origins for HAIs include:
  • Environment: Contaminated surfaces within the hospital.
  • Person-to-Person: Can be endogenous (from within the patient) or exogenous (from external sources).
  • Food Supply and Air Supply: Contamination can occur here.
  • Fomites: Inanimate objects that carry infection.
  • Vectors: Such as insects that can transmit infection.
  • Water Supply: Contaminated water can lead to infections.

Hospital Settings and Infection Risks

• Despite being healing environments, hospitals can be sources of infections through:
  • Intravenous Access: Invasive procedures carry infection risks.
  • Urinary Catheters: Indwelling catheters can lead to UTIs.
  • Surgeries: Breaks in sterile techniques can introduce contaminants.

The Chain of Infection in Nosocomial Infections

• Source: Where microorganisms replicate and spread.
• Route of Infection: How pathogens leave the infected source to reach a susceptible host.
• Host: Factors affecting susceptibility include age and immune status.

Controlling Nosocomial Infections

• Prevention of Infection Chain: Hospital infection control plans aim to eliminate risks by:
  • Rendering sources non-infectious.
  • Preventing microorganisms from leaving their source.
  • Disrupting the pathways for infection.
  • Preventing entry of pathogens into hosts.
  • Efficient identification and detection of infection sources.

Role of Hospital Infection Control Team

• Infection control is a collective responsibility that includes:
  • Implementing good clinical practices (e.g., isolating infected patients).
  • Ensuring proper isolation methods (e.g., wound, respiratory isolation).
  • Type-specific isolation techniques (e.g., prion diseases, airborne diseases).
  • Following universal precautions as developed after the AIDS outbreak in the 1980s.

Universal Precautions

• Treat every patient as potentially infectious:
  • Emphasis on:
  • Hand washing
  • Use of gloves and barriers
  • Aseptic techniques and proper sharps handling.
• Additional Precautions for specific infections include managing:
  • Airborne and droplet transmissions.
  • Contamination via contact with surfaces or bodily fluids.

Infection Control in Community Settings

• Community-level infection control is influenced by:
  • Social and environmental factors.
  • Health education and food safety measures.
  • Vector control and immunization strategies.
  • Prophylactic treatments during outbreaks.
  • Involvement of national and international health agencies.

Cleaning, Sterilization, and Disinfection

• Understanding cleanliness:
  • Equates to removing visible soil and pathogens.
• Methods of Cleaning/Sterilization:
  • Physical methods: Heat treatment (dry/moist), radiation, filtration.
  • Chemical methods: Use of chemical disinfectants.

Factors Affecting Disinfectant Efficacy

• Effectiveness is contingent upon:
  • Concentration of the disinfectant.
  • Type of microorganism being targeted.
  • Contact time and temperature conditions.
  • Presence of organic or inorganic load.

Resistance to Disinfectants

• Microorganism resistance hierarchy:
  • Spores/cysts
  • Mycobacteria
  • Fungi
  • Vegetative bacteria
  • Enveloped viruses

Hand Hygiene Techniques

• Antiseptics: Used pre-surgery to reduce flora on hands and skin.
• Hand Rubs: Typically contain 60-70% ethanol and primarily remove transient flora.

Importance of Proper Hand Washing

• Correct hand washing techniques are crucial in preventing infections in healthcare settings.