Microorganisms and Infection

Microorganisms

• Microorganisms exist everywhere in water, soil, and on body surfaces.
• Many organisms are harmless, others are lethal, and some are a normal part of the human body.

Infection

• Infection is the growth of microorganisms in body tissue where they are not usually found.
• Infection is an invasion and multiplication of pathogenic microorganisms within the body, leading to tissue damage and an immune response.

Chain of Infection

• The chain of infection is a model used to understand how infections are transmitted and spread.
• This model outlines six components, each of which must be present for an infection to occur.
• By breaking any link in this chain, healthcare providers can effectively control and prevent the spread of infections.

Infectious Agent

• The infectious agent is the pathogen (microorganism) that causes disease.
• Examples:
  • Bacteria: Single-celled organisms that can multiply rapidly and may be pathogenic. Examples include Staphylococcus aureus (causes skin infections) and Escherichia coli (causes gastrointestinal infections).
  • Viruses: Microscopic infectious agents that require a host cell to replicate. Examples include influenza virus (causes the flu) and HIV (causes AIDS).
  • Fungi: Eukaryotic organisms that include yeasts, molds, and mushrooms. Examples include Candida albicans (causes yeast infections) and Aspergillus spp. (causes respiratory infections).
  • Parasites: Organisms that live on or in a host and benefit at the host's expense. Examples include protozoa (single-celled) or multicellular organisms (like worms).

Reservoir

• The reservoir is the natural habitat of the infectious agent, where it lives and multiplies.
• Examples: Humans, Animals, Environment.

Portal of Exit

• The portal of exit is the route through which the infectious agent leaves the reservoir.
• Examples: Respiratory tract, skin, gastrointestinal tract.

Mode of Transmission

• The mode of transmission refers to how the infectious agent is spread from one host to another.
• Examples:
  • Direct Contact: Touching a person with an active infection.
  • Indirect Contact: Touching contaminated surfaces or objects like doorknobs or utensils.
  • Droplet Transmission: Respiratory droplets expelled when an infected person coughs or sneezes.
  • Airborne Transmission: Infectious agents that remain suspended in the air.

Portal of Entry

• The portal of entry is the route by which the infectious agent enters the new host.
• This can be the same as the portal of exit, such as respiratory droplets entering through the nose or mouth.

Susceptible Host

• A susceptible host is an individual who is at risk of contracting an infection.
• Factors that increase susceptibility include:
  • Age (very young or very old)
  • Weakened immune system
  • Underlying medical conditions
  • Chronic diseases
  • Medications that suppress the immune system

Preventing Infection

• The most effective way to prevent the spread of infections is to break the chain of infection.
• This can be achieved through measures like hand hygiene, immunization, proper isolation procedures, and disinfection of surfaces.

Sterile Technique

• Sterile technique is essential for preventing the spread of infections in healthcare settings.
• It refers to the use of methods to ensure that objects and surfaces are free of microorganisms.
• Sterile technique is practiced in operating rooms, special diagnostic procedures, and many general care procedures.

Principles of Surgical Asepsis

• All objects used in a sterile field must be sterile.
• Sterile objects become unsterile when touched by unsterile objects.
• Sterile objects that are out of sight or below the waist or table level are considered unsterile.
• Fluids flow in the direction of gravity.
• The edges of a sterile field are considered unsterile.
• The skin cannot be sterilized and is unsterile.
• Conscientiousness, alertness, and honesty are essential qualities in maintaining surgical asepsis.
• An object is sterile only when it is free of all microorganisms.
• Sterile objects may become unsterile by prolonged exposure to airborne microorganisms.
• Moisture that passes through a sterile object draws microorganisms from unsterile surfaces above or below to the sterile surface by capillary action.

Sterile Technique Practices

• Sterilization of Instruments: All surgical instruments and equipment must be sterilized using methods such as autoclaving (steam under pressure), ethylene oxide gas, or chemical sterilants.
• Sterile Fields: Creating and maintaining a sterile field using sterile drapes and covers during surgical procedures to ensure that only sterile items come into contact with the surgical site.
• Proper Gowning and Gloving: Surgical staff must wear sterile gowns, gloves, and masks to prevent contamination during procedures.
• Hand Hygiene: Handwashing is the single most important factor in preventing the spread of infections.

Personal Protective Equipment (PPE)

• Face Masks: Masks are worn to reduce the risk for transmission of microorganisms by droplet contact or airborne routes and by splatters of body substances.
  • The CDC recommends that masks be worn by those close to the client if the infection is transmitted by large particle aerosols and by all individuals entering the room if the infection is transmitted by small particle aerosols.
• Eye Wear: Protective eye wear (goggles, glasses, face shields) and masks are indicated in situations where body substances may splatter the face.

Key Concepts

• Nurses play a vital role in infection control.
• By understanding the chain of infection and practicing proper infection control measures, nurses can help prevent the spread of infections.