Infection Control
Objectives
Mastery of content in this chapter will enable you to:
Define the key terms listed.
Explain the relationship between the chain of infection and the transmission of infection.
Identify the body's normal defenses against infection.
Describe the events in the inflammatory response.
Describe the signs and symptoms of a localized and a systemic infection.
Identify patients most at risk for infection.
Explain conditions that promote the transmission of health care-associated infection.
Explain the difference between medical and surgical asepsis.
Give an example of preventing infection for each element of the infection chain.
Perform proper procedures for hand hygiene.
Explain the rationale and components of routine practices.
Explain the rationale and practices for additional (isolation) precautions.
Explain how infection-control measures in the home may differ from those in the hospital.
Properly don and doff a surgical mask, sterile gown, and sterile gloves.
Key Terms
Aerobic: Microorganisms that require oxygen for survival.
Anaerobic: Microorganisms that thrive in environments without oxygen.
Asepsis: The absence of pathogenic microorganisms.
Broad-spectrum antibiotics: Antibiotics that are effective against a wide range of bacteria.
Carriers: Individuals who harbor pathogens without showing symptoms of illness.
Colonizing: Occurs when microorganisms are present on a site without causing harm.
Communicable: Capable of being transmitted from one host to another.
Disinfection: The process of cleaning something to destroy or deactivate pathogenic microorganisms.
Edema: Swelling caused by excess fluid trapped in the body's tissues.
Endogenous infection: An infection originating from within the body.
Epidemiology: The study of how diseases spread and can be controlled.
Exogenous infection: An infection originating from outside the body.
Exudates: Fluids that leak from blood vessels into nearby tissues; often associated with inflammation.
Hand hygiene: Practices to keep hands clean and free of pathogens.
Health care-associated infection (HAI): Infections acquired in a health care setting.
Immune response: The body's defense system against pathogens.
Immunocompromised: An individual whose immune system is weakened or impaired.
Inflammatory response: The complex biological response of vascular tissues to harmful stimuli
Invasive: Procedures that involve entering the body, often through puncture or incision.
Isolation precautions: Procedures to prevent the spread of infections from infected individuals.
Leukocytosis: Increase in white blood cells, often indicative of infection.
Localized: An infection that is confined to a specific area of the body.
Medical asepsis: Practices to reduce the number and spread of microorganisms.
Microorganisms: Tiny living organisms that can be seen only with a microscope, including bacteria, viruses, and fungi.
Necrotic: Relating to or denoting the death of tissue.
Normal flora: Nonpathogenic microorganisms that reside on the skin and in certain body areas.
Nosocomial infection: Another term for health care-associated infections.
Pathogenicity: The ability of a microorganism to cause disease.
Pathogens: Microorganisms that cause disease.
Phagocytosis: The process by which certain cells engulf and digest microorganisms and debris.
Purulent: Containing or producing pus.
Resident microorganism: Microorganisms that are a permanent part of a particular location on the body.
Routine practices: Standard precautions recommended to prevent infection in health care settings.
Sanguineous: Pertaining to blood.
Serosanguineous: A mix of serum and blood.
Serous: Of, resembling, or producing serum; typically describes a type of fluid.
Sterile field: An area free of all living microorganisms.
Sterilization: The process of killing or removing all microorganisms.
Superinfection: A second infection that occurs on top of an already existing infection.
Surgical asepsis: Practices to render and keep objects and areas free from all microorganisms.
Susceptibility: The likelihood or tendency for an individual to acquire an infection.
Systemic: Referring to an infection that affects the whole body.
Transient microorganism: Microorganisms that are temporarily present on a given site, easily removed by washing.
Virulence: The degree of pathogenicity of an organism, indicative of its ability to cause disease.
Case Study
Patient Profile: Susan, a 48-year-old woman with end-stage renal failure due to focal segmental glomerulosclerosis, dialysis dependent, presents with:
Complaints of chills, headache, fatigue.
A painful maculopapular rash across her upper chest and abdomen (involving over two dermatomes).
Infection Control Importance
Good health relies partly on a safe environment. Techniques that control or prevent transmission of infection protect patients and healthcare workers.
Patients are at risk due to:
Lower resistance to infections.
Increased exposure to pathogens.
Invasive procedures (e.g., insertion of catheters).e
Health Education
Patients and families should learn to recognize infection sources and implement protective measures, including:
Modes of transmission.
Methods of infection prevention.
Infection Control Measures
Infection control aims to:
Protect patients from infections.
Protect healthcare workers from exposure.
Safeguard the population from infectious diseases.
Techniques used for infection control often simultaneously protect healthcare workers and patients.
Nurses must always be vigilant to prevent the spread of infection.
Infectious Agents
Microorganisms include:
Bacteria
Viruses
Fungi
Protozoa
Resident vs. Transient Flora
Resident Flora: Permanent skin residents that don’t usually cause harm; difficult to remove.
Transient Flora: Temporary residents that attach through contact with contaminated objects or individuals; easily removed.
Factors Influencing Pathogenicity
Sufficient number of organisms
Virulence (ability to produce disease)
Ability to enter and survive in the host
Susceptibility of the host
Reservoirs of Infections
A reservoir is a place where a pathogen survives but may not multiply (e.g., humans, animals, water, soil).
Carriers are persons or animals harboring pathogens without symptoms (e.g., hepatitis B carriers).
Pathogens require food, oxygen (aerobic or anaerobic), water, temperature, pH, and minimal light to thrive.
Common Pathogens and Their Reservoirs (Table 34.1)
Clostridioides difficile: Colon -> Colitis, diarrhea.
Escherichia coli: Colon -> Gastroenteritis, urinary tract infection.
Staphylococcus aureus: Skin, hair, anterior nares -> Wound infection, pneumonia, etc.
Streptococcus organisms (Group A/B): Oropharynx, skin, genitalia -> Various infections.
Mycobacterium tuberculosis: Droplet nuclei -> Tuberculosis.
HIV: Blood, etc. -> AIDS.
Microorganisms’ Requirements for Survival
Nourishment: Microorganisms need nutrients; some thrive on organic matter, while others require undigested food.
Oxygen: Aerobic bacteria need oxygen, while anaerobic bacteria thrive without it.
Water: Necessary for most organisms to survive, particularly in moist environments.
Scientific Knowledge Base
Microorganisms can only be seen with microscopes, include various types like bacteria and fungi.
Most are nonpathogenic; pathogens cause disease and can lead to infections.
An infection occurs when pathogens enter and multiply in host tissues, leading to clinical signs and symptoms of disease.
Chain of Infection
Elements of the Chain: The presence of an infection relies on:
An infectious agent (pathogen)
A reservoir (source for pathogen growth)
A portal of exit from the reservoir
A mode of transmission
A portal of entry to a host
A susceptible host
Infection occurs if the chain is intact; breaking it is essential for prevention.
Diagram of Chain of Infection
Diagram: Not included in the transcript but described conceptually.
Importance: Nurses must follow infection prevention to interrupt this chain and prevent infections from developing.