chapter 26 infection control. 26-2 copyright 2004 by delmar learning, a division of thomson...

Chapter 26

Infection Control

26-2Copyright 2004 by Delmar Learning, a division of Thomson Learning, Inc.

Infection Control

Infection control practices are directed at controlling or eliminating sources of infection in the health care agency, home, or community.


Pathogens, Infection, and Colonization

Pathogenicity is the ability of a microorganism to produce disease.

Microorganisms that cause diseases in humans are called pathogens.

Virulence is the degree of pathogenicity of an infection’s microorganism.



Infection is an invasion and multiplication of microorganisms in body tissue that results in cellular injury.

These microorganisms are called infectious agents.



Communicable Disease • The result of a communicable agent being

transmitted to a client by direct or indirect contact, through a vehicle (or vector) or airborne route



Colonization is the multiplication of microorganisms on or within a host that does not result in cellular injury.

Flora are the vegetation of microorganisms on the human body.• Resident flora• Transient flora


Agent, Host, and Environment

Agents capable of causing disease:• Biological agents• Chemical agents• Physical agents


Agent, Host, and Environment

A host is a simple or complex organism that can be affected by an agent.• A susceptible host is a person who lacks

resistance to an agent.• A compromised host is a person whose

normal defense mechanisms are impaired and who is therefore susceptible to infection.


Agent, Host and Environment

The environment consists of everything other than the agent and host.• Water, food, plants, animals• Housing conditions• Noise• Meteorological conditions• Environmental chemicals


Chain of Infection

Microorganism (infectious agent) Source or reservoir Portal of exit from reservoir Mode of transmission Portal of entry into host Susceptible host


Infectious Agents (Microorganisms)

Agents that produce infections can consist of bacteria, viruses, fungi, protozoa, and rickettsia


Infectious Agents

The ability of a microorganism to infect a client is related to:• Virulence of the agent• Number of microorganisms present• Ability of the agent to enter and live in the

client• Susceptibility of the client


Infectious Agents

Resident Infectious Agents • Microorganisms which are always present

on skin.• Can be reduced through handwashing, but

not totally removed.


Infectious Agents

Transient Infectious Agents• Agents that are picked up by the skin from

another person or object.• Attach themselves to the skin and then may

be transmitted to a susceptible host.


Source or Reservoir

Required for the microorganism to survive while awaiting a host.

May allow the organism to multiply, making it more dangerous.• The human body is the most common

reservoir.• Food, plants, animals, and feces are other

common reservoirs.


Portal of Exit

Pathway by which pathogens leave the body of a host. Accessed by:• Direct Contact• Indirect Contact• Airborne Transmission


Portal of Exit

Direct Contact• Transmission of disease from the host• Touching, kissing, and sexual intercourse

Sources of Direct Contact• Skin, mucus membranes, urine, feces,

reproductive tract, blood


Portal of Exit

Indirect Contact • Occurs with the use of vehicles and vectors

Vehicles (fomites)• Toys, hospital supplies, instruments, dishes,

cups, or surgical dressings, food, fluids, blood


Portal of Exit

Airborne Transmission• Transmission of infectious agents through

coughing, sneezing, dust particles• Usually entry via the person’s respiratory

tract


Portal of Entry

Pathway by which infectious agents gain access to the body


Susceptible Host

A person with a reduced immune response has increased susceptibility.

The immune response is the body’s natural defense against infection.


Factors Influencing Production of an Infectious Disease

Age Heredity Stress Surgery Nutrition Health Status



Age• The elderly and children under two years of

age are at greatest risk.

Heredity• Conditions or diseases resulting in the

absence of or inability to form immune defenses.



Stress• Increase in metabolic rate which results in

using up stored energy• Elevation of blood cortisol, decreasing anti-

inflammatory responses• Continued stress produces exhaustion,

further depleting ability to ward off infection.



Surgery• Eliminates primary barrier of infection.• Predisposes clients to surgical site

infections.• Localized infection at wound site can

progress to a systemic infection.• Additional risks include catheters and tubes.



Nutrition• Insufficient protein consumption reduces

antibody production and inhibits the body’s ability to ward off infection.

Health Status• Clients with disease of their immune system

are at greater risk.• Chronic diseases can predispose the client

to infection.


Normal Defense Mechanisms

Nonspecific and specific immune defenses work in harmony to defend the host from pathogens.


Normal Defense Mechanisms

Nonspecific Immune Defenses• Protect the host from all microorganisms• Not dependent on prior exposure to the

antigen


Nonspecific Immune Defenses

Skin and Normal Flora Mucous Membranes Sneeze, Cough Reflexes Tearing Reflexes Elimination Acidic Environment Inflammatory Response



Skin• Intact skin is the body’s first line of defense

against infection.• Sebum is produced by the skin and contains

fatty acids that kill some bacteria.



Normal Flora• Normal flora residing on the skin compete

with pathogenic flora for food and inhibit their multiplication.

• Inappropriate antibiotic use may disrupt the balance of normal flora.



Mucous Membranes• Mucus entraps infectious agents and

contains substances that inhibit bacterial growth.

• Cilia trap and propel mucus and microorganisms away from the lungs.



Sneeze and Cough Reflexes• Physically expel mucus and microorganisms

from the respiratory tract and oral cavity with force

Tearing Reflex• Protects the eyes by continually flushing

away microorganisms



Elimination Patterns and Acidic Environment• Resident flora of the large intestines • Mechanical process of defecation• Flushing action of urination• Acidic environment of urine and vagina



Inflammatory Response• Tissue injury caused by bacteria, trauma,

chemicals, heat, or any other phenomenon• Release of substances that produce

secondary changes in the tissue


Specific Immune Defense (The Immune Responses)

Immunity is a specific defense mechanism that creates an immune response to a specific invading antigen.


Specific Immune Defense (The Immune Responses)

Immune Responses• Active immunity• Passive immunity• Acquired immunity• Natural immunity• Artificial immunity


Immune Responses

Active immunity results from the development within the body of antibodies that neutralize the infective agent.

Passive immunity is acquired by the introduction of preformed antibodies.


Immune Responses

Acquired immunity results either from exposure to an antigen or from the passive injection of immunoglobulins.

Natural immunity refers to the genetically determined response of protection within a specific species.

Artificial immunity is produced following a vaccine.


The Humoral Immune Response

B lymphocytes recognize the antigen as an enemy.

Immunoglobulins are plasma protein cells that produce five different classes of antibodies (IgM, IgG, IgA, IgD, and IgE).

Immunoglobulins circulate throughout the bloodstream for the purpose of destroying antigens.


Cell-Mediated Immunity

Fights pathogens that survive inside cells.

Antigen stimulates the release of activated T cells.• T-helper cells• T-suppressor cells• T-cytotoxic cells


Localized Versus Systemic Infections

Infection results from tissue invasion and damage by an infectious agent.• Localized infections are limited to a defined

area or single organ.• Systemic infections affect the entire body

and involve multiple organs.


Four Stages of Infection

Incubation Prodromal Illness Convalescence


Nosocomial Infections

Infections acquired in a health care setting that were not present or incubating at the time of the client’s admission


Common Sites of Nosocomial Infections

Urinary tract Surgical sites Respiratory tract


Nosocomial Infections

Procedures identified as possible sources of infection are:• Inadequate handwashing • Catheterization technique• Improper suctioning technique• Improper dressing-change technique• Contamination of closed drain system


Infection Chain

Breaking the chain of infection; preventive measures follow each critical link in the chain of infection.


Asepsis

Asepsis is the absence of microorganisms.

Aseptic technique is the infection control practice used to prevent the transmission of pathogens.


Medical Asepsis (Clean Technique)

Practices to reduce the number, growth, and spread of microorganisms• The most common cause of nosocomial

infections is contaminated hands of health care providers.

• Wash hands before and after every client contact.


Surgical Asepsis (Sterile Technique)

Practices that eliminate all microorganisms and spores from an object or area• Surgical scrub• Surgical attire• Sterile fields• Sterile instruments and equipment


Reduce or Eliminate Infectious Agents

Infection control practices to break the chain of infection • Cleansing• Disinfection • Sterilization



Cleansing • Removal of soil or organic material from

instruments and equipment used in providing care

• Water, mechanical action, detergent



Disinfection • Elimination of pathogens, except spores,

from inanimate objects • Use of germicides and antiseptics.



Sterilization• Methods used for total elimination of all

microorganisms including spores are:- Moist heat or steam (autoclave, boiling water)- Radiation- Chemicals- Ethylene oxide gas



Home Health Care Considerations• Adapting acute care infection control

practice to the home care setting involves:- Cleaning and disinfecting equipment- Using clean versus sterile technique- Handling of the nursing supply bag



Disposal of Infectious Waste in the Home Biological Hazard Symbol OSHA Regulations


Guidelines for Standards Precautions

Barrier Precautions• Use of masks, gowns, and gloves to

minimize the risk of exposure to blood and body fluids


Guidelines for Standards Precautions

Body Substances• Blood• All body fluids • Secretions • Contaminated items regardless of whether

or not they contain visible blood• Nonintact skin• Mucous membranes


Role of Health Care Personnel and Health Agencies in Infection Control

Mask and eye protection or face shield Non-sterile gown Tuberculosis masks Isolation precautions initiated when

positive cultures from a draining wound are reported



This nurse is interacting with a client who requires isolation precautions.



Reinforce adherence to isolation. Post signs indicating type of isolation. Provide necessary supplies. Place clients in a private room with

adequate ventilation. Use disposable supplies and equipment.



Labeling of all articles leaving the room Use of impermeable bags or double

bagging Client and family instruction Alert to psychological discomfort



Blood Borne Pathogen Exposure• OSHA requires that all health agencies

make available the hepatitis B vaccine and vaccination series to all employees.



Exposure Control Plan• Begins with standard precautions and

moves to postexposure prophylaxis• Specific follow-up for blood-borne pathogens• Postexposure prophylaxis only in cases of

highest risk


Alternative Therapies Used to Treat Infections

Herbal Products• Antimicrobial action• Augment and vitalize the body’s own

defenses

Client’s alternative practices should be documented.

Possible adverse reactions are possible when used with prescribed drugs.

chapter 26 infection control. 26-2 copyright 2004 by delmar learning, a division of thomson...

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sources of infection