Infection Control

INFECTION CONTROL Infection - is an invasion of body tissue by microorganisms and their growth there Disease – a detectable alteration in normal tissue. Communicable Disease – it results if the infectious agent can be transmitted to an individual by direct or indirect contact or as airborne infection. Pathogenicity – is the ability to produce disease; thus a pathogen is a microorganism that causes disease. - a “true” pathogen causes disease or infection in a healthy individual. Opportunistic pathogen – causes disease only in a susceptible individual. Asepsis – is the freedom from disease – causing microorganisms. To decrease the possibility of transferring microorganisms from one place to another, aseptic technique is used. Types of Asepsis  Medical asepsis – includes all practices intend to confine a specific microorganisms to a specific area, limiting the number, growth, and transmission of microorganisms. Objects are referred as clean and dirty.  Surgical asepsis or sterile technique – refers to those practices that keep an area or object free of all microorganisms. It is used for all procedures involving the sterile areas of the body. Sepsis – is the state of infection and can take many forms, including septic shock. Types of Microorganisms Causing Infections 1. Bacteria are by far the most common infection – causing microorganisms. e.g., Staphylococcus aureus, Streptococcus pneumoniae, Lactobacillus, Excherichia coli,and etc. 2. Viruses consist primarily of nucleic acid and therefore must enter living cells in order to reproduce. Common virus families: rhinovirus, hepatitis, herpes, and human immunodeficiency virus 3. Fungi include yeasts and molds Candida albicans is a yeast considered to be normal flora in the human vagina. 4. Parasites live on the other living organisms. They include protozoa. Colonization is the process by which strains of microorganisms become resident flora.

Types of Infection  Local infection is limited to the septic part of the body where the microorganisms remain.  Systemic infection if the microorganisms spread and damage different parts of the body ▓ bacteremia is when a culture of the person’s blood reveals microorganisms. ▓ septicemia is when a bacteremia results in a systemic infection.  Acute infections generally appear suddenly or last a short time.  Chronic infections may occur slowly, over a very long period, and may last months or years. Nosocomial Infections  are classified as infections that are associated with the delivery of health care services in a health care facility.  Can either develop during a client’s stay in a facility or manifest after discharge.  May also be acquired by health personnel in the facility and can cause significant illness and time lost from work  Endogenous source – microorganisms that cause nosocomial infections can originate from the clients themselves  Exogenous source – from the hospital environment and hospital personnel.  Iatrogenic infections are the direct result of diagnostic or therapeutic procedures. Chain of Infection Six Links Etilologic Agent The extent which any microorganisms is capable of producing an infectious process depends on the number of microorganisms present, the virulence and potency of the microorganisms to enter the body, the susceptibility of the host, and the ability of the microorganisms to live in the host's body. Reservoir There are many reservoirs, or source of microorganisms. Common source are other humans, the client’s own microorganisms, plants, animals, or the general environment. Carrier is person or animal reservoir of a specific infections agent that usually does not manifest any clinical signs of disease. Portal of Exit from Reservoir Before an infection can establish itself in a host, the microorganisms must leave the reservoir.

Method of Transmission After a microorganism leaves its source or reservoir, it requires a means of transmission to reach another person or host through a receptive portal of entry. Three Mechanisms: 1. Direct transmission. Involves immediate and direct transfer of microorganisms from person to person through touching, biting, kissing, or sexual intercourse and droplet transmission. 2. Indirect transmission. May be either vehicle – borne or vector – borne. 3. Airborne transmission. May involve droplets or dust. Droplet nuclei, the residue of evaporated droplets emitted by an infected host. The material is transmitted by air currents to a suitable portal of entry, usually the respiratory tract, of another person. Portal of Entry to the Susceptible Host Microorganism must enter the body. The skin is a barrier to infectious agents; however any break in the skin can readily serve as a portal of entry. Susceptible Host Any person who is at risk for infection. A compromised host is a person at increased risk, an individual who for one or more reasons is more likely than others to acquire an infection. 1 Etiologic agent (microorganisms)

2 Reservoir (source)

6 Susceptible host

The Chain of infection

5 Portal of entry to the susceptible host

3 Portal of Exit from reservoir

4 Method of transmission

Body Defenses against Infection ♦ Nonspecific defenses ♦ Specific (immune) defenses Inflammatory Responses Inflammation is local and nonspecific defensive response of the tissues to an injurious or infectious agent. Five Signs: a. Pain (dolor) b. swelling (tumor) c. redness (rubor) d. heat (color/calor) e. impaired function of the part Three stages of inflammatory response: First stage: Vascular and cellular responses Second stage: Exudate production Third stage: Reparative phase Specific Defenses ●Antigen is a substance of the body that induces a state of sensitivity or immune responsiveness (immunity). If the protein originates in a person’s own body, the antigen is called an autoantigen. ●Antibodies also called immunoglobulins, are part of the body’s plasma prorein. 2 Components > Antibody-mediated defenses – is humoral (circulating) immunity because theses defenses reside ultimately in the B lymphocytes and are mediated by antibodies produced by B cells. > Cell mediated defenses or cellular immunity; occur through the T-cell system. Types of Immunity TYPE 1.Active a. Natural b. Artificial 2. Passive a. Natural b. Artificial

ANTIGEN OR ANTIBODY SOURCE Antibodies are produced by the body in response to an antigen. Antibodies are formed in the presence of active infection in the body. Antigens (vaccines or toxoids) are administered to stimulate antibody production.

DURATION Long Lifelong Many years; the immunity must be reinforced by booster Short

Antibodies are produced by another source, animal or human Antibodies are transferred naturally from an 6 mos to 1 yr immune mother to her baby through the placenta or in colustrum. Immune serum (antibody) from an animal or 2 to 3 weeks another human is injected.