Chapter 25: Asepsis and Infection Control

Chapter 25- Asepsis and Infection Control

    Host: living being where and infectious, parasitic, or pathogenic agent resided and receives sustenance.

    Antimicrobials: drugs that treat infections by killing or slowing the growth of microbes causing infection.

    CDC: responsible for investigating, preventing, and controlling disease.

    Infection: disease state that results from presence of pathogens in or on the body

    Infectious agent- bacteria categorized shapes are cocci (spherical), rod shaped (bacilli), or corkscrew shaped (spirochetes).

      Gram neg or gram positive based on gram stain.

      Gram positive have thick cell walls that result in discolorization and stained violet.

      Gram negative has complex cell walls that can be decolorized by alcohol.

      Aerobic- need oxygen to live and grow.

      Anaerobic- dont need oxygen.

    Reservoir- growth and multiplication of microorganisms is the natural habitat of the organisms.

      People, animals, soil, food, water, milk, and inanimate objects.

      Some people act as reservoirs for infectious agent and show signs and symptoms.

      People who dont are considered carriers. Aka asymptomatic.

    Portal of exit- point of escape for the organism from the reservoir.

      Cannot exiter its influence unless moves away from original reservoir.

      Respiratory, GI,GU, blood and tissues are exampls of portal of exit.

    Means of transmission- transmitted from its reservoir by various means or routes.

    Direct Contact- requires close proximity between host and infected person or carrier.

    Indirect Contact- involves personal contact either with a vector or inanimate object.

    Vector: creature that transmits and infectious agent to human.

    Fomite: inanimate object.

    Portal of entry- point which organisms enter a new host.

      It will die without portal of entry to a host.

      Entry route into the new host is often the same as teh exit route.

    Susceptible host- microorganisms survive only in a source that provides shelter and nourishment.

    Viruses: smallest of all microorganisms, visible through microscope.

    Antivirals only shorten course of illness such as HIV

      The antiretroviral given in HIV are initiated after diagnosis to effectively disturb the cycle and to block replication and render the virus undetectable.

    Fungi: plantlike organisms (mold and yeasts)

    Present in air, soil, and water.

      Most are resistant to treatment.

    Parasites: organisms that live on or in a host and rely on it for nourishment.

    Organisms potential to produce depends on:

      Number of organisms

      Virulence: the ability to cause disease

      Competence of person’s immune system

      Length and intimacy of contact between person and microorganism.

    Endemic: occurs with predictability in one specific region or population.

    Pandemic: global outbreaks of a novel virus that did not have an immunization or treatment.

    Microorganisms commonly inhabit body sites and are part of the body’s natural defense, the normal flora.

    Opportunist: harmless organism that generates infection.

    E.Coli- resides in intestinal tract and causes no harm

      When it migrates, can lead to UTI.

    C. Diff- resides in the body but not signs of infection.

    Colonization: infection is present once the person exhibits specific manifestations of the disease.

Stages of Infection

    Incubation period- interval between the pathogens invasion of the body and the appearance of symptoms of infection.

    Organisms are growing and multiplying.

    Prodromal stage- most infectious. Early signs and symptoms start to present, but often vague.

    Last from several hours to several days.

    Patient is likely unaware of being contagious

    Full stage of Illness-presence of infection specific signs and symptoms.

    Determins length and severity of illness.

    Convalescent period- involves recovery from infection

    Depends on severity and general conditions.

    Skin and mucous membrane are the first-line defenses.

      Others include: normal flora.

    Inflammatory response: protective mechanisms

    Helps body neutralize, control, or eliminate the offending agent, and prepare the site for repair.

    Vascular and Cellular response:

      Vascular phase, small blood vessels constrict in the area and lead to vasodilation of arterioles and venules that supply the area.

      Histamine is release, leading to increased permeability of vessels, which allows protein-rich fluid to pour onto the area.

      Cellular state- white blood cells move in the area.

      Neutrophils, primary phagocytes, engulf the organism and consume cell debris and foreign material.

      Exudate is released from wound

    Contains red blood cells or pus (purulent).

    Amount depend on size and location.

    Immune response- involves the collective reaction of the immune system to an invading organism.

    Antigen: foreign material invading organism.

    Antibody: component of overall immune response

    Healthcare associated infections: originating in a hospital.

    Exogenous: causative organism acquired from other people.

    Endogenous: causative organism comes from microbial life.

    Iatrogenic is resulted from treatment or diagnostice procedure.

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