Infection

Unit 12

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Understanding Microbes• Location of microbes:

• Skin• Mouth• Within our bodies (intestines)• In and on food we eat (meats, condiments)• On what we touch or handle (desk, doors,

handrails, etc.)• Nonpathogens: microbes that are useful to us. They

do not cause disease.• Pathogens: disease-producing organisms; they

grow best in warm, moist, dark environment where food and oxygen needs can be met.

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Classification of Microbes• Protozoa: Simple, one-celled parasitic organisms• Bacteria: Simple, one-celled microbes• Fungi: Two Types –

• Yeast: Simple, one-celled budding form of a fungus

• Mold: saprophytic (organism that lives on dead matter)

fungi that can cause mold or moldiness• Viruses: smallest microbe that depends completely

on the invaded host cells for reproduction• Usually spread in blood, secretions from

respiratory, intestinal tracts or reproductive tracts• Can cause serious illness – no cure

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Infectious Disease Process• Chain of Infection: Six components:

• Causative Agent: microorganism that causes disease

• Reservoir for Agent: where causative agent lives• Human• Environmental • Can leave reservoir by secretions in body fluid

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Infectious Disease Process• Mode of Transmission: way disease is spread

• Airborne (float through air)• Droplet (coughing/sneezing)• Contact (direct touch)• Common Vehicle (instrument(s))• Vector-borne (fleas, ticks, mosquitoes)

• Portal of Entry: entry made through:• Breakthroughs in the skin• Inhalation• Sexual transmission• Ingestion

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Infectious Disease Process• Susceptible Host: person who is likely to get

infection:• Very young (immature immune system)• Very old (declining immune system)• Persons with compromised immune systems

• Portal of Exit: area through which infectious secretions leave the body

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Susceptible Host

Reservoir orSource

Portal of Exit

Method of Transmission

CausativeAgent

Portal of Entry

Chain of Infection

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Infectious Disease Process• Risk Factors:

• Strength of immune system• Compromised immunity (example: HIV/AIDS)• Not being vaccinated• Other factors: age, heredity, sex, nutritional

status, life-style, occupation, and stress.• Any breakdown of the bodies natural defenses

(example: skin breakdown)

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Infections• Infections can be:

• Local (an infected abrasion)• Generalized (infected hand from infected

laceration)• Systemic (in the blood stream)

• Carriers: people who have pathogens in their bodies, but do not show signs of infections; these people can transmit disease to others

• Normal Flora: microbes living in the body that can cause infection if they become pathogenic; or move from one area of the body to another area where they don’t belong, or if antibiotics given for another infection upset the normal balance of flora.

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How Pathogens Affect The Body• An infection cannot occur unless all links in the

chain of infection are present.• Microbes act in different ways to produce disease;

• Attack and destroy cells• Produce toxins• Cause allergies

• Internal defenses against pathogens:• Fever• Inflammation • Phagocytes• Immune response

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Immunity• Immunity: the ability to resist infection

• When pathogen enters body, it becomes an antigen.

• The body develops antibodies to protect against the antigen and provide immunity from disease

• Vaccinations of artificial or weakened antigens help the body develop antibodies to resist certain diseases.

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Immunity• Immunosuppression: when the immune system is

unable to fight/resist disease• Advanced age• HIV• Spleen injury• Chemo Therapy• Radiation Therapy

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Serious Infections In Health Care Facilities• Bacteria: can cause skin, respiratory, and urinary

infections• Diagnosed by way of a culture and sensitivity test

(to antibiotic)• Antibiotics: need to be taken as prescribed until

they are all finished – even if patient feels symptom free!• Drug resistance may develop, if the antibiotics are

stopped too soon• Antibiotic Resistant Pathogens: pathogens that are

resistant to most antibiotics• Can cause serious infections• MRSA (methicillin resistant staphylococcus aureus)

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Serious Infections In Health Care Facilities• Antibiotic Resistant Pathogens: pathogens that

are resistant to most antibiotics• Can cause serious infections• MRSA (methicillin resistant staphylococcus aureus)• VRE (vancomycin resistant enterrococci)

• Other serious pathogens:• Pseudomonas aeroginosa• Escherrichia coli (E-coli)• Streptococcus A• Salmonella• Mycobacterium Tuberculosis (TB)

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Serious Infections In Health Care Facilities• Tuberculosis (TB): was a widespread disease with

a high fatality rate prior to the development of antibiotics• New cases have increased since 1985 (drug-

resistant)• People at high risk for TB:

• HIV positive• Those living in poverty• Immigrants from countries where TB is common• Individuals that have had TB exposure

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Serious Infections In Health Care Facilities• Signs & Symptoms of Tuberculosis (TB):

• Fatigue• Weight loss• Loss of appetite• Weakness• Elevated temperature in afternoon/evening• Night sweats• Hemoptysis (coughing up blood)• Coughing

• Can be spread through droplets in respiratory secretions

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Serious Infections In Health Care Facilities• Can be diagnosed by:

• Sputum culture• Chest x-ray• Positive skin test (Mantoux test)

• Treatment:• Antibiotics for 6 months to 2 years• They are initially contagious for 2-3 weeks

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Serious Infections In Health Care Facilities• Escherrichia Coli (E-coli):

• Transmitted in • Contaminated or undercooked meat• Produce that has been rinsed in water

contaminated with feces• Has been found on cutting boards and utensils

• Multiplies rapidly• Produces toxins• Causes diarrhea, dehydration, renal failure• Standard precautions are used (gloves,

handwashing), but contact precautions are used for diapered (infants/adults) or incontinent patients

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Serious Infections In Health Care Facilities• Pseudomembranous colitis: caused by Clostridium

difficile (C-diff), common pathogen in health care facilities• Picked up on hands from contaminated

environmental surfaces and equipment• Frequent, severe diarrhea and dehydration• Standard/contact precautions

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Viral Infections• Shingles (herpes zoster): occurs in people infected

with chicken pox, but the virus remained in the body in an inactive state; years later it becomes active, causing painful blisters

• Influenza (flu): caused by a family of viruses and can lead to serious complications. Some types of flu may be prevented with vaccinations

• Hepatitis: inflammation of the liver that can be caused by several different viruses; Hep A, Hep B, and Hep C are the most common

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Viral Infections• Acquired immune deficiency syndrome (AIDS):

caused by human immunodeficiency virus; transmitted primarily through direct contact of secretions of another person’s infected bodily secretions• Blood• Vaginal secretions• Semen• Saliva• Breast milk

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Viral Infections• Human Immunodeficiency Virus (HIV): has many

variants and does not live long outside of the body; can be eliminated by common chemicals such as bleach• Depresses body’s immune system and makes

the infected person more susceptible to infections and other complications; not everyone who is exposed becomes infected

• Following infection with HIV, virus may not be immediately active – yet the person IS INFECTED. Most will show antibodies to HIV in blood within 3 to 6 months after infection.

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Viral Infections• Human Immunodeficiency Virus (HIV):

• Infection with HIV is called HIV disease; this condition may progress to AIDS

• HIV may not ever develop into AIDS, but person is a carrier of disease and is able to infect others

• Progression of HIV disease is seen by a decrease in CD4 (T4) cells; as a result the immune system is suppressed and the ability to resist infection decreases

• When CD4 level drops to <200, the person is diagnosed with AIDS (Normal= 600-1500/µL)

• Risky behavior should be avoided!

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Viral Infections• Human Immunodeficiency Virus (HIV):

• Symptoms:• Flu-like:

• Fever• Night sweats• Fatigue• Swollen lymph nodes• Sore throat• Gastrointestinal problems• Headache

• ¼ to ½ of those infected show signs of illness within 5-10 years of antibody development

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Viral Infections• Human Immunodeficiency Virus (HIV):

• No vaccine is available to prevent HIV/AIDS• Therapy consists of drugs that slow down the

disease process and reinforce the immune system• Some drugs are used to prevent and treat infection• Nutritional support is also very important• Drug therapy must be taken EXACTLY as

prescribed or the condition will worsen• The is no cure for this disease

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Viral Infections• Hantavirus:

• Spread by contact with rodents or their excrement (poop)

• When disturbed, viral particles in the excretions become airborne and are inhaled by susceptible hosts

• As disease progresses, patient becomes very short of breath, eventually requiring respiratory support (ventilator)

• Not transmitted from person to person

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Other Important Infections• Coccidoidomycosis (valley fever): respiratory

infection caused by a fungus; can be fatal in immunosuppressed persons

• Giardiasis: protozoa found in water; causes severe diarrhea; can be treated with antibiotics

• Cryptospoidiosis: protozoa found in digestive tract of infected animals; causes severe diarrhea; no specific treatment

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Other Important Infections• Guidelines for preventing infections:

• Maintain adequate fluid/nutritional intake• Toilet patients regularly• Wipe from FRONT to BACK – always!• Perform catheter care as directed; avoid opening

the closed drainage system• Keep patients clean• Avoid reporting to work ill• Follow facility’s policies on infection control

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Other Important Infections• Guidelines for preventing infections:

Promptly Report Abnormalities In:

Urine Discharge from wound

Respirations Change in skin color

Mental changes Nausea/vomiting

Bowel Pattern Red/swollen areas on body

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Bioterrorism• Bioterrorism: use of biological agents, including

pathogens or agricultural pests, for terrorist purposes• Many individuals can be affected by a biological

weapon before the cause is detected• Smallpox is a serious viral infection that was

eliminated during the 20th century, but contained stockpiles still exist in laboratories around the world

• Hospitals have a voluntary smallpox vaccination program for workers which provides high-level immunity for 3-5 years, then immunity gradually decreases

• Vaccine contains LIVE virus

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Bioterrorism

• Anthrax (Bacillus anthracis) is a bacteria that can form endospores.

• Endospores can live for centuries!• Spores can be used as a biological weapon• Causes fatal pneumonia if inhaled• Cause skin lesions on contact• Anthrax toxin used as a weapon and instantly fatal if

inhaled.

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Bioterrorism

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Outbreak of Disease in Health Care Facility• If outbreak is detected: immediate action must be

taken to contain infection• Nursing assistants will receive specific instructions

regarding precautions to be taken as well as containment procedures

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Self Care• The nursing assistant can stay healthy by

• eating a healthy diet • getting adequate sleep • keeping body clean • living in clean environment• have mechanisms to effectively deal with stress• avoid unhealthy habits (smoking/drugs/alcohol)• avoid risky behaviors/situations

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The End