1 Microbiology DA 116 Infection Control. 2 Study of microorganisms –Small living organisms...
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Transcript of 1 Microbiology DA 116 Infection Control. 2 Study of microorganisms –Small living organisms...
1
Microbiology
DA 116 Infection Control
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• Study of microorganisms – Small living organisms
• Important to know– Pathogens = disease-causing microorganisms
• Also called microbes
– Prevent transmission of disease through infection control
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Helpful or Harmful?
• Equally:
– Helpful = non-pathogenic• Ex. Food products: Aged
cheeses, wines, yogurt• Ex. Soil fertilization,
production of life-saving drugs
– Harmful = pathogenic• Ex. Infectious diseases
• Dental Health Concerns – Dental caries = bacteria
(streptocoocus mutans)– Periodontal disease =
bacteria + protozoa
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Bacteria
Protozoa
Fungi
Viruses
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Bacteria
• Singular = bacterium
• Good and bad
• Can live independently under favorable environmental conditions– 98.6°, dark, moist
• Some types require oxygen to grow and survive– Aerobic
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Bacteria: classified by shape
• Cocci (sometimes described as spherical-shaped)
– Chain-shaped• Streptococci
– Strep throat, tonsillitis, pneumonia, endocarditis
– Cluster-shaped• Staphylococci
– Boils, skin infections, pneumonia, endocarditis
• Bacilli– Rod-shaped
– Tuberculosis
• Spirochetes (spirilla)
– Spiral-shaped– Lyme disease, syphilis
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Bacterial Spores
• Most resistant form of life known– Harmless spores used to test sterilization
techniques in infection control
• Caused by unfavorable conditions• Alive, but inactive– Cannot reproduce or cause disease
• If conditions improve, become active and disease-causing
• Examples:– Tetanus, tuberculosis, strep throat
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Protozoa
• One-celled organisms
• Do not cause disease• Live in hosts which
can cause disease – intestinal infections– invade blood, lungs,
liver or brain
• Not usually dental office infection control concern
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Fungi
• Plants– Mushrooms, yeasts,
molds
• Candidiasis– Common yeast found
throughout body– Opportunistic
• Affect very young, very old, or very ill patients
• Oral candidiasis– white membranes on
tissues throughout oral cavity
– common under dentures
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Viruses
• Tiny disease-causing organisms
• Live and multiple only inside a host– Human, animal, plant,
or bacteria– Invades host cell,
replicates, and destroys host cell allowing virus cells to release into the body
• Great concern to DHCW
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Characteristics of Viruses
• Specificity: – some live only in certain cells
• HIV
– others affect only certain organs • Mumps = thyroid, pancreas, testicles, ovaries)
• Latency:– Can be dormant for years and then reactivate
• HIV and Hepatitis C “carriers” (3-5% of adults with HBV)
• Dental Office Concern = herpes simplex– HSV 1 = lips, mouth, face– HSV 2 = genital area– Both can be found in oral or genital areas
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Treatment and Transmission of Viruses
• Treatment: – Viruses can mutate to adapt to new situations– only symptoms, not infective cause (virus)– Immunization EVERY year
• Infection control: easy to destroy in external environment
• Transmission– Direct contact– Indirect contact– Insects– Contaminated food or water
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• http://www.youtube.com/watch?v=9xSJckErbcc&feature=related
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Viral Hepatitis
• Inflammation of the liver• Five types
– HAV Hepatitis A food-borne (fecal/oral) immunization
– HBV Hepatitis B blood-borneimmunization
– HCV Hepatitis C blood-borne – HDV Hepatitis D occurs in HBV or HCV carrier
» (HBV immunization protects against HDV)
– HEV Hepatitis E food or water-borne (fecal/oral)
• Latency– HAV outside body for months– HBV 7 days and still transmit infection– HCV 16 hours – 4 days still transmit infection
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Transmission of Hepatitis Viruses• HAV and HEV
– Fecal/oral• Contaminated food and water• Handwashing and clean food preparation methods
• HBV and HCV– Bloodborne– Contaminated needles or sharps injuries– Sharing needles– Tattoos from contaminated needles or instruments– Infected mothers to newborns
• HDV– Must have had HBV or HCV in the past
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HIV
• Human immunodeficiency virus– Body’s immune system breaks down
• Symptoms can include– fatigue, weight loss, fever and sweats, skin
rashes, short term memory loss
• HIV patient can remain healthy for years• Routes of transmission– Blood, semen, vaginal fluids, breast milk
• AIDS– Acquired immunodeficiency syndrome– Caused by HIV related serious illnesses and
infections
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Always follow Standard Precautions!• Remember:– You cannot know which patients have some sort
of infectious disease by • Looking at them• Talking to them• Reading their medical history forms• Even if they are your family or friends
• Because:– Symptoms don’t always appear until after you’ve
treated the patient, yet the patient can be contagious!
– Symptoms in the blood aren’t visible at all!