1. Chapter 8
Microbiology
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2. Important People in Microbiology
Anton Van Leeuwenhoek
Magnifying glass
Saw microorganisms from teeth for the first time
Louis Pasteur
Process of fermentation
Proved bacteria causes disease
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3. Important People in Microbiology
Robert Koch
Koch’s Postulates
Organism must be present in all cases of the disease
Organism must be isolated in pure culture
Organism must be capable of producing the disease in another person or animal
Organism must be recovered again in pure culture
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4. Groups of Microorganisms
Bacteria and virus groups
Gram stain used to differentiate
Gram positive if they keep their dark purple color
Gram negative if they lose the color
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5. Bacteria Need for oxygen
Aerobic bacteria must have oxygen to grow and live.
Anaerobic bacteria are destroyed in the presence of oxygen and live only without oxygen.
Facultative anaerobic bacteria grow with or without oxygen present.
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6. Bacteria Colonies of bacteria Pairs Clusters Chains
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7. Diseases Caused by Bacteria
Tuberculosis
Bacteria is found in the lungs
Fatigue, fever, weight loss, persistent cough
Airborne; dental personnel must wear masks
Detected by a skin test and/or chest x-ray
Treatment is antibiotics or other drugs
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8. Diseases Caused by Bacteria
Diphtheria
Severe throat infection and fever
Pertussis
Respiratory disease
Mainly affects infants and young children
Tetanus
Stiffness of the jaw (“lockjaw”)
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9. Diseases Caused by Bacteria
Strep throat
Very common
Sore throat, fever, general malaise
Streptococcus mutans, a species of the same bacteria; implicated in dental caries and endocarditis
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10. Diseases Caused by Bacteria
Staphylococcal infections
Bacteria groups grow in clusters:
Staph infection
Gangrene
Toxic shock syndrome
Venereal diseases
Some forms of pneumonia
Antibiotics are the first line of treatments.
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11. Diseases Caused by Bacteria
Anthrax
Humans can get disease through cuts in the skin or by eating diseased meat
Powder form
symptoms within 1 to 6 days; fever, weakness, dry hacking cough
prevention by vaccination or antibiotic treatment before symptoms
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12. Diseases Caused by Bacteria
Chlamydiae
Group of microorganisms that behave like bacteria and are small in size, somewhere between bacteria and viruses
Responsible for genital, eye, and lymph node infections
Most common sexually transmitted disease in the United States
Antibiotics to treat
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13. Protozoa Just below visibility of the naked eye
Always dividing and changing shape
Flagella
Many have this long, threadlike appendage
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14. Diseases Caused by Protozoa
Amebic dysentery
Severe diarrhea, abscesses may develop in liver
Prevalent in countries where the drinking water is contaminated and overall poor hygiene conditions prevail
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15. Diseases Caused by Protozoa
Periodontal disease (protozoa and bacteria)
Both are found in inflamed tissue around the tooth
Protozoa is found in the plaque in the periodontal pockets around the tooth
Treatments include removal, cleaning of plaque and tissue, and oral hygiene maintenance
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16. Diseases Caused by Protozoa
Malaria
Symptoms during the first two weeks
Fever and soreness at point of entry
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17. Rickettsiae Parasites cannot live outside a host
Lice, fleas, ticks, and mites transmit the disease to humans
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18. Diseases Caused by Rickettsiae
Head lice
Common among children in schools
Transmitted easily through direct contact
Eggs reproduce in hair shafts
Treatment is medicated shampoo and cleaning of everything, such as bedding, brushes, and clothing, with very hot water
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19. Diseases Caused by Rickettsiae
Rocky Mountain spotted fever
Rare, curable
Small pink dots appear
Typhus
Rare, treatable
Severe headache, back and limb pain, constipation, rash, and confusion
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20. Yeasts and Molds Includes bread yeast, mushrooms, and bread molds
Cannot be killed by bacterial antibiotics (made from mold but does not act on it)
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21. Diseases Caused by Yeasts and Molds
Candidiasis
Covered by mucus in areas such as the inside of the mouth or the vaginal area
Treated by antibiotics
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22. Diseases Caused by Yeasts and Molds
Tinea (“athlete’s foot”)
Itching and cracking of the foot
Treatment in form of creams, ointments, and lotions
Tinea unguium
White patches on the toe or fingernail
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23. Viruses Must live inside hosts Antibiotics cannot kill the virus
Treatment is primarily to ease the symptoms for the patient’s comfort
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24. Diseases Caused by Viruses
Measles
Rash, fever
Spread by airborne droplets of nasal secretions
Mumps
Swelling of the parotid (salivary) glands on one or both sides
Spread by airborne droplets
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25. Diseases Caused by Viruses
Rubella or German measles
Rash on face that may spread to trunk and limbs
Only serious when it affects women in early stages of pregnancy (may cause birth defects)
Vaccines are highly effective and given to most infants at age 15 months
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26. Diseases Caused by Viruses
Poliomyelitis or polio
Attacks the central nervous system (severe paralysis is a possibility)
Vaccine given at age 5 years.
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27. Diseases Caused by Viruses
Chicken pox
Very common and contagious in children
Rash and fever
Spread through airborne droplets
Usually only contract once in a lifetime
Before age 10 years is better than as an adult
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28. Diseases Caused by Viruses
Common cold and influenza
Treatments for fever, upset stomach, headache, body ache
Cold is spread through airborne droplets, contact with contaminated objects, or hand-to-hand contact
Flu vaccines are successful in 60% of patients
Flu is contagious from 12 to 72 hours after symptoms appear
Flu is spread through airborne droplets
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29. Diseases of Major Concern to the Dental Assistant
Herpes simplex virus (HSV)
Herpes simplex virus I (HSV I) is associated with infections of the lips, mouth, and face
Herpes simplex virus II (HSV II) is associated with the genital area (can also be found in oral cavity)
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30. Diseases of Major Concern to the Dental Assistant
Treatment of HSV I depends on its type, site, and severity
Dental teams may suggest to reschedule patient if the sores are apparent (primarily for patient comfort, although some offices may have policies)
Many treatments readily available
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31. Diseases of Major Concern to the Dental Assistant
Bloodborne diseases
Hepatitis B
Human immunodeficiency virus (HIV)
Brain damage and dementia may occur
May develop into acquired immune deficiency syndrome (AIDS)
No cure
Much research is being done to find a cure
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32. Diseases of Major Concern to the Dental Assistant
High risk behavior
Injuries or sticks with sharp objects contaminated with blood or body fluid
Multiple sexual partners; unprotected sex
Sharing contaminated needles
Exposure to non-intact skin or open wound with contaminated blood or body fluid
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33. Diseases of Major Concern to the Dental Assistant
Viral hepatitis
Hepatitis A and E
Transmitted by personal contact or ingestion of contaminated water or food
Vaccines and boosters are available for children in areas at high risk
Hepatitis B (major dental concern)
Transmitted mainly through needles and syringes
May or may not have symptoms
Loss of appetite, abdominal pain and tenderness, fever, weakness, muscle pain, and jaundice
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34. How the Body Resists Diseases
Infection
Pyogenic membrane: dam built around the infected area preventing it to spread further
Antibodies: produced as a final defense against foreign substances
Antitoxins: neutralizes the toxins given off by certain bacteria
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35. How the Body Resists Diseases
Fever
Fights off infection or pathogens
Few bacteria can survive beyond 102° F
Inflammation
Increase in the blood vessels to a specific area allowing antibodies to enter
Erythema (redness)
Heat
Edema (swelling)
Pain
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36. How the Body Resists Diseases
Immunity
Ability to resist disease
Natural immunity
Acquired immunity
Passive acquired immunity
Active acquired immunity
Natural acquired immunity
Artificial acquired immunity
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37. How the Body Resists Diseases
Antigen substance injected into the body to stimulate specific antibodies
Allergens
Hypersensitive
Anaphylactic shock
Sometimes fatal
Requires going through patient’s health history
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38. Normal Routes of Microorganism Exposure
Direct contact: when a dental provider touches the lesion or blood of an infected person while working in the oral cavity
Standard precautions
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39. Normal Routes of Microorganism Exposure
Indirect contact: when dental provider or next patient obtains disease from contaminated instruments, supplies, or equipment
Standard precautions
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40. Normal Routes of Microorganism Exposure
Inhalation: takes place during the use of the high-speed handpiece, which creates an aerosol spray during patient care
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