Download Microbiology

Chapter 8
Microbiology
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
1
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
2
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
3
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
4
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.
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
5
Bacteria
• Colonies of bacteria
Pairs
Clusters
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
Chains
6
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
7
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”)
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
8
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
9
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.
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
10
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
11
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
12
Protozoa
• Just below visibility of the naked eye
• Always dividing and changing shape
• Flagella
– Many have this long, threadlike appendage
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
13
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
14
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
15
Diseases Caused by Protozoa
• Malaria
– Symptoms during the first two weeks
• Fever and soreness at point of entry
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
16
Rickettsiae
• Parasites cannot live outside a host
– Lice, fleas, ticks, and mites transmit the
disease to humans
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
17
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
18
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
19
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)
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
20
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
21
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
22
Viruses
• Must live inside hosts
• Antibiotics cannot kill the virus
• Treatment is primarily to ease the
symptoms for the patient’s comfort
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
23
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
24
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
25
Diseases Caused by Viruses
• Poliomyelitis or polio
– Attacks the central nervous system
(severe paralysis is a possibility)
– Vaccine given at age 5 years.
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
26
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
27
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-tohand 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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
28
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)
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
29
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
30
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
31
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
32
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
33
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
34
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
35
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
36
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
37
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
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
38
Normal Routes of
Microorganism Exposure
• Indirect contact: when dental provider or
next patient obtains disease from
contaminated instruments, supplies, or
equipment
– Standard precautions
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
39
Normal Routes of
Microorganism Exposure
• Inhalation: takes place during the use of
the high-speed handpiece, which creates
an aerosol spray during patient care
Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.
40