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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