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Introduction to microbiology


INTRODUCTION TO MICROBIOLOGY Biology II Mrs. Hieneman Cutaneous Cutaneous anthrax usually occurs when spores from the bacteria enter a cut or scrape on the skin. – PowerPoint PPT presentation

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Title: Introduction to microbiology

Introduction to microbiology
  • Biology II
  • Mrs. Hieneman

Definition of Microbiology
  • the study of those organisms best observed with
    the aid of a microscope.
  • employs techniques and procedures required to
    study microorganisms.

Fields of microbiology
  • Bacteriology prokaryotic cells
  • Virology viruses
  • Mycology fungi
  • Protozoology protozoans (single celled
  • Parasitology parasites
  • Immunology
  • Medical Microbiology
  • Microbial Genetics
  • Microbial Ecology
  • Biotechnology

Anthon van Leeuwenhoek
  • (1632 1723)
  • Dry goods merchant
  • Lens grinder
  • Produced simple (single lens) microscopes
  • In report dated Oct 9 1676 is the first
    description of bacteria.

Louis pasteur
  • (1822 1895)
  • Frenchman trained as a chemist.
  • Discovered isomers of tartaric acid.
  • Discovered the process of fermentation and
    developed a method of pasteurization to reduce
    microbial contamination of wine and beer.
  • Developed anthrax and rabies vaccines.

  • Humoral theory an imbalance of the four body
    humors (black bile, yellow bile, phlegm, blood)
    resulted in disease. Treatments bloodletting,
    expectorants, purgatives.
  • Demonic theory cast out the demons exorcists
    conducted this practice.
  • Miasmatic theory something in the air (miasma
    poisonous vapor) malaria bad air influenza
    influence of the stars.
  • Germ theory particulate matter transmissible
    from one person to another initiated disease.

Germ Theory of Disease
  • Agostino Bassi
  • Silkworm disease caused by a fungus (1835)
  • Ignaz Semmelweis
  • Invisible agent caused sepsis (1841)
  • M.J. Berkeley
  • Potato blight of Ireland caused by a fungus
  • Joseph Lister
  • Introduced concept of sterile surgical field
  • Use of antiseptics followed
  • Developed limiting dilution technique

Robert Koch (1843 1910)
  • German physician (and Pasteurs rival)
  • Studied the disease anthrax
  • Developed a method to identify the etiologic
  • First utilized to identify Bacillus anthracis as
    etiologic agent of anthrax (1877)
  • Developed a set of postulates

Kochs postulates
  • The microorganism must be present in the diseased
    host, and absent for the healthy.
  • Microbe must be isolated and grown in a pure
  • Isolated microbe must cause disease when
    inoculated into healthy laboratory host.
  • Must re-isolate the microbe from the diseased
    laboratory host.

Bacillus anthracis
  • Large, aerobic, non-motile, gram positive,
    spore-forming rod.
  • Easily cultured on ordinary medium.
  • Spores can be found in soil world wide.
  • Affects humans and livestock
  • Can be transferred from animals to humans.

  • Iran 1945 outbreak killed 1 million sheep.
  • Russia 1979 accidental release of spores
    infected 79, killed 68 (inhalational anthrax)
  • Easily weaponized to produce a biological warfare
  • Bioterror attack through U.S. Postal Service on
    East Coast Oct. 2001 23 cases.
  • 17 nations believed to have biological warfare

  • Incubation Period (Time from initial infection
    to appearance of symptoms) 1-7 days to a few
  • Symptoms onset of abrupt fever and chest pain,
    lethargy, progressing rapidly to a hemorrhagic
  • NOT contagious from person to person
  • THREE forms
  • Inhalational, cutaneous, gastrointestinal

  • Cutaneous anthrax usually occurs when spores from
    the bacteria enter a cut or scrape on the skin.
    Cutaneous anthrax infection has the following
  • Skin infection begins as a small, raised bump
    that might itch-similar to an insect or spider
  • Within 1 to 2 days, the bump develops into a
    fluid-filled blister about 1cm to 3cm in
    diameter. Within 7 to 10 days, the blister
    usually has a black center of dying tissue
    (eschar) surrounded by redness and swelling. The
    blister is usually painless.
  • Additional blisters may develop.
  • Other symptoms may include
  • Swollen lymph nodes close to the area of the
  • Fever.
  • Headache.
  • A general feeling of discomfort.

  • The most lethal form of exposure occurs from
    inhalational anthrax . The incubation period for
    this form of anthrax may be 60 days or more,
    although it is usually 2 to 3 days. Initial
    symptoms can include
  • Sore throat.
  • Mild fever.
  • Muscle aches.
  • Symptoms can progress rapidly after just a few
    days to include
  • Severe difficulty with breathing.
  • Shock, which can develop rapidly.
  • Meningitis, which develops frequently.
  • Death can occur within 24 to 36 hours after such
    complications occur. Respiratory symptoms may be
    similar to those of pneumonia.

  • No confirmed cases of gastrointestinal anthrax
    have been reported in the United States.2 This
    form of anthrax occurs after eating meat
    contaminated with the bacteria that cause
    anthrax. Gastrointestinal anthrax can be more
    serious than cutaneous anthrax but can be treated
    effectively with prompt use of antibiotics. But
    if untreated, gastrointestinal anthrax causes
  • Ulcers at the base of the tongue or tonsils.
  • Sore throat.
  • Loss of appetite.
  • Vomiting.
  • Fever.
  • These symptoms are followed by
  • Abdominal pain.
  • Vomiting of blood.
  • Bloody diarrhea.
  • Within 2 to 4 days after these symptoms develop,
    fluid (ascites) fills the abdomen shock and
    death usually follow within 2 to 5 days.