Transcript 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
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Bacteriology – prokaryotic cells
Virology – viruses
Mycology – fungi
Protozoology – protozoans (single celled prokaryotes)
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
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(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.
WHAT CAUSED DISEASE?
• 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 (1857)
• Joseph Lister
– Introduced concept of sterile surgical field
– Use of antiseptics followed
– Developed limiting dilution technique
ROBERT KOCH (1843 – 1910)
• German physician (and Pasteur’s rival)
• Studied the disease anthrax
• Developed a method to identify the etiologic agent.
• First utilized to identify Bacillus anthracis as etiologic agent of anthrax
(1877)
• Developed a set of postulates
KOCH’S POSTULATES
• The microorganism must be present in the diseased host, and absent
for the healthy.
• Microbe must be isolated and grown in a pure culture.
• 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.
ANTHRAX
ANTHRAX
• 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 agent.
• Bioterror attack through U.S. Postal Service on East Coast Oct. 2001; 23
cases.
• 17 nations believed to have biological warfare programs
ANTHRAX
• Incubation Period – (Time from initial infection to appearance of
symptoms) 1-7 days to a few weeks.
• Symptoms – onset of abrupt fever and chest pain, lethargy,
progressing rapidly to a hemorrhagic pathology.
• NOT contagious from person to person
• THREE forms:
– Inhalational, cutaneous, gastrointestinal
Cutaneous
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Cutaneous anthrax usually occurs when spores
from the bacteria enter a cut or scrape on the
skin. Cutaneous anthrax infection has the
following characteristics:
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Skin infection begins as a small, raised bump that
might itch-similar to an insect or spider bite.
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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.
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Additional blisters may develop.
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Other symptoms may include:
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Swollen lymph nodes close to the area of the
blister.
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Fever.
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Headache.
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A general feeling of discomfort.
Inhalational
• 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.
Gastrointestinal
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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:
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Ulcers at the base of the tongue or tonsils.
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Sore throat.
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Loss of appetite.
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Vomiting.
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Fever.
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These symptoms are followed by:
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Abdominal pain.
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Vomiting of blood.
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Bloody diarrhea.
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Within 2 to 4 days after these symptoms develop, fluid (ascites) fills the abdomen;
shock and death usually follow within 2 to 5 days.