Basic Microbiology Chapter 3, Section 4

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Basic MicrobiologyChapter 3, Section 4

• Health Technologies II
• Mr. Kestner

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Basic Microbiology

• The science that studies living organisms that
  cannot be seen with the naked eye
• A microscope is only way to view the millions of
  tiny creatures living in our environment
• They are found almost everywhere on planet
• They are on our skin, in the air we breathe, on
  every surface we touch, and even inside our bodies

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Microbiology

• Are also referred to as microbes, or more
  commonly, germs, especially to laypeople
  (layperson one not in the field in this case,
  those without a science background)
• Usually do not notice microorganisms until they
  cause physical illness
• We often forget microbes play beneficial role in
  human health benefits are greater than problems
  created by microbes

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Problems v. Benefits

• PROBLEMS
• Various infections in human beings and animals
  are caused by microorganisms

• BENEFITS
• They prevent exposure to other harmful
  microorganisms
• They support production of bread, cheese, yogurt,
  beer, and several other foods and beverages
• They contribute to health of soil for farming
• They aid in purifying waste water

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Nature of Microorganisms

• Small number of microorganisms, called pathogens,
  cause disease
• Most are harmless, called non-pathogens
• Some may be pathogenic in one situation, and not
  in others (e.g., Escherichia coli (E. coli)
  bacterium), certain varieties cause diarrhea
• Normally in intestinal tract, breaks down waste,
  aids in synthesis of Vit K (helps control
  bleeding)
• If E. coli moves to another part of body, major
  problems result

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Factors influencing growth

• Whether microorganism is harmful or beneficial,
  it needs favorable conditions to grow
• Conditions vary with type of microbe
• Temperature
• pH (acidity versus alkalinity)
• Food
• Moisture
• Oxygen (for certain bacteria)

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Factors influencing growth

• Conditions vary all over human body
• All microbes need food and moisture to survive
• Most pathogens prefer warm, dark environment
• Only few tolerate acidic environment (low pH)
• Some live only in presence of O2 aerobic
• Others grow in absence of O2 anaerobic
• Some consume only living matter tissues
• Others prefer dead matter tissues
• Altering living environment is a way to destroy

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Methods of Destruction

• Three common practices used to prevent growth and
  spread of microorganisms
• Antiseptics
• Disinfection
• Sterilization

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Antiseptics

• Solutions applied directly to skin
• Prevent or slow down growth
• Alcohol and betadine are often used
• Not useful against all microorganisms

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Disinfection

• Uses strong chemicals such as bleach solution and
  zephirin to kill many pathogens
• Used mainly on objects and not on the skin
  because they may cause skin irritation and trauma
• Disinfectants and antiseptics have limited
  effects against viruses and spores
• Spores are cells produced by bacteria either to
  reproduce or to be resistant to a harsh
  environment

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Sterilization

• Best way to kill all microbes and their spores
• Autoclave is used to sterilize medical
  instruments
• Uses steam under pressure
• Other methods include use of chemicals,
  radiation, and gas
• Not all microbes require sterilization to become
  nontoxic or non-pathogenic, many microbes can be
  eliminated by disinfecting procedures

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Types of Microorganisms

• Microorganisms are tiny living plants or animals
• The five major types are
• Bacteria
• Fungi
• Protozoa
• Rickettsiae (parasites)
• Viruses

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Bacteria

• Most familiar of microbes that infect humans
• One-celled plants classified by shape and
  arrangement
• Diseases such as strep throat and pneumonia are
  caused by form of bacteria
• Can be categorized according to how arranged
  arrangement is way to identify exact species

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Bacteria
http//www.life.umd.edu/classroom/bsci424/Pathogen
Descriptions/StreptococcusImages.htm

• Some are
• Round cocci
• Streptococci chains
• Staphlococci in groups or clusters
• Diplococci in pairs
• Micrococci

Strep
Staph
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Bacteria

• Some are
• Rod-shaped bacilli
• In pairs, single or in chains
• Flagella tail

Salmonella
http//www.bmb.leeds.ac.uk/mbiology/ug/ugteach/icu
8/uti/gnb.html
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Bacteria

• Some are
• Spiral, or corkscrew-shaped spirilla
• Vibrios
• Spirochetes

Which picture is yogurt?
http//www.biology.iastate.edu/Courses/201L/CellTy
pes/
http//www.biology.iastate.edu/Courses/201L/CellTy
pes/
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Fungi

• Also contribute to illness
• Is a plantlike organism that lives on dead matter
• Responsible for conditions such as ringworm,
  athletes foot, and yeast infections

Say ahhh
http//www.swedishmedical.org/PERT/images/thrush.j
pg
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Protozoa

• Tiny animals found in contaminated water supplies
• Microorganisms that cause diseases such as
  malaria, trichomoniasis, and amebic dysentery

http//www.mblwhoilibrary.org/exhibits/leuckart/vi
rtual_tour/images/protoza_large13.jpg
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Rickettsiae

• Parasites that must live inside cells of other
  living organisms
• One type of bacteria
• Diseases caused by these microbes are transmitted
  to humans by the animal parasite inhabits, such
  as fleas, lice, and ticks
• Humans bitten by infected insect may contract
  diseases such as Rocky Mountain spotted fever,
  Lyme disease, or Typhus

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Viruses

• Smallest of all microorganisms
• Only be seen through electron microscope
• Difficult to destroy
• Grow and reproduce only inside other living cells
• Humans are infected by contact with other living
  beings
• Spread by contact with blood and body fluids
• Diseases associated with viruses are common cold,
  chickenpox, herpes, hepatitis B, and HIV/AIDS
• Health care workers are at great risk of being
  exposed to blood and body fluids PPE!

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Video Clips

• Various microscopic clips from Microbiologybytes.c
  om
• 13 Minute video clip about 1918 flu from PBS.org