Basic Microbiology Chapter 3, Section 4

1. Basic MicrobiologyChapter 3, Section 4 Health Technologies II Mr. Kestner

2. 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

3. 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

4. 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

5. 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

6. 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)

7. 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

8. Methods of Destruction • Three common practices used to prevent growth and spread of microorganisms: • Antiseptics • Disinfection • Sterilization

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

10. 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

11. 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

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

13. 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

14. Bacteria http://www.life.umd.edu/classroom/bsci424/PathogenDescriptions/StreptococcusImages.htm • Some are: • Round – cocci • Streptococci – chains • Staphlococci – in groups or clusters • Diplococci – in pairs • Micrococci Strep Staph

15. Bacteria • Some are: • Rod-shaped – bacilli • In pairs, single or in chains • Flagella – tail Salmonella http://www.bmb.leeds.ac.uk/mbiology/ug/ugteach/icu8/uti/gnb.html

16. Bacteria • Some are: • Spiral, or corkscrew-shaped – spirilla • Vibrios • Spirochetes Which picture is yogurt? http://www.biology.iastate.edu/Courses/201L/CellTypes/ http://www.biology.iastate.edu/Courses/201L/CellTypes/

17. Fungi • Also contribute to illness • Is a plantlike organism that lives on dead matter • Responsible for conditions such as ringworm, athlete’s foot, and yeast infections Say “ahhh…” http://www.swedishmedical.org/PERT/images/thrush.jpg

18. 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/virtual_tour/images/protoza_large13.jpg

19. 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

20. 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!

21. Video Clips • Various microscopic clips from Microbiologybytes.com • 13 Minute video clip about 1918 flu from PBS.org