1. BASIC MICROBIOLOGY

2. Definition
Microbiology is the science that studies living organisms that cannot be seen with the naked eye (microorganisms or microbes)
microorganisms are commonly known as germs

3. Nature of Microorganisms
Pathogens: microorganisms that cause disease
most microorganisms are harmless
some microorganisms found in the body are beneficial to us
when a microorganism enters a part of the body other than where it is intended to be, it can be harmful
eg. E. coli from the colon (breaks down waste/makes vitamin K) can enter the urinary tract and cause an infection

4. Factors that Influence Microbial Growth
5 factors affect the growth of microorganisms:
temperature
pH (only a few live in acidic environments)
moisture
food
oxygen
these factors must be favorable if microorganisms are to live
different microorganisms require different conditions for survival
eg. aerobic microorganisms grow best with high levels of oxygen, while anaerobic microorganisms grow best in the absence of oxygen
Type of food varies: living matter or tissue or dead matter
Most pathogens prefer a warm, dark environment

5. Methods that Destroy Microorganisms
3 common methods destroy microorganisms:
Antiseptics (eg. alcohol and betadine)
used on the skin
slow or prevent the growth of pathogens
Disinfection (eg. bleach solution & zephirin)
not used on skin because irritation may result
Sterilization
autoclaves use steam under pressure to kill ALL microorganisms (first two methods are not effective against spores)
other methods include the use of chemicals, radiation, and gas
Spores are cells produced by bacteria either to reproduce or to be resistant to a harsh environment

6. Types of Microorganisms
5 major types are:
Bacteria
Fungi
Protozoa (protists)
Parasites (rickettsiae)
Viruses

7. Bacteria most familiar of the microbes that infect humans
classified by their shape and arrangement
Type
Shape
Arrangement
Diplococci
Round
in pairs
Staphylococci
in groups or clusters
Streptococci
in chains
Bacilli
Rod-shaped
in pairs, single, or in chains
Spirilla
Cork-screw or spiral
single