Introduction to Medical Microbiology Ch 1 Flashcards
What are microorganisms?
Organisms too small to be seen with unaided eye
What do microorganisms do?
- Few are pathogenic (disease-producing)
- Some cause food spoilage
- Decompose organic waste
- Incorporate nitrogen gas in air into organic compounds
- Generate oxygen by photosynthesis
- Produce chemical products: ethanol, acetone, and vitamins
- Produce fermented foods: vinegar, cheese, yogurt, alcoholic beverages, and bread
- Can be used in Industry to manufacture products: Cellulose, insulin, drugs (antibiotics)
What is the microbiome (microbiota)?
= group of microbes that live stably on/in the human body
- Adult humans compose 30 trillion body cells but harbor another 40 trillion bacterial cells.
- Begin to be acquired before birth
- May colonize the body indefinitely
- May colonize the body fleetingly (Called transient microbiota)
- Help to maintain good health
- Can prevent growth of pathogenic microbes
- May help train the immune system to discriminate threats
Naming and classifying microorganisms (Scientific names)
- Are italicized or underlined
- composed of 2 names:
- Genus: which is capitalized
- Specific epithet (species name), which is lowercase. - (Are latinized and used Worldwide)
EXAMPLES:
- Escherichia coli (E. coli)
- Honors the discoverer, Theodor Escherich
- Describes the bacterium’s habitat—the large intestine, or colon
- Honors the discoverer, Theodor Escherich
- Staphylococcus aureus (S. aureus)
- Describes the clustered (staphylo-) spherical (coccus) cells
- Describes the gold-colored (aureus) colonies
Classification of Microorganisms
- Developed by Carl Woese in 1978
- Three domains based on cellular organization (Prokaryotes vs Eukaryotes)
-Bacteria (prokaryotes)
-Archaea (Prokaryotes)
-Eukarya (Eukaryote)
- protists
- Fungi
- Plants
- Animals
Classification of Bacteria
Cell walls contain a protein -carbohydrate complex called peptidoglycan
Classification of Archaea
Cell walls, if present, lacks peptidoglycan
Classification of Eukarya
- Protists (Slime, molds, yeasts, protozoa, and algae)
- Fungi (Unicellular yeasts, multicellular molds, and mushrooms)
- Plants (mosses, ferns, conifers, and flowering plants)
- Animals (Sponges, worms, insects)
Infectious Diseases
Infectious disease are caused by microorganisms (microbes)
- Including major infectious disease of temperate and tropical
climates
Other categories of disease
-Inherited (genetic) diseases
- Nutritional deficiencies
-Physiological disorders
- Diabetes
- Cerebral Palsy
- Degenerative diseases
- Osteoarthritis
- Neoplastic diseases (Cancers)
- HPV -> causes cervical cancer
- Mental disorders, etc.
Infection
Results from an invasion of part of the body by a microorganism
Microbes that cause infections are described as
- Infectious
- Infectious agent
- Pathogens
- Pathogenic microorganisms
Types of Infectious Agents
- Prions
- Viruses
- Bacteria
- Fungi
- Algae (non-infectious/toxins)
- Protozoa
- helminths (worms)
- arthropods (ticks, fleas, insects)
mnemonic: “Pretty Vicious Bacteria Find All Pathogens Horribly Annoying”
- Pretty = Prions
- Vicious = Viruses
- Bacteria = Bacteria
- Find = Fungi
- All = Algae
- Pathogens = Protozoa
- Horribly = Helminths
- Annoying = Arthropods
Medical Microbiology
Is the study of bacteria, fungi, viruses and protozoa
- Can also include helminths (worms) and arthropods (ticks,
mites, insects)
- Not microbes but important vectors of pathogens
Subdivisions in Medical Microbiology
Divisions depending on microorganism:
- Bacteriology (study of bacteria)
- Virology (Study of viruses)
- Mycology (Study of fungi)
- Parasitology (study of parasites: protozoans, worms, insects)
mnemonic: “Big Viruses Make problems”
Big = Bacteriology (study of bacteria)
Viruses = Virology (study of viruses)
Make = Mycology (study of fungi)
Problems = Parasitology (study of parasites: protozoans, worms, insects)
People for first observation & Brief History
- Robert Hooke (1665)
- Anton van Leeuwenhoek (1673 - 1723)
Robert Hooke (1665)
- Said that living things are made of “cells”
- He marked the beginning of the = Cell theory: “all living things are
composed of cells”
Anton van Leeuwenhoek (1673-1723)
- First person to observe microbes through the magnifying glass (crude microscope)
- Identified “animalcules” —> Bacteria and protozoa
Spontaneous generation
Hypothesis that living organisms arise from non-living matter;
- A “vital force” forms life
Biogenesis
Hypothesis that living organisms arise from preexisting life (living organisms)
Francesco Redi (1668)
- Filled 6 jars with decaying meat
- He first challenged spontaneous generations, showing how maggots comes from flies of the eggs
John Needham (1745)
- Heated broth, then placed it in a sealed flask
- Resulted in microbial growth
Lazzaro Spallanzani (1765)
- Broth placed in flask, then heated, then sealed
- No microbial growth
Louis Pasteur (1861)
- Demonstrated that microorganisms are present in air
- Heated broth in flask (no sealed)
- Microbial growth was observed
-Heated broth in a flask which was sealed.
- No microbial growth was observed
-Disproving the theory of spontaneous generation
