MICROORGANISMS

What we don’t see CAN kill us!

MICROORGANISMS Also called microbes Cannot be seen without a microscope May be non-pathogen or pathogen

depending on where it is in body

MICROORGANISMS Aerobes are a variety of bacteria that

require oxygen to grow. Anaerobes are bacteria that grow in

the absence of oxygen and are destroyed by oxygen.

Facultative anaerobes are organisms that can grow in either the presence or the absence of oxygen.

TYPES OF INFECTIONS Endogenous- originates inside the

body

Exogenous-originates outside the body

Nosocomial- infection obtained in a health care facility (Ex: MRSA)

Opportunistic- occurs when host resistance is down

BACTERIA Single cell 3 types: Cocci, Bacilli, Spirilla

BACTERIA-COCCI Round shaped

Micrococci- single cell

Diplococci-two celled

BACTERIA-COCCI Staphylococci-clustered

Streptococci- in chains

EXAMPLES OF COCCI DISEASES “Strep throat” Scarlet Fever Rheumatic fever “Flesh eating” disease Endocarditis Pneumonia MRSA Toxic Shock

BACTERIA-BACILLI Rod Shaped May have flagella that help the

bacteria to move Often produce spores Occur singly, in pairs or in chains Many produce poisons called toxins

SPORES Some bacteria change into the most

resistant form of life known called spores.

Bacteria remain alive in the spore form but are inactive.

They can survive extremes of heat and dryness and even the presence of disinfectants and radiation.

EXAMPLE OF BACILLUS Anthrax

EXAMPLES OF DISEASES FROM BACILLI Leprosy Tuberculosis Tetanus Botulism Diphteria Typhoid

BACTERIA-SPIRILLA Spiral shaped May be other “unusual” shapes Example: syphilis and cholera

BACTERIA-RICKETTSIAE The rickettsiae are short, nonmovable

rods that normally live in the intestinal tract of insects such as lice, fleas, ticks, and mosquitoes.

They are very small and require host cells to reproduce.

Diseases caused by rickettsiae include typhus and Rocky Mountain spotted fever.

These diseases are transmitted to humans by way of the bite of an infected insect.

CHLAMYDIA Smallest of all bacteria Originally thought to be a virus

GRAM STAINING Gram staining requires crystal violet

dye, iodine solution, alcohol solution, and a safranin dye be used in a certain order.

The bacteria that are stained by the dye are classified as Gram-positive. (They appear dark purple under the microscope.)

Gram negative bacteria will appear pink. Bacteria that are positive but stain as

negative are called Gram variable or there’s mixed colored staining.

GRAM POSITIVE

GRAM NEGATIVE

BACTERIA REVIEW

ALGAE Algae range from microscopic single-cell

organisms to larger multiple-cell organisms such as seaweed and kelp.

All algae contain chlorophyll, as well as pigments that cause them to appear yellow-green, brown, or red.

Algae are found in abundance in both freshwater and marine habitats.

Most algae do not produce human disease.

ALGAE

Red Tide

PROTOZOA One celled animal-like, may contain

flagella Often found in decayed materials,

animal feces, and contaminated water Cause malaria, dysentery (severe

diarrhea), and African sleeping sickness Not too common in the US

FUNGI Fungi are plants, such as mushrooms,

yeasts, and molds, that lack chlorophyll. Diseases include athlete’s foot,

vaginitis, “Jock itch”, and ringworm

HELMINTHS Multi-cellular worms or flukes Can be injected in food or obtained

when bitten by a mosquito Examples: pinworms, hookworms,

trichinella spiralis, tapeworms

VIRUS Viruses are smallest of all microbes

and only seen with electron microscope.

Viruses can live and multiply only inside an appropriate host cell.

A virus invades a host cell, copies itself, and then destroys the host cell so the viruses are released into the body.

Spread from human to human through body secretions

VIRUS- DISEASES HIV Common cold Influenza- Ex:H1N1 HPV- Human Papilloma Virus Polio Chickenpox Herpes

Zoster- shinglesSimplex Type 1- cold soresSimplex Type 2- genital herpes

VIRUS- DISEASES Hepatitis

HAV HBV HCV HDV HEV HGV

Vowels: Food and Fecal Borne Consonants: Blood Borne

PRIONS Infectious agent composed of primarily

protein that is misfolded Must reproduce inside a host cell Gets the other proteins to misfold as

well

PRIONS Prions are responsible for “mad cow”

disease and possibly Alzheimer disease. Prion-caused diseases have been found

in human beings and animals. Prions are highly resistant to heat,

chemical agents, and irradiation. There is no treatment or vaccine against

prion diseases, and the only preventive measure is not eating suspect food.

MICROBES TREE MAPMicroorganisms

Chlamydia

Algae

Protozoas Bacteria

Viruses

CocciMicrococciDiplococciStaphylococciStreptococci

Fungi PrionsHelminths

Bacilli

Rickettsiae

Spirilla