MICROORGANISMSMICROORGANISMS

DefinitionsDefinitions

Microorganism: microbe, small living plant or animal that is not visible to the naked eye.

Examples: bacteria, protozoa, fungi, rickettsiae, and viruses.

DefinitionsDefinitions

Nonpathogens: microorganisms that are a part of the normal flora of the body and are beneficial to maintaining certain body processes.

Pathogens: microorganisms that cause infection and disease . (germs)

From one to another…From one to another… Microorganisms that are beneficial in one

area of the body, can become harmful if they are present in another area of the body..

SO..Nonpathogens can become Pathogens!!

Example: E coli is normal in the large intestine..and aid in digestion..BUT if E coli is found in the urinary system or blood it causes infections.

ClassificationsClassifications

Bacteria: one celled plants that multiply rapidly.

Protozoa: one celled animals found in decayed materials and contaminated water.

Fungi: Simple plantlike organisms that live on dead organic matter.

ClassificationsClassificationsRickettsiae: parasites..cant live

outside the cells of another organism.

Viruses: smallest living organism, visable only with the use of an electron microscope.

They cant reproduce unless they are inside another living cell.

ExamplesExamples

Spirilli: spiral shaped.–Causes cholera and syphilis.

ExamplesExamplesBacteria:

– Cocci- round or spherical shaped, occur in pairs chains and clusters.Diplococci: pair of cocciStreptococci: chains (think of a strip of cocci)

Staphlococci: Clusters (think of grapes)

ExamplesExamplesBacteria continuedBacteria continued

Bacilli: rod shaped, occurs singly, in pairs, or in chains. Some contain flagella (threadlike projections that are similar to tails that allow bacilli to move)– Able to form spores (thick walled

capsules) when conditions are poor for growth.

–Extremely difficult to kill!

ExamplesExamples

Protozoa: amoeba– Pathogenic ones cause malaria,

amebic dysentery, trichomonas, and African sleeping sickness.

ExamplesExamples

Fungi: yeast and molds/Causes diseases such as

ringworm, athlete’s foot, histoplasmosis, and thrush.

ExamplesExamples

Rickettsiae: found on fleas, ticks, and lice, and mites.

Causes diseases such as typhus fever, and Rocky Mountain spotted fever.

ExamplesExamples

Viruses: HIV and HBVSpread from human to human by blood

and body fluids.Difficult to kill, resistant to disinfectants,

and are not usually affected by antibiotics.

Causes many diseases: AIDS, hepatitis B colds, measles, mumps, chicken pox, herpes, warts, flu and polio

What they NEED!What they NEED!Microorganisms NEED :

Warm environment: body temperature is ideal

Darkness: again..inside the body is protected from light..some microbes are immediately killed by sunlight.

Moisture and Food: blood

Oxygen vs. NonoxygenOxygen vs. Nonoxygen

Aerobic: REQUIRE oxygen.Anerobic: does NOT REQUIRE oxygen.

– *The human body is an ideal supplier of all the needs of microorganisms.

Inside or OutsideInside or Outside

Exogenous: infections or disease that originate OUTSIDE the body.

Endogenous: infections or disease that originate INSIDE the body.– Example: tumors, congenital abnormalities, or

metabolic disorders.

NosocomialNosocomial

An infection that originates in the health care facility.

Example:

Post surgical

Pneumonia

Chain of InfectionChain of Infection

Causative Agent Pathogen

ReservoirWhere Pathogen

lives

Chain of InfectionChain of Infection

Portal of Exit:– Way to escape the

reservoir– Urine , feces,

saliva, blood, tears, mucous discharge, sexual secretions,and draining wounds