Nature of Microorganisms Pathogens are microorganisms that cause disease. Non-pathogens are...
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Transcript of Nature of Microorganisms Pathogens are microorganisms that cause disease. Non-pathogens are...
Nature of Microorganisms
Pathogens are microorganisms that cause disease.
Non-pathogens are microorganisms that do not cause disease.
Factors That Influence Microbial Growth
Following factors influence microbial growth: Temperature. pH, or the values used in chemistry to
express the degrees of acidity of a substance. Food. Moisture. Oxygen.
Factors That Influence Microbial Growth (cont.)
Aerobic microbes – live only in the presence of oxygen.
Anaerobic microbes – grow best in the absence of oxygen.
Methods That Destroy Microorganisms
Antiseptics – solutions applied directly to the skin that prevent or inhibit the growth of pathogens. Disinfection – using strong chemicals, such as bleach to destroy pathogens, usually on objects, not skin.Sterilization – the most effective way to destroy all microorganisms.
Microorganisms
Microorganism (microbe) Small living organism Need a microscope to see it
Pathogens Can cause disease or infection
Normal flora Microbes that are beneficial when present Not all microbes are pathogens
Microorganisms
Bacteria One-celled Multiply rapidly Cocci = round Bacilli = rod-shaped Spirilla = spiral Antibiotics kill bacteria Gonorrhea, strep throat, tetanus, botulism
Bacteria
Cocci
SpirillaBacilli
Types of MicroorganismsBacteria One-celled microorganisms
that are classified according to their shape and arrangement.
Cause diseases such as strep throat, pneumonia, and tuberculosis. (Table 3-4)
Some bacteria produce spores, which help them reproduce.
A. B.
C. D.
E.
F. G.
H. I.
Name the microorganisms A to I. Click HERE to see answers.
Microorganisms
Protozoa One-celled animal-like organism Many flagella – aids in movement Malaria, amebic dysentery
Fungi Plant-like Live on dead organic matter Yeasts and molds are common forms Ringworm, athlete’s foot, thrush
Types of Microorganisms (cont.)Fungi A plantlike organism that lives on
dead matter. Cause conditions such as ringworm,
athlete’s foot, yeast infections, and thrush.
Protozoa Tiny animals found in contaminated
water. Cause diseases such as malaria,
trichomoniasis, and amebic dysentery.
Types of Microorganisms (cont.)
Rickettsiae Parasites that live inside the
cells of other living organisms. Transmitted to humans by fleas,
lice, and ticks. Cause diseases such as Rocky
Mountain spotted fever.
Viruses Smallest of all microorganisms. Live inside cells. Spread by contact with blood and
other body fluids. Difficult to destroy. Associated with diseases such as
the common cold, chicken pox, herpes, hepatitis B, and acquired immune deficiency syndrome (AIDS).
Types of Microorganisms (cont.)
Microorganisms Rickettsiae Parasitic – live inside other living organisms Live in fleas, lice, ticks – whose bite transmits
disease to humans Rocky Mountain Spotted Fever
Viruses Smallest, seen with electron microscope Reproduce inside other living cells Spread by blood and other body secretions Common cold, measles, mumps, chicken pox,
AIDS
Microorganisms
Most grow best in environment that is: Warm Moist Dark
Aerobic Require oxygen to live
Anaerobic Live and reproduce without oxygen
Pathogens
Cause infection in different ways Some produce toxins (poison) Some cause allergic reaction in the body Some attack and destroy living cells
Nosocomial infections Transmitted in a health care facility
Opportunistic infections Occur when body defenses are weak
Pathogens
Transmission of disease Person-to-person contact Contaminated hands!!! Contaminated substances
• Food• Soil• Insects• Equipment
Droplets in the air (cough, sneeze)
Infection Control
Asepsis Absence of pathogens
Aseptic technique Handwashing Good personal hygiene Disposable gloves Proper cleaning of equipment
and environment
Handwashing
Most effective way to prevent the spread of infection Wash your hands: Whenever they become contaminated. Before and after lab procedures. After personal use of the bathroom. After you cough, sneeze or use a tissue. Before and after eating, drinking, and using
contact lenses.
Handwashing
Soap
Warm water
Friction
Clean all surfaces
Fingertips pointed down
Dry paper towel for turning the faucet on and off
Alcohol-Based Handrub
Used in healthcare facilities
Used between patients when hands not soiled