Transcript Following factors influence microbial growth

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
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One-celled
Multiply rapidly
Cocci = round
Bacilli = rod-shaped
Spirilla = spiral
Antibiotics kill bacteria
Gonorrhea, strep throat, tetanus, botulism
Bacteria
Cocci
Bacilli
Spirilla
Types of Microorganisms
Bacteria
 One-celled
microorganisms that are
A.
B.
classified according to
their shape and
arrangement.
 Cause diseases such as
C.
D.
F.
strep throat, pneumonia,
and tuberculosis. (Table
3-4)
 Some bacteria produce
spores, which help them
H.
reproduce.
Name the microorganisms A to I. Click HERE to see answers.
E.
G.
I.
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.
Types of Microorganisms (cont.)
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).
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
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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:
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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