Week3 Control Of Micobial Growth Flashcards
Who and What is the CDC?
The Center for Disease Control collaborates to create the expertise, information, and tools that people and communities need to protect their health - through health promotion, prevention of disease, injury and disability, and preparedness for new health threats.
The CDC seeks to accomplish its mission by working with partners throughout the nation and the world to:
• monitor health,
• detect and investigate health problems,
• conduct research to enhance prevention, develop and advocate sound public health policies,
• implement prevention strategies,
• promote healthy behaviors,
• foster safe and healthful environments, provide leadership and training.
Gloves
Categories of Disinfecting / Sterilizing
Chemicals
Dental Unit Waterlines (DUWLs), Biofilm and Water Quality
- Discharge air and water for 20-30 seconds after each client, from any dental device connected to the dental water system that enters clients mouth. (handpieces, cavitron, air/water syringe)
- Flush dental waterlines and faucets for 1-5 minutes before using for client care.
* - Disinfect dental unit waterlines (DUWLs).
*Reminder: this is CDC; we do 2 mins!
Infectious Disease
• Infectious disease: occurs when a microorganism in the body multiplies and causes damage to the tissue
Pathogens
Micro organisms that cause infectious diseases
Opportunistic Pathogens
When normal microorganisms have favourable conditions for them to become harmful
Endogenous diseases
Are caused by microorganisms in or in the body
Exogenous disease
Caused by microorganisms not normally present on or in the body
Contaminated from outside
Toxigenic disease
Eating contaminated food
When microorganisms come from exogenous, then infect body
Bacteriophage
Viruses that infect bacteria
1915-1922
Prion
Infection agent composed of protein
Causes degenerative brain disease
In humans called Creutzfeldt-Jacob
Prions are not microorganisms
Always Fatal
In animal- mad cow
Asepsis is
Cleaning and disinfecting
Standards precautions
Standard Precautions
Are a set of infection control practices used to prevent the transmission of diseases through the contact with:
1. blood
2. all body fluids, secretions, and excretions (except sweat) regardless of whether they contain blood
3. nonintact skin
4. mucous membranes.
Modes of Disease Transmission
Direct Contact
- Direct Contact: Contact with microorganisms at the source as in the clients mouth. Touching soft tissue or teeth.
Can penetrate the body through small breaks or cuts in the skin, fingernails of ungloved hands
•Ex: Herpes infections of the fingers, STD’s, Skin diseases
Modes of Disease Transmission
Indirect
- Indirect Contact: Contact with items contaminated with a clients microorganisms such as:
> surfaces, hands, contaminated sharps, contaminated instruments, equipment.
> carry a variety of pathogens through blood, saliva, other secretions from previous client
• Hep B and C viruses
• Ex: Needlesticks
•Skin infection and common cold are spread by this mode
Modes of Disease Transmission
Droplet Infection
- Droplet Infection: Contact with sprays, splashes, aerosols or splatter containing microorganisms. E.g use of cavitron
•Transmitted through close contact
•Enter through unprotected skin, eyes, nose, mouth.
•Masks, eyeglasses, face shields
•Influenza, mumps, rubella, herpes virus
Modes of Disease
Transmission
Airborne Infection
- Airborne Infection: smaller particles, can remain airborne for hours, can be inhaled
•Tuberculosis, chickenpox, measles
•Surgical masks are not designed to protect
•N-95 respirator
Chain of Infection
Routes of Entry Into the Body
Sterilization:
• process intended to destroy/kill all mo’s in a material or on an object
• highest level that can be achieved.
• Destroys spores which are the most difficult to destroy.
Disinfection:
• process that destroys mo’s, NOT spores & viruses OR
• decreases/minimizes amount of pathogenic organisms on objects or in materials so that they pose no threat of disease.
Bactericides
Kills Bacteria
Bacteriostatic
Stop of Growth does not kill
Pasteurization
Reduce bacteria and destroy pathogens. (Milk)
Lyophilization
Preserving microbes by removing water, then rapidly freeze, dry using vacuum pump
SPORES
• One of the resistant forms of life against heat, drying, and chemicals
• Bacteria that develop a defense mechanism against death
• Biologic monitors: spores of Geobacillus stearothermophilus, and Bacillus atrophaeus used to monitor use and function of heat and gas sterilizers
Sterilization
• The three common types of sterilization used in dentistry are:
1. Heat Sterilization
2. Gas Sterilization
3. Liquid Chemical Sterilization
Heat Sterilization
• Steam, dry heat, and unsaturated chemical vapour
• Heat sterilizers 121C-190.6C and monitored using bacterial spores (biological monitoring)
• Effective
Gas Sterilization
Ethylene oxide gas sterilizers- not commonly used
Long exposure time
High cost of gas sterilizers
Special handling of ethylene oxide gas sterilant
Liquid Chemical Sterilization
Room temp
Used on items that can be damaged by heat sterilization
Glutaraldehyde, special hydrogen perovide, Glutaraldehyde-phenate
No spore tests, difficult to monitor
Estimate chemical concentration of active sterilant
Disinfecting ingredients
Factors Influencing Microbial Growth
- Temperature
- Atmospheric Pressure
- pH
- Salinity
- Osmotic Pressure
- Hydrostatic Pressure
- Radiation
Factors Affecting Microbial Growth
- MESOPHILES
Optimal growth is at body temperature (37°C). Eg. human body.
о
Can grow @ temperatures ranging from 22-45°C
Bacteria in human body, including those causing infectious diseases such as:
• caries,
• periodontal disease,
• tuberculosis,
• bacterial pneumonia,
• tetanus.
Factors Affecting Microbial Growth
- THERMOPHILES
• heat-loving bacteria.
• range of 45-70°C. (Ideal temp. for growth is 56°C)
• Eg. Compost, “geyser” hot water
Factors Affecting Microbial Growth
- PSYCHROPHILES
• cold-loving bacteria.
• Temperature ranges from 1-22°C, (Ideal temp. for growth is 7°C)
• Eg. Refrigerator, ocean bacteria, principal cause of spoilage of
refrigerated food
Atmospheric Pressure (oxygen metabolism)
• Many microorganisms require molecular oxygen to carry on metabolic activities.
• Microorganisms can also be classified according to the requirement for oxygen:
1. Obligate Aerobes- grow only in presence of oxygen (20% concentration).
2. Obligate Anaerobes- grow only in absence of oxygen
3. Facultative Anaerobes- grow in the presence or absence of oxygen
- in absence of oxygen they undergo anaerobic respiration or fermentation & produce less ATP=less growth
4. Microaerophiles- can tolerate only low conc. of oxygen (4%)
99% of the bacteria in the mouth are obligate anaerobes or facultative anacrobes
PH levels
Acidogenic
Bacteria produce acid during growth
Aciduric
Bacteria that survive and grow in an acidic environment
Contribute to dental caries
Salinity
Halophilic Bacteria
NACL loving Bacteria
• Halophiles :
Halophiles are organisms that thrive in high salt
concentrations. They are a type of extremophile organisms.
Salinity
Haloduric Bacteria
- Haloduric Bacteria- capable of existing(do not prefer) in a medium containing a high concentration of salt(sodium chloride)
Example: Staphylococcus aureus
Osmotic Pressure
Osmotolerant
• Osmotolerant :
Osmotolerant bacteria are those bacteria that
can tolerate high osmolarity. Osmolarity is established when there are solutions of different concentrations on either sides of a semipermeable membrane.
Osmotic Pressure
Saccharophiles
Hydrostatic
Pressure
(pressure exerted by a fluid)
Barotolerant-survive in varying pressure environment;
adaptable
barophile, also sometimes called a piezophile, is 1 organism which thrives at high pressures, such as eep sea bacteria or archaea.
History of Antimicrobials
• Paul Ehrlich (1854-1915) was the first person to use chemotherapeutic drug or antimicrobials to treat a bacteria infection.
• He used sulfonamides to treat the disease syphilis.
• Alexander Fleming (1881-1955) discovered a
“Penicillium” mold producing a substance he
called
“Pericillin” that killed staphylococci bacteria.
How Do Antimicrobials Work?
• Interfere with growth and replication of microbes.
• Inhibit the metabolic machinery of the host cell to replicate.
• Cause damage to the host cells.
Antibiotics
• Discovery of antibiotics occurred in the 1950’s
• Antibiotics are one type of antimicrobial and act on a bacterial cell (prokaryotic cell).
• Antibiotics do not impact or harm eukaryotic cells or viruses.
Sulfonamide
• Antimicrobial agents
• Bacteriostatic and inhibit growth and multiplication of bacteria, but do not kill them.
