Chapter 5 (LAB) Flashcards
process that destroys or eliminates forms of microbial life
Sterilization
process that eliminates many or all pathogenic microorganisms or inanimate objects with the exception of bacterial spores
Disinfection
process of preventing the growth of infectious germs like bacteria, virus and fungi
Antisepsis
substance that used to kill broad range of infection
Antiseptic
Typed of Antisepsis
Physical
Mechanical
Chemical
Biological
Mixed
substance that kills bacteria or microorganisms
Bactericidal
used as chemical to combat pests and pathogens of plants, weeds as well as parasites and vectors of dangerous disease.
Germicidal Agent
- agent that is capable of inhibiting growth of bacteria without necessarily killing them.
- limits the growth of bacteria
Bacteriostatic agent
“Anti” and “Sepsis” means?
Anti = AGAINST
Sepsis = PUTREFACTION
He developed the first antiseptic methods for surgical procedures using carbolic acid.
Joseph Lister
2 Types of Germicidal Agent
- Oxidizing Germicides
- Non-oxidizing Germicides
- agents that is capable of destroying spores, fungi, and viruses
- kills vegetative microorganisms
Sporicidal Fungicidal
- most common PHYSICAL METHOD of STERILIZATION.
- expresses in TDT or Thermal Death Time.
Heating
Mechanical of Heating
a. Formation of single-stranded breaks in the bacterial DNA
b. Coagulation and denaturation of proteins
c. Accumulation of toxic levels of electrolytes
d. Alteration of cell membranes
Temperature and Time
as the temperature increases, the time taken to sterilize decreases
Number of microorganisms
the more the microorganisms , the higher the temperature and the longer the duration of process required to destroy all of them.
Withstand extreme conditions of starvation, acidity, temp, and dessication by spores.
Spore Forming Bacteria
more susceptible to environmental stresses like heat and desiccation
Non-spore Forming Bacteria
- more rapid killing action that dry heat.
- its mechanism of action is to cause coagulation and denaturation of proteins.
Moist Heat
method of disease producing organisms in milk products as well as beverages
Pasteurization
used for killing non-sporing bacteria which may be present in vaccine
Vaccine Bath
used for inactive bacteria contaminating in serum preparation
Serum Bath
used to solidify and disinfect egg containing and serum-containing media
Inspissation
method that involves utilizing water at boiling temperature of 100 degree Celsius or 212 degree Fahrenheit
Boiling
involves exposing the material to be sterilize to live steam at 100 degree Celsius.
Fractional Sterilization
it is used to sterilize surgical equipment , laboratory instruments , pharmaceutical items and other materials.
Autoclave
- it is used to sterilize materials in enclosed tubes, oils, jellies, powders and glasswares.
- its effectiveness depends on the penetration of heat through the materials to be sterilized.
Dry Heat
2 Types of Dry Heat
- Static air type
- Forced air or mechanical convection sterilizer
process of instant sterilization by holding the instrument in a bunsen burner till they become red hot.
Red Flame
- device that temporarily emits a flame that is directly exposed to outside elements.
- not recommended for use in the lab
- it generates aerosol, which may contain pathogens.
Open Flame
- method that aims at burning organisms into ashe.
- use a device called incinerator
Incineration
It can sterilize the object that cannot be sterilized by moist heat.
Hot air oven
articles to be sterilized are placed in a conveyor belt and passed through a tunnel that is heated by infrared radiators
Infrared Rays
it is the state of extreme dryness or the process of extreme drying and can be used to control microbial growth
Dessication
it halts the activities of spoilage microorganisms in and on foods and can preserve some microorganisms for a long time
Freezing
form of mechanical sieving that does not kill microorganisms but merely seperates from the fluid
Filtration
- It is an energy that travels through space at the speed of light from a source
- it is also known as “electromagnetic waves”
Radiation
- it is used to disinfect hospital wards, operating room, laboratories and other rooms in the hospital that need to be sterilized.
- its disadvantage is that it has low penetrance
Ultraviolet Light / Non-Ionizing Radiation
- It have greater penetrance than UV rays
- it exert its effect by causing formation of free radicals that chemically interact with proteins and nucleic acid
Ionizing Radiation
It is a technique used commonly to sterilize pharmaceutical packaging products and medical devices
Electron beams
- It is produced from nuclear disintegration of selective radioactive isotopes.
- it have greater penetrance than electron beams but require longer exposure time
Electromagnetic Rays (Gamma Rays)
It is a cavitation procedure that uses high frequency sound waves to agitate bubbles that permeate every surface of medical devices including holes and crevices
Sonic and Ultrasonic Vibrations
It can cause the bacterial cell to collapse when the concentration of the fluid surrounding the organism is altered
Osmotic pressure
process of using low temperature chemicals to kill, eliminate and remove all germs, viruses and bacteria.
Chemical Sterilization
Duration of exposure
the longer the time of exposure to the chemical agent, the better the killing action
Temperature
A higher temperature speeds up the rate of chemical reaction and thus accelerates killing action
Number of microorganisms
the larger the number of microorganisms present , the more time needed for a disinfectant to destroy all of them.
A good chemical agent must posses the following characteristics:
- Be broad spectrum - able to destroy a wide variety of microorganisms.
- Be fast-acting - able to destroy microbes within the short time of period.
- Active in the presence of organic matter
- Active in any ph
- Should be stable
- Non-toxic, Non-allergenic, Non-irritative and Non-corrosive.
- Be soluble to water and easy to apply
- Leave a residual antimicrobial film on the treated surface.
- High Penetrating power
- Not expensive and must be easily available
- Safe under storage and shipping for reasonable periods of time
- Do not have a bad odor.
Chemical disinfectants may be classified based on the following:
- Consistency
- Spectrum activity
- Mechanism of action
2 forms of Chemical Disinfectants
- Liquid chemical Disinfectants
- Gaseous chemical Disinfectants
3 Types of Chemical disinfectants based on Spectrum activity
- High level disinfectants
- Low level disinfectants
- Intermediate level disinfectants
- it lowers the surface tension of an aqueous solution and are used as wetting agents, detergents, emulsifiers, antiseptic and disinfectants
- also referred to as “surfactants”
Surface Active Agents
- a positive charge on their hydrophilic end
- it can also serves as antimicrobial agents, so they are often used as disinfectants
Cationic Agents
- most widely used as versatile surfactants
- most effective at removing oil residue
- removes dirt through the process of emulsion and are most effective at acidic pH
Anionic Agents
- used as antiseptic at low concentrations
- used as disinfectant at high concentration
- has corrosive property
Phenolic Compound
a phenol derivative commonly used as surface disinfectant
Cresol
a disinfectant and antiseptic that is used for skin disinfection before surgery and sterilize surgical equipments.
Chlorhexidine
- an antiseptic and disinfectant agent used for skin disinfection and surgicsl equipments.
- it is listed on WHO list of essential Medicines.
Chloroxylenols
- useful as topical anti-infective, , antibacterial agent often found in soaps and toothpaste
- also knows as Nabac
Hexachlorophene
an antibacterial and antifungal agent present in some consumer products
Triclosan
- it is generally classified as low level disinfectants - primarily due to the fact that it has no or limited sporicidal activity.
- it is commonly used in different ways in the healthcare settings.
Alcohol
- used as skin antiseptic, it is bactericidal and remove lipids from skin surfaces
- used in medical wipes and hand sanitizer as an antiseptic effect
Ethyl alcohol
- it has greater bactericidal activity than ethyl alcohol and is less volatile
- it can be used as surface disinfectant.
- inhalation of its fume may cause narcosis
Isopropyl alcohol
- acts as preservative for foods products
- prevents growth of bacteria without killing it
- play an important role in extending shelf life of cosmetics and personal care products.
Benzyl Alcohol
It is fungicidal and sporicidal used in disinfecting inoculation hoods
Methyl Alcohol
defined as process in which a molecule structure deviates from its original state when exposed in denaturing ageents
Denaturation
used for denoting mercury, lead, zinc, silver and copper
Heavy Metals
- it used as biocidal agents and antiseptic
- active agents against viruses at dilution of 1:500 to 1:1000
Mercurials
its solution is used clinically as treatment for Opthalmia neonatrum Crede’s prophylaxis
Silver Compounds and the solution I’m referring to is Silver Nitrate.
bactericidal oxidizing agents that cause oxidation of essential sulfhydryl groups of enzymes causing inactivation of the enzymes
Halogens
- considered as best antisepsis because it is sporicidal, fungicidal, bactericidal, virucidal and amoebacidal.
- it also penetrates bacterial cell wall
Iodine
It has been used for deactivation of pathogens in drinking water, swimming pool water, and wastewater
Chlorine
weak antiseptic and used only for cleaning wounds and in the disinfection of surgical devices and soft plastic contact lenses.
Hydrogen peroxide
group of strong disinfectants that act by replacing atom within a molecule with an alkyl group, thereby inactivating enzymes and nucleic acid.
Alkylating agents
type of chemical substance made from alcohol
Aldehyde
- commonly used in solution at a concentration of 37% known as formalin or as gaseous disinfectant and biocide
- used to kill Mycobacterium tuberculosis in sputum and fungi in athletes foot
Formaldehyde
- used to eliminate harmful microorganisms on surgical equipments.
- commonly used as 2% solution for sterilization and is marketed under brand name of Cidex
- it’s efficacy is dependent on pH and temperature
Glutaraldehyde
- it can sterilize heat or moisture sensitive medical equipments without deleterious effects on the material used in the medical devices
- more potent but slower acting
Ethylene oxide
