Download - Lab2 Destruction of microbes
• By:Hibah A. W. Abusulaiman
Second year Lab Medicine (Females)1433- 1434 A.H. / 2012- 2013
Microbiology Practical (Course I)
Once upon a time…
Please don’t sleep
Fashionable friends
Abrar’s…
Sara started the preparation early
She got a luxurious manicure and padicure plus…
An elegant evening gown
Lubna started the preparation 2 days before the wedding
She got an elegant evening gown, but…
A poor manicure and padicure
Both attended the wedding in…
After 45 days, Lubna was suffering from…
Diagnosed as Hepatitis Patient
After discussion with the Doctor, she knew it’s because of the poor hygienic manicure and pedicure
Good hygiene Poor hygiene
Destruction of Microorganisms
So, do you think we are in a war with…?!
Simply because they are the agents of…
Contamination, infection and decay
Early civilization
In the 1800s
Aseptic techniques invented to prevent contamination of surgical
wounds
Many organizations classified infection control systems and substances into:
• Physical methods.• Chemical methods.
Referred broadly as Germicides
Germicidal systems fall into three categories:
1. Decontamination.2. Disinfection.3. Sterilization.
1 .Decontamination:
• Reduction of pathogenic microorganisms to be safe to handle without protective attire.
• The Lowest level of control.• Includes physical cleaning with soap and
detergents and removing of most organic and inorganic materials.
• It is the critical step toward disinfection and steilisation.
2. Disinfection:
• Disinfectants are liquid chemical agents that kill targeted pathogens but not spores . It can also be solid or gaseous.
• It is the next level of control.
3. Sterilization
• The complete elimination of viable organisms including spores.
• The highest level of control
Factors influencing disinfection
• Number of microorganisms.• Species and type of microorganism.• Temperature.
Destruction of Microorganisms
Physical Antimicrobial
Agents
Chemical Antimicrobial
agents
Physical Antimicrobial Agents
• Physical environmental agents can destroy large concentrations of microorganisms in lab cultures or a clinical specimen.
Physical Antimicrobial Agents
Physical sterilization
Dry heat
Moist heat
Incineration
Osmotic pressure
Filtration
Radiation
Radiation
UV Light
To inactivate microorganisms on surfaces
Filtration
•Filtration is used to remove bacteria, fungi and their endospores from air or solutions.
Osmotic Pressure
• Extremely hypertonic conditions can cause plasmolysis.
Incineration
AutoclaveMoist heat- Steam sterilization
121OC for 15 min
Dry heat160OC for 2 hours OR 170OC for an hour
Chemical Antimicrobial Agents
• In considering their application to patient care, two general classes:1. Those destroying pathogenic microorganisms in
the environment (disinfectants) or on skin (antiseptics).
2. Those administered to patients for treatment of infectious diseases (antimicrobial agents, often called antibiotics).
Desinfectants Viricidal Fungicidal Sporicidal Bctericidal Disinfectant
good Good Poor Good Ethyl and isopropyl alcohols
Good Good Good Good Chlorine Disinfectants
Good Good Good Good Formaldehyde and
GlutaraldehydeGood Good Good Good Hydrogen
peroxideGood Good Poor Good Iodophors
Evaluating a disinfectant
• Direct spray method.
• Testing the quality of disinfectant from different brands.
5 mL Bacterial Suspension in Nutrient
Broth (Control)
5 mL Dettol5 mL DAC 5 mL Gento5 mL Clorox
Testing Disinfectant from Different Brands
0.5 mL
Bacteria in Clorox
Testing Disinfectant from Different Brands
Bacterial Suspension in Nutrient Broth (Control)
Bacteria in DettolBacteria in DAC Bacteria in Gento
Water Bath
Bacterial Suspension in Nutrient Broth (Control)
Water Bath
After 5min in Water Bath
After 10 min inWater Bath
After 20 min inWater Bath
48 hrsIncubation
in the 37O C
Testing Disinfectant from Different Brands
2 Loopfulls
Observe the bacterial growth
Objectives
• Some infection control terms.• Factors influencing disinfectants.• Physical destruction of microorganisms.• Chemical destruction of microorganisms.• Methods of evaluating disinfectants.
Thank you for listeningAny questions!?
Thank you for paying attention
Any questions!?