• 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!?