20. In the 1800s
Aseptic techniques invented to
prevent contamination of surgical
wounds
21. Many organizations classified infection
control systems and substances into:
• Physical methods.
• Chemical methods.
Referred broadly as Germicides
22. Germicidal systems fall into three
categories:
1. Decontamination.
2. Disinfection.
3. Sterilization.
23. 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.
24. 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.
25. 3. Sterilization
• The complete elimination of viable organisms
including spores.
• The highest level of control
27. Physical Chemical
Antimicrobial Antimicrobial
Agents agents
Destruction of
Microorganisms
28. Physical Antimicrobial Agents
• Physical environmental
agents can destroy large
concentrations of
microorganisms in lab
cultures or a clinical
specimen.
36. 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).
37. Desinfectants
Disinfectant Bctericidal Sporicidal Fungicidal Viricidal
Ethyl and Good Poor Good good
isopropyl
alcohols
Chlorine Good Good Good Good
Disinfectants
Formaldehyde Good Good Good Good
and
Glutaraldehyde
Hydrogen Good Good Good Good
peroxide
Iodophors Good Poor Good Good
38. Evaluating a disinfectant
• Direct spray method.
• Testing the quality of disinfectant from
different brands.
39. Testing Disinfectant from Different
Brands
0.5 mL
5 mL Bacterial 5 mL Clorox 5 mL DAC 5 mL Gento 5 mL Dettol
Suspension in Nutrient
Broth (Control)
40. Testing Disinfectant from Different
Brands
Water Bath
Bacterial Suspension in Nutrient Bacteria in DAC Bacteria in Gento Bacteria in Dettol
Broth (Control) Bacteria in Clorox
41. Testing Disinfectant from Different
Brands
2 Loopfulls
48 hrs
Water Bath Incubation
in the 37O C
After 5min After 10 min in After 20 min in
Bacterial Suspension in in Water Bath Water Bath Water Bath
Nutrient Broth (Control)
43. Objectives
• Some infection control terms.
• Factors influencing disinfectants.
• Physical destruction of microorganisms.
• Chemical destruction of microorganisms.
• Methods of evaluating disinfectants.
