Question

MODULE 15 EFFECTS OF DISINFECTANTS AND ANTISEPTICS OBJECTIVES Be familiar or be able to describe 1) Antimicrobial substances: Chemical and biological 2) Bacteriocidal versus Bacteriostatic chemicals 3) Sterilization versus disinfection by chemical antimicrobials 4) Difference between disinfectants, antisepties, and antibiotics in terms of a. Antimicrobial activity b. Where they would be used c. Role of organic matter in their effectiveness d. Differential effects on Gram positive and Gram negative bacteria. 5) Phenol coefficient test 6) Disk Diffusion method of assessing the effectiveness of an antimicrobial chemical 7) Factors that determine the amount of inhibition KEYWORDS Sterilization Disinfection Bacteriocidal Bacteriostatic Organic matter Disk Diffusion Method Disinfectant Antiseptic Antibiotic Antimicrobial Phenol Zone of Inhibition Chemical antimicrobial Biological Antimicrobial Gold Standard Phenol coefficient Synergism Carbolic Acid INTRODUCTION Sterilization is a process by which all microbes are destroyed. Bacteriocidal means that bacterial cells are killed on a surface, object, or media. Sterilization is a bacteriocidal process and is usually achieved by autoclaving. Bacteriostatic means that bacterial proliferation or growth is inhibited. Substances that are bacteriostatic cannot be used on surgical instruments or for preparing microbiology media. Any substance that is bacteriocidal or bacteriostatic can be considered to be an antimicrobial. Chemical antimicrobials are known as disinfectants or antisepties whereas biological antimicrobials are known as antibioties. A disinfectant is an antimicrobial chemical agent that can be used on inanimate objects such as instruments or surfaces. An antiseptie is an antimicrobial chemical agent that can be safely used on living tissue such as skin and throat without causing any harm - 109 -

Answer 1

Question 1

a.) Answer: Disinfectants are chemicals agents that have antimicrobial property. They are used to clean the surfaces or instruments. Antiseptics are chemical agents that have antimicrobial property. They are used to clean on living tissues such as skin and throat.

b.) Answer: Chemical antimicrobials are chemical agents that kill microorganisms or prevent their growth. Example: Disinfectants and antiseptics. Biological antimicrobials are derived from biological organisms. Examples: antibiotics.