Sterilisation and disinfection

INTRODUCTION

Microorganisms are the agents of contamination, infection, and decay.

Hence it becomes necessary to remove them from materials and areas.

Early civilization practiced salting, smoking, pickling and exposure to sunlight .

In mid 1800s Lister developed

Aseptic techniques to prevent contamination of surgical wounds. Prior to this development:

Nosocomial infections caused death in 10% of surgeries.

Up to 25% mothers delivering in hospitals died due to infection.

DEFINITION

STERILIZATION

The process of freeing an article from microorganisms including their spores.

Sepsis: Comes from Greek for decay or putrid. Indicates bacterial contamination.

Asepsis: Absence of significant contamination.

Aseptic techniques are used to prevent contamination of surgical instruments, medical personnel, and the patient during surgery.

Aseptic techniques are also used to prevent bacterial contamination in food industry.

Bacteriostatic Agent:

An agent that inhibits the growth of bacteria, but does not necessarily kill them.

Bactericide:

An agent that kills bacteria. Most do not kill Endospores.

Sporicide:

An agent that kills spores.

Methods of Sterilisation

Physical Methods of Sterilisation

Sterilisation By Dry Heat:

Uses:

To sterilise Forceps, Scissors, Scalpels, Swabs.

Pharmaceuticals products like Liquid paraffin, dusting powder, fats and grease.

FLAMING

Inoculation loop or Wire, the tip of Forceps and spatulas are held in a bunsen flame till they are red hot.

INCINERATION

This is an excellent method of destroying materials such as contaminated cloth, animal carcasses and pathological materials.