Unit 5  Infection Prevention and Control

Chapter 1  Nosocomial Infections

Nosocomial Infections  The term is used to describe a hospital-acquired infection. In its broad meaning, nosocominal means that the infection results while the patient is receiving health care, and the source may be either exogenous or endogenous.

Types of the Nosocomial Infection

    Endogenous infection means that causative organisms come from microbial life the person himself harbors. Normal bacterial folora in the surface of the patient’s body, e.g., the skin and mucous membrane, normally multiply without damage to the patient. However, infections may occur in hospitalized patient. When his resistance is weakened, he or she may be infected.

    Exogenous infection means that causative organism is acquired from other people or environment.

Preventing Nosocomial Infections

    For various reasons and sometimes despite best efforts, certain clients in health agencies develop infe- ctions that were not noted to be present on admission. The term nosocomial is used to describe a hospital- acquired infection. In its broad meaning, nosocomial means that the infection results while the client is receiving health care, and the source may be either exogenous or endogenous. An exogenous infection means that the causative organism is acquired from other people; an endogenous infection means that the causative organism comes from microbial life the person himself harbors. An infection is referred to as iatrogenic when it occurs as a result of a treatment or diagnostic procedure. Not all nosocomial infections have an iatrogenic component.

Chapter 2  Cleansing, Disinfection and Sterilization

Relating to Concepts

Cleansing:  Cleansing is a method of eliminating the dirty, dust and organisms on the surfaces of the item and limiting the number of microorganisms and their growth and spread.

Disinfection (Asepsis): Asepsis refers to the absence of all disease-producing microorganisms, exclu- ding spores.

Sterilization: Sterilization is the absence of all forms of microorganisms, including bacteria, viruses, spores, and fungi.

Physical Sterilization

Physical sterilization includes boiling, autoclaving, dry heat (oven), flaming, sunlight and ultraviolet rays and so on.

Boiling  Boiling is one of the oldest methods of disinfection. This method is most often used for items such as metal instruments, springs and needles, bowls and receivers, rubber materials and plastics.

Autoclaving  Autoclaving is the most reliable and commonly used sterilization procwww.med126.com/jianyan/edure in modern health care facilities today. It is also the fastest, safest, and least expensive method available.

The autoclave is an apparatus used for the sterilization of articles by immersing them in dry steam under pressure. By increasing the pressure, the temperature of' the steam is raised.

Ultraviolet rays  Ultraviolet (UV) rays can kill vegetative bacteria, fungi, and lipoprotein viruses. Because the rays must make directly contact with organisms, the distance of ultraviolet lights used to sterilize the air of the wards is less than 2m from the floor and the time of sterilization is between 30 and 60 minutes. The distance of Ultraviolet lights used to sterilize the items is between 25 and 60cm from the items and the time of sterilization is between 20 and 30 minutes. When the temperature of the wards is between 20℃ and 40℃ and the humidity of the wards is between 40% and 60%, the bactericidal effect of Ultraviolet rays is the best.

Dry heat (oven)  The articles should be exposed to a temperature of 160℃ for 1 hour in order to destroy all organisms and their spores. This method is suitable for sharp-edged instruments such as knife blades and all types of glass ware including glass syringes (but not glass-and metal- syringes as the fixative holding the glass and metal together will melt in the high temperature), also suitable for anhydrous oils, petroleum products, and bulk of powders.

Free steam  Free steam, 100℃, is used for the objects that would be destroyed at the higher temperature and pressure of the autoclave. Usually it is necessary to steam the article for 30 minutes on 3 consecutive days.

Pasteurization  Pasteurization is used in the disinfection of milk and similar substances. They are heated to a moderate temperature for a specific time. The temperature of disinfection is usually at 71℃ and the time is about 15 minutes.

Flaming  As an emergency measure instruments such as knife blades can be sterilized by holding them over an open flame before the use for minor incisions. Heat test apparatus and needles for puncturing the tip of the finger for hemoglobin tests are also sterilized by this method.

Sunlight  Direct sunlight kills many micro-organisms including the tubercle bacillus (the organism that causes tuberculosis). This method may also be used for airing beds and bed accessories such as blankets, mattresses, back-rests and pillows.

Chemical Disinfection

Principles of using the disinfectants

● The disinfectant must be used according to the nature of the equipment, the characteristics of the organisms presented.

● The disinfectant must be used at a prescribed strength for a specific length of time and with the right method.

● The material to be sterilized must first be thoroughly cleaned and dried and then completely immersed in the disinfectant or in direct contact with the disinfectant.

● The disinfectant must be changed and checked at regular intervals.

● The material must be rinsed with sterile water before use.

● Some microorganisms such as those that cause tetanus (spore forming bacteria) and tuberculosis (acid-fast bacilli) are more resistant to the action of liquid disinfectants than that of heat.

Usages of disinfectants

● Immersio  Immersion is done to immerse a clean and dry item completely in a disinfectant.

● Rubbing  Rubbing is done to rub the dirties of the surfaces of the contaminated item or the skin of the body with the disinfectant. It is usually used for the disinfection of the floor, the walls of the ward and the skin of body.

● Nebulization  Nebulization is done to nebulize a disinfectant evenly to the air of the ward or the surfaces of the object with a nebulizer. It is often used for the disinfection of the floor, the wall, and the air of the ward and the hospital environment.

● Fumigation  Fumigation is done to change a disinfectant to a gas by heat or oxide. It is usually used for the disinfection of the air of the ward and the operation room.

Chapter 3  Hand-Washing and Disinfection of Hands

Hand-washing 

Hand-washing is, without a doubt, the most effective way to help prevent the spread of organisms. Varied opinions persist in proper cleaning agents, length of time for washing, and ideal frequency of adequate hand-washing, but everyone agrees that hand-washing is the most important procedure in preventing nosocomial, or hospital-acquired infections. Attention needs to be refocused on this simple procedure that can interrupt the chain of infection. Health personnel should wash their hands in following conditions：

● Before entering and leaving the wards.

● Before contacting with any clean equipment, after handling any contaminated equipment.

● Before and after going to a toilet.

● Befwww.med126.comore and after the sterile procedures

● Before and after contacting with a patient.

● Before and after contacting with wounds or cuts.

● At the start and the end of delivering nursing care.

● Before leaving for coffee or a meal.

● Before charting or preparing medications.