Hand Washing
![Picture](/uploads/2/4/1/8/24180446/_117816.jpg)
Micro-organisms are found everywhere, in the environment, on surfaces in the air and also on the human body. While most micro-organisms are not pathogenic, in the microbiology laboratory we assume that all micro-organisms are potentially pathogenic and act accordingly. Correct hand-washing is the single most effective technique that prevents the transmission of micro-organisms either directly or indirectly to others.
Click to see video.
Two types of micro organism are present on the skin:
Indigenous organisms, such as Staphylococcus epidermis, which are part of the natural microbial flora of the skin and are firmly attached to the skin and are found in skin crevices. While causing no harm to the original host some strains may be pathogenic to another person, especially if that individual is compromised in any way e.g. very old, very young or ill. The second type are the transient organisms such as Escherichia coli which may be pathogenic.
Skin micro-organisms are also present on skin flakes that are shed from the human body and so can be present in the air.
The object of hand-washing is to remove the transient organisms and to reduce the numbers of indigenous organisms. The most common parts of the hands that are missed are the backs, the nails and the wrists. Care must be taken to ensure that the dominant hand is washed as well as the dominant one. Antibacterial products can be used to disinfect hands but correct hand-washing technique is more important. Many products contain 4% chlorohexadine gluconate which has the advantage of having residual action. Other products such as 7.5% povidone iodine can be used in the case of allergy to chlorohexadine gluconate.
Click to see video.
Two types of micro organism are present on the skin:
Indigenous organisms, such as Staphylococcus epidermis, which are part of the natural microbial flora of the skin and are firmly attached to the skin and are found in skin crevices. While causing no harm to the original host some strains may be pathogenic to another person, especially if that individual is compromised in any way e.g. very old, very young or ill. The second type are the transient organisms such as Escherichia coli which may be pathogenic.
Skin micro-organisms are also present on skin flakes that are shed from the human body and so can be present in the air.
The object of hand-washing is to remove the transient organisms and to reduce the numbers of indigenous organisms. The most common parts of the hands that are missed are the backs, the nails and the wrists. Care must be taken to ensure that the dominant hand is washed as well as the dominant one. Antibacterial products can be used to disinfect hands but correct hand-washing technique is more important. Many products contain 4% chlorohexadine gluconate which has the advantage of having residual action. Other products such as 7.5% povidone iodine can be used in the case of allergy to chlorohexadine gluconate.
Validation of handwashing
Fluorescent dyes
![Picture](/uploads/2/4/1/8/24180446/_6568458.jpg)
It is essential to show that the hand-washing method does in fact remove micro-organisms from skin.
To test the technique, fluorescent dye is applied to the hands prior to washing. Following washing the hands are examined under UV light for any traces of dye.
Compare your handwashing with the diagram that shows commonly missed area
To test the technique, fluorescent dye is applied to the hands prior to washing. Following washing the hands are examined under UV light for any traces of dye.
Compare your handwashing with the diagram that shows commonly missed area
![Picture](/uploads/2/4/1/8/24180446/_8030141.jpg)
In this case , all the dye has been successfully washed off.
Finger Dab
![Picture](/uploads/2/4/1/8/24180446/_1382393293.png)
To make sure that bacteria on the skin have been removed, a finger dab test is carried out. Unwashed and washed finger tips are pressed onto the surface of a NA plate and examined after incubation.
What is your conclusion on the handwashing technique from observing the plate in the picture?
What is your conclusion on the handwashing technique from observing the plate in the picture?