Searching for microbes Part I V. Microbes and outer influences Decontamination methods, and how to assess their effectiveness. Ondřej Zahradníček To practical for VLLM0421c Contact to me: [email protected] Content of this slideshow. Microbes and outer influences.
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Microbes and outer influences
Decontamination methods: survey
Hand washing and disinfection
Higher level disinfection
Checking effectiveness of decontamination
It sounds strange, does not it? Well, that is today‘s world: men use to tell to women that they are sexy, instead of telling them that they are beautiful
lower growth limit (inhibitory)
upper growth limit (inhibitory)
upper survival limit (bactericidal)Microbes and outer influences I
At decontamination methods, it is absolutelly necessary to reach a value of the acting physical or chemical factor that is sufficient to kill the microbe.
Primarilly, we are interested in survival limit (usually the upper one), and not growth limit (important for microbial cultivation).
Above the line: we act by a certain temperature, 24 h
Below: 4 h only, then back to optimal temperatureMethodological difference
Sometimes the action of factor combines
The factor allways important is the time
An antiseptic is a remedy.
A disinfectant is not a remedy.
(Czech public note No. 195/2005)
Tools, that are mechanically dirty, should be cleaned before decontamination. Without cleaning it would not be effective enough.
In booklets and other materials, often following alphabetical system is used:
Some disinfectants are only suitable for disinfection of surfaces, other are only for skin. Usually disinfectants are classified for
For hands, the rules are different than for tools of surfaces. Usually there is no thick layer of dirtiness on your hands
Recent legislative uses following terms:
During the working day, it is recommended rather to disinfect one‘s hands and not to wash them too often
What areas are the most frequently missed left palm and vice versa
The most commonly forgotten areas are light blue, dark blue are also frequently missed.
„when using gloves, washing and disinfection is not necessary“
very dangerous nonsense!
http://www.chilledfood.org/_gallery/Handwash%20poster.gif left palm and vice versa
Steam sterilizer left palm and vice versa
Formaldehyde sterilizer left palm and vice versa
Photo O. Z. assessmentThe end
(5 April 1827 – 10 February 1912)
Lister became aware of a paper published by Louis Pasteur. Lister used carbolic acid (phenol) as a means of deodorizing sewage. He also made surgeons wear clean gloves and wash their hands before and after operations with 5% carbolic acid solutions. As the germ theory of disease became more widely accepted, it was realized that infection could be better avoided by preventing bacteria from getting into wounds in the first place. This led to the rise of sterile surgery. Some consider Lister "the father of modern antisepsis." In 1879 Listerine mouthwash was named after him for his work in antisepsis. Also named in his honor is the bacterial genus Listeria, typified by the food-borne pathogen Listeria monocytogenes.
(1818 – 1865)
He discovered that cases of puerperal fever, also known as childbed fever, could be cut drastically if doctors washed their hands in a chlorine solution before gynaecological examinations.
While employed at the Vienna General Hospital in Austria, Semmelweis introduced hand washing with chlorinated lime solutions for interns who had performed autopsies. This immediately reduced the incidence of fatal puerperal fever. Semmelweis' hypothesis, that there was only one cause, was largely ignored, rejected or ridiculed. He was dismissed from the hospital and harassed by the medical community in Vienna, which eventually forced him to move to Budapest. Semmelweis' practice only earned widespread acceptance years after his death, when Louis Pasteur developed the germ theory of disease. He is considered a pioneer of antiseptic procedures.