Summary

This document describes the role of decontamination in preventing the spread of infection in healthcare settings. It covers the importance of cleaning, disinfection, and sterilization of reusable medical devices. The document also introduces microbiology and the different types of microorganisms. It includes questions on the topic.

Full Transcript

The CSSD has an extremely important role to play in preventing the spread of infection to and between patients, and staff who work with or around reusable medical devices. Since some of these microorganisms have the potential to cause disease, the decontamination facility makes sure that reusable m...

The CSSD has an extremely important role to play in preventing the spread of infection to and between patients, and staff who work with or around reusable medical devices. Since some of these microorganisms have the potential to cause disease, the decontamination facility makes sure that reusable medical devices are thoroughly cleaned, disinfected and/or sterilized before reuse. This module will help you 101 understand just how critical the role of decontamination is in reducing the risks of microbial infection to patients and to the staff working in the CSSD. Pre-Module Quiz Keep these questions in mind as you go through the content, and don’t worry if you don’t know the answers—that is what you are here to learn. Q: Is the work wear worn in the CSSD designed to protect the wearer or the reusable medical device? Q: If microbes are not visible to the naked eye, how do you think you can ensure their removal from reusable medical devices? Q: What is the difference between a bacteria and a virus? Q: How would you kill a microbe? Is there a microbiology laboratory in your hospital? Q: What type of testing and analysis is the lab set up for—protozoa, fungi, yeasts, bacteria, viruses, or prions? Q: Does the lab perform routine clinical microbiology doing culture and antibiotic sensitivity testing? Q: Does the lab do virus testing, or test for any other types of microbes apart from bacteria? Q: If not, where is the nearest lab that can do these? Q: Can the lab test air quality? Q: Can it test water quality? Q: Is the lab used by the decontamination unit? Q: What are the potential risks that one works with in a CSSD? Q: Why is training and education so important for staff in a CSSD? Q: Do you know how many work zones there are in a typical CSSD? Microbiology and Decontamination Microbiology is the study of microscopic organisms, also known as micro-organisms, microbes or germs. The largest of these measure only two or three microns in size and 102 the smallest are almost 100 times smaller than that. Microbes are invisible to the naked eye—we can see things only as small 90 microns, about the thickness of a human hair. there are, and what types may be present on or in your hands, the water, the air and your working environment, including reusable medical devices. It also means that it is impossible to tell visually when all microbes have been removed during the decontamination processes. The presence of microscopic organisms are detected by two methods—viewing them up close with light and electron microscopes or by culturing the microbes until they grow into a detectable form. These processes require specialist training and equipment and take a considerable amount of time. The specialists who do this work are called microbiologists. Below is a closer view of the tip of the same needle under much higher magnification. You can see large numbers of bacteria, two microns long, sticking to the needle. To decontaminate this needle, you would first clean it to remove any dirt, soil and as many bacteria as possible. You would then put it through a disinfection process to kill as many of the remaining microbes as possible. A sterilization process will kill all remaining microbes. Look at how uneven the supposedly smooth surface is when viewed under high magnification (see Figure M2–2). Unevenness of reusable medical device surfaces can make it difficult to clean reusable medical devices properly. Dirt and microbes may resist removal by lodging in any crevices or surface imperfections. This is why 103 disinfection or sterilization comes after the cleaning process—in order to kill any microbes missed by the cleaning procedures. As Figures M2–1 and M2–2 show, microscopic organisms can’t be seen with the human eye and are even difficult to see with high magnification. Figure M2–3 shows the range 104 of sizes the human eye, the light microscope and the electron microscope allow us to see. Since microbes are not visible to the human eye, specialists in CSSD do not look for microbes on the equipment and reusable medical devices they process. Instead, they strictly comply with validated procedures and processes proven to clean and decontaminate—ensuring the safety and sterility of their reusable medical devices. These procedures are developed and thoroughly checked by microbiologists. Manufacturers also supply instructions for use (IFU) for proper decontamination of their reusable medical devices. It is important for the CSSD specialist to know about microbiology and microbes to understand where the risks are, why they are doing things in a particular way and what the consequences are if things go wrong. There may not be procedures to cover every contamination risk in the decontamination wash room, so it is very important for specialists to be 105 vigilant and to understand the basic principles of what they are doing and how to minimize the risks. Microorganisms What are they and which types might you encounter? There are millions of different microbial species. It is estimated that less than 10% of these have been identified or studied. The best studied microbes are the ones that cause disease—these microbes are referred to as pathogens. Although all types may be encountered, bacteria and viruses are the most commonly occurring contaminating microbes. Every year, new varieties of microorganisms are discovered. Scientists are becoming better at finding and recognizing them, and mutations and genetic exchange regularly create new forms from existing microbes. Some types, such as the influenza virus, have a high rate of mutation. They avoid being recognized by our immune system and create an outbreak risk. Many microbial infections are no longer treatable using antibiotics. Bacteria, fungi and yeasts can develop or pick up antibiotic resistance genes from other microbes. It becomes a serious problem when infections can no longer be treated successfully using the previously effective antibiotics. In some cases, they may become resistant to many or all of the available antibiotics, making the infection untreatable. Recent examples of this are Methicillin Resistant Staphylococcus aureus (MRSA), multidrug resistant Tubercle bacillus (MDR TB) and Carbapenem-resistant Enterobacteriaceae (CRE). Environmental Conditions What environmental conditions do microbes like? All microorganisms grow and reproduce in an optimal range of conditions. Their basic requirements are food and moisture. Anything that changes these conditions to a range 106 that is not tolerable will inhibit or kill the microorganisms. Human-infecting microorganisms tend to have optimal growth conditions similar to human tissue. Some microorganisms, including protozoa, fungi and bacteria, develop survival strategies to cope with stressful conditions. Cysts in protozoa; spores, somnicells (non-culturable cells) and biofilms in bacteria; and spores and altered metabolism in fungi are all examples of survival strategies. Bacteria, under optimal growth conditions, can multiply very rapidly, doubling in number every 20-30 minutes. This is why it is so important to clean reusable medical devices as soon as possible after use Some yeasts, like Candida, can also multiply as quickly as bacteria. Fungi grow more slowly but can reproduce in large quantities. Because viruses, prions and some protozoa are unable to grow or reproduce outside of host cells, they do not increase in number in the environment. They maintain their capability to infect host cells, remain biologically inert, and persist for various lengths of 107 time—depending on structure and type. In the case of both prions and viruses, they may persist when attached to soil or dirt containing traces of moisture. Why are Biofilms Important? Because most studies on microbes were carried out in laboratories on artificial growth medium in unnatural conditions, it was not realized until 1978 that the natural form of growth for most microbes is as a biofilm. A biofilm develops by microbes (usually bacteria) either sticking to each other or to a nearby surface. Once this happens, they secrete a matrix of slime which covers them like a tent. This protection from disinfectants and various other stressful situations allows them to continue multiplying, and resist removal. Once a biofilm has formed, other types of microbes can also take refuge in it. They have great protection there—like living within a walled city. Within our bodies we have useful natural biofilms growing in our intestines, oral cavity, respiratory tract and skin. Pathogens can also form biofilms in all of these areas and in wounds, and on surgical implants and catheters, making them more difficult to eradicate. Microbes or pieces of biofilm in blood or soil can form more biofilms on reusable medical devices if left on them for any length of time. Their degree of attachment 108 becomes stronger with time so by the time they get to the decontamination zone in the CSSD, they are more difficult to detach in the cleaning process. It is best practice to avoid delays before starting decontamination of used reusable medical devices. When this is not possible, keep the reusable medical devices moist and treat them with a neutral detergent and cleaning enzymes until they can be properly decontaminated. Biofilms also become a problem in a number of areas of the CSSD. They can form on, and inside, ultrasonic baths, hoses, housekeeping cleaning equipment, the water system, wash basins, waste pipes, taps, plumbing of washers and washer disinfectors, and moist surfaces. Strict regular cleaning and decontamination protocols must be in place to prevent spread of microbes to processed reusable medical 109 devices and staff within the CSSD. Regular microbiological testing monitors the efficacy of these protocols. 110 111 112 113 114 115 116 117 119 120 121 122 124 125 127 128 130 131 132 134

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