infection prevention and control infection prevention and control infection prevention and control is the discipline concerned with preventing healthcare-associated infections; a practical rather than academic sub-discipline of epidemiology. in northern europe, infection prevention and control is expanded from healthcare into a component in public health, known as "infection protection" (smittevern, smittskydd, infektionsschutz in the local languages). it is an essential part of the infrastructure of health care. infection control and hospital epidemiology are akin to public health practice, practiced within the confines of a particular health-care delivery system rather than directed at society as a whole. infection control addresses factors related to the spread of infections within the healthcare setting, whether among patients, from patients to staff, from staff to patients, or among staff. this includes preventive measures such as hand washing, cleaning, disinfecting, sterilizing, and vaccinating. other aspects include surveillance, monitoring, and investigating and managing suspected outbreaks of infection within a healthcare setting. a subsidiary aspect of infection control involves preventing the spread of antimicrobial-resistant organisms such as mrsa. this in turn connects to the discipline of antimicrobial stewardship—limiting the use of antimicrobials to necessary cases, as increased usage inevitably results in the selection and dissemination of resistant organisms. antimicrobial medications (aka antimicrobials or anti-infective agents) include antibiotics, antibacterials, antifungals, antivirals and antiprotozoals. the world health organization (who) has set up an infection prevention and control (ipc) unit in its service delivery and safety department that publishes related guidelines. infection prevention and control aseptic technique is a key component of all invasive medical procedures. similar control measures are also recommended in any healthcare setting to prevent the spread of infection generally. hand hygiene main article: hand washing hand hygiene is one of the basic, yet most important steps in ipc (infection prevention and control). hand hygiene reduces the chances of hai (healthcare associated infections) drastically at a floor-low cost. hand hygiene consists of either hand wash(water based) or hand rubs(alcohol based). hand wash is a solid 7-steps according to the who standards, wherein hand rubs are 5-steps. the american nurses association (ana) and american association of nurse anesthesiology (aana) have set specific checkpoints for nurses to clean their hands; the checkpoints for nurses include, before patient contact, before putting on protective equipment, before doing procedures, after contact with patient’s skin and surroundings, after contamination of foreign substances, after contact with bodily fluids and wounds, after taking off protective equipment, and after using the restroom. to ensure all before and after checkpoints for hand washing are done, precautions such as hand sanitizer dispensers filled with sodium hypochlorite, alcohol, or hydrogen peroxide, which are three approved disinfectants that kill bacteria, are placed in certain points, and nurses carrying mini hand sanitizer dispensers help increase sanitation in the work field. in cases where equipment is being placed in a container or bin and picked back up, nurses and doctors are required to wash their hands or use alcohol sanitizer before going back to the container to use the same equipment. independent studies by ignaz semmelweis in 1846 in vienna and oliver wendell holmes, sr. in 1843 in boston established a link between the hands of health care workers and the spread of hospital-acquired disease. the u.s. centers for disease control and prevention (cdc) state that "it is well documented that the most important measure for preventing the spread of pathogens is effective handwashing". in the developed world, hand washing is mandatory in most health care settings and required by many different regulators. in the united states, osha standards require that employers must provide readily accessible hand washing facilities, and must ensure that employees wash hands and any other skin with soap and water or flush mucous membranes with water as soon as feasible after contact with blood or other potentially infectious materials (opim). in the uk healthcare professionals have adopted the 'ayliffe technique', based on the 6 step method developed by graham ayliffe, jr babb and ah quoraishi. mean percentage changes in bacterial numbers method usedchange inbacteria present paper towels (2-ply 100% recycled).- 48.4% paper towels (2-ply through-air dried, 50% recycled)- 76.8% warm air dryer+ 254.5% jet air dryer+ 14.9% drying is an essential part of the hand hygiene process. in november 2008, a non-peer-reviewed study was presented to the european tissue symposium by the university of westminster, london, comparing the bacteria levels present after the use of paper towels, warm air hand dryers, and modern jet-air hand dryers. of those three methods, only paper towels reduced the total number of bacteria on hands, with "through-air dried" towels the most effective. the presenters also carried out tests to establish whether there was the potential for cross-contamination of other washroom users and the washroom environment as a result of each type of drying method. they found that: the jet air dryer, which blows air out of the unit at claimed speeds of 400 mph, was capable of blowing micro-organisms from the hands and the unit and potentially contaminating other washroom users and the washroom environment up to 2 metres away use of a warm air hand dryer spread micro-organisms up to 0.25 metres from the dryer paper towels showed no significant spread of micro-organisms. in 2005, in a study conducted by tuv produkt und umwelt, different hand drying methods were evaluated. the following changes in the bacterial count after drying the hands were observed: drying method effect on bacterial count paper towels and roll decrease of 24% hot-air drier increase of 117% cleaning, disinfection, sterilization the field of infection prevention describes a hierarchy of removal of microorganisms from surfaces including medical equipment and instruments. cleaning is the lowest level, accomplishing substantial removal. disinfection involves the removal of all pathogens other than bacterial spores. sterilization is defined as the removal or destruction of all microorganisms including bacterial spores. cleaning cleaning is the first and simplest step in preventing the spread of infection via surfaces and fomites. cleaning reduces microbial burden by chemical deadsorption of organisms (loosening bioburden/organisms from surfaces via cleaning chemicals), simple mechanical removal (rinsing, wiping), as well as disinfection (killing of organisms by cleaning chemicals). in order to reduce their chances to contract an infection, individuals are recommended to maintain a good hygiene by washing their hands after every contact with questionable areas or bodily fluids and by disposing of garbage at regular intervals to prevent germs from growing. disinfection disinfection uses liquid chemicals on surfaces and at room temperature to kill disease causing microorganisms. ultraviolet light has also been used to disinfect the rooms of patients infected with clostridium difficile after discharge. disinfection is less effective than sterilization because it does not kill bacterial endospores. along with ensuring proper hand washing techniques are followed, another major component to decrease the spread of disease is sanitation of all medical equipment. the ana and aana set guidelines for sterilization and disinfection based on the spaulding disinfection and sterilization classification scheme (sdscs). the sdscs classifies sterilization techniques into three categories: critical, semi-critical, and non-critical. for critical situations, or situations involving contact with sterile tissue or the vascular system, sterilize devices with sterilants that destroy all bacteria, rinse with sterile water, and use chemical germicides. in semi-critical situations, or situations with contact of mucous membranes or non-intact skin, high-level disinfectants are required. cleaning and disinfecting devices with high-level disinfectants, rinsing with sterile water, and drying all equipment surfaces to prevent microorganism growth are methods nurses and doctors must follow. for non-critical situations, or situations involving electronic devices, stethoscopes, blood pressure cuffs, beds, monitors and other general hospital equipment, intermediate level disinfection is required. "clean all equipment between patients with alcohol, use protective covering for non-critical surfaces that are difficult to clean, and hydrogen peroxide gas. . .for reusable items that are difficult to clean." sterilization sterilization is a process intended to kill all microorganisms and is the highest level of microbial kill that is possible. sterilization, if performed properly, is an effective way of preventing infections from spreading. it should be used for the cleaning of medical instruments and any type of medical item that comes into contact with the blood stream and sterile tissues. there are four main ways in which such items are usually sterilized: autoclave (by using high-pressure steam), dry heat (in an oven), by using chemical sterilants such as glutaraldehydes or formaldehyde solutions or by exposure to ionizing radiation. the first two are the most widely used methods of sterilization mainly because of their accessibility and availability. steam sterilization is one of the most effective types of sterilizations, if done correctly which is often hard to achieve. instruments that are used in health care facilities are usually sterilized with this method. the general rule in this case is that in order to perform an effective sterilization, the steam must get into contact with all the surfaces that are meant to be disinfected. on the other hand, dry heat sterilization, which is performed with the help of an oven, is also an accessible type of sterilization, although it can only be used to disinfect instruments that are made of metal or glass. the very high temperatures needed to perform sterilization in this way are able to melt the instruments that are not made of glass or metal. effectiveness of the sterilizer, for example a steam autoclave is determined in three ways. first, mechanical indicators and gauges on the machine itself indicate proper operation of the machine. second heat sensitive indicators or tape on the sterilizing bags change color which indicate proper levels of heat or steam. and, third (most importantly) is biological testing in which a microorganism that is highly heat and chemical resistant (often the bacterial endospore) is selected as the standard challenge. if the process kills this microorganism, the sterilizer is considered to be effective. steam sterilization is done at a temperature of 121 c (250 f) with a pressure of 209 kpa (~2atm). in these conditions, rubber items must be sterilized for 20 minutes, and wrapped items 134 c with pressure of 310 kpa for 7 minutes. the time is counted once the temperature that is needed has been reached. steam sterilization requires four conditions in order to be efficient: adequate contact, sufficiently high temperature, correct time and sufficient moisture. sterilization using steam can also be done at a temperature of 132 c (270 f), at a double pressure. dry heat sterilization is performed at 170 c (340 f) for one hour or two hours at a temperature of 160 c (320 f). dry heat sterilization can also be performed at 121 c, for at least 16 hours. chemical sterilization, also referred to as cold sterilization, can be used to sterilize instruments that cannot normally be disinfected through the other two processes described above. the items sterilized with cold sterilization are usually those that can be damaged by regular sterilization. a variety of chemicals can be used including aldehydes, hydrogen peroxide, and peroxyacetic acid. commonly, glutaraldehydes and formaldehyde are used in this process, but in different ways. when using the first type of disinfectant, the instruments are soaked in a 2–4% solution for at least 10 hours while a solution of 8% formaldehyde will sterilize the items in 24 hours or more. chemical sterilization is generally more expensive than steam sterilization and therefore it is used for instruments that cannot be disinfected otherwise. after the instruments have been soaked in the chemical solutions, they must be rinsed with sterile water which will remove the residues from the disinfectants. this is the reason why needles and syringes are not sterilized in this way, as the residues left by the chemical solution that has been used to disinfect them cannot be washed off with water and they may interfere with the administered treatment. although formaldehyde is less expensive than glutaraldehydes, it is also more irritating to the eyes, skin and respiratory tract and is classified as a potential carcinogen, so it is used much less commonly. ionizing radiation is typically used only for sterilizing items for which none of the above methods are practical, because of the risks involved in the process personal protective equipment disposable ppe personal protective equipment (ppe) is specialized clothing or equipment worn by a worker for protection against a hazard. the hazard in a health care setting is exposure to blood, saliva, or other