Infection control is the discipline concerned with preventing nosocomial or healthcare-associated infection, a practical (rather than academic) sub-discipline of epidemiology. It is an essential, though often underrecognized and undersupported, 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. Anti-infective agents include antibiotics, antibacterials, antifungals, antivirals and antiprotozoals.
Epidemiology is the study and analysis of the distribution and determinants of health and disease conditions in defined populations.
Public health has been defined as "the science and art of preventing disease, prolonging life and promoting human health through organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the health of a population and the threats it faces is the basis for public health. The public can be as small as a handful of people or as large as a village or an entire city; in the case of a pandemic it may encompass several continents. The concept of health takes into account physical, psychological and social well-being. As such, according to the World Health Organization, it is not merely the absence of disease or infirmity.
Infection control addresses factors related to the spread of infections within the healthcare setting (whether patient-to-patient, from patients to staff and from staff to patients, or among-staff), including prevention (via hand hygiene/hand washing, cleaning/disinfection/sterilization, vaccination, surveillance), monitoring/investigation of demonstrated or suspected spread of infection within a particular health-care setting (surveillance and outbreak investigation), and management (interruption of outbreaks). It is on this basis that the common title being adopted within health care is "infection prevention and control."
Aseptic technique is a key component of all invasive medical procedures. Similarly, infection control measures are most effective when Standard Precautions (health care) are applied because undiagnosed infection is common.
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. [ citation needed ]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.
Ignaz Philipp Semmelweis was a Hungarian physician of ethnic-German ancestry, now known as an early pioneer of antiseptic procedures. Described as the "saviour of mothers", Semmelweis discovered that the incidence of puerperal fever could be drastically cut by the use of hand disinfection in obstetrical clinics. Puerperal fever was common in mid-19th-century hospitals and often fatal. Semmelweis proposed the practice of washing hands with chlorinated lime solutions in 1847 while working in Vienna General Hospital's First Obstetrical Clinic, where doctors' wards had three times the mortality of midwives' wards. He published a book of his findings in Etiology, Concept and Prophylaxis of Childbed Fever.
Vienna is the federal capital and largest city of Austria, and one of the nine states of Austria. Vienna is Austria's primate city, with a population of about 1.9 million, and its cultural, economic, and political centre. It is the 7th-largest city by population within city limits in the European Union. Until the beginning of the 20th century, it was the largest German-speaking city in the world, and before the splitting of the Austro-Hungarian Empire in World War I, the city had 2 million inhabitants. Today, it has the second largest number of German speakers after Berlin. Vienna is host to many major international organizations, including the United Nations and OPEC. The city is located in the eastern part of Austria and is close to the borders of the Czech Republic, Slovakia, and Hungary. These regions work together in a European Centrope border region. Along with nearby Bratislava, Vienna forms a metropolitan region with 3 million inhabitants. In 2001, the city centre was designated a UNESCO World Heritage Site. In July 2017 it was moved to the list of World Heritage in Danger.
Boston is the capital and most populous city of the Commonwealth of Massachusetts in the United States. The city proper covers 48 square miles (124 km2) with an estimated population of 685,094 in 2017, making it also the most populous city in New England. Boston is the seat of Suffolk County as well, although the county government was disbanded on July 1, 1999. The city is the economic and cultural anchor of a substantially larger metropolitan area known as Greater Boston, a metropolitan statistical area (MSA) home to a census-estimated 4.8 million people in 2016 and ranking as the tenth-largest such area in the country. As a combined statistical area (CSA), this wider commuting region is home to some 8.2 million people, making it the sixth-largest in the United States.
In the United States, OSHA standardsrequire 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.
Graham Arthur John Ayliffe was an English medical microbiologist. He was Emeritus Professor in Medical Microbiology, University of Birmingham, United Kingdom. Graham Ayliffe was instrumental in founding the International Federation for Infection Control (IFIC) in association with the World Health Organization (WHO) in 1987. He was elected Chair in 1990. He was also a founder member of the Hospital Infection Society and editor of its journal (1980–84), a former Chair (1980–84) and President (1988–94). The Graham Ayliffe Training Fellowship was established in 2013.
|Method used||Change in|
|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-reviewedstudy 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 University of Westminster is a public university in London, United Kingdom. Its antecedent institution, the Royal Polytechnic Institution, was founded in 1838 and was the first polytechnic institution in the UK. Westminster was awarded university status in 1992 meaning it could award its own degrees.
Paper towel is an absorbent towel made from paper instead of fabric. In Britain rolls of paper towels specifically for kitchen use are known as kitchen rolls. For home use, it usually sold in a roll of perforated sheets, but some are sold in stacks of pre-cut and pre-folded layers for use in paper-towel dispensers. Unlike cloth towels, paper towels are disposable and intended to be used only once. Paper towels soak up water because they are loosely woven which enables water to travel between the fibers, even against gravity. Paper towels have similar purposes to conventional towels, such as drying hands, wiping windows and other surfaces, dusting and cleaning up spills. Paper towel dispensers are often used in toilets shared by many people, as paper towels are often considered more hygienic than hot-air hand dryers.
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:
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%|
Sterilization is a process intended to kill all microorganisms and is the highest level of microbial kill that is possible. Sterilizers may be heat only, steam, or liquid chemical.Effectiveness of the sterilizer (e.g., 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.
Sterilization, if performed properly, is an effective way of preventing bacteria from spreading. It should be used for the cleaning of the medical instruments or gloves, and basically 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 can be sterilized: autoclave (by using high-pressure steam), dry heat (in an oven), by using chemical sterilants such as glutaraldehydes or formaldehyde solutions or by radiation (with the help of physical agents). The first two are the most used methods of sterilizations 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.
Steam sterilization is done at a temperature of 121 C (250 F) with a pressure of 209 kPa (15 lbs/in2). 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. 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 are mandatory to 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.
Other sterilization methods exist, though their efficiency is still controversial. These methods include gas, UV, gas plasma, and chemical sterilization with agents such as peroxyacetic acid or paraformaldehyde.
Infections can be prevented from occurring in homes as well. 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 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.
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 bodily fluids or aerosols that may carry infectious materials such as Hepatitis C, HIV, or other blood borne or bodily fluid pathogen. PPE prevents contact with a potentially infectious material by creating a physical barrier between the potential infectious material and the healthcare worker.
The United States Occupational Safety and Health Administration (OSHA) requires the use of Personal protective equipment (PPE) by workers to guard against blood borne pathogens if there is a reasonably anticipated exposure to blood or other potentially infectious materials.
Components of PPE include gloves, gowns, bonnets, shoe covers, face shields, CPR masks, goggles, surgical masks, and respirators. How many components are used and how the components are used is often determined by regulations or the infection control protocol of the facility in question. Many or most of these items are disposable to avoid carrying infectious materials from one patient to another patient and to avoid difficult or costly disinfection. In the US, OSHA requires the immediate removal and disinfection or disposal of a worker's PPE prior to leaving the work area where exposure to infectious material took place.
The inappropriate use of PPE equipment such as gloves, has been linked to an increase in rates of the transmission of infection,and the use of such must be compatible with the other particular hand hygiene agents used.
Microorganisms are known to survive on non-antimicrobial in animate ‘touch’ surfaces (e.g., bedrails, over-the-bed trays, call buttons, bathroom hardware, etc.) for extended periods of time.This can be especially troublesome in hospital environments where patients with immunodeficiencies are at enhanced risk for contracting nosocomial infections.
Products made with antimicrobial copper alloy (brasses, bronzes, cupronickel, copper-nickel-zinc, and others) surfaces destroy a wide range of microorganisms in a short period of time.The United States Environmental Protection Agency has approved the registration of 355 different antimicrobial copper alloys and one synthetic copper-infused hard surface that kill E. coli O157:H7, methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus , Enterobacter aerogenes, and Pseudomonas aeruginosa in less than 2 hours of contact. Other investigations have demonstrated the efficacy of antimicrobial copper alloys to destroy Clostridium difficile , influenza A virus, adenovirus, and fungi. As a public hygienic measure in addition to regular cleaning, antimicrobial copper alloys are being installed in healthcare facilities in the U.K., Ireland, Japan, Korea, France, Denmark, and Brazil. The synthetic hard surface is being installed in the United States as well as in Israel.
Health care workers may be exposed to certain infections in the course of their work. Vaccines are available to provide some protection to workers in a healthcare setting. Depending on regulation, recommendation, the specific work function, or personal preference, healthcare workers or first responders may receive vaccinations for hepatitis B; influenza; measles, mumps and rubella; Tetanus, diphtheria, pertussis; N. meningitidis; and varicella.
Surveillance is the act of infection investigation using the CDC definitions. Determining the presence of a hospital acquired infection requires an infection control practitioner (ICP) to review a patient's chart and see if the patient had the signs and symptom of an infection. Surveillance definitions exist for infections of the bloodstream, urinary tract, pneumonia, surgical sites and gastroenteritis.
Surveillance traditionally involved significant manual data assessment and entry in order to assess preventative actions such as isolation of patients with an infectious disease. Increasingly, computerized software solutions are becoming available that assess incoming risk messages from microbiology and other online sources. By reducing the need for data entry, software can reduce the data workload of ICPs, freeing them to concentrate on clinical surveillance.
As of 1998, approximately one third of healthcare acquired infections were preventable.Surveillance and preventative activities are increasingly a priority for hospital staff. The Study on the Efficacy of Nosocomial Infection Control (SENIC) project by the U.S. CDC found in the 1970s that hospitals reduced their nosocomial infection rates by approximately 32 per cent by focusing on surveillance activities and prevention efforts.
In the health care context, medical isolation refers to various physical measures taken to interrupt nosocomial spread of contagious diseases. Various forms of isolation exist, and are applied depending on the type of infection and agent involved, to address the likelihood of spread via airborne particles or droplets, by direct skin contact, or via contact with body fluids.
In cases where infection is merely suspected, individuals may be quarantined until the incubation period has passed and the disease manifests itself or the person remains healthy. Groups may undergo quarantine, or in the case of communities, a cordon sanitaire may be imposed to prevent infection from spreading beyond the community, or in the case of protective sequestration, into a community. Public health authorities may implement other forms of social distancing, such as school closings, to control an epidemic.
When an unusual cluster of illness is noted, infection control teams undertake an investigation to determine whether there is a true outbreak, a pseudo-outbreak (a result of contamination within the diagnostic testing process), or just random fluctuation in the frequency of illness. If a true outbreak is discovered, infection control practitioners try to determine what permitted the outbreak to occur, and to rearrange the conditions to prevent ongoing propagation of the infection. Often, breaches in good practice are responsible, although sometimes other factors (such as construction) may be the source of the problem.
Outbreaks investigations have more than a single purpose. These investigations are carried out in order to prevent additional cases in the current outbreak, prevent future outbreaks, learn about a new disease or learn something new about an old disease. Reassuring the public, minimizing the economic and social disruption as well as teaching epidemiology are some other obvious objectives of outbreak investigations.
According to the WHO, outbreak investigations are meant to detect what is causing the outbreak, how the pathogenic agent is transmitted, where it all started from, what is the carrier, what is the population at risk of getting infected and what are the risk factors.
The results of outbreak investigations are always made public in the means of a report in which the findings are communicated to the authorities, media, scientific community and so on. These reports are commonly used as pedagogical tools.
Practitioners can come from several different educational streams. Many begin as nurses, some as medical technologists (particularly in clinical microbiology), and some as physicians (typically infectious disease specialists). Specialized training in infection control and health care epidemiology are offered by the professional organizations described below. Physicians who desire to become infection control practitioners often are trained in the context of an infectious disease fellowship.
In the United States, Certification Board of Infection Control and Epidemiology is a private company that certifies infection control practitioners based on their educational background and professional experience, in conjunction with testing their knowledge base with standardized exams. The credential awarded is CIC, Certification in Infection Control and Epidemiology. It is recommended that one has 2 years of Infection Control experience before applying for the exam. Certification must be renewed every five years.
A course in hospital epidemiology (infection control in the hospital setting) is offered jointly each year by the Centers for Disease Control and Prevention (CDC) and the Society for Healthcare Epidemiology of America.
In 2002, the Royal Australian College of General Practitioners published a revised standard for office-based infection control which covers the sections of managing immunisation, sterilisation and disease surveillance.However, the document on the personal hygiene of health workers is only limited to hand hygiene, waste and linen management, which may not be sufficient since some of the pathogens are air-born and could be spread through air flow.
Currently, the federal regulation that describes infection control standards is found at 29 CFR Part 1910.1030 Bloodborne pathogens.
Universal precautions refers to the practice, in medicine, of avoiding contact with patients' bodily fluids, by means of the wearing of nonporous articles such as medical gloves, goggles, and face shields. The practice was introduced in 1985–88. In 1987, the practice of universal precautions was adjusted by a set of rules known as body substance isolation. In 1996, both practices were replaced by the latest approach known as standard precautions. Use of personal protective equipment is now recommended in all health settings.
An epidemic is the rapid spread of infectious disease to a large number of people in a given population within a short period of time, usually two weeks or less. For example, in meningococcal infections, an attack rate in excess of 15 cases per 100,000 people for two consecutive weeks is considered an epidemic.
Hygiene is a set of practices performed to preserve health. According to the World Health Organization (WHO), "Hygiene refers to conditions and practices that help to maintain health and prevent the spread of diseases." Personal hygiene refers to maintaining the body's cleanliness.
In epidemiology, an outbreak is a sudden increase in occurrences of a disease in a particular time and place. It may affect a small and localized group or impact upon thousands of people across an entire continent. Two linked cases of a rare infectious disease may be sufficient to constitute an outbreak. Outbreaks include epidemics, which term is normally only used for infectious diseases, as well as diseases with an environmental origin, such as a water or foodborne disease. They may affect a region in a country or a group of countries. Pandemics are near-global disease outbreaks.
A bloodborne disease is a disease that can be spread through contamination by blood and other body fluids. Bloodborne pathogens are microorganisms such as viruses or bacteria. The most common examples are HIV, hepatitis B (HVB), hepatitis C (HVC) and viral hemorrhagic fevers.
Hand washing, also known as hand hygiene, is the act of cleaning hands for the purpose of removing soil, dirt, and microorganisms. If water and soap is not available, hands can be cleaned with ash instead.
Klebsiella pneumoniae is a Gram-negative, non-motile, encapsulated, lactose-fermenting, facultative anaerobic, rod-shaped bacterium. It appears as a mucoid lactose fermenter on MacConkey agar.
A hospital-acquired infection (HAI), also known as a nosocomial infection, is an infection that is acquired in a hospital or other health care facility. To emphasize both hospital and nonhospital settings, it is sometimes instead called a health care–associated infection. Such an infection can be acquired in hospital, nursing home, rehabilitation facility, outpatient clinic, or other clinical settings. Infection is spread to the susceptible patient in the clinical setting by various means. Health care staff can spread infection, in addition to contaminated equipment, bed linens, or air droplets. The infection can originate from the outside environment, another infected patient, staff that may be infected, or in some cases, the source of the infection cannot be determined. In some cases the microorganism originates from the patient's own skin microbiota, becoming opportunistic after surgery or other procedures that compromise the protective skin barrier. Though the patient may have contracted the infection from their own skin, the infection is still considered nosocomial since it develops in the health care setting.
Hand sanitizer is a liquid generally used to decrease infectious agents on the hands. Formulations of the alcohol-based type are preferable to hand washing with soap and water in most situations in the healthcare setting. It is generally more effective at killing microorganisms and better tolerated than soap and water. Hand washing should still be carried out if contamination can be seen or following the use of the toilet. The general use of non-alcohol based versions has no recommendations. Outside the health care setting evidence to support the use of hand sanitizer over hand washing is poor. They are available as liquids, gels, and foams.
Waterborne diseases are conditions caused by pathogenic micro-organisms that are transmitted in water. Disease can be spread while bathing, washing or drinking water, or by eating food exposed to contaminated water. While diarrhea and vomiting are the most commonly reported symptoms of waterborne illness, other symptoms can include skin, ear, respiratory, or eye problems.
Hospital-acquired pneumonia (HAP) or nosocomial pneumonia refers to any pneumonia contracted by a patient in a hospital at least 48–72 hours after being admitted. It is thus distinguished from community-acquired pneumonia. It is usually caused by a bacterial infection, rather than a virus.
In health care facilities, isolation represents one of several measures that can be taken to implement infection control: the prevention of contagious diseases from being spread from a patient to other patients, health care workers, and visitors, or from outsiders to a particular patient. Various forms of isolation exist, in some of which contact procedures are modified, and others in which the patient is kept away from all others. In a system devised, and periodically revised, by the U.S. Centers for Disease Control and Prevention (CDC), various levels of patient isolation comprise application of one or more formally described "precaution".
An airborne disease is any disease that is caused by pathogens that can be transmitted through the air. Such diseases include many of considerable importance both in human and veterinary medicine. The relevant pathogens may be viruses, bacteria, or fungi, and they may be spread through breathing, talking, coughing, sneezing, raising of dust, spraying of liquids, toilet flushing or any activities which generates aerosol particles or droplets. Human airborne diseases do not include conditions caused by air pollution such as Volatile Organic Compounds (VOCs), gases and any airborne particles, though their study and prevention may help inform the science of airborne disease transmission.
Antimicrobial copper-alloy touch surfaces can prevent frequently touched surfaces from serving as reservoirs for the spread of pathogenic microbes. This is especially true in healthcare facilities, where harmful viruses, bacteria, and fungi colonize and persist on doorknobs, push plates, railings, tray tables, tap (faucet) handles, IV poles, HVAC systems, and other equipment. These microbes can often survive on surfaces for surprisingly long periods of time.
Transmission-based precautions are additional infection control precautions in health care, and the latest routine infection prevention and control practices applied for patients who are known or suspected to be infected or colonized with infectious agents, including certain epidemiologically important pathogens. The latter require additional control measures to effectively prevent transmission.
Didier Pittet is as an infectious diseases expert and the director of the Infection Control Programme and WHO Collaborating Centre on Patient Safety, University Hospital of Geneva, Geneva, Switzerland. Since 2005, Pittet is also the External Lead of the World Health Organization (WHO) Global Patient Safety Challenge "Clean Care is Safer Care" and African Partnerships for Patient Safety.
Infectious disease, also known as infectiology, is a medical specialty dealing with the diagnosis, control and treatment of infections. An infectious disease (ID) specialist's practice may consist largely of managing nosocomial (hospital-acquired) infections, or it may be out-patient based.
Barrier nursing is a largely archaic term for a set of stringent infection control techniques used in nursing. The aim of barrier nursing is to protect medical staff against infection by patients and also protect patients with highly infectious diseases from spreading their pathogens to other non-infected people.
Prevention of viral hemorrhagic fever is similar for the different viruses. There are a number of different viral hemorrhagic fevers including Ebola virus disease, Lassa fever, Rift valley fever, Marburg virus disease, Crimean-Congo haemorrhagic fever (CCHF) and yellow fever. Lassa, Ebola, Marburg and CCHF can be spread by direct contact with the body fluids of those infected. Thus the content here covers the prevention of Ebola.
The International Society for Infectious Diseases (ISID), established in 1986, is a non-profit organization that works to control infectious disease outbreaks and improve the care of patients afflicted with these conditions.