Infection control is the process by which health care facilities attempt to limit or eliminate health care-associated infections. Infection control is part of the branch of medicine known as epidemiology, the study of diseases in large populations of people. Among the most common infection control methods today are ensuring that the health care environment is kept clean; using appropriate methods and agents to clean, disinfect, and sterilize equipment; maintaining proper hand hygiene; and wearing and properly disposing of gloves and other personal protective equipment.

Infection control in healthcare settings is paramount for several reasons. Not only are sick individuals congregating in these environments, but they may also have weakened immune systems, making them more vulnerable to infections. Furthermore, the presence of antibiotic-resistant strains adds an extra layer of complexity and urgency to the need for effective infection control measures.

Health care-associated infections can occur at any type of health care facility, including, but not limited to, acute care hospitals, emergency rooms, intensive care units, surgical centers, dialysis facilities, physical therapy and rehabilitation centers, outpatient care facilities, and long-term care facilities, such as nursing homes. In all these settings, implementing robust infection control protocols, educating staff and patients about hygiene practices, and maintaining a clean environment are critical for reducing the risk of HAIs and ensuring patient safety.

Among the most common healthcare-associated infections are the following: central line-associated bloodstream infections – Central lines are “catheters that doctors place in a large vein in the neck, chest, or groin to give medication or fluids or to collect blood for medical tests.” Central line-associated bloodstream infections are infections that occur when germs enter the bloodstream through a central line. (Source: www.cdc.gov/hai/bsi/clabsi-resources.html)

To help prevent the spread of health care-associated infections, health care professionals must adhere to systems of both work-practice controls and engineering controls. Work-practice controls focus on behaviors and practices that can directly reduce the risk of infections. This includes proper hand hygiene, which is one of the most effective ways to prevent the transmission of pathogens. Personal protective equipment like gloves, masks, and gowns also play a vital role in protecting healthcare workers and patients from exposure to infectious agents. Proper handling, disposal, and disinfection methods for blood and bodily fluids, as well as the prevention of device contamination and percutaneous exposures, are essential components of infection control protocols.

Cleaning in a health care environment involves the following three levels of cleanliness: • clean • disinfected • sterilized The level of cleanliness required for a particular device or location depends on what that device or location is designed to accomplish and should not be based on killing any particular kind of pathogen.

Hands that are unclean can easily pass along infectious agents through a process known as cross-contamination. In health care, cross-contamination usually involves a transfer of pathogens resulting from a health care worker failing to use proper hand hygiene techniques. Hand hygiene represents one of the simplest ways that health care workers can prevent the spread of health care-associated infections. Infectious agents are most often passed from one patient to another via the hands of a health care worker when:

Personal protective equipment (PPE) is equipment worn to prevent the spread of health care-associated infections and to minimize workplace injuries and illnesses.” In health care, PPE is meant to protect both health care workers and patients and is used to create barriers between an individual and a material or bodily fluid that might contain pathogens. The most common PPE items are:

Disease is an abnormal medical condition that negatively affects a person and is accompanied by a distinguishing set of signs and symptoms. Disease in humans can result from injuries, unhealthy lifestyle choices, genetics, socio-economic circumstances, and the normal process of aging.

Most infectious diseases are acquired as part of normal living, such as when a sick child sneezes and transmits a virus to another child. When infections are passed along in this manner, they are called community-acquired infections.

For a health care-associated infection to be transmitted from one person to another, conditions must be right. A person might be sick, but if they are isolated, then the infection won’t be transmitted. Likewise, if a person is exposed to an infection but has an immune system strong enough to fight it off, then, again, the infection won’t be transmitted. For a health care-associated infection to be transmitted between individuals, a specific set of circumstances must be present.

For a health care-associated infection to be transmitted there first has to be an infectious agent. The infectious agent, or pathogen, is the organism that causes disease. Types of pathogens include the following:

In order to be a viable organism, an infectious agent needs a place to live. This place is called the reservoir, which is the second link in the chain of infection. Pathogens can use many things as reservoirs, including humans, animals, the soil, and water. Reservoirs can also be non-organic items such as toothbrushes and doorknobs. A human who serves as a reservoir for a pathogen does not always become ill as a result of the pathogen. Reservoirs can simply be carriers of the pathogen without suffering any ill effects from its presence.

The portal of exit is the third link in the chain of infection. The portal of exit is the way in which the infectious agent (the first link) leaves its reservoir (the second link). In humans, an infectious agent can exit the body as drainage, excretion, secretion, discharge, or other substances through systems such as the respirator tract, the gastrointestinal tract, the genitourinary tract, the skin or mucous membranes, the placenta, and the blood.

An infectious agent living in a reservoir and then finding a way of that reservoir represent the first, second, and third links in the chain of infection. The fourth link is the mode of transmission, the manner in which an infectious agent is passed from one person to another. The transmission of the infectious agent can be done either directly or indirectly. Direct transmission methods are more immediate and often involve close contact, while indirect methods can involve various pathways that don't necessarily require direct physical interaction. This understanding helps public health officials and healthcare workers develop targeted strategies for preventing transmission in different scenarios.

The portal of entry is just as critical as the portal of exit in the chain of infection. It's interesting how pathogens often use the same pathways for entry and exit, emphasizing the importance of understanding these routes to prevent and control infections effectively. For instance, respiratory pathogens like influenza viruses can exit an infected person through respiratory secretions when they cough or sneeze. These pathogens can then enter a new host through inhalation of contaminated droplets, demonstrating the direct link between portal of exit and portal of entry.

The susceptible host is the sixth and final link in the chain of infection. The susceptible host is the person the infectious agent enters and in whom it causes disease. When an infectious agent enters a person, that person does not automatically become sick. A healthy person with no other vulnerabilities can often fight off an infection using the body’s natural defenses. However, when certain risk factors are present, a person is more susceptible to becoming ill. Risk factors include:

The US Centers for Disease Control and Prevention, or CDC, created the epidemiologic triangle to explain how an infectious agent can moves efficiently along the chain of infection and infect a large number of people. The triangle represents the interactions between host, pathogen, and environment.