infection control

Infection Control 

Definition

Infection control refers to policies and procedures used to minimize the risk of spreading infections, especially in hospitals and human or animal health care facilities.

Purpose

The purpose of infection control is to reduce the occurrence of infectious diseases. These diseases are usually caused by bacteria or viruses and can be spread by human to human contact, animal to human contact, human contact with an infected surface, airborne transmission through tiny droplets of infectious agents suspended in the air, and, finally, by such common vehicles as food or water. Diseases that are spread from animals to humans are known as zoonoses; animals that carry disease agents from one host to another are known as vectors.

Infection control in hospitals and other health care settings

Infections contracted in hospitals are also called nosocomial infections. They occur in approximately 5% of all hospital patients. These infections result in increased time spent in the hospital and, in some cases, death. There are many reasons nosocomial infections are common, one of which is that many hospital patients have a weakened immune system which makes them more susceptible to infections. This weakened immune system can be caused either by the patient's diseases or by treatments given to the patient. Second, many medical procedures can increase the risk of infection by introducing infectious agents into the patient. Thirdly, many patients are admitted to hospitals because of infectious disease. These infectious agents can then be transferred from patient to patient by hospital workers or visitors.

Infection control has become a formal discipline in the United States since the 1950s, due to the spread of staphylococcal infections in hospitals. Because there is both the risk of health care providers acquiring infections themselves, and of them passing infections on to patients, the Centers for Disease Control and Prevention (CDC) established guidelines for infection control procedures. In addition to hospitals, infection control is important in nursing homes, clinics, child care centers, and restaurants, as well as in the home.

To lower the risk of nosocomial infections, the CDC began a national program of hospital inspection in 1970 known as the National Nosocomial Infections Surveillance system, or NNIS. The CDC reported that over 300 hospitals participate in the NNIS system as of the early 2000s. Data collected from the participating hospitals show that infection control programs can siginificantly improve patient safety, lower infection rates, and lower patient mortality.

Dental health care settings are similar to hospitals in that both personnel and equipment can transmit infection if proper safeguards are not observed. The CDC issued new guidelines in 2003 for the proper maintenance and sterilization of dental equipment, hand hygiene for dentists and dental hygienists, dental radiology, medications, and oral surgery, environmental infection control, and standards for dental laboratories.

Selected Infectious Diseases And Corresponding Treatment
Disease	Symptoms	Transmittal	Treatment
Chicken pox	Rash, low- grade fever	Person to person	None
Common cold/ Influenza	Runny nose, sore throat, cough, fever, headache, muscle aches	Person to person	None
Hepatitis	Jaundice, flu- like symptoms	Sexual contact with an infected per- son, contami- nated blood, food, or water	None
Legionnaire's Disease	Flu symptoms, peneumonia, diarrhea, vomiting, kidney failure, respiratory failure	Air condition- ing or water systems	Antibiotics
Measles	Skin rash, runny nose and eyes, fever, cough	Person to person	None
Meningitis	Neck pain, headache, pain caused by exposure to light, fever, nausea, drowsiness	Person to person	Antibiotics for bacterial meningitis, hospital care for viral meningitis
Mumps	Swelling of salivary glands	Person to person	Anti-inflam- matory drugs
Ringworm	Skin rash	Contact with infected ani- mal or person	Antifungal drugs applied topically
Tetanus	Lockjaw, other spasms	Soil infection of wounds	Antibiotics, antitoxins, muscle relaxers

The newest addition to the infection control specialist's resources is molecular typing, which speeds up the identification of a disease agent. Rapid identification in turn allows for timely containment of a disease outbreak.

Threat of emerging infectious diseases

Due to constant changes in our lifestyles and environments, new diseases are constantly appearing that people are susceptible to, making protection from the threat of infectious disease urgent. Many new contagious diseases have been identified in the past 30 years, such as AIDS, Ebola, and hantavirus. Increased travel between continents makes the worldwide spread of disease a bigger concern than it once was. Additionally, many common infectious diseases have become resistant to known treatments.

The emergence of the severe acute respiratory syndrome (SARS) epidemic in Asia in February 2003 was a classic instance of an emerging disease that spread rapidly because of the increased frequency of international and intercontinental travel. In addition, the SARS outbreak demonstrated the vulnerability of hospitals and health care workers to emerging diseases. Clusters of cases within hospitals occurred in the early weeks of the epidemic when the disease had not yet been recognized and the first SARS patients were admitted without isolation precautions.

The SARS epidemic also raised a number of ethical and legal questions regarding current attitudes toward infection control.

Problems of antibiotic resistance

Because of the overuse of antibiotics, many bacteria have developed a resistance to common antibiotics. This means that newer antibiotics must continually be developed in order to treat an infection. However, further resistance seems to come about almost simultaneously. This indicates to many scientists that it might become more and more difficult to treat infectious diseases. The use of antibiotics outside of medicine also contributes to increased antibiotic resistance. One example of this is the use of antibiotics in animal husbandry. These negative trends can only be reversed by establishing a more rational use of antibiotics through treatment guidelines.

Bioterrorism

The events of September 11, 2001, and the anthrax scare that followed in October 2001 alerted public health officials as well as the general public to the possible use of infectious disease agents as weapons of terrorism. The Centers for Disease Control and Prevention (CDC) now has a list of topics and resources related to bioterrorism on its web site.

Description

The goals of infection control programs are: immunizing against preventable diseases, defining precautions that can prevent exposure to infectious agents, and restricting the exposure of health care workers to an infectious agent. An infection control practitioner is a specially trained professional, oftentimes a nurse, who oversees infection control programs.

Commonly recommended precautions to avoid and control the spread of infections include:

• Vaccinate people and pets against diseases for which a vaccine is available. As of 2003, the vaccines used against infectious diseases are very safe compared to most drugs.
• Wash hands often.
• Cook food thoroughly.
• Use antibiotics only as directed.
• See a doctor for infections that do not heal.
• Avoid areas with a lot of insects.
• Be cautious around wild or unfamiliar animals, or any animals that are unusually aggressive. Do not purchase exotic animals as pets.
• Do not engage in unprotected sex or in intravenous drug use.
• Find out about infectious diseases when you make travel plans. Travelers' advisories and adult vaccination recommendations are available on the CDC web site or by calling the CDC's telephone service at 404-332-4559.

Because of the higher risk of spreading infectious disease in a hospital setting, higher levels of precautions are taken there. Typically, health care workers wear gloves with all patients, since it is difficult to know whether a transmittable disease is present or not. Patients who have a known infectious disease are isolated to decrease the risk of transmitting the infectious agent to another person. Hospital workers who come in contact with infected patients must wear gloves and gowns to decrease the risk of carrying the infectious agent to other patients. All articles of equipment that are used in an isolation room are decontaminated before reuse. Patients who are immunocompromised may be put in protective isolation to decrease the risk of infectious agents being brought into their room. Any hospital worker with infections, including colds, are restricted from that room.

Hospital infections can also be transmitted through the air. Thus care must be taken when handling infected materials so as to decrease the numbers of infectious agents that become airborne. Special care should also taken with hospital ventilation systems to prevent recirculation of contaminated air.

Resources

Books

Beers, Mark H., MD, and Robert Berkow, MD, editors. "Immunizations for Adults." Section 13, Chapter 152. In The Merck Manual of Diagnosis and Therapy. Whitehouse Station, NJ: Merck Research Laboratories, 2004.

Periodicals

Ashford, D. A., R. M. Kaiser, M. E. Bales, et al. "Planning Against Biological Terrorism: Lessons from Outbreak Investigations." Emerging Infectious Diseases 9 (May 2003): 515-519.

Gostin, L. O., R. Bayer, and A. L. Fairchild. "Ethical and Legal Challenges Posed by Severe Acute Respiratory Syndrome: Implications for the Control of Severe Infectious Disease Threats." Journal of the American Medical Association 290 (December 24, 2003): 3229-3237.

Ho, P. L., X. P. Tang, and W. H. Seto. "SARS: Hospital Infection Control and Admission Strategies." Respirology 8, Supplement (November 2003): S41-S45.

Jacobson, R. M., K. S. Zabel, and G. A. Poland. "The Overall Safety Profile of Currently Available Vaccines Directed Against Infectious Diseases." Expert Opinion on Drug Safety 2 (May 2003): 215-223.

Jarvis, W. R. "Benchmarking for Prevention: the Centers for Disease Control and Prevention's National Nosocomial Infections Surveillance (NNIS) System Experience." Infection 31, Supplement 2 (December 2003): 44-48.

Kohn, W. G., A. S. Collins, J. L. Cleveland, et al. "Guidelines for Infection Control in Dental Health-Care Settings—2003." Morbidity and Mortality Weekly Reports: Reports and Recommendations 52, RR-17 (December 19, 2003): 1-61.

Peng, P. W., D. T. Wong, D. Bevan, and M. Gardam. "Infection Control and Anesthesia: Lessons Learned from the Toronto SARS Outbreak." Canadian Journal of Anaesthesiology 50 (December 2003): 989-997.

Petrak, R. M., D. J. Sexton, M. L. Butera, et al. "The Value of an Infectious Diseases Specialist." Clinical Infectious Diseases 36 (April 15, 2003): 1013-1017.

Sehulster, L., and R. Y. Chinn. "Guidelines for Environmental Infection Control in Health-Care Facilities. Recommendations of CDC and the Healthcare Infection Control Practices Advisory Committee (HICPAC)." Morbidity and Mortality Recommendations and Reports 52, RR-10 (June 6, 2003): 1-42.

Subramanian, D., J. A. Sandoe, V. Keer, and M. H. Wilcox. "Rapid Spread of Penicillin-Resistant Streptococcus pneumoniae Among High-Risk Hospital Inpatients and the Role of Molecular Typing in Outbreak Confirmation." Journal of Hospital Infection 54 (June 2003): 99-103.

Organizations

American College of Epidemiology. 1500 Sunday Drive, Suite 102, Raleigh, NC 27607. (919) 861-5573. http://www.acepidemiology.org.

American Public Health Association (APHA). 800 I Street NW, Washington, DC 20001-3710. (202) 777-APHA. http://www.apha.org.

American Veterinary Medical Association (AVMA). 1931 North Meacham Road, Suite 100, Schaumburg, IL 60173-4360. http://www.avma.org.

Centers for Disease Control and Prevention. 1600 Clifton Rd., NE, Atlanta, GA 30333. (800) 311-3435, (404) 639-3311. http://www.cdc.gov.

National Institute of Allergy and Infectious Diseases (NIAID). 31 Center Drive, Room 7A50 MSC 2520, Bethesda, MD, 20892. (301) 496-5717. http://www.niaid.nih.gov.

---

infection (infek´shn),

n an invasion of the tissues of the body by disease-producing microorganisms and the reaction of these tissues to the microorganisms and/or their toxins. The mere presence of microorganisms without reaction is not evidence of infection.

infection, adenovirus,

n a proliferation of the adenovirus that may cause any number of illnesses, including “swimming pool conjunctivitis” and gastrointestinal or respiratory diseases, among others; it is possible to be infected without manifesting any symptoms.

infection, airborne,

n an infection contracted by inhalation of microorganisms contained in air or water particles.

infection control,

n procedures and protocols designed to prevent or limit cross-contamination in the health care delivery environment.

infection control, blood bank and blood transfusion,

n.pl the precautions taken to ensure that blood-borne pathogens are not transmitted via donated blood; includes rejection of potential donors whose medical history shows evidence of viral hepatitis, drug addiction, or recent blood transfusions or tattoos, as well as laboratory testing of all donated blood for the presence of hepatitis B and C, syphilis, and the HIV-1 antibody.

infection control, surveillance,

n the monitoring of the transmission of a disease in order to limit its occurrence.

infection, focal,

n the process in which microorganisms located at a certain site, or focus, in the body are disseminated throughout the body to set up secondary sites, or foci, of infection in other tissues.

infection, hemolytic streptococcal,

n 1. an infection usually caused by Group A hemolytic streptococci. Such infections include scarlet fever, streptococcal sore throat, cellulitis, and osteomyelitis.
2. an infection caused by streptococci that produce a toxic substance (hemolysin) that will lyse the erythrocytes and liberate hemoglobin from red blood cells.

infection, inflammatory,

n an influx or accumulation of inflammatory elements (cellular and exudative) in the interstices of the tissues as a result of tissue injury by physical, chemical, microbiologic, and other irritants. Cellular elements include lymphocytes, plasma cells, polymorphonuclear leukocytes, and the macrophages of reticuloendothelial origin.

infection, latent,

n a lingering infection that may lie dormant in the body for a time but may become active under certain conditions.

infection, local,

n the prevention of excitation of the free nerve endings by literally flooding the immediate area with a local anesthetic solution.

infection, nosocomial,

n an infection that first occurs during a patient's stay at a health care facility, regardless of whether it is detected during the stay or after.

infection, opportunistic,

n an illness or condition that occurs when pathogens are able to exploit a vulnerable host. An infection that is able to take hold because resistance is low.

infection, primary,

n the original outbreak of an illness against which the body has had no opportunity to build antibodies; the originating infection.

infection, recurrent,

n a reoccurrence of the same illness from which an individual has previously recovered.

infection, Vincent's,

n.pr See gingivitis, necrotizing ulcerative.

infection, waterborne,

n an illness that occurs as the result of drinking contaminated water or of eating fish that has been taken from contaminated waters.

---

infection

1. invasion and multiplication of microorganisms in body tissues, especially that causing local cellular injury due to competitive metabolism, toxins, intracellular replication or antigen-antibody response.

2. an infectious disease.

---

acute infection

short duration, of the order of several days.

airborne infection

infection by inhalation of organisms suspended in air on water droplets or dust particles.

arrested infection

restrained in its development by a capsule or adhesion but still containing infective material.

chronic infection

long duration, of the order of weeks or months.

infection control

the utilization of procedures and techniques in the surveillance, investigation and compilation of statistical data in order to reduce the spread of infection, particularly nosocomial infections.

cross infection

infection transmitted between patients infected with different pathogenic microorganisms.

droplet infection

infection due to inhalation of respiratory pathogens suspended on liquid particles exhaled by an animal that is already infected.

dustborne infection

infection by inhalation of pathogens that have become affixed to particles of dust.

endogenous infection

that due to reactivation of organisms present in a dormant focus, as occurs in tuberculosis, etc.

exogenous infection

that caused by organisms not normally present in the body but which have gained entrance from the environment.

general infection

see systemic infection (below).

latent infection

the animal is infected but there are no clinical signs nor infectious agent detectable in discharges.

local infection

has a common syndrome of varying degree, depending on the site and acuteness of the lesion and the type of microorganisms present, including fever, toxemia and leukocytosis with a left shift. The specific individual signs relate to the location of the lesion and the pressure it exerts on nearby organs. See also abscess, cellulitis, phlegmon, osteomyelitis, omphalophlebitis, empyema, adenitis, metritis, mastitis, periphlebitis.

masked infection

an infection is known to occur but the infectious agent cannot be demonstrated, e.g. the sheep-associated malignant catarrhal fever virus.

mixed infection

infection with more than one kind of organism at the same time.

nosocomial infection

pertaining to or acquired in hospital.

opportunistic infection

infection with organisms which are normally harmless but become pathogenic when the body's defense mechanisms are compromised.

patent infection

one in which the infectious agent can be demonstrated in discharges of the patient.

persistent infection

a characteristic of some viruses, particularly herpesviruses and lentiviruses, in which there may be long-lasting or life-long latent infections, with asymptomatic periods and recurring acute episodes of clinical disease (herpesviruses) or onset of severe clinical disease (lentiviruses).

pyogenic infection

infection by pus-producing organisms.

secondary infection

infection by a pathogen following an infection by a pathogen of another kind.

infection stones

see struvite urolith.

subclinical infection

infection associated with no detectable signs but caused by microorganisms capable of producing easily recognizable diseases, such as mastitis or brucellosis; often detected by the production of antibody, or by delayed hypersensitivity exhibited in a skin test reaction to such antigens as tuberculoprotein.

super infection

a second infection occurs in an animal which is already experiencing an infection with another agent.

systemic infection

the infection is widespread throughout the body and must be assumed to be in all organs.

terminal infection

an acute infection occurring near the end of a disease and often causing death.

transmissible infection

an infection capable of being transmitted from one animal to another. Called also contagious.

waterborne infection

infection by microorganisms transmitted in water.

---

infection control

Medtalk A hospital department that identifes infections occurring in the facility, which is also responsible for instituting safeguards to prevent the transmission of infections