The mysteries of infection have been unfolding since Koch, Pasteur, and other microbiologists uncovered the link between bacteria and infection in the late 19th century. Despite our increased understanding of infectious diseases and the advent of programs to survey, prevent, identify, and control them, more than 2 million nosocomial infections occur each year. They raise health care costs by about $4.5 billion, lengthen hospital stays, and lead directly or indirectly to about 25,000 patient deaths annually.
Not all nosocomial infections can be prevented. Immunocompromised patients and those receiving immunosuppressive therapy, for example, may succumb to nosocomial infection despite all precautions. However, studies have shown that about one-third of all nosocomial infections could be prevented every year by faithful adherence to infection control principles. This chapter contains detailed instructions for using these principles effectively.
Causes and incidence
Infections result from aerobic and anaerobic bacteria, viruses, parasites, and fungi. The most common nosocomial infections involve the urinary tract, surgical wounds, the lower respiratory tract, and blood.
Urinary tract infections commonly result from catheter insertion or urogenital surgery or instrumentation. Surgical wound infections result from contamination during surgery, skin damage from preoperative hair removal, impaired blood supply, or coexisting medical problems. Lower respiratory tract infections can result from aspiration of oropharyngeal secretions, contaminated ventilation equipment, lung seeding by blood-borne pathogens, or airborne pathogens from other patients or caregivers. Bacteremia may arise as a complication of other infections, such as pneumonia and surgical wound infections, or from the presence of an intravascular device such as a central venous line.
The risk of nosocomial infection rises with the patient's age, underlying medical condition, use of invasive devices, and duration of hospitalization.
Infection control programs
According to recommendations issued in 1958 by the Joint Commission on Accreditation of Hospitals (now the Joint Commission on Accreditation of Healthcare Organizations) and the American Hospital Association, every accredited health care facility must have an infection control committee and a surveillance system as part of a formal infection control program. As health care delivery systems have changed since 1958, so has the challenge of adapting infection control programs for the surveillance, prevention, and control of infection. An effective infection control program can reduce the incidence of nosocomial infections by about one-third.
To guide health care facilities in their infection control efforts, in 1970 the Centers for Disease Control (now the Centers for Disease Control and Prevention [CDC]) published a manual that detailed seven categories of isolation techniques. The recommendations were revised in 1983 to reduce unnecessary procedures; to adapt to the increased use of intensive care units, invasive procedures, and immunosuppressive treatments; and to counter the spread of drug-resistant pathogens. In 1985, the CDC introduced its universal precautions, which recommended that health care workers wear gloves and other personal protective equipment (such as a mask, goggles, and a gown) to reduce exposure to blood and body fluids implicated in the transmission of blood-borne infections. In 1987, a new approach to infection control, known as body substance isolation, called for health care workers to wear gloves for contact with mucous membranes and broken skin, and anticipated contact with any moist body substances.
The CDC determined, however, that health care workers were confused about some aspects of universal precautions and body substance isolation; thus, in 1996 the CDC again revised the terminology used in its recommendations by introducing standard precautions as the basic unit of isolation precautions. Standard precautions call for health care workers to wear personal protective equipment appropriate for the task being performed and the risk of exposure to or contact with any moist body substance, mucous membrane, or broken skin. Three other transmission-based categories of isolation precautions were added to standard precautions as necessary to prevent the transmission of infection among patients, health care workers, and visitors. These categories are airborne precautions, droplet precautions, and contact precautions.
In most health care facilities, infection control practitioners are responsible for coordinating surveillance and other infection control activities. Although specific responsibilities may vary among facilities, typical activities include:
  • teaching the staff the importance of correct hand hygiene between patient contacts (the most effective way to reduce infection risk)
  • assessing patients for infection and recommending proper precautions against cross-contamination
  • developing infection control guidelines, instructing the staff, and monitoring isolation procedures
  • assisting staff in implementing procedures and using products to reduce the risk of nosocomial infection
  • serving as a resource to the facility and the staff on the prevention and control of infection.
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Isolation as prevention
Most isolation procedures aim at preventing transmission of disease from infected patients to other patients, health care workers, and visitors. In contrast, isolation may also aim at protecting immunocompromised patients from exogenous pathogens. Many factors contribute to the development of nosocomial infections. Strict adherence to your facility's infection control policies and the procedures outlined in this chapter can go a long way toward keeping infection at bay.