• AIRBORNE TRANSMISSION
  The passage of microorganisms suspended in the air on water droplets or dust particles that enter the host by inhalation.
  
  
• ASEPSIS
  Freedom from infection or infectious material.

• BACTERIOSTATIC
  Arresting the growth or multiplication of bacteria. An antibiotic may be classified as a bacteriostatic medication.

• BODY SUBSTANCE ISOLATION
  A technique based upon the premise that all body substances may contain pathogens. Never touch with the bare hand anything wet that comes from the body or body cavity. Protective gloves must be worn at all times when there is contact with mucus membrane, nonintact skin, or body substances. Body substances include blood, urine, feces, saliva, wound drainage, or aspirated fluids.

• COLONIZATION
  The presence and multiplication of microorganisms without tissue invasion or damage. The infected individual demonstrates no signs or symptoms of infection, while the potential to infect others still exists.

• CONTACT TRANSMISSION
  The physical transfer of an organism between an infected or colonized person and a susceptible host involving direct or indirect contact. Indirect contact occurs when a patient comes in contact with equipment contaminated with infectious microorganisms. Direct contact occurs when an infected person transfers the organism directly to a susceptible host. If a nurse touches a patient's wound and pathogenic microorganisms come in contact with a cut on the nurse's hand, the nurse becomes infected through direct transmission.

• DROPLET TRANSMISSION
  Inhalation of respiratory pathogenic microorganisms suspended on liquid particles exhaled by someone already infected. For example, a patient suffering from an upper respiratory infection sneezes, allowing pathogenic microorganisms to exit the patient's body and be inhaled by another person within close proximity.
  
  
• INFECTIOUS AGENT
  A microbial organism with the ability to cause disease. The greater the organism's virulence (ability to grow and multiply), invasiveness (ability to enter tissue), and pathogenicity (ability to cause disease), the greater the possibility that the organism will cause an infection. Infectious agents are bacteria, viruses, fungi, and parasites.
  

• ISOLATION
  Techniques used to prevent or limit the spread of infection. Patients diagnosed with an infectious disease are placed on isolation to prevent the transmission of pathogens to others.
  
  
• INCUBATION
  The time between exposure to an infectious organism and the appearance of clinical systems of disease.
  

• MEDICAL ASEPSIS
  Techniques used to control and to reduce the spread of pathogenic microorganisms. A medical aseptic technique is hand washing.
  
  
• MODE OF TRANSMISSION
  Method of transfer by which the organism moves or is carried from one place to another. The hands of the health care worker may carry bacteria from one person to another.



• MRSA
  Methicillin-resistant staphylococcus aureus (MRSA) is a microbe that adapted to changes in the environment to compete for survival. Staphylococcus aureus, a common organism, developed resistance to medication. Patients infected with the resistant strain may remain infected or colonized for long periods. The main mode of transmission is via the hands of the health care worker. It is important to understand the appropriate method of protection and control when providing nursing care for someone infected with MRSA.

• NOSOCOMIAL INFECTION
  An infection acquired during hospitalization.

• PATHOGEN
  Any disease producing microorganism.

• PARTICULATE RESPIRATOR
  Mask-like apparatus that fits snugly over the nose and mouth of the health care worker and filters out organisms as small as one micron. It is worn to prevent contamination by airborne diseases such as tuberculosis.
  
  
• PORTAL OF ENTRY
  An opening allowing the microorganism to enter the host. Portals include body orifices, mucus membranes, or breaks in the skin. Portals also result from tubes placed in body cavities, such as urinary catheters, or from punctures produced by invasive procedures such as intravenous fluid replacement.
  
  
• PORTAL OF EXIT
  A place of exit providing a way for the microorganism to leave the reservoir. For example, the microorganism may leave the reservoir through the nose or mouth when someone sneezes or coughs. Microorganisms, carried away from the body by feces, may also leave the reservoir of an infected bowel.
  

• PROTECTIVE ISOLATION
  Individuals suffering from a weakened immune system and susceptible to microorganism invasion are isolated to avoid exposure.
  
  
• RESERVOIR
  A place where microorganisms can thrive and reproduce. For example, microorganisms thrive in human beings, animals, and inanimate objects, such as water, tabletops, and doorknobs.
  

• STANDARD PRECAUTIONS
  A synthesis of universal precautions and body substance isolation techniques designed to provide protection against the transmission of bloodborne and other infectious microorganisms. These techniques are applied to all individuals regardless of medical diagnosis.

• SURGICAL ASEPSIS
  Techniques used to destroy all pathogenic organisms before they can enter the body. One surgical aseptic technique is sterilization of surgical equipment. The principles of surgical asepsis apply when invasive procedures involve placing equipment or instruments inside the human body. The principles of surgical asepsis guide the nurse who inserts a foley catheter (a sterile tube inserted to allow urine to flow from the bladder) into the patient.
  
  
• SUSCEPTIBLE HOST
  A person who cannot resist a microorganism invading the body, multiplying, and resulting in infection. The host is susceptible to the disease, lacking immunity or physical resistance to overcome the invasion by the pathogenic microorganism.
  

• TRANSMISSION-BASED PRECAUTIONS
  Barrier or isolation techniques, based upon knowledge of the mode of transfer of an infectious organism, applied to control the spread of the organism. An example of a transmission based precaution is wearing protective gloves when handling body secretions infected with hepatitis B.

• UNIVERSAL PRECAUTIONS
  Techniques utilized with all patients, regardless of diagnosis, to protect against bloodborne pathogens such as HIV and hepatitis B. Universal precautions are applied to blood or any body fluid potentially contaminated with blood.

• VEHICLE TRANSMISSION
  The transfer of microorganisms by way of contaminated items. For example, blood can carry hepatitis and HIV.
  
  
  
• VRE
  Vancomycin resistant Enterococcus (VRE) is an organism that resists the effects of the antibiotic Vancomycin. For many patients infected with VRE, there is no known effective medication. VRE is one of the common causes of nosocomial infection and is easily transmitted on the hands of the health care worker.

Craven, R. & Hirnle, C. (2000). Fundamentals of Nursing (3rd ed.).  Philadelphia: Lippincott.

Miller, B. F. (1997). Miller-Keane Encyclopedia & Dictionary of Medicine, Nursing & Allied Health (6th ed.). Philadelphia: W.B. Saunders.