July 2, 2006 Hospital Acquired Infections Infections that are acquired after a patient is admitted to the hospital are known as nosocomial infections. Generally symptoms that develop 48 hours after admission are considered to be hospital-acquired infections. The most common types of infections are urinary tract infections, lower respiratory tract infections, infection at the surgical site and septicemia (infectious micro-organisms circulating in the bloodstream). Researchers estimate hospital acquired infections may occur in up to 9.9 percent of hospitalizations. The infections often prolong the hospital stay and increase the risk of death. Health care costs for treatment of hospital acquired infections are estimated to be about $4.5 billion/year. Taking Steps to Reduce the Risk of Infection Research shows that one of the most important methods for preventing hospital acquired infection is thorough hand washing. Hospitals also use several different methods of decontamination to remove infectious agents from equipment and the hospital environment. There are three main methods of decontamination. Cleaning is the removal of dirt from surfaces. The process removes a large number of micro-organisms (but not all) and the surface particles in which they live. It is the least costly and least effective method of decontamination. Disinfection is a process to decrease the numbers of micro-organisms to a level that reduces the risk of infection in at-risk patients (i.e. not all micro-organisms are destroyed). Heat is the preferred method of disinfection. However, equipment that is sensitive to high temperatures can be disinfected with chemicals. Sterilization is a method of decontamination that destroys all micro-organisms. Areas that have been sterilized are "free of germs". Sterilization can be performed with heat (autoclaving for example), radiation or chemicals. Ultraviolet Light for Decontamination Ultraviolet light is the bandwidth of sunlight that is beyond the spectrum of visible light. It is a shorter wavelength of light and contains more energy than visible light. Ultraviolet light is divided into three wavelengths. Ultraviolet A (UVA) is made of longer waves ranging from 315 nm to 400 nm. UVA passes through the earths atmosphere and is associated with suntan or sunburn. Ultraviolet B (UVB) is composed of medium waves of light from 280 to 315 nm. Some UVB light is blocked by the atmosphere. Ultraviolet C (UVC) is the shortest wavelength of light and ranges from 200 to 280 nm. UVC from sunlight is almost entirely filtered by the atmosphere and doesnt reach the earths surface. UVC light contains the highest level of energy in the ultraviolet light spectrum. When organisms are exposed to UVC, the light energy damages the cellular DNA, damaging the genetic material that allows the cell to reproduce. Eventually, the micro-organisms die off. Some scientists have developed special UVC light devices that can be used to decontaminate surfaces. Studies show UVC light can be effective in destroying/inactivating viruses and bacteria commonly found in hospitals (including strains of bacteria that are resistant to powerful antibiotics). Unlike other types of cleaning or decontamination, there is no need for filters, powerful (and potentially harmful) chemicals or special disposal systems. Several companies have developed UVC devices. A company called UV Solutions is developing devices that can disinfect stethoscopes or kill germs that may enter the body at a catheter site. Other potential uses of the technology include decontamination of drinking water and sanitization of baby products (like pacifiers and bottles) and personal care items (like toothbrushes). While manufacturers say the UVC systems are safe for patient use, there are some things to keep in mind. A report from the National Toxicology Program of the Department of Health and Human Services lists UVC as "reasonably anticipated to be a human carcinogen". Scientists say exposure to UVC damages cellular DNA (which is why it works against micro-organisms) and high doses are known to cause skin tumors in rats and mice. UVC light from a man-made device can cause skin irritation and eye damage in humans. Users are advised not to look directly at the light source. AUDIENCE INQUIRY For information about the UVC disinfection technology: http://www.uvs-ultraclean.com BIBLIOGRAPHY Banning, M., "Bacteria and the Gastrointestinal Tract," British Journal of Nursing, February 9-22, 2006, Vol. 15, No. 3, pp. 144-149. Bissett, L., "Reducing the Risk of Acquiring Antimicrobial-resistant Bacteria," British Journal of Nursing, January 26-February 8, 2006, Vol. 15, No. 2, pp. 68-71. 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