Infectious diseases such as tuberculosis, mucormycosis (a flesh-eating fungal infection), AIDS are mostly caused by pathogens including bacteria, fungi and viruses. Worldwide, infectious disease, maternal, neonatal and nutrition conditions collectively were responsible for 23% or 12.88 million global deaths in 2012 according to WHO . Health care-associated infections, or HAIs, are infections that patients acquire while they are receiving treatment for another condition in a healthcare setting. HAIs can be acquired anywhere healthcare is delivered, including inpatient acute care hospitals, outpatient settings such as ambulatory surgical centers and end-stage renal disease facilities, and long-term care facilities such as nursing homes and rehabilitation centers .
Based on the CDC’s healthcare-associated infection (HAI) prevalence survey released in March 2014 , on any given day, about 1 in 25 hospital patients has at least one healthcare-associated infection. There were an estimated 722,000 HAIs in U.S acute care hospitals alone in 2011. About 75,000 hospital patients with HAIs died during their hospitalizations. More than half of all HAIs occurred outside of the intensive care unit.
The culprits range from 20~400 nm for viruses, from 0.5~10 µm for bacteria and from 5~50 µm for most fungi. They are all beyond our normal eye vision that is usually about 100 µm. Even we do not see them, they are all around us. Clinical relevant pathogens such as Methicillin-resistant Staphylococcus aureus (MRSA), Mycobacterium tuberculosis, Pseudomonas aeruginosa, C.diff and Klebsiella and many more have been isolated from environmental surfaces. The duration of persistence can range from days to months even not in spore forms . Further, more published peer-reviewed clinical evidence has proved that environmental contamination plays an important role in the transmission of some key HAI pathogens [5-7].
Besides various environmental surfaces in the hospital can serve as a point source leading HAIs, reusable medical devices such as surgical instruments and endoscopes can also harbor pathogens and be responsible for HAIs. Surgical site infections (SSI) account for about 22% HAIs in the US . In the US, about 57.1 million outpatient surgeries and 51.4 million inpatient surgeries per year according to data from CDC [8,9]. The American Society for Gastrointestinal Endoscopy (ASGE) reports that 14.2 million colonoscopies, 2.8 million flexible sigmoidoscopies, and nearly as many upper endoscopies are performed in the U.S. each year. Due to lack of effective surveillance and difficulties in differentiating endogenous and exogenous infections, the true rate of endoscope related transmission and HAIs may go unrecognized .
Disinfection is the process of eradicating pathogens on the environmental surfaces, reusable medical devices and other inanimate objects. It can be accomplished by using chemical or physical agents. Increasing clinical evidences have shown proper disinfection able to disrupt the transmission pathways, which is further linked to reduced HAIs . Those evidence based infection prevention studies warrants the importance of proper disinfection of environmental surfaces and reusable medical devices in hospitals.
 Axel Kramer, et. al. How long do nosocomial pathogens persist on inanimate surfaces? A systematic review. BMC Infectious Diseases. 2006, 6: 130
 Boyce JM. Environmental contamination makes an important contribution to hospital infection. J Hosp Infect 2007; 65 (suppl 2):50–54.
 Weber DJ, Rutala WA, Miller MB, et al. Role of hospital surfaces in the transmission of emerging healthcare-associated pathogens: norovirus, Clostridium difficile, and Acinetobacter species. Am J Infect Control 2010; 38:S25–S33.
 Otter JA, Yezli S, Salkeld JAG, French GL. Evidence that contaminated surfaces contribute to the transmission of hospital pathogens and an overview of strategies to address contaminated surfaces in hospital settings. Am J Infect Control 2013; 41 (suppl 5):S6–S11.
 Julia Kovalevaa, Frans T. M. Petersb,Henny C. van der Meic and John E. Degenera. Transmission of Infection by Flexible Gastrointestinal Endoscopy and Bronchoscopy. Clin. Microbiol. Rev. 2013; 26: 231-254.
 Curtis J Donskey. Does improving surface cleaning and disinfection reduce health care-associated infections? American journal of infection control 2013; 41(5 Suppl):S12-9.