at an increased risk of acquiring health care associated
opportunistic infections. Trends in health care delivery
(e.g. early discharge of patients from acute care facilities)
also change the distribution of patient populations and
increase the number of immunocompromised patients in
The environment is often overlooked as a passive player
in hospital acquired infections owing to the emphasis laid
on other more risky modes of transmission. However, with
the ever-changing face of modern medicine disrupting the
existing environmental stability could open a Pandora’s
box of dangerous environmentally linked infections.
A couple of such cases observed in the recent years
(a) transmission of infections caused by Mycobacterium
tuberculosis, Varicella Zoster Virus (VZV), and Measles
facilitated by inappropriate air-handling systems in health
care facilities; (b) disease outbreaks caused by Aspergillus
species, Mucoraceae, and Penicillium species associated
with the absence of environmental controls during periods
of health care facility associated construction; (c) infections
and/or colonization of patients and staff with vancomycin
resistant. Enterococcus faecium [VRE] and Clostridium
care facilities; and (d) outbreaks of pseudoepidemics
aqueous solution in health care facilities.
In many instances, it is still difficult to decide on the
appropriate method of decontamination even after taking
into consideration the nature and risk involved. However,
it is useful to remember that the risk of transmitting
infection from a surface that has been thoroughly
cleaned and disinfected is very small. Thorough cleaning
removes potential bacterial nutrients (organic matter)
as well as a significant load of bacteria. Studies have
shown prior cleaning achieves approximately a 4-log
reduction of microorganisms. Disinfection achieves a
99.9% reduction if performed using the right disinfectant
as per the standardized procedure. Disinfection of hard
surfaces is performed by combination of a cleaning and
disinfecting agent. Thus, it can be seen that cleaning is an
essential prelude effective disinfection and one should not
underplay the importance of either of the processes.
Formal procedures for sterilization of instruments and
medical devices, liquids, and other materials used in
hospitals have developed over a century. The initiation
of infectious diseases and hence the need to use sterile
materials in surgery and other hospital related activities.
Although the concept of hospital infection control was in
its infancy, hospitals and medical-device industry began to
sterilize instruments and materials used to treat patients.
Earlier methods of sterilization used different forms
of heat such as dry heat, moist heat to sterilize medical
devices and instruments. The 50s marked the increased
use of heat sensitive devices and hence the need for low
temperature sterilization methods or liquid chemical
Sterilization and disinfection are two terms, which are
often used interchangeably. However, sterilization is a
more absolute term, which implies complete elimination
or destruction of all forms of microbial life. Disinfection on
the other hand describes a process that eliminates many
or all pathogenic microorganisms, with the exception of
bacterial spores. The success of these processes is largely
dependent on the right method of choice, which often
became a difficult decision for health care professionals.
In 1968, Dr EH Spaulding devised a rational classification
scheme that could be used to decide whether a medical
instrument needs to be sterilized or disinfected. His
classification was extremely simple yet logical and has
been endorsed and adapted by the CDC, FDA and
numerous other reviewers and professional societies
today. The Spaulding classification revolved around the
central idea that medical devices or items need to be
categorized based on the risk of infection involved in their
of modern medicine endoscopes.
Endoscopes are notorious to nosocomial infections.
Reports of nosocomial infections related only to
endoscopes state a wide variety of infections transmitted
these infections ranged from asymptomatic colonization
to death. Major reasons for transmission are inadequate
cleaning and improper selection of a disinfectant. Very
often the fear of the dreaded blood borne infectious
disease like HIV and HBV results in overlooking the
more challenging microorganisms. It thus, becomes
helpful to know the resistance pattern of some frequently
Enveloped viruses Easy to kill
As more and more heat labile instruments enter the
medical arena, foolproof disinfection of these instruments
owing to their heat sensitivity and complex structures is a
challenge to health care professionals and manufactures
alike. Numerous disinfectants are available in the market;
glutaraldehyde continues to be the most commonly used
disinfectant owing to its effectiveness and broad range of
material compatibility. Other chemicals like per acetic acid,
hydrogen peroxide and more recently orthophthaldehyde
are also used for high-level disinfection or cold sterilization.
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