Long before the discovery of bacteria and the introduction
of antiseptic surgery, a variety of substances had been
used to prevent infections. Pasteur’s initiation of the
science of bacteriology was probably the foundation of the
development and use of skin antisepsis. Joseph Lister an
academic surgeon who was greatly influenced by Pasteur’s
works and bacteria causing infection causing infection
ventured into ‘antiseptic surgery’. His solution was to apply
some chemical substance ‘in such a manner that not
only would the microbes already present be destroyed,
but also the germ killing substance would act as a barrier
between the wound outside source of infection’. Lister hit
on the idea of using carbolic acid, which was first used on
compound fractures. Later, the method was refined by use
of different concentrations of carbolic acid and extended
to instruments, ligatures and even room air.
Among surgical patients, surgical side infections (SSIs)
were the most common nosocomial infection accounting
for 38% of all such infections. When surgical patients with
nosocomial SSI died, 77% of the deaths were reported to
be related to the infection, and the majority (93%) were
serious infections involving the organs or spaces accessed
during the surgery. Microbial contamination of the
surgical site is a necessary precursor of SSI. Quantitatively
it has been shown that if a surgical site is contaminated
microorganism per gram of tissue, the risk of
SSI is markedly increased. For most SSIs, the source of
pathogens is the endogenous flora of the patient’s skin,
mucous membranes or hollow viscera. When mucous
membranes or skin is incised, the exposed tissues are
at risk of contamination with endogenous flora. These
microorganisms are usually aerobic gram-positive cocci
(e.g. staphylococci) but may also include fecal flora (e.g.
anaerobic bacteria and gram-negative aerobes). The
flora may also change as per the site of the incision of the
type of organ exposed during surgery. An important SSI
prevention measure would include techniques directed
at reducing microbial flora by localized skin prepping
(at the surgical site). Before the skin preparation of a
patient is initiated, the skin should be free from gross
contamination (i.e. dirt, soil or any other debris). The
patient’s skin is prepared by applying an antiseptic in
concentric circles, beginning in the area of the proposed
incision. This procedure is a vital step in removing all
transient microorganisms and ensuring an extremely sub
minimal population of resident flora (Table 2.1).
Since the days of Lister, antiseptic development
has been in a state of flux. Despite this, SSIs remain a
substantial cause of morbidity and mortality among
hospitalized patients. Thus, to reduce the risk of SSI, a
systematic but realistic approach must be applied with the
awareness that this risk is influenced by characteristics of
the patient, operation, personnel and hospital.
The health care environment contains a diverse
population of microorganisms, but only a few are
environments, but some can also persist in dry conditions.
Although, pathogenic microorganisms can be detected
in air and water and on fomites, assessing their role in
causing infection and disease is difficult. The surface
and environment therefore would be considered
one of a number of potential reservoirs for the pathogen
but not the ‘de facto’ source of exposure. An understanding
of how infection occurs after exposure based on the
principles of the “chain of infection”, is important in
evaluating the contribution of the environment to health
Chain of infection components comprises of (a)
adequate number of pathogenic microorganisms,
(b) pathogenic microorganisms of sufficient virulence,
(c) a susceptible host, (d) an appropriate mode of
transmission or transferal of the microorganism in sufficient
numbers from the source to host, (e) the correct portal or
entry into the host. The presence of the susceptible host is
one of these components that underscore the importance
of healthcare environment and opportunistic pathogens
on fomites and in air and water. All of the components of
the ‘chain’ must be operational for the infection to occur.
A variety of airborne infections in susceptible hosts
reservoirs (i.e. soil, water, dust and decaying organic
TABLE 2.1: Summary of CDC recommendations
Management of infected/colonized surgical personnel (Anti
Cleaning and disinfection of environmental surfaces
Sterilization of surgical instruments
Asepsis and surgical technique
3. Postoperative incision care
Source: CDC guidelines for prevention of SSI, 1999.
indoors into a health care facility by any of a number of
vehicles (e.g. people, air currents, water, construction
materials and equipment), the attendant microorganisms
can proliferate in various indoor ecological niches and
if subsequently disbursed into the air, serve as a source
for airborne health care associated infections. It can be
observed that the infection cycle then is completed very
quickly resulting in extensive infections.
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