INTRODUCTION
Antiseptics
are chemical agents of disinfection that are mild enough to be used on human
skin or tissues. They are crucial in the prevention of wound infections,
colonization of medical devices as well as nosocomial and community
transmission of microorganisms (Cairncross, 2000).
Because
of these crucial roles, they are expected to be of optimal efficacy an absence
of which normally results in substantial infectious morbidity, mortality and
increased health care cost (Boyce, 2002).
For
antiseptics to function optimally however, several factors have to be taken
into consideration. One major factor is the concentration of the antiseptic. It
is known that there is an exponential relationship between potency and
concentration of an antimicrobial agent (Gorman, 2004). This means that the
more concentrated an agent, the greater its efficacy, and the shorter the time
necessary to destroy the microorganisms. Because of the possibility of
toxicity, however, the concentration of antiseptics must be strictly
controlled. Concentration exponent is the numerical value that relates
concentration to the antimicrobial effectiveness of an antimicrobial agent.
There are various classes of antiseptics and agents which constitute members of
these classes have similar concentration exponents. Thus, peroxides have values
of 0.5 to 1.0, aldehydes, 1.0, quaternary ammonium compounds, 0.8 to 2.5,
phenolic compounds, 4 to 10.0 and aliphatic alcohols, 6.0 to 12.7. Other
classes include: acids and their esters, alcohols, biguanides, halogens, heavy
metals, surface active agents, quinoline and isoquinoline derivatives and dyes
(Gorman, 2004). Antiseptics that are examples of each of these classes normally
constitute the active ingredients, either singly or in multiple, in the
antiseptics available under various trade names all over the world. The study
will in this regard examine the production of antiseptic.
Antiseptics
and disinfectants are used extensively in hospitals and other health care
settings for a variety of topical and hard-surface applications. in particular,
they are an essential part of infection control practices and aid in the
prevention of nosocomial infections (Gorman, 2004). Mounting concerns over the
potential for microbial contamination and infection risks in the food and
general consumer markets have also led to increased use of antiseptics and
disinfectants by the general public. A wide variety of active chemical agents
(or "biocides") are found in these products, many of which have been
used for hundreds of years for antisepsis, disinfection, and preservation (Gorman,
2004). Despite this, less is known about the mode of action of these active
agents than about antibiotics. In general, biocides have a broader spectrum of
activity than antibiotics, and, while antibiotics tend to have specific
intracellular targets, biocides may have multiple targets. The widespread use
of antiseptic and disinfectant products has prompted some speculation on the
development of microbial resistance, in particular cross- resistance to
antibiotics. This review considers what is known about the mode of action of,
and mechanisms of microbial resistance to, antiseptics and disinfectants and
attempts, wher¬ever possible, to relate current knowledge to the clinical
envi¬ronment.
A
summary of the various types of biocides used in antisep¬tics and
disinfectants, their chemical structures, and their clin¬ical uses is shown in
Table 1. It is important to note that many of these biocides may be used singly
or in combination in a variety of products which vary considerably in activity
against microorganisms. Antimicrobial activity can be influenced by many
factors such as formulation effects, presence of an or¬ganic load, synergy,
temperature, dilution, and test method. These issues are beyond the scope of
this review and are discussed elsewhere (l23, 425, 444, 446, 451).
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