Triclosan et la résistance aux antibiotiques
6. Conclusions of the SCCS
- 6.1 Does triclosan pose a risk, and what are the current gaps in knowledge?
- 6.2 Is it still safe to use triclosan as a preservative in cosmetic products?
6.1 Does triclosan pose a risk, and what are the current gaps in knowledge?
Resistant bacteria can survive biocide concentrations that
would kill others.
The Scientific Committee on Consumer Safety (SCCS) concludes
that at present there are important scientific and technical
gaps in knowledge.
- Environmental studies to measure any
following the use of
- There are some studies that measure whether exposure
to relatively low
triclosan leads to
This research should be extended to a much wider range of
- There is evidence from laboratory samples that
triclosan could have a role in antibiotic resistance. To
determine whether or not these results have any relevance
for public health, full
studies are needed.
- Bacteria have the capacity to transfer
information from one another, and this can in theory lead to
the propagation of resistance or virulence. It is not known
at present if this process is affected by the presence of
- We need to have standard methods of measuring
- To assess the amount of
exposed to, we need information on the amount of triclosan
that is manufactured and used.
- Triclosan is widespread in the environment but we need
to know the actual values much more accurately. To determine
whether or not resistance will develop in the environment,
we also need to know in more detail which
come into contact with triclosan, how much of it they take
up and whether or not their
genetic make up is
such that resistance
genes could be activated and perhaps transferred to
- We need methods of measuring the minimum concentration
of triclosan that can lead to
- Laboratories need to use
than single bacterial
cells, to assess the efficacy of
biocides and there
need to be European standards of such tests for healthcare
There are several reasons why the use and release of
triclosan into the
environment could pose a risk:
- From a genetic
point of view, exposing
bacteria for short
periods of time to
are not high enough to kill them, makes bacteria secrete
substances involved in
genes in bacteria. Some of these
genes are also
involved in resistance to different drug families, can move
from one bacterium to
another and, in principle could be activated in bacteria
already present in soils.
- Triclosan, like any other
contributes to the selection of less susceptible bacteria,
because it eliminates competition since it wipes out those
bacteria that are more susceptible to it. However, the
impact of such a selection is unclear.
- Biofilms are
widespread in the environment and show increased resistance.
They have a tough exterior, a wide range of defence
mechanisms and the potential to exchange resistance genes
species of bacteria
that live together as part of a colony.
Triclosan is the most
studied biocide with
respect to bacterial
resistance. However, there is still not enough
information to do a full risk analysis. In particular, we need
to know the amount of triclosan that
bacteria are exposed to
in the environment, and how much of this they actually take up.
We cannot tell either how much each different type of product
contributes to the pool of triclosan found in the environment.
Other chemicals that can also affect
found together with triclosan so it is difficult to tease out
the effects of each biocide separately.
There are no
linking exposure to triclosan
in cosmetics or other
products, and outbreaks of
bacteria that are harmful
for humans or animals.
When used appropriately,
triclosan, have an
important role to play in disinfection, antisepsis and
preservation. Information on the expression/triggering of
resistance mechanisms should be considered to (re-)assess
the uses of triclosan in order to preserve its efficacy.
6.2 Is it still safe to use triclosan as a preservative in cosmetic products?
To date, there is no evidence that using
triclosan leads to an
increase in antibiotic
resistance. However it is
too early to say that triclosan exposure never leads to
One cannot ignore the hazards identified in laboratory studies
so it is important that industry continues investing in research
to understand better the role of
resistance. The research available was state-of-the-art
at the time it was done but modern tools are much more powerful
than these so there should be additional studies, particularly
on bacteria taken from
hospitals or the environment, rather than on isolated samples
grown in the laboratory.