| Antibacterial Products May
Fuel Growth of Superbugs
SAN DIEGO (Reuters
Health) - New study findings
add to growing concerns that widespread use of products containing
the antibacterial agent triclosan may be promoting the growth
of dangerous superbugs.
Triclosan is found in a variety of soaps, household cleaners, toothpastes,
baby toys, sponges and other products.
But questions have emerged
as to whether these products are doing more harm than good.
In the latest research,
Stanford University investigators conducted laboratory studies
involving triclosan and a variety of strains of the E. coli bacterium.
They found that some E. coli strains that were resistant to triclosan
became increasingly hardy over time.
"The results from the
experiment indicate that constant exposure to triclosan can cause
bacteria to tolerate it better and become more and more resistant,"
said study author Clara Davis, a PhD student.
"This increased level
of resistance can also be accompanied by an increased (bacterial)
growth rate," said Davis, whose findings were released here Saturday
at a meeting of the American Society for Microbiology.
This latter finding is
unusual, she said, because bacteria that develop resistance to
an antibiotic or other antibacterial agent generally grow more
slowly than bacteria that are sensitive to the agent, she explained.
From a public-health standpoint, this is beneficial because when
the antibacterial agent is not present, the drug-sensitive strain
may grow to dominate the drug-resistant strain.
But the new research
suggests that E. coli bacteria that are resistant to triclosan
may continue to persist, even thrive, whether triclosan is present
The results raise questions
of how well triclosan may continue to work in the future, Davis
"Just as the antibiotics
used to treat infections do not always work due to bacterial resistance,
our results imply that resistance (to triclosan) could arise in
a bacterial population and persist," she said.
Studies are needed to
understand how these laboratory findings apply to a home environment
where triclosan products are used, Davis added.
One industry representative
agreed that bacterial resistance to triclosan in the lab may not
reflect that occurring in the home.
"Although a few laboratory
studies have found evidence of bacterial resistance under very
specific experimental conditions, review of the available information
leads to the conclusion that triclosan does not induce nor selects
for resistance against antibiotics used for the therapy of human
diseases under actual use or "real-life" conditions," according
to Keith A. Hostetler, a spokesperson from Ciba Specialty Chemicals,
a manufacturer of triclosan.
Reference Source 89