|
Arming a type of friendly bacteria
to do battle with cavity-promoting bacteria could offer a new way to prevent
tooth decay.
In experiments with cells and
rats, scientists found that a type of "good" bacteria called
lactobacillus could be genetically modified to produce an antibody that
kills off a particular cavity-causing bacterium and helps prevent dental
woes.
Lactobacillus bacteria have
long been used in food fermentation and are commonly found in items such
as yogurt. Some forms of the bacterium dwell normally in the human intestines.
Lactobacillus-laden foods and supplements -- commonly referred to as "probiotics"
-- have grown increasingly popular because they are believed to promote
good gastrointestinal health.
In addition, lactobacilli have
been proposed as "carriers" for oral vaccines.
In their study, rats were given
lactobacilli armed to produce antibodies against Streptococcus mutans,
a bacterium that lives in the human mouth and causes cavities by converting
sugar into enamel-eroding lactic acid. The rats were given the good bacteria
over 2 weeks, and the researchers found that the friendly bugs were still
in the animals' mouths 1 week after the final treatment.
Moreover, the treated rats
showed a sharp reduction in S. mutans in the mouth and developed far fewer
cavities compared with untreated animals.
The researchers conclude that
the effectiveness of the transformed lactobacilli, coupled with their
persistence in the rats' oral cavity, suggest a "viable approach"
to preventing or treating tooth decay in humans.
Nature
Biotechnology July 2002;20:702-706
| 