Hola Montse,
Las Borrelias tienen una peculiaridad respecto al resto de Bacterias y es que no necesitan hierro para su supervivencia como el resto de los mortales, pueden pasar sin él, así que su suplementación no te va a perjudicar como ocurriría en el resto de infecciones.
Además, según los investigadores que lo descubrieron, un exceso de hierro es extremadamente tóxico para las Borrelias, si esto es así entonces puede que lo que hayas notado sea en realidad un Herx.
Saludos,
Miguel
Friday, May 26, 2000
WRITER: Phil Williams, 706/542-8501, pwilliam@...
CONTACT: Frank Gherardini, 706/542-4112, frankg@...
JUST-PUBLISHED RESEARCH SHOWS FOR THE FIRST TIME THAT LYME DISEASE BACTERIUM
DOES NOT REQUIRE IRON TO INFECT HOST
ATHENS, Ga.--New research from scientists at the University of Georgia, just
published in the journal Science, demonstrates that Borrelia burgdorferi, the
bacterium that causes Lyme disease in humans, is the first pathogenic bacterium
identified that does not need or use iron.
"All bacterial pathogens described to date have developed specialized systems
to acquire iron from their hosts,"said microbiologist Frank Gherardini.
"Current dogma states that to be successful in humans, bacteria must overcome
strict iron limitations that the human body imparts on them. Although iron is
abundant in humans, the amount of free iron is well below the levels required
to support the growth of most bacteria. To our surprise, we found that B.
burgdorferi doesn't even require iron. In fact, iron is extremely toxic to it."
Understanding how these bacteria are able to successfully colonize humans and
cause disease will ultimately lead researchers to more effective ways to
prevent and control the disorder.
Some 30 years ago, doctors were puzzled by a large number of arthritis cases in
children who lived in and near Lyme, Conn. After exhaustive study, they
discovered that the disorder, which has symptoms that vary in kind and
severity, was caused by a bacterium transferred to humans from the bite of the
deer tick, Ixoides scapularis. Since then, there have been major efforts to
understand the bacterium and its life-cycle, and Gherardini's lab has been
involved for a number of years, publishing many papers on the subject.
Gherardini's graduate student James E. Posey was co-author on the paper
published today in Science.
Borrelia burgdorferi is a spiral-shaped organism called a spirochete. Some
scientists believe that Lyme disease came from Europe a century ago but was
only recently detectable when it became more common. A resurgent deer
population-along with mice, the reservoir host for the bacterium, coupled with
increased outdoor activities by humans, has helped insure increased occurrence
and spread of the disease.
The first symptom of Lyme disease is usually a red rash that often resembles a
bull's eye. This rash, which can be small or cover a person's entire back,
appears within a few weeks of a tick bite when the spirochete is introduced
into the human host. The infection spreads to different parts of the body and
is often accompanied by such symptoms as fatigue, body aches, headache, fever
and a stiff neck. Treatment with antibiotics in early stages of the disease is
effective in most cases.
The Lyme disease microbe is extremely difficult to isolate or culture, so most
doctors look for evidence of the rash at the site of the tick bite or
antibodies to B. burgdorferi in the blood. Despite available tests and
therapies, many cases go undiagnosed for months. Humans with late-stage Lyme
disease are largely out of luck, and doctors can only treat the symptoms.
Though people don't die from Lyme disease, the attendant joint discomfort and
other symptoms can create ongoing misery. That's why laboratories are still
working hard to understand the ways in which Borrelia infects and survives in
its hosts.
Until recently, Gherardini said, standard wisdom held that all bacterial
pathogens require iron. The new finding probably doesn't indicate that Borrelia
evolved, though natural selection, a life-cycle designed not to need iron. On
the other hand, natural selection pressure on the entire genome clearly made it
possible for Borrelia to exist without iron, though why remains unclear.
The studies in Gherardini's lab were helped immeasurably by the fact that the
genome for Borrelia burgdorferi has been completed, so scientists know the
location of the bug's genes on its chromosomes-and what these genes do.
The proof the researchers needed came slowly and painstakingly. First, they
showed that the activities of several common iron-dependent enzymes were
undetectable in cell extracts. Second, they found no iron-containing proteins
in the bacterium during an analysis of the complete genome sequence. Third, B.
burgdorferi grew normally in the presence of high levels of iron-limiting
compounds, and fourth, the bacterium doesn't appear to alter gene expression in
response to iron-limiting conditions. Finally, by using mass spectroscopy and
radioactive iron transport techniques, they found that the levels of iron
inside the cells of B. burgdorferi are 1,000-fold less than those measured in
other pathogenic bacteria.
"Uptake experiments using iron suggest that B. burgdorferi does not transport
iron and there are less than five atoms of iron per cell," said Gherardini. To
date, Lactobacillus planatarum, a free-living soil bacterium, is the only other
organism for which experimental data demonstrate that iron is not required for
growth. Apparently, B. burgdorferi belongs to a unique category of pathogenic
bacteria that use a novel strategy to overcome iron limitation in the human
host.
Just how this new discovery can be used in developing either new vaccines or
new therapies for those infected with Lyme disease is not yet clear. While a
vestigal iron pathway may still exist in Borrelia burgdorferi, simply adding
iron to a diet or as a medical therapy would do little good. Still, because
other metals such as manganese are used by the bacterium, the discovery of how
iron is unneeded by the bug could point toward an entirely new way to limit the
occurrence and severity of the disease in humans.
"The ultimate goal of the bacterium is not to wipe out the host," says
Gherardini. "It's just to find another place to live. This should tell use a
lot about how they do that."
The good news is that probably far less than 1 percent of all ticks are
infected with B. burgdorferi, though in some areas, more than half harbor the
microbe. Gherardini said anecdotal evidence is that in Georgia, few, if any,
strains of B. burgdorferi have been isolated from ticks.
If you discover a tick on your body, pull it out gently with tweezers, being
careful not to squeeze the tick's body, then apply an antiseptic to the bite.
Studies by National Institutes for Health-supported scientists indicate that a
tick must be attached to its host for many hours to transmit the Lyme disease
bacterium.
WRITER: Phil Williams, 706/542-8501, pwilliam@...
CONTACT: Frank Gherardini, 706/542-4112, frankg@...
JUST-PUBLISHED RESEARCH SHOWS FOR THE FIRST TIME THAT LYME DISEASE BACTERIUM
DOES NOT REQUIRE IRON TO INFECT HOST
ATHENS, Ga.--New research from scientists at the University of Georgia, just
published in the journal Science, demonstrates that Borrelia burgdorferi, the
bacterium that causes Lyme disease in humans, is the first pathogenic bacterium
identified that does not need or use iron.
"All bacterial pathogens described to date have developed specialized systems
to acquire iron from their hosts,"said microbiologist Frank Gherardini.
"Current dogma states that to be successful in humans, bacteria must overcome
strict iron limitations that the human body imparts on them. Although iron is
abundant in humans, the amount of free iron is well below the levels required
to support the growth of most bacteria. To our surprise, we found that B.
burgdorferi doesn't even require iron. In fact, iron is extremely toxic to it."
Understanding how these bacteria are able to successfully colonize humans and
cause disease will ultimately lead researchers to more effective ways to
prevent and control the disorder.
Some 30 years ago, doctors were puzzled by a large number of arthritis cases in
children who lived in and near Lyme, Conn. After exhaustive study, they
discovered that the disorder, which has symptoms that vary in kind and
severity, was caused by a bacterium transferred to humans from the bite of the
deer tick, Ixoides scapularis. Since then, there have been major efforts to
understand the bacterium and its life-cycle, and Gherardini's lab has been
involved for a number of years, publishing many papers on the subject.
Gherardini's graduate student James E. Posey was co-author on the paper
published today in Science.
Borrelia burgdorferi is a spiral-shaped organism called a spirochete. Some
scientists believe that Lyme disease came from Europe a century ago but was
only recently detectable when it became more common. A resurgent deer
population-along with mice, the reservoir host for the bacterium, coupled with
increased outdoor activities by humans, has helped insure increased occurrence
and spread of the disease.
The first symptom of Lyme disease is usually a red rash that often resembles a
bull's eye. This rash, which can be small or cover a person's entire back,
appears within a few weeks of a tick bite when the spirochete is introduced
into the human host. The infection spreads to different parts of the body and
is often accompanied by such symptoms as fatigue, body aches, headache, fever
and a stiff neck. Treatment with antibiotics in early stages of the disease is
effective in most cases.
The Lyme disease microbe is extremely difficult to isolate or culture, so most
doctors look for evidence of the rash at the site of the tick bite or
antibodies to B. burgdorferi in the blood. Despite available tests and
therapies, many cases go undiagnosed for months. Humans with late-stage Lyme
disease are largely out of luck, and doctors can only treat the symptoms.
Though people don't die from Lyme disease, the attendant joint discomfort and
other symptoms can create ongoing misery. That's why laboratories are still
working hard to understand the ways in which Borrelia infects and survives in
its hosts.
Until recently, Gherardini said, standard wisdom held that all bacterial
pathogens require iron. The new finding probably doesn't indicate that Borrelia
evolved, though natural selection, a life-cycle designed not to need iron. On
the other hand, natural selection pressure on the entire genome clearly made it
possible for Borrelia to exist without iron, though why remains unclear.
The studies in Gherardini's lab were helped immeasurably by the fact that the
genome for Borrelia burgdorferi has been completed, so scientists know the
location of the bug's genes on its chromosomes-and what these genes do.
The proof the researchers needed came slowly and painstakingly. First, they
showed that the activities of several common iron-dependent enzymes were
undetectable in cell extracts. Second, they found no iron-containing proteins
in the bacterium during an analysis of the complete genome sequence. Third, B.
burgdorferi grew normally in the presence of high levels of iron-limiting
compounds, and fourth, the bacterium doesn't appear to alter gene expression in
response to iron-limiting conditions. Finally, by using mass spectroscopy and
radioactive iron transport techniques, they found that the levels of iron
inside the cells of B. burgdorferi are 1,000-fold less than those measured in
other pathogenic bacteria.
"Uptake experiments using iron suggest that B. burgdorferi does not transport
iron and there are less than five atoms of iron per cell," said Gherardini. To
date, Lactobacillus planatarum, a free-living soil bacterium, is the only other
organism for which experimental data demonstrate that iron is not required for
growth. Apparently, B. burgdorferi belongs to a unique category of pathogenic
bacteria that use a novel strategy to overcome iron limitation in the human
host.
Just how this new discovery can be used in developing either new vaccines or
new therapies for those infected with Lyme disease is not yet clear. While a
vestigal iron pathway may still exist in Borrelia burgdorferi, simply adding
iron to a diet or as a medical therapy would do little good. Still, because
other metals such as manganese are used by the bacterium, the discovery of how
iron is unneeded by the bug could point toward an entirely new way to limit the
occurrence and severity of the disease in humans.
"The ultimate goal of the bacterium is not to wipe out the host," says
Gherardini. "It's just to find another place to live. This should tell use a
lot about how they do that."
The good news is that probably far less than 1 percent of all ticks are
infected with B. burgdorferi, though in some areas, more than half harbor the
microbe. Gherardini said anecdotal evidence is that in Georgia, few, if any,
strains of B. burgdorferi have been isolated from ticks.
If you discover a tick on your body, pull it out gently with tweezers, being
careful not to squeeze the tick's body, then apply an antiseptic to the bite.
Studies by National Institutes for Health-supported scientists indicate that a
tick must be attached to its host for many hours to transmit the Lyme disease
bacterium.
----- Original Message -----Sent: Friday, October 03, 2008 11:25 AMSubject: [Lyme-E] Perfusión de hierro
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