Antibiotics' efficiency wanes due to global spread
(2010-08-12 10:35:23)
标签:
nmd-1杂谈 |
分类: 生物技术 |
刘涛题记:我是做生物技术的基因检测,看到柳叶刀的这篇文章,我很震惊。其标题这么写的:耐药性细菌全球蔓延,抗生素效力渐失。我们以后怎么办,万一如SARS一样大流行,那是很恐怖的!以下是其英语全文:
The efficiency of antibiotics is
decreasing due to the spread of a bacterial gene conferring high
levels of drug resistance. Photograph: Murdo Macleod for the
Guardian
International travel and medical tourism have led to the rapid,
global spread of drug-resistant bacteria that may presage the end
of antibiotics and leave doctors struggling to treat infected
patients, scientists warn today.
A new gene conferring high levels of resistance to almost all
antibiotics has been found to be widespread in forms of gut
bacteria that can cause potentially life-threatening pneumonia and
urinary tract infections.
In just three years, says Professor Tim Walsh of Cardiff University
who discovered the gene, it has grown in prevalence from being
rarely observed at all to existing in between 1% and 3% in patients
with Enterobacteriaceae infections in India.
"It is absolutely staggering," said Walsh. "Because of
international travel, globalisation and medical tourism, [the gene]
now has the opportunity to go anywhere in the world very
quickly."
Walsh's paper on the spread of drug-resistant bacteria containing
the gene appears today in the Lancet infectious diseases
journal.
He and his colleagues have found NDM-1 (New Delhi
metallo-beta-lactamase) 1 positive bacteria not only in India and
Pakistan but also in the UK. Some of the infected British patients
had travelled to India for kidney or bone marrow transplants,
dialysis, pregnancy care or burns treatment, while others had
undergone cosmetic surgery.
Walsh says it is not possible to know how widespread the bacteria
now is in the UK. The Health Protection Agency has issued an alert,
but doctors report only those cases they treat.
Alarmingly, there are only two antibiotics that still work against
NDM 1-producing bacteria, and the likelihood is that they will also
be overcome before long.
"In many ways, this is it," he said. "This is potentially the end.
There are no antibiotics in the pipeline that have activity against
NDM 1-producing Enterobacteriaceae."
Even if scientists started work immediately on discovering new
antibiotics against the threat, he added, there will be nothing
available soon.
"We have a bleak window of maybe 10 years, where we are going to
have to use the antibiotics we have very wisely, but also grapple
with the reality that we have nothing to treat these infections
with.
"It is the first time it has got to this stage with these type of
bacteria."
Walsh and his colleagues' work also shows that the NDM 1-producing
bacteria are widespread not only in hospitals but quite probably in
the wider community in India, where contamination of drinking water
allows gut-borne bugs to be transmitted easily. Drug-resistant
bacteria could also potentially be passed from one person to
another in the UK, he said.
Ten years ago, scientists believed the greatest threat from
drug-resistant infections involved what are known as Gram-positive
bacteria, which include the so-called superbug MRSA
(methicillin-resistant staphylococcus aureus).
But now, says the Lancet paper, clinical microbiologists
increasingly agree that multidrug-resistant Gram-negative bacteria,
which thrive in the gut, pose the greatest risk to public
health.
Not only is the genes' resistance to antibiotics growing more
rapidly, but there are fewer new drugs to fight them.
Walsh discovered the NDM 1 gene after investigating the case of a
patient in Sweden who was admitted to hospital in India infected
with Klebsiella pneumoniae and E. coli bacteria.
The gene made the bacteria resistant to the group of antibiotics
called carbapenems. The carbapenems are normally kept for
emergencies and used when bacteria is found to be resistant to more
commonly prescribed antibiotics.
The gene is carried on a plasmid, a small section of DNA that can
move from one bug to another, passing on drug-resistance as it
goes. These have, according to the paper, "an alarming potential to
spread and diversify among bacterial populations."
Walsh says: "The plasmids are highly promiscuous."
Given the likely worldwide spread of these multidrug-resistant
bacteria, the paper says: "It is disturbing … to read calls in the
popular press for UK patients to opt for corrective surgery in
India with the aim of saving the NHS money.
"As our data shows, such a proposal might ultimately cost the NHS
substantially more than the short-term saving and we strongly
advise against such proposals."
In a commentary in the journal, Johann Pitout from the University
of Calgary in Canada calls for patients who have received medical
treatment in India to be screened before they are admitted for care
back home. He warns that medical tourism, fuelling the spread,
could grow in India by 30% every year over the next five
years.