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Showing posts with label NDM-1. Show all posts
Showing posts with label NDM-1. Show all posts

14 September 2010

Gone. (Again.) And it's really exciting. (And some NDM-1, too.)

Constant readers, cast your minds back to early summer, when SUPERBUG briefly bugged out of here to Scienceblogs. Scienceblogs was a great community, but not quite the right fit, and so I ended up happily back here, doing my own thing, and you very kindly followed me. And it's been an exciting few months back here, with lots of news on NDM-1 (look here for the archive), and flu and C. diff and HAIs.

And now, some real news. SUPERBUG is moving again. And this is going to be great.

I'm thrilled to be one of seven launch bloggers in a new network set up at Wired.com: Wired Science. It's an amazing, diverse group, high-performance and hyper-cool: Frontal Cortex, Neuron Culture, Laelaps, Dot Physics, Clastic Detritus, Genetic Future, and me. I'm beyond flattered to be among them.

Our launch announcement is here. My new page is here. (The complete addy, which may change in a few weeks after a tweak, but keep it for now:
/wiredscience/superbug/)

My inaugural post is the latest news, from the ICAAC meeting, on NDM-1.

We're having some issues with the archives, so I'll be leaving this site up as a resource. But I'd love to see you there as well as here. Please come check us out. And thank you, so much, for your loyalty, interest and attention over these years.

20 August 2010

NDM-1: The World Health Organization warns governments

The World Health Organization released a statement this afternoon, prompted by news of the NDM-1 multi-resistance gene. It's worth taking a look: The agency recommends that countries around the world pay serious attention to the emergence of this resistance factor.

WHO calls for  broad action within countries, from hospital infection-control and antibiotic-stewardship programs, to increased surveillance for the emergence of resistance, to legislative control of over-the-counter sales. Those sound like (and are) minimal and rational suggestions — but they have the potential to be quite controversial in some countries, from India where OTC antibiotic purchases are a major economic sector, to the US where best practices for hospital control of resistant organisms continue to be, umm, vociferously debated.

The WHO says:
Those called upon to be alert to the problem of antimicrobial resistance and take appropriate action include consumers, prescribers and dispensers, veterinarians, managers of hospitals and diagnostic laboratories, patients and visitors to healthcare facilities, as well as national governments, the pharmaceutical industry, professional societies, and international agencies.
WHO strongly recommends that governments focus control and prevention efforts in four main areas:
  • surveillance for antimicrobial resistance;
  • rational antibiotic use, including education of healthcare workers and the public in the appropriate use of antibiotics;
  • introducing or enforcing legislation related to stopping the selling of antibiotics without prescription; and
  • strict adherence to infection prevention and control measures, including the use of hand-washing measures, particularly in healthcare facilities.

The WHO has been working on antibiotic resistance for a while now, though the effort seems to be continually obscured by urgent news of outbreaks such as SARS, H5N1, H1N1 and so on. Here's their short fact sheet, detailed program page,  and Global Strategy for Containment of Antibiotic Resistance (sadly 9 years old, so it predates the emergence of community MRSA, not to mention NDM-1).

18 August 2010

NDM-1: The early warnings

Sorry to drop out of sight, constant readers; a little medical emergency at Casa Superbug, but all better now. There are some new developments regarding the novel resistance factor NDM-1, which renders Gram-negative bacteria resistant to almost all antibiotics:
  • Germany has announced its first identifications — plural, apparently. (Bloomberg News)
  • Vietnam says it has also recorded its presence.  (Thanh Nien Daily, h/t H5N1)
  • And France says that it will begin testing for the gene's presence in bacteria carried by patients being admitted to hospitals, in hopes of keeping the plasmid from transferring to other bacterial species and creating a wider resistance problem. (Agence France Presse) This is a reasonable fear; it is analogous to the process by which MRSA became vancomycin-resistant (VRSA), by acquiring the gene for vancomycin resistance from VRE, vancomycin-resistant Enterococcus. But there's much more to be said about what it will take for a hospital to keep this bug from entering or spreading; more on that in a future post.
Before we  get too much further from the initial news, I want to go back over the history of NDM-1's discovery — because, as with so many superbugs that take the public by surprise (recall the furor when the CDC's estimate of 19,000 MRSA deaths a year was published in late 2007), it turns out that there have actually been alarm bells ringing on this for a while. Largely, of course, unheard.

The first finding was in an older man of South Asian origin, living in Sweden, who went back to India in 2007, was hospitalized in New Delhi as a result of longstanding health problems, returned to his new home, was hospitalized there also in January 2008, and was discovered there to be carrying this resistance factor. The first public description of his case was made in October 2008, during a poster session at the annual ICAAC meeting (Interscience Conference on Antimicrobial Agents and Chemotherapy). That was later expanded to a journal article that was published in Antimicrobial Agents and Chemotherapy in December 2009; the full text is online in PubMed Central.

In the interim, though, the UK's Health Protection Agency published its first alert, in July 2009, describing 19 patients carrying this resistance  in 2008 and the first half of 2009, 9 of whom had received medical care in South Asia:
One UK patient, who developed a bloodstream infection with an E. coli that produced NDM-1 enzyme had received treatment for a haematological malignancy in both India and the UK; two others had undergone cosmetic surgery in India and one of these presented to a UK hospital with a wound infection that grew a mixed microbial flora including K. pneumoniae with NDM-1 enzyme; others had received renal or liver transplantation in Pakistan.
Meanwhile, other researchers in Europe were becoming alert to the threat that NDM-1 posed if it were to spread widely; English researchers warned of it in September 2009, and Scandinavian researchers did the same in November 2009.

And in June 2010, the CDC published its first report and warning of NDM-1 in patients in the US, noting that all three, who lived in different states, had received medical care in India.

But what's important to note is that,  despite the surprise and indignation coming from South Asia after the publication of last week's Lancet Infectious Diseases papers (article, editorial) describing the spread of NDM-1, the existence of that resistance factor has been discussed in Indian medicine since sometime last year.

From August to November 2009. a team of physicians at the Hinduja National Hospital and Medical Research Centre in Mumbai surveyed their ICU patients, and found 22 isolates carrying NDM-1. Their paper was submitted very quickly, in December 2009, and published in March 2010 in the Journal of the Association of Physicians of India:
We sought to identify NDM-1 positive strains among the carbapenem resistant Enterobacteriaceae isolates at our tertiary care centre. In a short span of 3 months, we identified 22 such organisms. The physicians at our institute follow the hospital antibiotic policy and do not indiscriminately use carbapenems. However being a tertiary centre we receive transfer in cases / referrals from other hospitals... The identification of NDM-1 in 22 of 24 isolates is a worrisome development indeed. NDM-1 being present among Enterobacteriaceae has the potential for further dissemination in the community. Such dissemination may endanger patients undergoing major treatment at centres in India and this may have adverse implications for medical tourism. Besides stringent infection control in hospitals, good sanitation in the community is also needed to contain the spread of such clones. (Deshpande et al., JAPI 2010)
News of their finding must have percolated through Indian medicine, because in January 2010 — before their paper was published — a worried letter discussing NDM-1, by a South Asian scientist working at the Royal Infirmary of Edinburgh, was published in the Indian Journal of Medical Microbiology:
The virtual nonexistence of antibiotic policies and guidelines in India to help doctors make rational choices with regard to antibiotic treatment is a major driver of the emergence and spread of multidrug resistance in India. This is augmented by the unethical and irresponsible marketing practices of the pharmaceutical industry, and encouraged by the silence and apathy of the regulating authorities. Poor microbiology services in most parts of the country add to the problem. (Krishna, IJMM 2010, DOI: 10.4103/0255-0857.66477)
 And in March 2010, Dr. K. Abdul Ghafur of the Apollo Hospital in Chennai published a passionate and despairing call to arms ("An obituary — on the death of antibiotics!") alongside the Mumbai team's findings. The full text is online and it is worth reading in its entirety:
Our country, India, is the world leader in antibiotic resistance, in no other country antibiotics been misused to such an extent. Microbes are the ultimate warriors. They have sophisticated weapons and use ingenious methods of attacks. They have always been many steps ahead of us. Even in the twenty first century with all the developments in the modern medicine, when we face microbes, we feel helpless. Whatever weapons we had in the form of antibiotics, we ourselves have ruined them. Indian medical community has to be ashamed of the NDM-1 (“New Delhi Metallo-1”) gene. Even though we have not contributed to carbapenem development, we have contributed a resistance gene with a glamorous name. The overuse of antibiotics is embedded in our Indian gene. It is an Indian tradition. (Ghafur, JAPI 2010)
That Ghafur's plea went unheard is all the more striking — because for almost a decade, Indian researchers had been reporting, in their own journals, a steady and troubling expansion of carbapenem resistance in Indian hospitals. More on that when I post next.

13 August 2010

More on NDM-1

One of the frustrations of being a working journalist and a blogger is that, when a big blog-story breaks, you're likely already to be working on something else. And so it is, unfortunately, with NDM-1: I'm on a magazine assignment and will be off interviewing people when I should be blogging.

(This s a great time to recommend that, for any breaking infectious disease news, you follow Crof at H5N1 (@crof) and Michael Coston at Avian Flu Diary (@Fla_Medic), who are dedicated, thoughtful, nimble and smart.)

Since I last posted, there's been lots of additional coverage of the "Indian superbug." Much of it, blog and media, is just echo chamber cannibalizing of the earliest reports (including but certainly not only mine), but there are some important new developments worth noting, which I'll list below.

There are also some important points that are getting lost in the echo-chamber bounce: First, it is not correct to say that every person who acquired this was seeking cheap medical care or engaged in medical tourism; a few of them were treated on an emergency basis while traveling, and a few have no apparent healthcare tie. So this is not a situation of people seeking to save money and, as some commenters seem to be suggesting, receiving their karmic payback. (C'mon: Seriously?) Second, it is also not correct to say that every case of this has been linked to a hospital — it's quite clear in the Lancet ID paper that in South Asia, a number of the cases were community infections. So it is not just a case of hospitals that are dirty or have poor infection control (which by the way is a problem in the US as well, right?); NDM-1 is already a community bug, which will make detection and defense much more complex.

OK, curated list:

First, if you're interested in more from me, CNBC asked me to write up a piece about NDM-1, which ran Thursday; and Friday morning I was on the WNYC-FM (and nationally syndicated) radio show The Takeaway.

Second, the list of potential victims of NDM-1 is growing. Most of them have survived, so marking their cases is really a way of measuring the resistance factor's previously undetected spread:

The UK has released a new statement, updating its earlier warning, and says it has found "around 50" cases carrying NDM-1, an update from the Lancet ID paper. (Side note: This statement, and the earlier warnings, came from the UK's Health Protection Agency. The UK has just announced that it will be shutting down that agency in a cost-cutting measure. Great timing.)

The government of Hong Kong has announced that it has seen one case of NDM-1, but the patient recovered.

Canada has disclosed that it has had two cases, not the one mentioned in the Lancet ID editorial, in two different provinces.

Australia says that it has had three cases scattered across the country.

Belgium has announced one death.

And finally — sadly but probably not surprisingly — India is objecting to the stigma of being characterized as the source of NDM-1. The study's first author has disassociated himself from the paper and members of the government are claiming a "pharma conspiracy." Medical tourism has become a significant industry in India, and it is true  some of these reports cast doubt on its safety. But still, I find this reaction disappointing.

Evading the stigma of an emerging disease is not a new impulse: Recall how the government of China suppressed for 6 months the news of the start of the SARS epidemic. They did not stop the epidemic, of course — it eventually sicked more than 8000 people across the globe and killed about 775 — but their suppression of the details of its spread kept other jurisdictions from mounting a defense in time. From my teaching gigs in Hong Kong I can testify how much bitterness endures in Hong Kong over this.

China's actions in 2002-03 led to the enactment of the new International Health Regulations by the WHO, which specify that, because expanding epidemics take no notice of borders, it is inappropriate for any government to attempt to impede the free flow of information about their spread. India is a signatory to the IHRs.

I am not suggesting that India is attempting any suppression of news about NDM-1 — there's no evidence of that — but the volatile language being used does concern me. I acknowledge that India is an extremely open society, with degrees of political expression that can sound surprising from this distance. But let's hope the government takes its commitment to the IHRs as seriously as any signatory should.

11 August 2010

NDM-1: Novel, global, complex and a serious threat

There's news today in the journal Lancet Infectious Diseases of the further spread of a troubling new resistance problem that I first talked about in June: Gram-negative bacteria carrying a novel resistance factor that has been dubbed New Delhi metallo-beta-lactamase, or NDM-1.

In writing about resistant bacteria, it's difficult to avoid overusing superlatives — but this resistance mechanism has spread widely, been transported globally, and brings common bacteria up to the brink of untreatable. It already has been found in India and Pakistan, Sweden, the Netherlands, Australia, Canada and the US, and has been distributed not just by travel but specifically by medical tourism. It has the potential to become an extremely serious global threat.

Necessary background: One major way that microbiologists classify bacteria is on the basis of the organisms' cell membranes; some have a single membrane, and others have two separated by fluid. The groups are identified by their response to a 4-step staining process, called Gram stain for the Danish physician who invented it in the 1880s. Cells that pick up the first stain applied, which is usually violet but sometimes blue, are single-walled; cells that resist the bath of the first stain, but pick up a lighter tint from another chemical in a later step, are double-walled. The single-membrane, dark-stained organisms are dubbed Gram-positive; the double-membrane organisms are known as Gram-negative.

Here's why that distinction is so important for understanding antibiotic resistance: Most of the drugs that kill or control bacteria act by attaching to or penetrating through cell membrane. The double membrane of the Gram-negatives presents a greater obstacle to drug-molecule interference than the single membrane of the Gram-positives — and thus makes developing drugs that can control Gram-negatives a more complex task. Hence, while there's abundant concern about the narrowing drug pipeline for Gram-positives including MRSA, there is even more alarm about the dearth of new drugs for Gram-negatives (as captured last year in this article from Clinical Infectious Diseases).

The novel resistance factor that is described today in Lancet ID appears only in Gram-negatives, primarily in E. coli and K. pneumoniae but also in other species. Bacteria that have acquired this mechanism are resistant to multiple classes of drugs commonly used against Gram-negatives: beta-lactams, fluoroquinolones, aminoglycosides, and most troublingly carbapenems, generally considered the drug class of last resort for those organisms. Several of the isolates found in the study were susceptible only to colistin, a drug that dates back to the 1960s and is considered toxic to the kidneys, and tigecycline, which was only licensed in the US in 2005. Several responded only to aztreonam. One was susceptible to nothing.

The real threat in today's news, though, is not only how resistant these organisms have become; it is also how they got that way, and how and by what means they are spreading.

As the Lancet ID paper reports, NDM-1 resides on a plasmid — a snippet of DNA, not on a chromosome, that reproduces on its own and can move freely between organisms. Intuitively, you would think that bacteria either inherit resistance from their progenitors or develop it on their own when they encounter a drug. Plasmids short-circuit both those processes, allowing resistance to spread rapidly within a single bacterial generation to organisms that have never experienced the drug they are acquiring defenses against. And as the paper testifies, NDM-1 has spread: The authors surveyed for NDM-1 in India, Pakistan and the UK, and found it both widely distributed in South Asia, and also present in UK residents who had family or business ties to South Asia, or had gone to the subcontinent for medical care. And unlike some resistant organisms, the bacteria carrying NDM-1 were not confined to the bug-friendly environment of hospitals or the the debilitated systems of hospital patients. Instead, it was out in the community, causing common illnesses such as urinary tract infections.

There are a couple of points embedded in that report that bear unpicking because they are so foreboding.

First, that this is happening in India, which not only harbors some of the world's largest manufacturers of generics, but also (and possibly synergistically) has some of the world's highest rates of antibiotic use. Some Indian researchers have been warning for years that the subcontinent is on the verge of a homebrewed crisis of drug resistance (Indian Journal of Bioscience, Indian Journal of Medical Microbiology, Indian Journal of Medical Ethics).

Second, that it is linked to medical care, and especially to medical tourism — which has become a booming international industry, not only for elective options such as cosmetic surgery, but because it offers an inexpensive way to perform major procedures that health systems might once have wanted to have done close to the patient's home. A study covered last January by The Independent in London recommended shipping UK patients to India for care, suggesting it could save the beleaguered health service more than $200 million.

And third, that these isolates were found in community infections caused by common organisms such as E. coli. That testifies not only to their wide distribution, but also to how difficult it might be to conduct surveillance for their presence — or, put another way, how easily they could evade detection while they continue to spread. It is not likely that physicians are going to culture every UTI that comes their way, either in the resource-poor developing world or in the overstressed conditions of Western medicine.

One example of the importance of surveillance: That's how NDM-1's first appearance in the United States was detected, via three isolates from three states that were tested at the CDC's national labs in the first half of this year. In a bulletin in June (the subject of my first post on NDM-1), the CDC urged clinicians to be alert for resistant infections in any patients who reported receiving medical care in India or Pakistan.

Unfortunately, given the drought of new drugs for Gram-negatives, surveillance may be the best bet for controlling or at least slowing NDM-1's further spread. It's the urgent recommendation of the author of a companion Lancet ID editorial, also published today (and who appears to have seen Canada's first case):
The spread of these multiresistant bacteria merits very close monitoring and worldwide, internationally funded, multicentre surveillance studies, especially in countries that actively promote medical tourism. Patients who have had medical procedures in India should be actively screened for multiresistant bacteria before they receive medical care in their home country. ...The consequences will be serious if family doctors have to treat infections caused by these multiresistant bacteria on a daily basis.

 Cites:
Kumarasamy KK, Toleman MA, Walsh TR et al. Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study. The Lancet Infectious Diseases, early online publication, 11 August 2010doi:10.1016/S1473-3099(10)70143-2
Pitout JDD, The latest threat in the war on antimicrobial resistance. The Lancet Infectious Diseases, early online publication, 11 August 2010. doi:10.1016/S1473-3099(10)70168-7

24 June 2010

News break: CDC alert on imported novel resistance

This is an addition for archival purposes of a post that originally appeared at Scienceblogs.

There's a troubling item in this afternoon's issue of the CDC's Morbidity and Mortality Weekly Report or MMWR: The first report in the United States of a novel resistance mechanism that renders gram-negative bacteria extremely drug-resistant and that has been linked to medical care carried out in India or Pakistan.

The short item describes three isolates (E. coli, Klebsiella pneumoniae and Enterobacter cloacaevideosgratis侏儒孕交 ) found in three patients in three states between January and June of this year. All three isolates produced New Delhi metallo-beta-lactamase (NDM-1), which has never been recorded in the US before. Because of that novel mechanism, the three isolates were resistant to the carbapenems usually used on the most serious gram-negative infections, in fact to all beta-lactam antibiotics (penicillins, cephalosporins, carbapenems, monobactams, etc.) except for one monobactam, aztreonam -- and they were also resistant to aztreonam through another mechanism that hasn't been identified yet. All three of the patients found carrying this novel resistance factor had undergone medical care in South Asia recently.

This may be the first finding of this mechanism in the US, but it's been causing alarm in Europe for at least two years.

The first identification of NDM-1 was in 2008, in a 59-year-old resident of Sweden who was of South Asian origin and had returned to India for several months. The man was not well -- he had long-standing type 2 diabetes and had experienced a number of strokes -- and while in India he was hospitalized for an abscess, underwent surgery, developed bedsores and was treated for them as well. He returned to Sweden and was hospitalized there in January 2008, where physicians found him to be suffering from a urinary tract infection caused by a Klebsiella strain carrying this never-seen resistance mechanism.

Last July, the UK's Health Protection Agency put out a national alert about NDM-1, warning that the novel mechanism had gone from never-seen in 2007, to 4 isolates in 2008, to 18 in the first half of 2009. They were not an outbreak, but represented repeated importations: The isolates were clonally diverse and had been collected at 17 different hospitals. They were, instead, a sign that long-standing two-way population movement between England and South Asia -- augmented by elective medical tourism (two patients had gone to India for cosmetic surgery) -- was bringing the high rates of antibiotic resistance in India back to a UK medical system that is already challenged by serious infection-control problems.

And now it's here. The special challenge of NDM-1 (which as today's finding suggests is on a mobile genetic element that has carried the resistance mechanism between species) is not only that it adds to an accumulating rogues' gallery of resistance factors that are rapidly making gram-negative bacteria ferociously drug-resistant, but also that there are so few drugs under development for gram-negatives that truly untreatable infections are not far off. The UK clearly is already struggling with attempting to use drugs that are old and toxic, untested against these organisms (and therefore with no agreed-upon dosing), or wrong for the organ systems affected:
Treatment presents major challenges. Most isolates with NDM-1 enzyme are resistant to all standard intravenous antibiotics for treatment of severe infections. Polymyxin is usually active in vitro ... but of uncertain clinical efficacy, especially in pneumonia, owing to poor lung penetration. Tigecycline is often active in vitro, but has low serum levels, is unsuitable for urinary infections and, more generally, is of unproven efficacy in severe infections.

The CDC's alert today asks any clinicians who come up against carbapenem-resistant gram-negatives to ask about contact with India or Pakistan as part of history-taking, and to forward isolates through state public health labs to the the CDC.

Update + fodder: I flipped over to my RSS reader and also discovered this paper posted overnight by Clinical Infectious Diseases, about extended-spectrum beta-lactamases in a particular strain of E. coli ("an important new public health threat"), and this one in Emerging Infectious Diseases, about carbapenem resistance moving between Klebsiella and E. coli.