Sunday, April 10, 2011

Like horror flicks? Read this…

I used to worry about MRSA…then I started seeing multi-resistant Gram negative bacteria in the hospital, like the carbapenem resistant (KPC) Acinetobacter I mentioned in my last post, usually infecting nursing home or chronic ventilator patients. That pales in comparison to the impending wave of infections caused by bacteria carrying the NDM-1 gene. NDM-1 stands for New Delhi Mettalo-beta-lactamase, an enzyme that chews up the “beta-lactam” ring, which is the backbone of many antibiotics, rendering them useless. NDM-1 was first described in a patient from India in 2008. Last year, a cluster of cases was described in 180 patient isolates. A common denominator was that most of the patients had received medical care in India or Pakistan.

As I’m preparing to go to India with a group of students next month who want to study public health, I was particularly struck by this week’s unsurprising news that the NDM-1 carrying bacteria had been identified in Delhi tap water and in standing water in the city—I said unsurprising, having seen some of the lack of sanitation first-hand.

What makes NDM-1 scarier than other recent superbugs is its ability to transfer its genetic material more readily. Part is because the transmission occurs via plasmids, small extra-chromosomal bits of DNA. Another part is that the transmission between bacteria can occur at water temperature, facilitating the spread in sewage-contaminated water. India also has a high rate of people without access to good sanitation or clean water, diarrheal disease, and access to over-the-counter antibiotics, all of which serve as enhanced breeding grounds for transfer. Even worse, the NDM-1 resistance gene is able to transfer to common bacterial pathogens there, such as cholera, typhoid, and the ubiquitous E. coli.

On my first trip to India, as the train approached the station in Delhi, I was rather shocked to see men lined up along the river like this:

Now take a look at this graph of antibiotic drug development from IDSA, to commemorate World Health Day:

Scary, isn't it?

Until CA-MRSA (community acquired MRSA), superbugs were fairly predictably associated with ill people and healthcare associated infections.

But now, this NDM-1 has now been isolated throughout the environment in one of the world’s most densely populated cities...and will soon spread globally.

Add to that the way antibiotics are squandered, irresponsible detailing by pharma and misuse by agribusiness…and you understand the insomnia...

A minor hope—may the student’s trip remain academic, and not become an experiential study.

(photo from

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