NDM-1 gene on the march: Europe losing battle against antibiotic-resistant superbugs.

[jose v]

NDM-1 gene on the march: Europe losing battle against antibiotic-resistant superbugs.
Antibiotic-resistant infections have reached unprecedented levels in Europe. They now outstrip current medical ability to fight them with existing drugs. Each year in the European Union, over 25,000 people die of bacterial infections which are able to outsmart even the newest antibiotics such as carbapenems.

The New Delhi (NDM-1) superbug has recently been found in UK patients. They brought the infection back with them from countries such as India and Pakistan, which they visited for cheap hospital-based medical treatment and cosmetic surgery.

NDM-1 (New Delhi metallo-beta-lactamase-1) is a gene carried by some bacteria. If a bacterial strain carries the NDM-1 gene in its DNA, it is resistant to nearly all antibiotics, including the antibiotics of last resort: carbapenems. Carbapenems are the most powerful antibiotics, used for many bacterial infections, such as E.coli and Klebsiella. The NDM-1 gene enables the bacterium to produce an enzyme which neutralises the activity of carbapenem antibiotics.

Bacteria with this new genetic resistance to antibiotics have contaminated Delhi's drinking water supply, meaning that millions of Indians there could be carriers. Between September and October 2010, a UK research team from Cardiff University, led by Timothy Walsh, collected 171 swabs of seepage water and 50 public tap water samples from sites within a 12km radius of central New Delhi. The NDM-1 gene was found in two of the 50 drinking-water samples and in 51 of the 171 seepage samples.

The NDM-1 gene was found to have spread to bacteria which cause dysentery and cholera. These pathogens can be easily passed from person to person via sewage-contaminated drinking water. The first case of a bacterial infection with NDM-1 resistance was identified in January 2008. So far, there have been around 70 cases of the infection recorded in the UK.

There are no current antibiotics to combat NDM-1. There is no research in the pipeline on drugs to combat NDM-1. A bacterium with the NDM-1 genome has the potential to be resistant to all current antibiotics, as well as to new antibiotics which may come onto the market in the near future. The NDM-1 DNA code can jump from one bacterial strain to another through horizontal gene transfer. IF NDM-1 jumps to an already antibiotic-resistant bacterium, there is a risk of dangerous infections which would spread rapidly from human-to-human. These infections might be untreatable.

At present, the only way to combat the spread of NDM-1 is through surveillance, prompt identification and isolation of infected patients, rigorous disinfecting of hospital equipment, and thorough hand-hygiene procedures in hospitals.

In the UK, in school Biology lessons, Year 10 pupils (14-15-year-olds) are taught about the work of the Hungarian obstetrician, Ignaz Philipp Semmelweis (1818–1865). When Semmelweis was a doctor in the mid-1850s, many women who gave birth in hospital died a few days later. They died from "Childbed Fever", but no-one knew what caused it. Semmelweiss realised that his medical students were going straight from dissecting a dead human body in the anatomy department to delivering a baby in the maternity ward without washing their hands.

Then a doctor of Semmelweis's acquaintance cut himself with a scalpel while dissecting a dead body. He died from symptoms which were identical to Childbed Fever. Semmelweis wondered if the fatal illness was caused by an infectious agent. He insisted that all his medical students wash their hands before delivering babies. They did, and immediately many fewer mothers died.

More about NDM-1 and carbapenem antibiotics here (07.04.11), here (12.08.10), here and here.