The World Health Organization has made a list of the most dangerous antibiotic-resistant bacteria

National Institute of Allergy and Infectious Diseases (NIAID)

For the first time ever, the World Health Organization has drawn up a list of the highest priority needs for new antibiotics — marching orders, it hopes, for the pharmaceutical industry.

The list, which was released Monday, enumerates 12 bacterial threats, grouping them into three categories: critical, high, and medium.

"Antibiotic resistance is growing and we are running out of treatment options. If we leave it to market forces alone, the new antibiotics we most urgently need are not going to be developed in time," said Dr. Marie-Paule Kieny, the WHO's assistant director-general for health systems and innovation.

"The pipeline is practically dry."

Three bacteria were listed as critical:

• Acinetobacter baumannii bacteria that are resistant to important antibiotics called carbapenems. These are highly drug resistant bacteria that can cause a range of infections for hospitalized patients, including pneumonia, wound, or blood infections.

U.S. Centers for Disease Control and Prevention

• Pseudomonas aeruginosa, which are resistant to carbapenems. These bacteria can cause skin rashes and ear infectious in healthy people but also severe blood infections and pneumonia when contracted by sick people in the hospital.

• Enterobacteriaceae that are resistant to both carbepenems and another class of antibiotics, cephalosporins. This family of bacteria live in the human gut and includes bugs such as E. coli and Salmonella.

Notably missing from the list is the bacterium that causes tuberculosis. That was not included, Kieny said, because the need for new antibiotics to treat it has already been designated the highest priority.

Although mounting concerns about the worsening problem of antibiotic resistance have reinvigorated research efforts, producing new antibiotics is an expensive and challenging task.

The international team of experts who drew up the new list urged researchers and pharmaceutical companies to focus their efforts on a type of bacteria known as Gram negatives. (The terminology relates to how the bacteria respond to a stain — developed by Hans Christian Gram — used to make them easier to see under a microscope.)

Dr. Nicola Magrini, a scientist with the WHO's department of innovation, access and use of essential medicines, said pharmaceutical companies have recently spent more efforts trying to find antibiotics for Gram positive bacteria, perhaps because they are easier and less costly to develop.

Microscopic image of gram-negative Pseudomonas aeruginosa bacteria (pink-red rods) Credit: wikipedia

Gram negative bacteria typically live in the human gut, which means when they cause illness it can be serious bloodstream infections or urinary tract infections. Gram positive bacteria are generally found outside the body, on the skin or in the nostrils.

Kieny said the 12 bacteria featured on the priority list were chosen based on the level of drug resistance that already exists for each, the numbers of deaths they cause, the frequency with which people become infected with them outside of hospitals, and the burden these infections place on health care systems.

Paradoxically, though, she and colleagues from the WHO could not provide an estimate of the annual number of deaths attributable to antibiotic-resistant infections. The international disease code system does not currently include a code for antibiotic-resistant infections; it is being amended to include one.

The critical pathogens are ones that cause severe infections and high mortality in hospital patients, Kieny said. While they are not as common as other drug-resistant infections, they are costly in terms of health care resources needed to treat infected patients and in lives lost.

Six others were listed as high priority for new antibiotics. That grouping represents bacteria that cause a large number of infections in otherwise healthy people. Included there is the bacteria that causes gonorrhea, for which there are almost no remaining effective treatments.

Three other bacteria were listed as being of medium priority, because they are becoming increasingly resistant to available drugs. This group includes Streptococcus pneumoniae that is not susceptible to penicillin. This bacterium causes pneumonia, ear and sinus infections, as well as meningitis and blood infections.

The creation of the list was applauded by others working to combat the rise of antibiotic resistance.

"This priority pathogens list, developed with input from across our community, is important to steer research in the race against drug resistant infection — one of the greatest threats to modern health," said Tim Jinks, head of drug-resistant infections for the British medical charity Wellcome Trust.

"Within a generation, without new antibiotics, deaths from drug-resistant infection could reach 10 million a year. Without new medicines to treat deadly infection, lifesaving treatments like chemotherapy and organ transplant, and routine operations like caesareans and hip replacements, will be potentially fatal."

The full list is:

Priority 1: Critical

1. Acinetobacter baumannii, carbapenem-resistant

2. Pseudomonas aeruginosa, carbapenem-resistant

3. Enterobacteriaceae, carbapenem-resistant, ESBL-producing

Priority 2: High

4. Enterococcus faecium, vancomycin-resistant

5. Staphylococcus aureus, methicillin-resistant, vancomycin-intermediate and resistant

6. Helicobacter pylori, clarithromycin-resistant

7. Campylobacter spp., fluoroquinolone-resistant

8. Salmonellae, fluoroquinolone-resistant

9. Neisseria gonorrhoeae, cephalosporin-resistant, fluoroquinolone-resistant

Priority 3: Medium

10. Streptococcus pneumoniae, penicillin-non-susceptible

11. Haemophilus influenzae, ampicillin-resistant

12. Shigella spp., fluoroquinolone-resistant

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The above post is reprinted from materials provided by Businessinsider . Note: Materials may be edited for content and length.

Scientists have created new forms of life containing '' Artificial DNA'' This could be the beginning of a whole new life form.

Credit: Kateryna Kon

Scientists have engineered the first ever 'semi-synthetic' organisms, by breeding E. coli bacteria with an expanded, six-letter genetic code.

While every living thing on Earth is formed according to a DNA code made up of four bases (represented by the letters G, T, C and A), these modified E. coli carry an entirely new type of DNA, with two additional DNA bases, X and Y, nestled in their genetic code.

The team, led by Floyd Romesberg from the Scripps Research Institute in California, engineered synthetic nucleotides - molecules that serve as the building blocks of DNA and RNA - to create an additional base pair, and they’ve successfully inserted this into the E. coli’s genetic code.

Credit: samsunkenthaber

Now we have the world’s first semi-synthetic organism, with a genetic code made up of two natural base pairs and an additional 'alien' base pair, and Romesberg and his team suspect that this is just the beginning for this new form of life.

"With the virtually unrestricted ability to maintain increased information, the optimised semi-synthetic organism now provides a suitable platform  to create organisms with wholly unnatural attributes and traits not found elsewhere in nature," the researchers report.

"This semi-synthetic organism constitutes a stable form of semi-synthetic life, and lays the foundation for efforts to impart life with new forms and functions."

Back in 2014, the team announced that they had successfully engineered a synthetic DNA base pair - made from molecules referred to as X and Y - and it could be inserted into a living organism.


Since then, they’ve been working on getting their modified E. coli bacteria to not only take the synthetic base pair into their DNA code, but hold onto it for their entire lifespan.

Initially, the engineered bacteria were weak and sickly, and would die soon after they received their new base pair, because they couldn’t hold onto it as they divided.

Credit: Wonderwhizkids

"Your genome isn't just stable for a day," says Romesberg. "Your genome has to be stable for the scale of your lifetime. If the semisynthetic organism is going to really be an organism, it has to be able to stably maintain that information."

Over the next couple of years, the team devised three methods to engineer a new version of the E. coli bacteria that would hold onto their new base pair indefinitely, allowing them to live normal, healthy lives.

The first step was to build a better version of a tool called a nucleotide transporter, which transports pieces of the synthetic base pair into the bacteria’s DNA, and inserts it into the right place in the genetic code. 

"The transporter was used in the 2014 study, but it made the semisynthetic organism very sick," explains one of the team, Yorke Zhang.

Once they’d altered the transporter to be less toxic, the bacteria no longer had an adverse reaction to it.

Next, they changed the molecule they’d originally used to make the Y base, and found that it could be more easily recognised by enzymes in the bacteria that synthesise DNA molecules during DNA replication.

Finally, the team used the revolutionary gene-editing tool, CRISPR-Cas9 to engineer E. coli that don’t register the X and Y molecules as a foreign invader.

The researchers now report that the engineered E. coli are healthy, more autonomous, and able to store the increased information of the new synthetic base pair indefinitely.

"We've made this semisynthetic organism more life-like," said Romesberg.

If all of this is sounding slightly terrifying to you, there's been plenty of concern around the potential impact that this kind of technology could have.


Back in 2014, Jim Thomas of the ETC Group, a Canadian organisation that aims to address the socioeconomic and ecological issues surrounding new technologies, told the New York Times:

"The arrival of this unprecedented 'alien' life form could in time have far-reaching ethical, legal, and regulatory implications. While synthetic biologists invent new ways to monkey with the fundamentals of life, governments haven’t even been able to cobble together the basics of oversight, assessment or regulation for this surging field."

And that was when the bacteria were barely even functioning. 

But Romesberg says there's no need for concern just yet, because for one, the synthetic base pair is useless. It can't be read and processed into something of value by the bacteria - it's just a proof-of-concept that we can get a life form to take on 'alien' bases and keep them.

The next step would be to insert a base pair that is actually readable, and then the bacteria could really do something with it.

The other reason we don't need to be freaking out, says Romesberg, is that these molecules have not been designed to work at all in complex organisms, and seeing as they're like nothing found in nature, there's little chance that this could get wildly out of hand.

"[E]volution works by starting with something close, and then changing what it can do in small steps," Romesberg told Ian Sample at The Guardian.

"Our X and Y are unlike natural DNA, so nature has nothing close to start with. We have shown many times that when you do not provide X and Y, the cells die, every time."


Time will tell if he's right, but there's no question that the team is going to continue improving on the technique in the hopes of engineering bacteria that can produce new kinds of proteins that can be used in the medicines and materials of the future.


The research has been published in Proceedings of the National Academy of Sciences.


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The above post is reprinted from materials provided by Sciencealert . Note: Materials may be edited for content and length.