Scientists have used bacteria to kill antibiotic-resistant superbugs.


Living antibiotics.

I know you’ve already got a lot to worry about, what with the North Pole being 20 degrees hotter than it’s supposed to be, and the polar bear that went and crushed all our hearts this week, but don’t forget to feel concerned about the looming antibiotic resistance crisis sometimes.

If things keep going as they are, antibiotic-resistant superbugs are expected to kill 10 million people by 2050, and so far, we have no solution. But researchers have found that we could actually fight fire with fire – a predatory bacterium has been shown to kill antibiotic-resistant bugs.

 The bacterium in question is called Bdellovibrio bacteriovorus, and it’s known as a predatory bacterium, because it seeks out and consumes its own kind.

A team from Imperial College London and the University of Nottingham in the UK decided to pit it against an antibiotic-resistant strain of the human pathogen Shigella flexneri – a common cause of food poisoning.

Shigella bacteria are responsible for making 160 million people sick each year (diarrhoea is its speciality), and more than 1 million people die each year from infection, mostly because of contaminated food.

There is currently no vaccine to prevent Shigella infection, and in many cases, antibiotics will not help – most patients are told to just wait it out until the infection resolves itself in five to seven days.

It’s a formidable foe – but not for Bdellovibrio, it seems.

When the researchers combined the two types of bacteria in the lab, Bdellovibrio caused the population of antibiotic-resistant Shigella to decline 4,000-fold.

Next they infected live zebrafish larvae with Shigella, and gave them a shot of Bdellovibrio. Rates of survival for the larvae were around 60 percent.

For the control group that didn’t get a shot of Bdellovibrio, only 25 percent of them lived long enough to reach the third day of infection.

The bacteria are so effective because they eat the Shigella bacteria from the inside out, growing large and swollen before bursting out of their dead host’s shell.

So far, the researchers have found no evidence of unwanted side effects from infecting the larvae with Bdellovibrio, and the same could be true for us, James Gallagher reports for the BBC, because previous research has found Bdellovibrio bacteria occurring naturally in healthy humans.

“This study really shows what a unique and interesting bacterium Bdellovibrio is, as it presents this amazing natural synergy with the immune system and persists just long enough to kill prey bacteria before being naturally cleared,” says one of the team, Serge Mostowy from Imperial College London.

While the introduced population of Bdellovibrio appeared to give the zebrafish larvae some level of protection even if they’d had their immune system compromised as part of the experiment, the researchers say the strongest response seems to come from the predatory bacteria working in tandem with the host’s own white blood cells.

“The predatory action of the Bdellovibrio breaks the Shigella-pathogen cells, and this stimulates the white blood cells; redoubling their ‘efforts’ against the pathogen and leading to increased survival of the zebrafish ‘patients’,” says one of the researchers, Liz Sockett from the University of Nottingham.

Of course, zebrafish aren’t humans, and humans aren’t zebrafish, so until similar results are demonstrated in humans, we can’t get too excited. But the researchers say this is a promising sign that the answer to the antibiotic resistance crisis could be the very thing we’re trying to fight.

“It may be unusual to use a bacterium to get rid of another, but in the light of the looming threat from drug resistant infections the potential of beneficial bacteria-animal interactions should not be overlooked,” Michael Chew from the Wellcome Trust in the UK, who wasn’t involved in the research, said in a press statement.

“We are increasingly relying on last line antibiotics, and this innovative study demonstrates how predatory bacteria could be an important additional tool to drugs in the fight against resistance.”

Just Add Sperm: Breakthrough Could Let Us Make Babies Without an Egg


IN BRIEF

New research into the possibility of “egg-less” fertilization in mammals has shown promise, with scientists being able to grow mice from modified embryos — a feat previously believed to be possible only for some vertebrate species.

INTRODUCING THE MAMMALIAN PARTHENOGENOTE

The first mammals were just produced without a fertilized egg; however, before you get too overly excited, neither were they produced with just the sperm. Instead, researchers from the University of Bath used a substitute for the fertilized egg — a modified, inactive mouse embryo or a parthenogenote.

Essentially, the parthenogenetic embryo is an egg that was “tricked” into becoming an embryo without prior fertilization. It’s not the first time this was done. Previous attempts, however, led to the embryo dying after just a few days.

The Bath researchers managed to keep the parthenogenetic embryo alive by bathing mouse egg cells with a salt called strontium chloride (SrCl2). It’s a chemical compound that prevents parthenogenetic embryos from going into a state of arrest, as previously discovered.

 

Credits: Toru Suzuki et al., 2016/Nature Communications
The process. Fertilizing the parthenogenetic embryo.
Toru Suzuki et al., 2016/Nature Communications

Basically, the team took mouse eggs, and they used chemicals in order to trick them into developing.

“[F]or the egg to be ‘tricked’ into initiating parthenogenetic development, one has to remove the activity that keeps it arrested in the meiotic cell cycle, and that, in effect, is what the SrCl2 does,” Tony Perry, lead researcher, explained to Gizmodo.

The resulting parthenogenote was injected with mouse sperm nuclei, initiating fertilization, and then the researchers worked on planting these into surrogates.

The work has been published in Nature Communications.

CHALLENGING CONVENTIONS

The parthenogenetic mice were able to grow normally and even reproduce, having regularly conceived baby mice of their own. The researchers are not quite sure of how the sperm genome was reprogrammed in these cases, which is an area for further studies.

Credits: Toru Suzuki et al., 2016/Nature Communications
The modified mice and their offspring.

While there is no evidence that suggests that the same thing can apply to human embryos (yet), the researchers believe that is very likely. To that end, it will take some years of study, but it ultimately means that, one day, men and women may become capable of self-fertilization. We could also use these methods to save species that are on the brink of extinction.

It would certainly challenge long-held conventions, including the conclusion that all mammals develop from eggs, a notion introduced in 1827 by biologist Karl Ernst Ritter von Baer and held until today.

For now, the researchers look to applying their study for treating infertility and other reproductive issues.

Parents can meet unborn children for first time in 3D virtual reality


Virtual reality images of the baby at 26 weeks after combining ultrasound and MRI scans
Virtual reality images of the baby at 26 weeks after combining ultrasound and MRI scans 

Seeing a baby in the womb for the first time on an ultrasound is a magical moment for most parents.

But a groundbreaking new scanning technology is allowing mothers and fathers to meet their unborn children in three dimensional virtual reality for the very first time.

The technique works by merging ultrasound imagery with magnetic resonance imaging (MRI), which scans segments of the womb and foetus to build a 3D model which can be brought to life by using a virtual reality headset.

Not only does it give the best ever view of a baby in the womb, but it can also help doctors pick up problems early, because it maps the entire internal structure of the foetus – not just the outside – meaning specialists can see how vital organs are developing.

British experts said it could also help parents bond with their children earlier. It is even possible to 3D print a model of the baby.

“We believe that these images will bring a new experience for parents when following the development of their unborn child,” said study co-author Dr Heron Werner Jr. from the Clínica de Diagnóstico por Imagem, in Rio de Janeiro, Brazil.

“The 3D foetal models combined with virtual reality immersive technologies may improve our understanding of anatomical characteristics and can be used for educational purposes and as a method for parents to visualize their unborn baby.”

MRI scanning is usually only used by doctors when an ultrasound fails to provide images of sufficiently high quality to check the development of the baby. But this is the first time the two techniques have been combined.

The models have been shown to be remarkably similar to the postnatal appearance of the newborn baby and they can helps doctors predict difficulties when the baby is born such as problems in the airways.

It is crucial that the airways are open and unblocked before birth, and so if doctors spotted an abnormal mass in the respiratory tract, they could make preparations for surgery to clear the obstruction as soon the baby was born.

A 3-D virtual model ultrasound view of fetus at 12 weeks
A 3-D virtual model ultrasound view of fetus at 12 weeks

The researchers say it will also help parents to understand malformations and make earlier treatment decisions.

The 3D  images are brought to life using Oculus Rift headsets which also play the sound of the baby’s heartbeat. Parents are able to look around their unborn child in virtual reality by moving their head.

“The experience with the Oculus Rift has been wonderful,” Dr. Werner said. “It provides fetal images that are sharper and clearer than ultrasound and MRI images viewed on a traditional display.

“And the physicians can have access to an immersive experience on the clinical case that they are working on, having the whole internal structure of the foetus in 3D in order to better visualise and share the morphological information.”

So far the technique has only been trialled at one clinic in Rio de Janeiro, where it was shown to pick up internal abnormalities which required immediated post-natal surgery. But the team is now hoping to roll it out worldwide.

A virtual reality image of the baby at 26 weeks after combining ultrasound and MRI scans 
A virtual reality image of the baby at 26 weeks after combining ultrasound and MRI scans 

Prof Simon Fishel, the founder and president of Care Fertility, Britain’s largest fertility group said: “Anything that improves the opportunity to observe foetal health accurately is important, especially with advancing surgical technology that is now being used successfully on the fetus in the womb , where applicable.

“Also for many there is great advantage of bonding early on.”

Prof Charles Kingsland, of the Hewitt Fertility Centre in Liverpool, added: “This clearly is an exciting piece of work with potential benefits for diagnosing more accurately, abnormalities in unborn babies with the added potential of correcting them  earlier.

“The pictures of the unborn babies for the excited parents could also be a great asset for those who want to see their unborn babies in a way that has never been done before.

I’m sure this technique, however will be very expensive until it has been refined.”