Bacteria

Scientists have used bacteria to kill antibiotic-resistant superbugs

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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.”

The research has been published in Cell Biology.

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This entry was posted in Bacteria, Biotechnology.

New treatment based on ocean bacteria shown to stop the spread of prostate cancer

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Scientists just completed a trial of a new, non-surgical prostate cancer treatment that uses a tumour-killing drug based on ocean bacteria, and the procedure saw almost half the patients go into complete remission.

The treatment is known as vascular-targeted photodynamic therapy (VTP), and is made possible by a drug called WST11, which is derived from bacteria that live at the bottom of the ocean. These light-sensitive organisms convert photons into energy, and when the same trick is mimicked by WST11, the compound kills cancer cells.

In a broad clinical trial at 47 treatment sites across 10 different European countries, 49 percent of patients with early prostate cancer that were treated with VTP went into complete remission, compared with 13.5 percent in the control group.

“These results are excellent news for men with early localised prostate cancer, offering a treatment that can kill cancer without removing or destroying the prostate,” says lead researcher Mark Emberton from University College London.

“This is truly a huge leap forward for prostate cancer treatment, which has previously lagged decades behind other solid cancers such as breast cancer.”

Men diagnosed with early or low-risk prostate cancer are usually monitored via regular testing to make sure the cancer isn’t spreading.

But if it does begin to spread, patients face a dilemma, as traditional treatments such as surgery or radiation therapy can cause lifelong erectile problems and incontinence.

For these reasons, a non-surgical treatment that doesn’t come with such negative side effects has long been a goal of researchers, and VTP with WST11 could be it.

In the study, the procedure only caused short-term urinary and erectile problems, which had resolved within three months, and all other side effects disappeared within two years.

“This changes everything,” Emberton told James Gallagher at the BBC.

“Traditionally the decision to have treatment has always been a balance of benefits and harms. … To have a new treatment now that we can administer, to men who are eligible, that is virtually free of those side effects, is truly transformative.”

The treatment involves injecting WST11 into the bloodstream, and inserting optical fibres into the prostate gland.

When the optical fibres are turned on, light beams activate the drug in the patient’s blood, causing it to release high-energy free radicals that destroy tumour tissue while leaving surrounding tissue unharmed.

Of the individuals who took part in the trial, cancer progressed in 58 percent of men in the control group, who maintained regular monitoring during the study. But for the men who received VTP, only 28 percent saw tumours spread.

According to Emberton, these results would be even stronger today, as the researchers in the trial didn’t have access to the latest MRI technology when they began their study in 2011.

“We can now pinpoint prostate cancers using MRI scans and targeted biopsies, allowing a much more targeted approach to diagnosis and treatment,” Emberton said in a press release.

“This means we could accurately identify men who would benefit from VTP and deliver treatment more precisely to the tumour. With such an approach, we should be able to achieve a significantly higher remission rate than in the trial and send nearly all low-risk localised prostate cancers into remission.”

There’s also scope to extend the procedure to other cancers, including breast and liver cancer, but first the researchers need to continue monitoring the patients who took part in this trial and see if the remission rates hold up over time.

Meanwhile, the European Medicines Agency (EMA) is currently reviewing the treatment, but it could be years before it’s made available to patients in the broader population.

It’s important to note that there’s still a lot we don’t know about this treatment, and despite its early promise, it’s not necessarily more effective than surgery or radiation therapy at removing the danger of cancer.

That said, it also doesn’t seem to offer the same kinds of complications, so depending on how further research pans out, it could be a valid avenue of treatment in the future.

One man who hopes the wait isn’t too long is Gerald Capon, a 68-year-old from West Sussex in the UK, who took part in the study.

“[T]he trial changed my life. I’m now cancer-free with no side effects and don’t have to worry about needing surgery in future,” he says.

“I feel so lucky to be in this position… I hope that other patients will be able to benefit from this treatment in future.”

The findings are reported in The Lancet Oncology.

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This entry was posted in Bacteria, Cancer.

Scientists discover how the brain helps the body fight bacteria

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The brain may not only control our thoughts and basic physical functions.

Recent studies indicate that it also controls the way our body responds to the threat of bacterial infections. It does this by boosting the production of a protective molecule called PCTR1 that helps white blood cells kill the invading bacteria.

Our body is in constant contact with bacteria. For the most part these do not pose a threat since we have evolved defence systems to keep these organisms at bay.

But in some instances, especially when the body’s defence systems are weakened or fail, bacteria may invade, leading to infection and, in extreme cases, sepsis, which can result in death.

In the 1920s, a breakthrough discovery was made: the identification of the antibiotic properties of penicillin. The discovery paved the way to a new era in infection treatment.

With antibiotics, we no longer had to rely on our body to get rid of bacteria. Instead, we could give it a helping hand by stunting the ability of bacteria to replicate, thus giving our immune system enough time to clear them.

Penicillin was the first in a long list of antibiotics developed to tackle different types of bacterial infections.

However, over the last few decades, the ability of antibiotics to stop bacterial growth has become considerably limited and increasing numbers of bacterial strains are becoming resistant to antibiotic treatment.

The threat of antibiotics resistance has prompted the scientific community to seek alternative ways to deal with bacterial infections.

A very important molecule

To identify novel avenues to treat bacterial infections we turned our focus to the central nervous system (the brain, spinal cord and optic nerves), as several studies have implicated the brain in orchestrating more than just our thoughts.

In our study we found that severing the right vagus nerve in mice, for example, leads to a significant impairment in their ability to clear E. coli infections.

When we investigated the reason for this delay, we found a significant decrease in the levels of a molecule called “protectin conjugate in tissue regeneration 1”, or PCTR1 for short.

PCTR1 is part of a group of molecules called specialised pro-resolving mediators that control how our body responds to inflammation. It is produced by white blood cells from a fish oil-derived essential fatty acid called docosahexaenoic acid.

We also found that the decrease in PCTR1 reduced the ability of macrophages – a type of white blood cell – to kill E. coli.

We then investigated how the vagus nerve regulates PCTR1 production in the abdominal cavity of the mice, where this nerve is known to regulate white blood cell behaviour during inflammation.

Here we found that the nerve releases a neurotransmitter called acetylcholine which then instructs another type of immune cell (innate lymphoid cells) to increase production of PCTR1. This in turn regulated macrophages’ ability to find and kill bacteria.

When we injected the mice with the severed vagus nerve with PCTR1, we found that it restored the ability of peritoneal macrophages to get rid of the bacteria as well as dampen the subsequent inflammatory response, accelerating the bacteria’s termination.

These results are expected to have wide-ranging implications in the fight against bacterial infections, especially in light of the alarming rate at which bacteria are becoming resistant to antibiotics.

This is because these findings demonstrate that we can give our body a hand by using PCTR1, and related molecules, to enhance its ability to clear bacteria during infections, reducing our reliance on antibiotics.

Jesmond Dalli, Senior Lecturer, Queen Mary University of London.

This article was originally published by The Conversation. Read the original article.

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This entry was posted in Bacteria, Health, immunity.