Preventing Vaginal Yeast Infections

Do Antibiotics Really Wipe Out Your Gut Bacteria?

Antibiotics are a staple of modern medicine and save millions of lives every year. But they can be harming the normal bacterial system our health relies on.

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Our bodies host trillions of bacteria that we can't live without – with the highest density in our guts. But are we permanently damaging this crucial part of our body every time we take antibiotics?

"The gut microbiome is a complex network of microbiotic lifeforms and all the things they need to sustain themselves in the niche of the body," says James Kinross, a consultant colorectal surgeon at Imperial College London.

The gut microbiome plays a huge role in maintaining our health, including regulating the immune system and aiding digestion. And experts argue that antibiotics are one of the biggest threats to our gut microbiomes.

Antibiotics, commonly prescribed to treat and prevent bacterial infections, are a cornerstone of modern medicine. But in the process of targeting the infection-causing bacteria in our bodies, antibiotics can also inadvertently wipe out the other bacteria in our bodies.

There are growing concerns among scientists about the health implications of our increasing reliance on antibiotics; between 2000 and 2015, global prescriptions of antibiotics increased by 65%. The problem with this rising use of antibiotics is two-fold: the damage caused to our gut microbiomes, and growing bacterial resistance towards antibiotics.

Antibiotics have become a cornerstone of modern medicine, but there are increasing concerns around overuse (Credit: Getty Images)

"Antibiotics disrupt the intricate ecosystem of our gut microbiome, and, in doing so, put the surviving bacteria at greater risk of donating their resistant genes over to pathogens," says Gautam Dantas, professor of laboratory and genomic medicine at Washington University's School of Medicine in St Louis in the US.

We know that the more diverse our gut bacteria population is, the better. But every course of antibiotics disrupts this population because antibiotics aren't targeted enough to only kill the pathogenic bacteria causing the infection. Instead, they go after all bacteria in our guts.

"There's collateral impact," says Dantas. "Think of a forest where you're trying to get rid of one weed infection; the way we deploy antibiotics is to carpet-bomb the forest, killing the good and the bad."

When scientists have looked retrospectively at the microbiomes of people who have had an infection followed by a course of antibiotics, they've found that microbiome diversity largely recovers within a few months, Dantas says. But in some people, some good bacteria never show up again, he adds.

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Dantas and his team of researchers have studied faecal samples collected from children treated at the paediatric hospital connected to his laboratory. These samples were collected routinely, before any infections and antibiotics, which allowed his team to see the changes in children who get an infection and are given antibiotics later on.  

Dantas has used these samples to compare changes to the gut microbiome after antibiotics in two groups of infants – pre-term babies, who are born before 36 weeks, and term infants, born after 36 weeks.

"What we know happens in adults after antibiotics happens more dramatically in babies: a lower diversity of the microbiome, and huge spikes in drug-resistant genes," he says.

While the effects differ from person to person, and depend on our age, the consensus among scientists is that the effects of one course of antibiotics can be permanent.

"Some people are very susceptible to damage in [their] microbiome from antibiotics, and their ecology of their microbiome will change dramatically and never return to what it was before the antibiotic dose," Kinross says.

"We're losing diversity in our guts and crucial microbes that have sustained us for hundreds of thousands of years [are being lost] on an unprecedented time scale."

But scientists are still trying to work out the long-term health consequences of antibiotic use on our gut microbiomes.

Pathogenic bacteria may pick up resistance from benign bacteria which survive a antibiotic treatment (Credit: Getty Images)

"We know that antibiotics have the capacity to affect every single domain of microbiome function." Kinross says. "They don't just lead to a depletion in the number of bacteria, but they also effect the function of microbes in complex, individualised ways that we don't understand well."

It's not just the impact on the gut bacteria that is causing concern, but also secondary consequences on the development of the immune system, Kinross adds.

Studies show that taking recurrent doses of antibiotics has a cumulative effect, and the impact is also greater if you take a take a more broad-spectrum dose. This is often referred to as the "multiple hit hypothesis".

"Those random extension events, every now and again, will hit a critical bug," says Dantas. "This is the weird evolutionary experiment we're running on ourselves every time we take an antibiotic."

The other consequence of long-term antibiotic use is the risk of resistance. When a population of bacteria is exposed to an antibiotic, those that lack the genes for antibiotic resistance tend to die off. But ones which do have them – either genes they have picked up from their environment, or mutations that have arisen spontaneously – will survive. In this way, the drugs actively select for bugs that are antibiotic-resistant. This becomes a problem when pathogenic bacteria reap the rewards of this adaptation.

"Every time we deploy antibiotics, it increases the proportional risk of the gut microbiome being enriched for drug-resistant genes, so that next time the pathogen comes around, it might be able to pick up some of these selective resistant genes from the gut," Dantas says.

And this process isn't confined to our guts, says Craig MacLean, professor of evolution and microbiology at the University of Oxford. "Resistant bacteria can migrate from the gut to other areas, so what happens in the gut has an impact on the rest of our body," he says.

Scientists say the indiscriminate use of antibiotics can have long-term effects on both gut health and the wider immune system (Credit: Getty Images)

The harmful and life-saving impact of antibiotics is one of the biggest conundrums troubling scientists around the world. While there is no one solution, there are approaches which could mitigate the harmful effects of antibiotics on our health.

"Antibiotics are amazing medicines that have saved millions of lives. They're very precious resources and should be used, but we need to understand how to precisely target them," says Kinross.

Scientists are now looking at antibiotics that are more targeted towards parts of the body, as well as ones that target specific bacteria, MacLean says, with the idea of only getting rid of the bacteria you want to get rid of, and leaving beneficial bacteria in the gut intact.

But the biggest tool currently at our disposal, says Anthony Buckley, associate professor in gut microbiology at the University of Leeds, is our diets. "Nutrition is one of the biggest drivers behind establishing the human microbiome," he says.

The University of Leeds' healthcare associated infections research group has been testing the effects of antibiotics on the microbiome for the last two decades.

The highest variety of foods we eat is usually associated with a higher variety of microbes in the gut, and fibre in particular seems to have a really positive impact," says Ines Moura, a research fellow at Leeds University's faculty of medicine and health, who is currently testing the effects of different nutrients on the gut microbiome and how they can reduce the negative effects of antibiotics.

Dietary fibre is particularly important because microbes in our body digest it and produce short chain fatty acids, which provide energy to the cells lining the colon, says Buckley.

"When you have antibiotics, the microbes that produce short-chain fatty acids get depleted and take time to recover. Our theory is that, by ingesting dietary fibre, they're providing a substrate for those microbes to grow on and produce short-chain fatty acids, and hopefully establish balance again," he says.

Eating a diet high in fibre is thought to help creative a gut environment more beneficial to healthy bacteria (Credit: Getty Images)

The irony underlying the use of antibiotics is that, with each course we take, we potentially lower our body's ability to fight infection, and, therefore, increase our reliance on antibiotics.

"It's much better to not have to rely on antibiotics," Kinross says, "And instead focus on the bio-resilience of our internal ecology by eating healthily, particularly in a person's early life, since this is when antibiotics cause the most damage."

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Can GM Food Cause Immunity To Antibiotics?

by SEAN POULTER, Daily Mail

Eating GM food can change the genetic make-up of your digestive system and could put you at risk of infections that are resistant to antibiotics, experts said yesterday.

A British study has revealed that volunteers who ate one meal containing genetically modified soya had traces of the modified DNA in bacteria in their small intestines.

Scientists now fear that GM foods, which are often modified to be resistant to antibiotics, will leave Britons vulnerable to untreatable illnesses.

The research contradicts repeated claims by the GM industry that gene transfer from foods to humans is extremely unlikely.

It also raises the possibility that millions of people may already have GM bacteria from food they have eaten.

The study, carried out at the University of Newcastle, consisted of feeding seven volunteers GM soya.

Researchers found that three of them had evidence of DNA gene transfer in the bacteria that occurs naturally in their digestive systems.

This is the first time this transfer has been identified in humans. Research leader Professor Harry Gilbert played down the dangers, but confirmed that 'surprising' levels of GM DNA transfer were found.

He said: 'There is some evidence of gene transfer, but it is at an extremely low rate and therefore it probably does not represent a significant risk to human health.'

The research report suggested that this transfer may have 'reflected previous exposure of the subjects to genetically modified plants'.

But yesterday experts claimed the possibility of eating GM crops containing antibiotic resistance genes raised 'serious concerns'.

Geneticist Dr Michael Antoniou, of Guy's Hospital, London, said the results indicated the need for an extensive GM foods testing programme.

He added: 'The most significant finding is that there is GM soya DNA in the bacteria at readily detectable levels in the small intestines.

'It was always said by the industry that this could not happen or was extremely unlikely.

'There is a whole slew of different antibiotic resistant genes that are being used in GM crops in their production in the laboratory. They stay in the final crop.'

These genes are often used as a marker to signal that the desired GM change, such as resistance to a particular weed killer, has taken place.

Dr Antoniou added: 'Bacteria in the gut are going to take up genes that will make them resistant to potentially therapeutic antibiotics.

'The possibility is that someone who picked up the antibiotic resistance through food and then fell ill, that a medical antibiotic might not be effective.'

However the Food Standards Agency tried to reassure consumers that GM foods are safe.

A spokesman said the findings had been assessed by several Government experts who had ruled that humans were not at risk.

In a statement on its website, the agency said the study had concluded it is 'extremely unlikely' that GM genes can end up in the gut of people who eat them.

Friends of the Earth GM expert Adrian Bebb said this response contradicted the opinions of many international scientists.

He added: 'The FSA's attitude to the release of this information has been extraordinary.

'It can only fuel concerns that the Government and its agencies only want the public to hear positive news about GM.

'This is the first time a change to bacteria in the gut has been identified in humans.

' It is enormously significant.

'This is something the GM industry said could not happen. Yet in the first experiment looking at just seven people, there it is.

'The suggestion that the GM DNA could have already been in the bodies of the participants raises important questions.

'Either it got into the gut many years ago and has been passed down or people are eating GM soya in their diet on a daily basis.

'Whatever the reason, it would seem millions of people could have GM DNA from this soya in their bodies.'

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Around One In Three Guys Have HPV

Plenty of men worldwide are carrying the human papillomavirus, or HPV, new research has found. The study estimates that about one in three men currently have at least one strain of genital HPV, while one in five have a strain known to increase the risk of certain cancers in both men and women. Many of the worst types of HPV are vaccine-preventable.

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HPV is considered the most common sexually transmitted viral infection in the U.S. And the world, and just about every person will be infected by it at some point in their lives. Thankfully, most HPV infections are symptomless, and the body typically clears an infection on its own within a few years. But there are over 200 types of HPV out there and some types can cause unpleasant symptoms like genital warts. These warts aren't dangerous and usually go away after a while, but are unseemly and sometimes painful. Other types of HPV cause no acute illness but raise the risk of several different cancers (one reason why is that these infections tend to linger much longer in the body).

HPV is best known for causing cervical cancer in women and is thought to account for the vast majority of these cancers. But high-risk HPV strains are also strongly linked to penile cancer in men as well as anal, throat, and mouth cancers in both men and women. While most people with high-risk HPV will not develop these cancers, most of these cancers are caused by HPV. About 60% of penile cancers are tied to high-risk HPV, for instance, along with 70% of throat cancers.

The focus on the link between cervical cancer and HPV has led to plenty of research on its prevalence among women. But according to the authors of this new study, published last month in The Lancet Global Health, much less attention has been paid to its prevalence in men. The authors, which included scientists from the World Health Organization as well as public health agencies in the U.S. And Spain, decided to review the evidence looking at this question.

They analyzed 65 studies from 35 countries conducted over the past 30 years on men aged 15 and older. All told, they estimated that the global pooled prevalence for men having any type of HPV was 31%, while the prevalence for any type of high-risk HPV was 21%. The risk of having HPV seemed to be highest in young men in their mid to late twenties. The prevalence of HPV was similar for men living in Europe and the Americas, but significantly lower in Eastern and Southeastern Asia (about half).

"Our findings show that HPV prevalence is high in men over the age of 15 years and support that sexually active men, regardless of age, are an important reservoir of HPV genital infection," the authors wrote.

While catching HPV early on in adulthood was perhaps once unavoidable, there are now effective childhood vaccines that can blunt its worst impacts. These vaccines help prevent up to nine different types of HPV, including the types most commonly linked to cancer and genital warts. And there's already evidence that vaccination is dramatically cutting young women's risk of cervical cancer. Many experts believe that cervical cancer can be eradicated in our lifetimes as a result, provided high enough uptake of these vaccines when recommended in the population.

Many countries have now started to recommend HPV vaccination for young boys and teens as well. And given their findings, that's a plan that's likely to help everyone, the authors note. In the U.S., two doses of the HPV vaccine are recommended for children starting at ages 11 to 12, though it can be given as early as nine. Some countries are also experimenting with whether one dose might be enough to provide lasting protection.

"These estimates emphasize the importance of incorporating men in comprehensive HPV prevention strategies to reduce HPV-related morbidity and mortality in men and ultimately achieve elimination of cervical cancer and other HPV-related diseases," the authors wrote.

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