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Published on Leave a comment on Researchers Revise The Number of Bacteria in Humans

A recent study has examined the issue of whether the 10 to 1 ratio of bacteria to human cells, which is widely quoted, is actually correct. Weizmann Institute of Science researchers currently feel that based on scientific evidence (which of course will change over time) and making "educated estimates", the actual ratio is closer to 1:1 (but overall there still are more bacterial than human cells). They point out that the 10:1 ratio was originally a "back of the envelope" estimate dating back to 1972.

The researchers also point out that the ratio may vary over the course of each day - as a person defecates out huge amounts of bacteria with each bowel movement. However, this study - which is not the final word - is an educated guess about bacteria only. What about the viruses, the fungi, etc that also reside on and within us? We know much less about all the other microbes. I am disturbed that article after article, and headline after headline, equates microbes and bacteria. Microbes does not mean only bacteria.  From Science Daily:

Germs, humans and numbers: New estimate revises our microbiome numbers downwards

How many microbes inhabit our body on a regular basis? For the last few decades, the most commonly accepted estimate in the scientific world puts that number at around ten times as many bacterial as human cells. In research published in the journal Cell, a recalculation of that number by Weizmann Institute of Science researchers reveals that the average adult has just under 40 trillion bacterial cells and about 30 trillion human ones, making the ratio much closer to 1:1.

The rising importance of the microbiome in current scientific research led the Weizmann Institute's Prof. Ron Milo, Dr. Shai Fuchs and research student Ron Sender to revisit the common wisdom concerning the ratio of "personal" bacteria to human cells.

The original estimate that bacterial cells outnumber human cells in the body by ten to one was based on, among other things, the assumption that the average bacterium is about 1,000 times smaller than the average human cell. The problem with this estimate is that human cells vary widely in size, as do bacteria. For example, red blood cells are at least 100 times smaller than fat or muscle cells, and the microbes in the large intestine are about four times the size of the often-used "standard" bacterial cell volume. The Weizmann Institute scientists weighted their computations by the numbers of the different-sized human cells, as well as those of the various microbiome cells. 

Some excerpts from the original journal article from Cell: Are We Really Vastly Outnumbered? Revisiting the Ratio of Bacterial to Host Cells in Humans

The human microbiome has emerged as an area of utmost interest....One of the most fundamental and commonly cited figures in this growing field is the estimate that bacteria residing in the human body outnumber human cells by a factor of 10 or more (Figure 1A). This striking statement often serves as an entry point to the field. After all, if a human being is a cell population composed of at least 90% bacteria, it is only natural to expect a major role for them in human physiology.

Both the numerator (number of microbial cells) and the denominator (human cells) of this 10:1 ratio are based on crude assessments. Most sources cite the number of human cells as 1013 or 1014.....We performed a thorough review of the literature and found a long chain of citations originating from one “back of the envelope” estimate (Figure 1). This estimate, though illuminating, was never meant as the final word on the question.

Recently, the estimate of a 10:1 bacterial to human cell ratio (B/H) ratio has received criticism (Rosner, 2014). Therefore, an alternative value and an estimate of the uncertainty range are needed. Bacteria are found in many parts of the human body primarily on the external and internal surfaces, including the gastrointestinal tracts, skin, saliva, oral mucosa, and conjunctiva. The vast majority of commensal bacteria reside in the colon, with previous estimates of about 1014 bacteria (Savage, 1977), followed by the skin, which is estimated to harbor ∼1012 bacteriaBerg, 1996). Less than 1012 bacteria populate the rest of the body.....Almost all recent papers in the field of gut microbiota directly or indirectly rely on a single paper (Savage, 1977) discussing the overall number of bacteria in the gut. Interestingly, review of the original Savage 1977 paper demonstrates that it actually cites another paper for the estimate (Luckey, 1972)....The estimate, performed by Luckey in 1972, is an illuminating example of a back-of-the-envelope estimate, which was elegantly performed, yet was probably never meant to serve as the cornerstone reference number to be cited decades later.

Updating the ratio of bacteria to human cells from 10:1 or 100:1 to closer to 1:1 does not take away from the biological importance of the microbiota. ...Although we still appear to be outnumbered, we now know more reliably to what degree and can quantify our uncertainty about the ratios and absolute numbers. The B/H ratio is actually close enough to one, so that each defecation event, which excretes about 1/3 of the colonic bacterial content, may flip the ratio to favor human cells over bacteria. This anecdote serves to highlight that some variation in the ratio of bacterial to human cells occurs not only across individual humans but also over the course of the day.

Published on Leave a comment on Some Have Pain From Electromagnetic Fields

 For years I have heard anecdotal stories about some people who sensed electromagnetic fields and were bothered by them. Many considered such stories a little woo-woo....but now comes this study on rats that was based on people with nerve injuries, who have weird sensations and pain from electromagnetic fields of power lines, cell towers, and cell phones on roam. The nerve injured rats had pain from electromagnetic fields similar to what people with nerve-injuries (such as post amputation) report. From Science Daily:

Energy from cellphone towers amplify pain in amputees

For years, retired Maj. David Underwood has noticed that whenever he drove under power lines and around other electromagnetic fields, he would feel a buzz in what remained of his arm. When traveling by car through Texas' open spaces, the buzz often became more powerful. "When roaming on a cellphone in the car kicked in, the pain almost felt like having my arm blown off again," said Underwood, an Iraq War veteran who was injured by an improvised explosive device (IED). His injuries have resulted in 35 surgeries and the amputation of his left arm.... "I didn't notice the power lines, cellphones on roam or other electromagnetic fields until I first felt them in my arm."

Until a recent study led by researchers at The University of Texas at Dallas was published online last month in PLOS ONE, there was no scientific evidence to back up the anecdotal stories of people, such as Underwood, who reported aberrant sensations and neuropathic pain around cellphone towers and other technology that produce radio-frequency electromagnetic fields.

"Our study provides evidence, for the first time, that subjects exposed to cellphone towers at low, regular levels can actually perceive pain," said Dr. Mario Romero-Ortega, senior author of the study and an associate professor of bioengineering in the University's Erik Jonsson School of Engineering and Computer Science. "Our study also points to a specific nerve pathway that may contribute to our main finding."

This is one of the first studies to look at the effects of electromagnetic fields (EMFs) in a nerve-injury model, said Romero-Ortega....There are nearly 2 million amputees in the United States, according to the Centers for Disease Control and Prevention, and many suffer from chronic pain. After interacting with Underwood, Romero-Ortega decided to study the phenomena that Underwood described.

The team hypothesized that the formation of neuromas -- inflamed peripheral nerve bundles that often form due to injury -- created an environment that may be sensitive to EMF-tissue interactions. To test this, the team randomly assigned 20 rats into two groups -- one receiving a nerve injury that simulated amputation, and the other group receiving a sham treatment. Researchers then exposed the subjects to a radiofrequency electromagnetic antenna for 10 minutes, once per week for eight weeks. The antenna delivered a power density equal to that measured at 39 meters from a local cellphone tower -- a power density that a person might encounter outside of occupational settings.

Researchers found that by the fourth week, 88 percent of subjects in the nerve-injured group demonstrated a behavioral pain response, while only one subject in the sham group exhibited pain at a single time point, and that was during the first week. After growth of neuroma and resection -- the typical treatment in humans with neuromas who are experiencing pain -- the pain responses persisted.

"Many believe that a neuroma has to be present in order to evoke pain. Our model found that electromagnetic fields evoked pain that is perceived before neuroma formation; subjects felt pain almost immediately," Romero-Ortega said....Romero-Ortega said since the research produced pain responses similar to those in anecdotal reports and a specific human case, the results "are very likely" generalizable to humans.

"There are commercially available products to block radio frequency electromagnetic energy. There are people who live in caves because they report to be hypersensitive to radiomagnetism, yet the rest of the world uses cellphones and does not have a problem. The polarization may allow people to disregard the complaints of the few as psychosomatic," he said. "In our study, the subjects with nerve injury were not capable of complex psychosomatic behavior. Their pain was a direct response to human-made radiofrequency electromagnetic energy."

At one point in the study, members of the research group showed Underwood video of subjects in the experiment and their response to radiofrequency electromagnetic fields. "It was exactly the same type of movements I would have around cellphones on roam, power lines and other electromagnetic fields," said Underwood, who has served on congressional medical committees and been exposed to some of the best doctors in the world.

Published on Leave a comment on Will the Blue Light From Device Screens Damage Our Eyes?

Now and then I hear people wondering whether the many hours we spend staring at computer, cell phone, and tablet screens is damaging our eyes. And what about fluorescent lighting (which seems to bother many people) and LED lights? After all, the blue light of all our device screens seems intense, and researchers have long known that blue light is toxic to the retina.

Recently researchers measured the blue light on various device screens and lamps (including over extended time periods) and compared it to looking at a clear blue sky in June (but not looking at the sun). They found that most devices put out less blue light than the blue sky on a clear day and all were less than international standards for blue light exposure limits. Whew...we're all OK. But don't use them for a long time at night because their bright emissionInternational Commission on Non-Ionizing Radiation Protectisuppresses melatonin (needed for sleep). From Medscape:

Blue Light From Screens, Bulbs Won't Damage Retina

Despite concerns that staring at devices putting out high amounts of the blue light wavelength could damage human retinas, a recent study finds that most devices put out less of that light than the blue sky on a clear day. "Even under extreme long-term viewing conditions, none of the low energy light bulbs, computers, tablets and mobile phones we assessed suggested cause for concern for public health," said lead author John O'Hagan, head of the Laser and Optical Radiation Dosimetry Group of Public Health England in Chilton, U.K., in an email.

As people are using computers and phones more often and low-energy lighting like fluorescent and LED bulbs is becoming more common, the types of light human eyes are encountering is changing, the researchers pointed out January 15 online in the journal Eye. Compared to traditional incandescent bulbs, electronic screens and low-energy light bulbs tend to emit more blue light, which has long been known to be toxic to the retina, they write.

Based on that toxicity research, the International Commission on Non-Ionizing Radiation Protection (ICNIRP) has proposed a safe exposure limit, below which blue light is unlikely to harm a viewer's eye. O'Hagan and his team measured the blue light emitted by several sources, including mobile phones, tablet computers, laptops and lamps, over time periods similar to the way people use the devices. Then they compared the emissions to the ICNIRP's exposure limits.

After comparing multiple colors on device screens, the researchers found that a white screen had the highest blue light emissions, so they used a white screen set at maximum brightness for their measurements.They also compared the blue light emissions from various devices to the levels people would encounter when looking at a clear blue sky in summertime in Chilton, in southern England, and also to an overcast winter sky in the same location.

The blue light exposure on a clear day in June was around 10 percent of the ICNIRP safe limit. A cloudy day in December produced around 3 percent of the limit. Comparing these natural exposures with light from lamps, computer screens and mobile devices like smartphones, the study team found that the artificial light produced even lower exposures than people normally encounter outdoors. That is, provided they're staring just at the sky, not directly at the sun.

 

Even considering that people may stare at computer screens for hours in the course of work or play, the study team concludes that there's no danger to the retina.They caution, however, that the amount of light that gets transmitted from the surface of the eye to the retina is age-related, so children may be more sensitive to blue light. Light sources that are comfortable for adults could be distressing for children, the authors warn.

Published on

This study is noteworthy and relevant to humans (it was done on mice) because it may explain why so many people taking antibiotics get frequent viruses or seem more susceptible to infections. Once bacteria (both good and bad) are killed by antibiotics, then the community becomes unbalanced (dysbiosis), so that viruses may gain a foothold and a viral infection develops. In a healthy microbial community all sorts of microbes can be found, even ones we typically consider pathogenic, but the whole community keeps them in balance. One can say that "depletion of commensal microbiota also affects antiviral immunity".

The study researchers said that the study findings were relevant to humans: that oral antibiotics could result in increased susceptibility to sexually transmitted infections, as well as other infectious viruses. Note: commensal microbes or commensalism is a the living together of two organisms (different species) in a relationship that is beneficial to one and has no effect on the other. Dysbiosis is microbial imbalance, the microbial community being "out of whack". From Science Daily:

Antibiotics may increase susceptibility to sexually transmitted infections

Commensal microbiota, populations of bacteria that inhabit the tissues of larger organisms, often have complex relationships with their hosts. Researchers have been aware for some time that commensal microbiota play a role in antiviral immunity by producing immune inductive signals that trigger inflammasome responses, among other things.

However, the role of dysbiosis on antiviral immunity hasn't been studied. Dysbiosis describes the loss of bacterial diversity within a microbiome, and the direct role that commensal microbiota play in antiviral immunity suggests that such loss would facilitate viral infections. Recently, a collaborative of Korean and Japanese scientists conducted a study into the effects of antibiotic-induced dysbiosis on antiviral immunity, and have published their results in the Proceedings of the National Academy of Sciences.

The researchers investigated the mechanisms of commensal microbial immunity on the genital mucosa by treating mice with antibiotics for four weeks and then exposing them to HSV-2. A control group received placebo. They report that the antibiotics caused dysbiosis within the vaginal microbiota, and resulted in a dramatic increase in innate immune response—specifically, they noted increases in an alarmin called IL-33, which blocked effector T cells from migrating into the vaginal tissues and secreting antiviral cytokines.

Antibiotic-treated mice succumbed to HSV-2 infection dramatically faster than control mice. They exhibited more severe pathology and all mice treated with antibiotics prior to viral exposure died within 11 days of infection. "Taking these data together, we find that depletion of commensal bacteria results in a severe defect in antiviral protection following mucosal HSV-2 infection," the researchers write.

By analyzing stool and vaginal washes from both groups of mice, they determined that antibiotic treatment induced an imbalance in the microbial composition of the vaginal mucosa. Further, they were able to determine that no single species of bacteria was responsible for the antiviral immunity effects of the commensal microbiome; rather, it was the imbalance of the microbiotic population that accounted for the effects.

 

The human mouth hosts a variety of microbes, some taking up residence on the mouth lining (blue) within days after birth. Credit: Martin Oeggerli (National Geographic)

Published on Leave a comment on BPA Free and BPA Plastic Have Similar Effects

Once again, research shows that "BPA-free" plastic does not mean it is safer than BPA plastic. Both BPA and BPS (the usual replacement for BPA) leach estrogenic chemicals into the foods and beverages, which means negative health effects when ingested. Both BPA and BPS mimic the effects of estrogen, as well as the actions of thyroid hormone. Yes, this study was done on zebrafish, but think of them as "the canaries in the mine" - if it affects them, it could affect humans also, especially developing fetuses and young children.

BPA  and BPS can leach into food, particularly under heat, from the lining of cans and from consumer products such as water bottles, baby bottles, food-storage containers, sippy cups, and plastic tableware. BPA can also be found in contact lenses, eyeglass lenses, compact discs, water-supply pipes, some cash register and ATM receipts, as well as in some dental sealants. A good way to minimize exposure to BPA , BPS, and other estrogenic chemicals is to try to avoid food and beverages in plastic containers and cans, but instead try to buy and store food in glass containers, jars, and bottles. From Science Daily:

'BPA-free' plastic accelerates embryonic development, disrupts reproductive system

Companies advertise "BPA-free" as a safer version of plastic products ranging from water bottles to sippy cups to toys. Many manufacturers stopped used Bisphenol A to strengthen plastic after animal studies linked it to early puberty and a rise in breast and prostate cancers.Yet new UCLA research demonstrates that BPS (Bisphenol S), a common replacement for BPA, speeds up embryonic development and disrupts the reproductive system.

Using a zebrafish model, Wayne and her colleagues found that exposure to low levels of BPA and BPS -- equivalent to the traces found in polluted river waters -- altered the animals' physiology at the embryonic stage in as quickly as 25 hours. "Egg hatching time accelerated, leading to the fish equivalent of premature birth," said Wayne, who is also UCLA's associate vice chancellor for research. "The embryos developed much faster than normal in the presence of BPA or BPS."

The UCLA team, which included first author Wenhui Qiu, a visiting graduate student from Shanghai University, chose to conduct the study in zebrafish because their transparent embryos make it possible to "watch" cell growth as it occurs.... In a second finding, the team discovered that the number of endocrine neurons increased up to 40 percent, suggesting that BPA overstimulates the reproductive system.... "We saw many of these same effects with BPS found in BPA-free products. BPS is not harmless."

After uncovering her first finding about BPA in 2008, Wayne immediately discarded all of the plastic food containers in her home and replaced them with glass. She and her family purchase food and drinks packaged in glass whenever possible. "Our findings are frightening and important," emphasized Wayne. "Consider it the aquatic version of the canary in the coal mine."

Finally, the researchers were surprised to find that both BPA and BPS acted partly through an estrogen system and partly through a thyroid hormone system to exert their effects. "Most people think of BPA as mimicking the effects of estrogen. But our work shows that it also mimics the actions of thyroid hormone," said Wayne. "Because of thyroid hormone's important influence on brain development during gestation, our work holds important implications for general embryonic and fetal development, including in humans."

Researchers have proposed that endocrine-disrupting chemicals may be contributing to the U.S.' rise in premature human births and early onset of puberty over the past couple of decades. "Our data support that hypothesis," said Wayne. "If BPA is impacting a wide variety of animal species, then it's likely to be affecting human health. Our study is the latest to help show this with BPA and now with BPS."

Published on Leave a comment on Microbes Partially Restored To C-Section Babies

I posted about this amazing research while it was still ongoing (Jan. 16, 2015), but now a study has been published. The small well-done pilot study looked at the microbiome (microbial communities) and microbial differences between different groups of infants during the first 30 days of life. They found significant differences in the bacteria of C-section infants (not exposed to their mother's vaginal fluid in the birth canal) compared to C-section infants who were swabbed with a gauze pad right after birth with their mother's vaginal fluids. They found that the microbiota (community of microbes) is partially restored in the swabbed C-section infants and more similar to that of vaginally delivered infants (who were exposed to the maternal bacteria naturally in the birth canal). They found that the procedure restored some bacteria, such as Lactobacillus and Bacteroides, which were nearly absent in the skin and anal samples of non-swabbed C-section babies.

In the C-section group, four mothers who were free of infections that might harm the babies, incubated a sterile gauze in their vaginas for one hour before the operation (C-section). Then, within two minutes of birth, the babies were swabbed with the gauze first over their mouths, then their faces, and then the rest of their bodies. These results are important because it is thought that microbiome differences (depending on method of birth) are long-lasting (with higher incidence of some health problems later in life with C-sections), and because the baby's early microbiome helps educate the baby's developing immune system.

Rob Knight (a leading microbiologist and one of the researchers) pointed out that the study "provides the proof-of-concept that microbiome modification early in life is possible." Now we need to see if these microbial differences persist over time and if it makes a health difference. From Science Daily:

Vaginal microbes can be partially restored to c-section babies

In a small pilot study, researchers at University of California, San Diego School of Medicine and Icahn School of Medicine at Mount Sinai determined that a simple swab to transfer vaginal microbes from a mother to her C-section-delivered newborn can alter the baby's microbial makeup (microbiome) in a way that more closely resembles the microbiome of a vaginally delivered baby. 

Babies delivered by C-section differ from babies delivered vaginally in the makeup of the microbes that live in and on their bodies. These early microbiomes help educate the baby's developing immune system. Previous research suggests a link between C-section delivery and increased subsequent risk of obesity, asthma, allergies, atopic disease and other immune deficiencies. Many of these diseases have also been linked to the microbiome, though the role a newborn's microbiome plays in current or long-term health is not yet well-understood....Other research suggests that microbiome differences between vaginal and C-section babies can persist for years."

In the study, the researchers collected samples from 18 infants and their mothers, including seven born vaginally and 11 delivered by scheduled C-section. Of the C-section-delivered babies, four were exposed to their mothers' vaginal fluids at birth as part of this study. To do this, sterile gauze was incubated in the mothers' vaginas for one hour before the C-section. Within two minutes of their birth, the babies delivered by C-section were swabbed with the gauze starting with the mouth, then the face and the rest of the body.

Six times over the first month after birth, the researchers collected a total of 1,519 anal, oral and skin samples from the mothers and infants. Knight's team then used a gene sequencing technique to map the types and relative quantities of bacterial species present at each body site.

Here's what they found: the microbiomes of the four C-section-delivered infants exposed to vaginal fluids more closely resembled those of vaginally delivered infants than unexposed C-section-delivered infants, though the difference was more distinct in their oral and skin samples than in their anal samples. This partial microbial restoration could be due to the fact that the infants received only one surface application of maternal vaginal fluids, Knight said.

Yet the oral and skin microbiome differences between C-section-delivered infants who received the microbial transfer and those who did not was still noticeable one month after birth. The results were not due to diet differences, as all of the infants received breast milk either exclusively or supplemented with formula during the first month of life. In addition, consistent with previous studies, the babies' microbiome profiles did not correlate with the amount of breast milk they received.

"The present work is a pilot study -- we need substantially more children and a longer follow-up period to connect the procedure to health effects," said Knight...."This study points the way to how we would do that, and provides the proof-of-concept that microbiome modification early in life is possible. In fact, we already have more than 10,000 additional samples collected as part of this study that still await analysis."

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Published on 4 Comments on Three Years of Sinusitis Treatment Success

It's now 3 years being free of chronic sinusitis and off all antibiotics! Three amazing years since I started using easy do-it-yourself sinusitis treatments containing the probiotic (beneficial bacteria) Lactobacillus sakei. My sinuses feel great! And yes, it still feels miraculous.

After reading the original ground-breaking research on sinusitis done by Abreu et al (2012), it led to finding and trying L. sakei as a sinusitis treatment. Of course, there is an entire community of microbes that live in healthy sinuses (the sinus microbiome), but L. sakei seems to be a key one for sinus health.

I just updated the post The One Probiotic That Treats Sinusitis (originally posted January 2015) using my family's experiences (lots of self-experimentation!) and all the information that people have sent me. The post has a list of brands and products with L. sakei, as well as information about some other promising bacteria. Thank you so much! [For latest see: The Best Probiotic For Sinus Infections]

Thank you all who have written to me  - whether publicly or privately. Please keep writing and tell me what has worked or hasn't worked for you as a sinusitis treatment. If you find another bacteria or microbe or product that works for you - please let me know. It all adds to the sinusitis treatment knowledge base. I will keep posting updates. 

(NOTE: I wrote our background story - Sinusitis Treatment Story back in December 2013, and there is also a  Sinusitis Treatment Summary page with the various treatment methods. One can also click on SINUSITIS under CATEGORIES to see more posts, such as "Probiotics and Sinusitis" - a discussion by one of the original sinusitis researchers about what she thinks is going on in sinus microbiomes and what is needed.)  

Published on Leave a comment on Exercise Alone May Not Lead to Weight Loss

Why exercise alone won't get those pounds off - it's because the body adapts to higher exercise levels. We all suspected that, but it is depressing... From Medical Xpress:

Why you won't lose weight with exercise alone

Exercise by itself isn't always enough to take off the weight. Now, evidence reported in the Cell Press journal Current Biology on January 28 helps to explain why that is: our bodies adapt to higher activity levels, so that people don't necessarily burn extra calories even if they exercise more.

People who start exercise programs to lose weight often see a decline in weight loss (or even a reversal) after a few months. Large comparative studies have also shown that people with very active lifestyles have similar daily energy expenditure to people in more sedentary populations.

Pontzer says this really hit home for him when he was working among the Hadza, a population of traditional hunter-gatherers in northern Tanzania."The Hadza are incredibly active, walking long distances each day and doing a lot of hard physical work as part of their everyday life," Pontzer says. "Despite these high activity levels, we found that they had similar daily energy expenditures to people living more sedentary, modernized lifestyles in the United States and Europe. That was a real surprise, and it got me thinking about the link between activity and energy expenditure."

To explore this question further in the new study, Pontzer and his colleagues measured the daily energy expenditure and activity levels of more than 300 men and women over the course of a week.In the data they collected, they saw a weak but measurable effect of physical activity on daily energy expenditure.

But, further analysis showed that this pattern only held among subjects on the lower half of the physical activity spectrum. People with moderate activity levels had somewhat higher daily energy expenditures—about 200 calories higher—than the most sedentary people. But people who fell above moderate activity levels saw no effect of their extra work in terms of energy expenditure."The most physically active people expended the same amount of calories each day as people who were only moderately active," Pontzer says.

Published on Leave a comment on Childhood Antibiotic Use Disrupts Gut Microbiome

This confirms what researchers such as Dr. Martin Blaser (in his book Missing Microbes) and others (such as Drs. Sonnenburg and Sonnenburg) have been saying about antibiotic use in infants and children: that there are negative effects to the gut microbiome from antibiotic use in early childhood, and the more frequent the use, the greater the negative effects. It is because the use of antibiotics  in early childhood "disrupts the microbiome".

Penicillins appear to be less disruptive, but macrolides (e.g., Clarithromycin, azithromycin) much more disruptive - the researchers found that the gut microbiota recovered within 6–12 months after a penicillin course, but did not fully recover from a macrolide course even after 2 years . Antibiotics can be life-saving, but they absolutely should not be used casually because there are hidden costs (such as microbiome changes). From Medical Xpress:

Antibiotic use in early life disrupt normal gut microbiota development

The use of antibiotics in early childhood interferes with normal development of the intestinal microbiota, shows research conducted at the University of Helsinki. Particularly the broad-spectrum macrolide antibiotics, commonly used to treat respiratory tract infections, have adverse effects. Macrolides appear also to contribute to the development of antibiotic-resistant strains of bacteria.  ...continue reading "Childhood Antibiotic Use Disrupts Gut Microbiome"

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Published on 1 Comment on Beards and Bacteria in Hospitals

Once again, two opposing views about beards have been in the news - that they harbor all sorts of nasty disease-causing bacteria vs they are hygienic. An earlier May 5, 2015 post was about the question of whether bearded men have more bacteria on their faces than clean shaven ones. I cited a 2014 study found that they don't, and that we are all covered with bacteria, all sorts of bacteria, and this is normal.

Now another study has looked at the issue of hospital workers with and without beards and whether they carry infectious bacteria. Researchers swabbed the faces (center of the cheek and the skin of the upper lip under the nostrils) of both clean shaven individuals and individuals with facial hair (beards) that worked in two hospitals (they all had direct contact with patients) and looked at the bacteria present. They especially looked for the presence of the bacteria Staphylococcus aureus, which surprisingly was found more in the clean-shaven men.

Also to their surprise, it was more of the clean shaven men who carried the pathogenic bacteria Methicillin-resistant Staphylococcus aureus (also known as MRSA). For those bacterial groups most closely associated with hospital acquired infections, such as Klebsiella species, Pseudomonas species, Enterobacter species., and Acinetobacter species, prevalence was low in both groups, and less than 2% for each group.

For other, less harmful bacteria, researchers found that bearded employees harbored no more bacteria than their clean-shaven colleagues. In summary: The researchers say that "results suggest that male hospital workers with facial hair do not harbour more potentially concerning bacteria than clean-shaven workers, and that in some instances, clean-shaven individuals are significantly more likely to be colonized with potential nosocomial pathogens". (NOTE: nosocomial means a disease originating or acquired in a hospital.)

And why is that? According to the study, one explanation is "microtrauma to the skin," which occurs during shaving and results in abrasions, which could support bacterial colonisation and growth of bacteria on the clean-shaven men. However, some other researchers have a different hypothesis — that beards themselves actually fight infection.

This stems from an experiment carried out by Dr. Michael Mosley who recently swabbed the beards of a variety of men and sent the samples to Dr. Adam Roberts, a microbiologist at University College London. Roberts grew more than 100 different bacteria from the beard samples, but found that in a few of the petri dishes a microbe was killing the other bacteria -  a bacteria called Staphylococcus epidermidis, and which they believe has antibiotic properties.

From the Journal of Hospital Infection: Bacterial ecology of hospital workers’ facial hair: a cross-sectional study

Summary: It is unknown whether healthcare workers' facial hair harbours nosocomial pathogens. We compared facial bacterial colonization rates among 408 male healthcare workers with and without facial hair. Workers with facial hair were less likely to be colonized with Staphylococcus aureus (41.2% vs 52.6%, P = 0.02) and meticillin-resistant coagulase-negative staphylococci (2.0% vs 7.0%, P = 0.01). Colonization rates with Gram-negative organisms were low for all healthcare workers, and Gram-negative colonization rates did not differ by facial hair type. Overall, colonization is similar in male healthcare workers with and without facial hair; however, certain bacterial species were more prevalent in workers without facial hair.

[Excerpts from Discussion]:Several studies to date have demonstrated that physician white coats and neck ties can act as significant sources of nosocomial bacteria. Our study suggests that facial hair does not increase the overall risk of bacterial colonization compared to clean-shaven control subjects. Indeed, clean-shaven control subjects exhibited higher rates of colonization with certain bacterial species. This finding may be explained by microtrauma to the skin during shaving resulting in abrasions, which may support bacterial colonization and proliferation. This may be akin to the enhanced risk of surgical site infections in patients shaved with razors prior to surgery. Further, our results are consistent with prior evidence pertaining to bacterial colonization on the hands and nares of HCWs (Health care workers).