The Trouble With Some Microbes . . .

7 02 2013

Our battle against bacteria is tilting in our favor. After all, we have vaccines and antibiotics on our side. That doesn’t mean we can get cocky. It’s tilting, not surrendering at our feet.

But we’re still struggling to find ways to kill viruses once they’ve infected us.  At best, we can sometimes control them.

Although we can kill viruses on our bodies and other surfaces with disinfectants, it’s difficult to kill them when they’re living inside our cells.  When we’re infected with a virus, it takes up residence in one of our cells and uses the cell’s machinery to reproduce itself.

Developing a drug that will kill the virus without disrupting the intracellular machinery of uninfected cells is no easy task. It’s like playing Jenga—eventually the whole structure will collapse.

Bacteria, on the other hand, generally live outside of our cells and are easier targets.

There are some bacteria that have developed a resistance to not just one drug, say for instance penicillin, but to many such drugs.  They’re known as multi-drug resistant microorganisms such as streptococcus pneumoniae and mycobacterium tuberculosis, germs that we thought were very much under control and are now surging back into the population.

One major factor in preventing us from understanding the world of microbes is the size of that world.

The folks at the University of Georgia College of Agricultural and Environmental Sciences put bacteria into perspective this way, “Bacteria vary somewhat in size, but average about 1/25,000 inch.  In other words, 25,000 bacteria laid side by side would occupy only one inch of space.  One cubic inch is big enough to hold nine trillion average size bacteria—about 3,000 bacteria for every person on earth.

“Bacteria make up the largest group of micro-organisms.  People often think of them only as germs and the harm they do.  Actually, only a small number of [the thousands of different] bacteria types are pathogenic (disease-causing).  Most are harmless and many are helpful.”

Neal Rolfe Chamberlain, professor at the Kirksville College of Osteopathic Medicine, explains viruses in this manner, “Viruses are very small forms of life.  In fact, people still argue over whether viruses are really alive.  Viruses range in size from about 20 to 300 nanometers (nm).  A nanometer is 0.000001 of a millimeter.  A millimeter is 1/25 of an inch.  So in other words, you can place 25,000,000 nanometers in an inch.  If the biggest virus is 300 nm then you could fit 83,333 of that virus in an inch.

“Viruses are major freeloaders.  They cannot make anything on their own.  To reproduce they must infect other living cells.  Viruses infect bacteria, parasites, fungi, plants, animals, and humans.  No one escapes them.  If you have had the flu, chickenpox, measles, a common cold, mono, a cold sore, or a sore throat you have been infected by a virus!”

Some viruses, like HIV and hepatitis C, tend to develop strains that can resist mono drug therapy (treating the patient with one drug at a time).  We have to try and control the viruses with combination, or “cocktail” drugs (treating the patient with several drugs at once), although even that approach does not always work.  Some viruses can keep mutating until we’ve run out of drugs to try.

All this is to say that fighting microbes is seldom a simple task, and seemingly one that is neverending. For example, we have a whooping cough vaccine, but new strains are popping up and new vaccines are needed for this astoundingly infectious microbe.

We will never be rid of our tiny co-inhabitants on this world, and anyway, most of them we want to keep around. It’s those others . . . wouldn’t it be nice to have a jail for nasty microbes?

By PKIDs’ Staff





Microbes R Us

14 06 2012

Well, they’ve finally done it. Researchers have mapped the microbes living on humans.

Seems like they wouldn’t be hard to find, since they’re all over and in the body, but they are little—hence the “micro” part. And there are trillions of them on each of us. But, they are accountable for only 1 to 3 percent of the body’s mass. So if you weigh 180 pounds, the microbes make up between 1.8 and 5.4 pounds. Imagine. Trillions of anything weighing just 1.8 pounds.

If you think about it too much, it’ll give you the willies. Tiny critters in your nose, on your eyelashes, on your mouth, on your skin, on your lips . . . you get the idea.

Humans do have mutually beneficial relationships with some of these microorganisms. The microbes in the gut are famous for being helpful. We give them a place to live and they give us the ability to digest certain foods and produce vitamins and anti-inflammatories.

Other microbes, called pathogens, can and do cause illness in some of us. Yet many healthy people carry pathogens that don’t cause disease. Go figure.

The National Institutes of Health organized a group of researchers to map out the “normal microbial makeup of healthy humans (in the Western population).” The results of this mapping will be a bumper crop of hypotheses followed by a flood of studies which will, it’s hoped, move infectious disease research considerably further down the road.

NIH shares a bit of what’s already come out of this mapping:

CLINICAL APPLICATIONS

As a part of HMP, NIH funded a number of studies to look for associations of the microbiome with diseases and several PLoS papers include medical results. For example, researchers at the Baylor College of Medicine in Houston compared changes in the vaginal microbiome of 24 pregnant women with 60 women who were not pregnant and found that the vaginal microbiome undergoes a dramatic shift in bacterial species in preparation for birth, principally characterized by decreased species diversity. A newborn is a bacterial sponge as it populates its own microbiome after leaving the sterile womb; passage through the birth canal gives the baby its first dose of microbes, so it may not be surprising that the vaginal microbiome evolved to make it a healthy passage.

Researchers at the Washington University School of Medicine in St. Louis examined the nasal microbiome of children with unexplained fevers, a common problem in children under 3 years of age. Nasal samples from the feverish children contained up to five-fold more viral DNA than children without fever, and the viral DNA was from a wider range of species. Previous studies show that viruses have ideal temperature ranges in which to reproduce. Fevers are part of the body’s defense against pathogenic viruses, so rapid tests for viral load may help children avoid inappropriate treatment with antibiotics that do not kill the viruses but may harm the child’s healthy microbiome.

These are among the earliest clinical studies using microbiome data to study its role in specific illnesses. NIH has funded many more medical studies using HMP data and techniques, including the role of the gut microbiome in Crohn’s disease, ulcerative colitis and esophageal cancer; skin microbiome in psoriasis, atopic dermatitis and immunodeficiency; urogenital microbiome in reproductive and sexual history and circumcision; and a number of childhood disorders, including pediatric abdominal pain, intestinal inflammation, and a severe condition in premature infants in which the intestine actually dies.

All good news, but the scope of the mass of microbes on and in me still gives me the willies.

By Trish Parnell

Image courtesy of NIH





Germs – It’s a Symbiotic Thing

26 04 2010

We have 100 trillion microbes in and on our bodies. Most of these little critters don’t affect us—no harm, no foul.  Some germs even help out with digestion and other functions, and some cause illness.

Despite the fact that we’re walking bags of bugs, we don’t want to think about it and we definitely don’t want to get more germs, at least not the disease-causing kind.

Photo courtesy "bmann"

To prevent disease and general yuckiness in the home and elsewhere, we are a sponge-and-cleaner wielding people. Some of us more than others. (That’s right, Mom, I’m talking about you.)

We can’t keep our homes and offices germ-free, nor should we.  We have a symbiotic relationship with the germs in our world that requires a delicate balance of healthy intimacy to maintain.

But, we don’t want pathogenic germs to get the upper hand.  They’re the germs capable of causing disease.

Being clean and tidy helps keep the nasty numbers down, but germs will always be with us. Our bodies fight pathogens off all day long as we go about our business.

And when we actually do get around to cleaning, we tend to focus on obvious trouble spots (bathrooms, kitchens) while ignoring places we don’t typically think of as germ hot zones. We’re talking about our offices, our phones, our keyboards.

Dr. Charles Gerba, a professor of microbiology at The University of Arizona at Tucson, has done a lot of research on viruses and bacteria in offices.

His work reveals startling facts. For instance, the germiest place in any type of office is something you use every day. “The phone is typically the dirtiest piece of equipment in an office because it goes straight to your mouth, and you never clean or disinfect it,” says Gerba.

Right behind phones are desks, which often pull double-duty as restaurant tables, and keyboards, which are tricky to clean and good at collecting things like dirt, hair, food particles, dust and bacteria. Many of us like to grab a bite while catching up on email, but studies may make you rethink that: keyboards are usually much germier than toilet seats.

Things get complicated if many people share a computer. This is bad news if you absent-mindedly bite your nails or touch your nose or eyes while working.

Women’s offices tend to have more germs in them, as women tend to bring in and take out more items like bags and purses, which can carry germs that get transferred to office equipment.

However, men’s wallets are often found to be germier than women’s purses.

So, how can you protect yourself at work without turning into a worrywart? In an interview with Entrepreneur, Gerba suggested you:

  • Wipe down your desk and surrounding items with a disinfecting wipe once a week.
  • Keep a hand sanitizer at your desk and use it throughout the day.
  • If you tend to eat at your desk on a regular basis, think again–this behavior is inviting bacteria to grow at your fingertips.
  • Wash coffee mugs and glasses on a regular basis.
  • If you’re sick, don’t go to work.

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