December 23, 2014

A world-famous hot spring in Yellowstone National Park owes its brilliant rainbow colors to tourist trash, a new study has revealed. Before the park began attracting millions of visitors each year, the pool was deep blue. According to the study, bottles, coins, rocks, and other objects thrown by tourists into the hot spring over the years are responsible for the pool’s new appearance.

Yellowstone, the oldest national park in the world, has more than 300 active geysers and thousands of hot springs. Most of the park’s landscape was created by volcanic eruptions about 600,000 years ago. A large mass of molten rock still lies beneath the surface of the park. This rock, called magma, furnishes the heat for the park’s geysers and hot springs. The colors in the pools come from bacterial mats–complex communities of bacteria.

Like other hot springs in Yellowstone National Park, Morning Glory Pool is famous for its jewel-like colors.  (© Sascha Burkard, Shutterstock)

To determine the hot springs’ original color, researchers from Montana State University and Germany’s Brandenburg University of Applied Sciences first created a mathematical model to explain how chemical reactions are producing the colors in Morning Glory Pool today. The model was based on data from images of the pool made with several kinds of light and on a chemical analysis of the water. Then the scientists “reverse-engineered” the process to determine the color of the water in 1872, when the park was established.

The waters of Morning Glory Spring were a brilliant blue in 1872, when Yellowsotne National Park was established. Today, the thermal pool displays yellow, orange, and green because of changes in the bacteria inhabiting the pool. (Joseph Shaw and Paul Nugent (Montana State
University), Michael Vollmer (Brandenburg University of Applied Sciences))

The scientists found that trash thrown into Morning Glory Pool by visitors has partially blocked one of the pool’s underwater vents, lowering the temperature of the water. As a result, the kinds of bacteria in the pool have changed, turning the water from deep blue to green, yellow, and orange.

Additional World Book articles:

• A Place Where Earth Speaks (a Special Report)
• The Biggest Eruptions on Earth (a Special Report)

September 19, 2013

Infections caused by superbugs could kill hundreds of thousands, if not millions of Americans, if medical and public health professionals as well as ordinary citizens do not combat the threat posed by these antibiotic-resistant bacteria. That is the conclusion of the authors of a new report, Antibiotic Resistance Threats in the United States, 2013, released by the Centers for Disease Control and Prevention (CDC) in Atlanta. In an effort to call attention to the problem, CDC officials have established a new rating system that provides “a snapshot of the burdens and threats posed by antibiotic-resistant germs having the most impact on human health.” CDC officials said urgent steps are needed to prevent some infections from becoming essentially untreatable. “Without urgent action now, more patients will be thrust back to a time before we had effective drugs,” said CDC Director Thomas Frieden.

So-called superbugs are bacteria with the ability to overcome medications and other substances that might kill them or interfere with their growth. Each year, more than 2 million Americans develop antibiotic-resistant infections; some 23,000 of these people die, according to the CDC. The main reason for the rise of the superbugs is the widespread use of antibiotics. Up to 50 percent of all antibiotics prescribed for Americans are unnecessary or inappropriate. For example, people often request and doctors prescribe antibiotics to treat the common cold or flu. However, these infections are caused by viruses, which cannot be controlled by antibiotics. Even more worrisome is the amount of antibiotics used to promote growth and prevent and treat infections in livestock–up to 80 percent of all antibiotics used in the United States. Human ingest these antibiotics by eating meat. The more an antibiotic is used, the more quickly it can develop resistance, the CDC emphasized.

Bacteria, such as these Streptococcus cells, cause many diseases, including ear infections, strep throat, and pneumonia. ((c) Oliver Meckes/Science Source from Photo Researchers)

The CDC rating system includes three threat levels–concerning, serious, and urgent–based on seven factors. These include how common a bacterium is, how easily it spreads, the number of people it infects or kills, and the availablity of antibiotics to combat it. Three superbugs made the “urgent” list in the new report: CRE bacteria, Clostridium difficile (C-Diff), and Neisseria gonorrhoeae.

The CRE family of bacteria includes E. coli, which can cause serious illness or even death. E. coli is often found on improperly washed vegetables. Some CRE bacteria are already resistant to antibiotics.

C-Diff kills up to 14,000 people and causes 250,000 hospitalizations each year. It is often acquired in hospitals in which the staff has failed to maintain sanitary standards. These bacteria are also resistant to many antibiotics. 

Neisseria gonorrhoeae is the drug-resistant form of the bacterium that causes gonorrhea, a sexually transmitted disease and the second most commonly reported infection in the United States, according to the CDC.

The CDC report listed four major steps to fight antibiotic resistance:

• Preventing infections (through immunizations, safe food handling, and handwashing);
• Tracking bacterial infections (to determine factors that contribute to their spread);
• Improving the use of antibiotics (using them only when necessary and appropriate);
• Developing new antibiotics and diagnostic tests (to track the spread of resistance and quickly distinguish between illnesses caused by bacteria and viruses).

Additional World Book articles:

• Sanitation
• Handwashing: The First Line of Defense Against Disease (a special report)
• The War on Superbugs (a special report)

September 12, 2013

Tuberculosis (TB), a major cause of death in developing countries, may be so hard to defeat because it likely originated among our ancestors in Africa more than 70,000 years ago. In fact, it may have originated even before modern people migrated from the continent, according to a new study by an international team of scientists led by Sebastien Gagneus, an expert on infectious diseases from the Tropical and Public Health Institute in Basel, Switzerland. For their study, the scientists examined DNA sequences of tuberculosis bacteria from 259 subjects throughout the world. These genetic analyses enabled the scientists to construct a “family tree” of the bacterium, tracing its history through time.

A little more than a century ago, TB ranked among the most common causes of death in the world. Rod-shaped bacteria called tubercle bacilli cause the disease. Tubercle bacilli belong to a genus (group) of bacteria called Mycobacterium. Today, improved methods of prevention, detection, diagnosis, and treatment have greatly reduced the number of people who get the disease and those who die from it. However, even today tuberculosis claims many lives in countries where these improved methods are not widely available.

Evolutionary scientists believe that anatomically modern humans first appeared in Africa during the past 100,000 years. Sometime before about 50,000 years ago, they migrated out of Africa to other parts of the world. The new research suggests that early modern humans suffered from tuberculosis and carried the bacterium with them on their journeys. The scientists believe that the TB bacterium’s ability to go dormant (inactive) for long periods enabled the deadly disease to spread with human populations across the globe.

A volunteer physician with Doctors Without Borders, an international relief organization, treats a patient in Kenya for tuberculosis. (AP/Wide World)

Scholars had long thought that human tuberculosis, which cannot survive or infect any other animal, was a relatively recent disease. They believed that human TB originated from tuberculosis varieties that affect animals, such as cattle. Over the past 10,000 years, as humans developed agriculture and began domesticating animals, scientists believed the tuberculosis bacterium was passed to humans from livestock. Bovine tuberculosis, which affects cattle and can sometimes infect humans, seemed to support this view. The new research, however, indicates that tuberculosis was established in human populations long before people began keeping livestock.

Additional World Book articles:

• BCG
• Calmette, Albert
• Trudeau, Edward Livingston
• Tuberculosis: An Old Foe Gains Ground (a special report)

March 12, 2013

Infections caused by a particularly frightening form of drug-resistant germ are on the rise in U.S. hospitals. Health-care experts and the U.S. Centers for Disease Control and Prevention (CDC) are warning in particular about the rise of a new form of bacteria, a drug-resistant enterobacteria. Enterobacteria are normal in the digestive system of humans, but they can cause infections and illness when they invade such other areas of the body as the blood stream or bladder. Infections caused by normal enterobacteria can be treated with antibiotics and cured. The new form of enterobacteria is resistant to all antibiotics, even drugs used by doctors as a last resort, such as carbapenems. Because of this resistance, the form is called carbapenem-resistant enterobacteria, or CRE’s.

Bacteria, such as this Clostridium, can cause serious infections in humans. (© David Phillips, Visuals Unlimited/Getty Images)

The fatality rate for people who contract this virtually untreatable type of infection in the bloodstream is around 50 percent. In addition, CRE’s have the ability to share their drug resistance–their genetic defenses against antibiotics–with other bacteria.

For now, CRE’s are found only in hospitals in the United States. Experts fear is that as it becomes more common in hospitals, it will eventually enter the community and begin infecting large populations.

It is possible for hospitals to reduce patients’ incidence of, and thereby infection with, drug-resistant bacteria. Some methods include 1) quickly identifying and  isolating patients who test positive for such bacteria; 2) monitoring closely and lowering usage of antibiotics in hospital settings, as many drug-resistant germs thrive in settings where antibiotics are widely used;  3) more careful cleaning of patient rooms; and 4) vigilant hand washing on the part of all staff and visitors.

One aid in fighting this infection could be on the horizon. An American epidemiologist, Mark Stibich, has invented a robot that disinfects hospital rooms using pulses of ultraviolet (UV) light. The light used can disinfect both hard and soft surfaces. Thus far, only about 100 hospitals worldwide use the robot, but studies at such hospitals report a 75-percent drop in the rate of infection with another supergerm, Clostridium difficile (or C. diff).  UV light works by disrupting the DNA of an organism, so it kills bacteria, even bacteria that have drug resistance.

Additional World Book articles:

• Antibiotic resistance
• Bacteria

Another website of interest:

• Centers for Disease Control and Prevention

March 5, 2013

Not all strains of acne bacteria are created equal, medical researchers at the University of California at Los Angeles (UCLA) have found. The bugs that cause acne can sometimes help prevent zits.

For teenagers, acne is often a dreaded fact of life. More than 80 percent of teens at some point suffer from the skin condition, which cause pimples and red, inflamed skin.  Acne is caused mainly by a type of bacteria called Propionibacterium acnes that naturally resides in the follicles and pores of skin, especially on the face. Zits occur when the bacteria feed on oils in the pores. This prompts an inflammatory response from the immune system, causing the characteristic redness and unsightly pimples.

The development of an acne pimple: Figure A (top left) shows a normal hair follicle and sebaceous gland. In figure B (top center), a blockage prevents the flow of oil out of the hair follicle. Bacteria breed in the backed-up oil. In figures C and D (top right and bottom left), the follicle swells with pus. The walls of the follicle eventually burst, and the pus drains away, as shown in figure E (bottom right). (Book illustrations by Charles Wellek)

Doctors often treat problem acne with antibiotics that kill P. acnes bacteria. However, billions of bacteria reside on the skin surface, and it is impossible to eliminate them all. Antibiotics don’t always reach into the pores on the surface. Antibiotics also kill bacteria indiscriminately, knocking off helpful bacteria as well.

In the study, UCLA molecular biologist Huiynig Li and her colleagues took samples of bacteria from 101 volunteers using ordinary adhesive pore-cleansing strips. Some of the volunteers had acne while others had clear skin. Li and her team expected to find that the volunteers with acne had greater quantities of P. acnes bacteria in their pores. Instead, they found that all volunteers had a similar abundance of P. acnes. Using DNA analysis techniques, the researchers identified several different strains (varieties) of P. acnes among the volunteers. More importantly, they found that not all of the strains of P. acnes were the same. Two of the newly identified strains, called RT4 and RT5, were found mainly in volunteers with acne. However, another strain, called RT6, seemed to work to keep skin clear and healthy. This strain was found almost exclusively in volunteers with no acne.

The discovery that some strains of P. acnes bacteria are actually helpful may help dermatologists develop new treatments for acne. They may be able to develop medication that targets the bad strains while sparing the good strains. Probiotic lotions, which promote the growth of protective strains, may offer a way to achieve clear skin without antibiotics or other harsh topical medications.

Additional World Book articles:

• Abscess
• Boil
• The Passage Through Puberty (a special report)

February 21

Scientists at the Infectious Disease Research Institute of Seattle announced that they had developed a fast and simple test to determine if a patient has leprosy (also known as Hansen’s disease). In the past, the test for leprosy was complex, requiring a doctor to cut open a suspicious nodule (lump) on a patient’s skin and search the tissue under a microscope for the cause of leprosy–a rod-shaped bacterium called Mycobacterium leprae. The new test requires only a drop of blood from the patient, which is then placed into a small plastic testing device connected to a smartphone. A doctor can read the test results on the phone’s screen in seconds. This simple test can also be performed in remote and rural areas by non-physicians. The new test has a huge advantage over former testing methods–that is, people who show no symptoms of leprosy can still be tested.

Leprosy can cause crippling deformities of the hands and feet. A new test that can diagnose people at much earlier stages of the disease holds out the hope that such advanced cases of leprosy may one day be eliminated. (© Thinkstock)

Scientists are not certain how leprosy is spread, but close and repeated contact with an infected person is likely necessary. Most people infected with the leprosy bacteria do not develop symptoms, as their immune system fights the disease. It usually takes from 3 to 5 years for symptoms to develop in a person whose immune system is unable to fight the disease, but it can take as long as 10 years. The first symptoms of leprosy are usually white or reddish patches of skin, called skin lesions. These lesions are often initially misdiagnosed as some common skin disease, such as eczema. When leprosy develops further, a person experiences a loss of feeling in the skin lesions and thickened nerves. The nerves can become severely damaged, causing weakness in the hands and feet. As a result, the fingers and toes may curl inward. Eventually, a patient’s body may absorb the calcium from the bones, giving the appearance that fingers or toes have “fallen off.” The skin may also thicken, and dark nodules may appear on many parts of the body. Once nerve damage has occurred in a patient, it cannot be reversed, which is why misdiagnosis at the early stages of the disease is so tragic.

The disease leprosy is ancient, at least 2,000 years old and probably older. The lesions and deformities of leprosy are so terrible that people who have suffered with the disease have been shunned by society and, often, forced to live in colonies away from other people, known as leprosariums. Since the 1940′s, antibiotics have been available to treat patients with leprosy. Today, patients are usually treated with a combination of three antibiotics. The drugs, if taken faithfully, can cure leprosy. Two former leprosariums in the United States still have a few former patients living there–Kalaupapa, on the island of Molokai in Hawaii, and Carville in Louisiana. These former patients are no longer quarantined at the sites, but some of the elderly people who had lived there for decades chose to continue living there after the sites were closed to new patients.

Around 250,00 people worldwide are diagnosed with leprosy each year, according to the World Health Organization. It is uncommon in the United States, but the disease still occurs in other regions, including South and Southeast Asia and some parts of Latin America.

Additional World Book articles:

• leprosy
• Damien, Father

February 19, 2013

Scientists announced this week that for the first time they had found living bacteria beneath a glacier in Antarctica. A team of scientists from the Whillans Ice Stream Subglacial Access Research Drilling (WISSARD), funded by the U.S. National Science Foundation, made the find. The bacteria were discovered in Lake Whillans, which is about one-half mile (800 meters) below the West Antarctic Ice Sheet. The lake is about 5-feet (1.5-meters) deep, and scientists had to drill through the entire half mile of ice to take a sample of the lake water. After running a culture of the sample, they were able to see the bacteria under a microscope. The bacteria are members of a new ecosystem of living things that is able to survive with little light, at very cold temperatures, and under large amounts of pressure.

Lake Whillans sits at the upper tip of the Ross Ice Shelf in West Antarctica. (World Book map; map data © MapQuest.com, Inc.)

DNA testing is required for scientists to be able to identify the bacteria. Once identification has occurred, it might give scientists a better idea of what the bacteria use as food.

In addition to the excitement of finding life under Antarctic ice, scientists were also very interested in the bacteria because the conditions in Lake Whillan are not unlike some of the terrains found in outer space. For example, Jupiter’s moon, Europa, and Saturn’s moon, Enceladus, both have water that exists under ice. If the bacteria discovered under Antarctica is, for example, found to consume minerals from surrounding rock as food, a similar lifeform might be able to exist elsewhere in the solar system.

Additional World Book articles:

• Jupiter
• Europa
• Saturn
• Enceladus