My Science School

Superbugs are bacteria that have acquired resistance to several types of antibiotic drugs either through genetic mutation or through build up of resistance over time chiefly due to the misuse or overuse of antibiotics. This means that certain antibiotics which have saved millions of lives earlier will no longer be effective against such bacteria. Scientists call them drug-resistant bacteria or antibiotic-resistant bacteria and they are posing a significant health threat globally today.

Scientists discovered one such superbug called the MRSA (or methicillin-resistant staphylococcus aureus) in 2011. It was thought to have emerged in cows given the large amounts of antibiotics used among cattle. However, a team of international researchers have found that drug-resistant bacteria MRSA evolved naturally about 200 years ago as a result of a battle between a parasitic fungus species and a bacteria species that share space on the skin of wild hedgehogs While the use of antibiotics often drives the evolution of superbugs, this study shows the origins of some antibiotic-resistant bacteria in Nature.

How did the superbug evolve on hedgehog?

Researchers found two kinds of organisms living on the skin of European hedgehogs. They were the superbug Staphylococcus aureus and the parasitic fungus Erinaceus europaeus. The fungus secretes the antibiotic methicillin (a form of penicillin), which inhibits the growth of Staphylococcus aureus to increase its chance of survival. The bacteria, in turn, evolved antibiotic resistance to outsmart their fungal rivals and thrive on their hedgehog hosts. Researchers believe that this particular strain of bacteria that colonised the hedgehogs, known as mecC-MRSA, might have found its way their livestock and eventually to humans.

What's more?

The team sequenced the genomes of the fungus on the hedgehogs and found the genes responsible for producing the antibiotics and then they sequenced the bacteria. Through genetic coding, researchers were able to establish a timeline of the evolution of the hedgehog-borne mecC-MRS. They found that the bacteria had resistance to methicillin as early as the 1800s, long before the clinical use of penicillin began in the 1940s.

(Alexander Fleming discovered penicillin in 1928, a fact you might have read about in your classes. If you remember the story of the penicillin discovery, you would know that Fleming noticed that the staphylococci on the petri dish he had left behind in his lab prior to a vacation had been destroyed by the mold or fungus that had developed on the gel in the dish.)

What led to the development of antibiotic resistance?

There are multiple factors that led to the increase in antibiotic resistance among bacteria.

• Bacteria are living organisms and they evolve, adapting to new environments and new challenges, just like any other organism.
• The trait of antibiotic resistance develops over time.
• Bacteria share genes with other bacteria, and thus pass on the resistance.
• Bacteria strong enough to survive a drug will have a chance to grow and multiply.
• While antibiotic resistance occurs naturally, misuse of antibiotics in humans and animals is accelerating the process.
• Unnecessary prescription by physicians or self-medication by patients: If an antibiotic is taken against a viral infection, the drug does not target the disease-causing virus but instead kills the good bacteria that aid in digestion and in fighting infection.
• Improper disposal of medical waste leads to contamination of water and soil where the bacteria acquire resistance.

Picture Credit : Google

More powerful, destructive, and deadlier storms will be the "new normal" as the effects of climate change take root, the top U.S. emergency management official said after massive tornadoes ravaged six states.

Meteorologists and other scientists have long warned of the growing intensity of weather events like storms, fires and flooding.

But the crisis hit the U.S. in a terrifying way when more than two dozen twisters raked across large swaths of the American heartland, leaving more than 90 people dead, dozens missing and communities in ruin.

"This is going to be our new normal," Deanne Criswell, head of the Federal Emergency Management Agency, told CNN'S "State of the Union." "The effects that we're seeing from climate change are the crisis of our generation," she added. Criswell warned of the challenge that the United States faces in addressing such severe weather events.

In another programme, she told ABC's "This Week," "We're seeing more intense storms, severe weather, whether it's hurricanes, tornadoes, wildfires. The focus I'm going to have is, how do we start to reduce the impacts of these events." The tornado that reduced several towns to rubble was a gargantuan twister. It rumbled along the ground for over 320 km, one of the longest, if not the longest on record.

What causes a tornado?

Tornadoes are whirling, vertical air columns that form from thunderstorms and stretch to the ground. They travel with ferocious speed and lay waste to everything in their path. Thunderstorms occur when denser, drier cold air is pushed over warmer, humid air, conditions scientists call atmospheric instability. As that happens, an updraft is created when the warm air rises. When winds vary in speed or direction at different altitudes- a condition known as wind shear-the updraft will start to spin. These changes in winds produce the spin necessary for a tornado. For especially strong tornadoes, changes are needed in both the wind's speed and direction.

Role of climate change

Scientists say figuring out how climate change is affecting the frequency of tornadoes is complicated. But they do say the atmospheric conditions that give rise to such outbreaks are intensifying in the winter as the planet warms. One paper published recently by scientific association AGU says its analysis "suggests increasing global temperature will affect the occurrence of conditions favourable to severe weather."

Rising global temperatures are driving significant changes for seasons that we traditionally think of as rarely producing severe weather. Stronger increases in warm humid air in fall, winter, and early spring mean there will be more days with favourable severe thunderstorm environments - and when these storms occur, they have the potential for greater intensity. Projections suggest that stronger, tornado-producing storms may be more likely as global temperatures rise, though strengthened less than we might expect from the increase in available energy. Studies have shown that the rate of increase in severe storm environments will be greater in the Northern Hemisphere, and that it increases more at higher latitudes.

Picture Credit : Google