Tag Archives: bacteria

Superbugs – Deadly Bacteria Take Hold

Superbugs by Jerome Groopman, New Yorker:

“My basic premise,” Wetherbee said, “is that you take a capable microÃ¶rganism like Klebsiella and you put it through the gruelling test of being exposed to a broad spectrum of antibiotics and it will eventually defeat your efforts, as this one did.” Although Tisch Hospital has not had another outbreak, the bacteria appeared soon after at several hospitals in Brooklyn and one in Queens. When I spoke to infectious-disease experts this spring, I was told that the resistant Klebsiella had also appeared at Mt. Sinai Medical Center, in Manhattan, and in hospitals in New Jersey, Pennsylvania, Cleveland, and St. Louis.
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Unlike resistant forms of Klebsiella and other gram-negative bacteria, however, MRSA can be treated. “There are about a dozen new antibiotics coming on the market in the next couple of years,” Moellering noted. “But there are no good drugs coming along for these gram-negatives.” Klebsiella and similarly classified bacteria, including Acinetobacter, Enterobacter, and Pseudomonas, have an extra cellular envelope that MRSA lacks, and that hampers the entry of large molecules like antibiotic drugs. “The Klebsiella that caused particular trouble in New York are spreading out,” Moellering told me. “They have very high mortality rates. They are sort of the doomsday-scenario bugs.”

Great article. Related: Bacteria Survive On All Antibiotic Diet – Bacteria Can Transfer Genes to Other Bacteria – New Yorker on CERN’s Large Hadron Collider – posts on health related topics

Nebraska Firm Expands Recall of Beef Products

Nebraska Firm Expands Recall of Beef Products Due To Possible E. coli O157:H7 Contamination, USDA

Nebraska Beef, Ltd., an Omaha, Neb., establishment is expanding its June 30 recall to include all beef manufacturing trimmings and other products intended for use in raw ground beef produced between May 16 and June 26, totaling approximately 5.3 million pounds
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FSIS advises all consumers to safely prepare their raw meat products, and only consume ground beef or ground beef patties that have been cooked to a safe internal temperature of 160Âº F. The only way to be sure ground beef is cooked to a high enough temperature to kill harmful bacteria is to use a thermometer to measure the internal temperature.
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Also as a result of the investigation, on June 25 FSIS announced a recall of ground beef products sold at Kroger retail establishments in Michigan and in Central and Northwestern Ohio.

Another example of the questionable state of food safety in the USA.

Alligator Blood Provides Strong Resistance to Bacteria and Viruses

Gator Blood May Be New Source of Antibiotics

The study authors, from McNeese State University and Louisiana State University, said their research is the first to take an in-depth look at alligator blood’s prospects as an antibiotic source. According to the researchers, alligators can automatically fight germs such as bacteria and viruses without having been exposed to them before launching a defense.

For the study, the researchers extracted proteins known as peptides from white cells in alligator blood. As in humans, white cells are part of the alligator’s immune system. The researchers then exposed various types of bacteria to the protein extracts and watched to see what happened.

In laboratory tests, tiny amounts of these protein extracts killed a so-called “superbug” called methicillin-resistant Staphylococcus aureus, or MRSA. The bacteria has made headlines in recent years because of its killing power in hospitals and its spread among athletes and others outside of hospitals.

The extracts also killed six of eight strains of a fungus known as Candida albicans, which causes a condition known as thrush, and other diseases that can kill people with weakened immune systems.

Bacteria Evolutionary Shift Seen in the Lab

Bacteria make major evolutionary shift in the lab

A major evolutionary innovation has unfurled right in front of researchers’ eyes. It’s the first time evolution has been caught in the act of making such a rare and complex new trait. And because the species in question is a bacterium, scientists have been able to replay history to show how this evolutionary novelty grew from the accumulation of unpredictable, chance events.
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sometime around the 31,500th generation, something dramatic happened in just one of the populations – the bacteria suddenly acquired the ability to metabolise citrate, a second nutrient in their culture medium that E. coli normally cannot use. Indeed, the inability to use citrate is one of the traits by which bacteriologists distinguish E. coli from other species.
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The replays showed that even when he looked at trillions of cells, only the original population re-evolved Cit+ – and only when he started the replay from generation 20,000 or greater. Something, he concluded, must have happened around generation 20,000 that laid the groundwork for Cit+ to later evolve.

Lenski and his colleagues are now working to identify just what that earlier change was, and how it made the Cit+ mutation possible more than 10,000 generations later.

Bacteria “Feed” on Earth’s Ocean-Bottom Crust

Once considered a barren plain dotted with hydrothermal vents, the seafloor’s rocky regions appear to be teeming with microbial life, say scientists
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“Initial research predicted that life could in fact exist in such a cold, dark, rocky environment,” said Santelli. “But we really didn’t expect to find it thriving at the levels we observed.” Surprised by this diversity, the scientists tested more than one site and arrived at consistent results, making it likely, according to Santelli and Edwards, that rich microbial life extends across the ocean floor. “This may represent the largest surface area on Earth for microbes to colonize,” said Edwards.
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Santelli and Edwards also found that the higher microbial diversity on ocean-bottom rocks compared favorably with other life-rich places in the oceans, such as hydrothermal vents. These findings raise the question of where these bacteria find their energy, Santelli said.

“We scratched our heads about what was supporting this high level of growth,” Edwards said. With evidence that the oceanic crust supports more bacteria than overlying water, the scientists hypothesized that reactions with the rocks themselves might offer fuel for life.

Why doesn’t this stuff make the news over what some celebrity did or politician said… (well I must admit I am just guessing since I don’t actually watch the news or read the mass media much – other than some science, investing or economics content). Oh well, at least you get to read the Curious Cat Science blog and find out about some of the cool stuff being learned every day.

Learning from Leprosy Diagnosis

A Scary Diagnosis Hits Home

The diagnosis that ultimately resulted — leprosy — turned the Blanchards’ world upside down and rippled through the lives of many people they knew or had contact with. It also raised issues that are often confronted when any contagious disease is diagnosed, particularly one with scary connotations: What precautions should be taken to protect the rights of the affected individual as well as the health of the community?
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For the Blanchards, some of the answers lay almost literally in their back yard. Baton Rouge is home to the National Hansen’s Disease (Leprosy) Clinical Center, part of the U.S. Public Health Service.
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About 300,000 new cases of leprosy are diagnosed annually, according to the World Health Organization. Now known as Hansen’s disease, after the Norwegian scientist who discovered the mycobacterium that causes the illness, it affects about 2 million to 3 million people worldwide.

Where it is left untreated, Hansen’s disease is a leading cause of disability and devastating deformity. It remains endemic in Bangladesh, India, Brazil and elsewhere. In the United States, roughly 6,000 people have the disease. One hundred to two hundred new cases are reported annually, and, like BB Blanchard, about two dozen of those new patients have never been beyond U.S. borders.
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How transmission occurs is a mystery. Humans and the armadillo are the only two creatures known to get the disease. No one knows where the microbe hides in nature, although the suspicion is that the leprosy mycobacterium may be airborne like its bacterial cousin, tuberculosis.

Most people think of leprosy as a skin disease. But the rash that BB Blanchard had and the disfiguring lesions often associated with it are just a symptom. The mycobacteria burrow into nerves, where they often remain undetected for years or even decades.

High School Student Isolates Microbe that Eats Plastic

WCI student isolates microbe that lunches on plastic bags

Daniel Burd’s project won the top prize at the Canada-Wide Science Fair in Ottawa. He came back with a long list of awards, including a $10,000 prize, a $20,000 scholarship, and recognition that he has found a practical way to help the environment.
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First, he ground plastic bags into a powder. Next, he used ordinary household chemicals, yeast and tap water to create a solution that would encourage microbe growth. To that, he added the plastic powder and dirt. Then the solution sat in a shaker at 30 degrees.

After three months of upping the concentration of plastic-eating microbes, Burd filtered out the remaining plastic powder and put his bacterial culture into three flasks with strips of plastic cut from grocery bags. As a control, he also added plastic to flasks containing boiled and therefore dead bacterial culture.

Six weeks later, he weighed the strips of plastic. The control strips were the same. But the ones that had been in the live bacterial culture weighed an average of 17 per cent less.
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The inputs are cheap, maintaining the required temperature takes little energy because microbes produce heat as they work, and the only outputs are water and tiny levels of carbon dioxide — each microbe produces only 0.01 per cent of its own infinitesimal weight in carbon dioxide, said Burd.

“This is a huge, huge step forward . . . We’re using nature to solve a man-made problem.” Burd would like to take his project further and see it be used. He plans to study science at university, but in the meantime he’s busy with things such as student council, sports and music.

Bacteriophages: The Most Common Life-Like Form on Earth

There are more bacteriophages on Earth than any other life-like form. These small viruses are not clearly a form of life, since when not attached to bacteria they are completely dormant. Bacteriophages attack and eat bacteria and have likely been doing so for over 3 billion years. Although initially discovered early last century, the tremendous abundance of phages was realized more recently when it was found that a single drop of common seawater typically contains millions of them. Extrapolating, phages are likely to be at least a billion billion times more numerous than humans. Pictured above is an electron micrograph of over a dozen bacteriophages attached to a single bacterium. Phages are very small — it would take about a million of them laid end-to-end to span even one millimeter. The ability to kill bacteria makes phages a potential ally against bacteria that cause human disease, although bacteriophages are not yet well enough understood to be in wide spread medical use.

Photo credit: Wikipedia Electron micrograph of bacteriophages attached to a bacterial cell. These viruses have the size and shape of coliphage T1.; Insert: Mike Jones

E. Coli Individuality

Expressing Our Individuality, the Way E. Coli Do by Carl Zimmer

A good counterexample is E. coli, a species of bacteria that lives harmlessly in every person’s gut by the billions. A typical E. coli contains about 4,000 genes (we have about 20,000). Feeding on sugar, the microbe grows till it is ready to split in two. It makes two copies of its genome, almost always managing to produce perfect copies of the original. The single microbe splits in two, and each new E. coli receives one of the identical genomes. These two bacteria are, in other words, clones.
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A colony of genetically identical E. coli is, in fact, a mob of individuals. Under identical conditions, they will behave in different ways. They have fingerprints of their own.
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E. coli appears to follow a universal rule. Other microbes exploit noise, as do flies, worms and humans. Some of the light-sensitive cells in our eyes are tuned to green light, and others to red. The choice is a matter of chance. One protein may randomly switch on the green gene or the red gene, but not both.

In our noses, nerve cells can choose among hundreds of different kinds of odor receptors. Each cell picks only one, and evidence suggests that the choice is controlled by the unpredictable bursts of proteins within each neuron. It’s far more economical to let noise make the decision than to make proteins that can control hundreds of individual odor receptor genes.

Identical genes can also behave differently in our cells because some of our DNA is capped by carbon and hydrogen atoms called methyl groups. Methyl groups can control whether genes make proteins or remain silent. In humans (as well as in other organisms like E. coli), methyl groups sometimes fall off of DNA or become attached to new spots. Pure chance may be responsible for changing some methyl groups; nutrients and toxins may change others.

Viruses Eating Bacteria

All the World’s a Phage by John Travis:

“Believe it or not, nobody had looked before,” says Suttle. “On average, there are 50 million viruses per milliliter in seawater. The question is, What the heck they’re doing there?” Microbiologists then documented similar, and even higher, concentrations of phages in soil samples. This led to estimates of 10³¹ bacteriophages worldwide, a staggeringly large number that many scientists initially dismissed. “We can’t wrap our brains around it,” says Pedulla. “If phages were the size of a beetle, they would cover the Earth and be many miles deep.”
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According to estimates put forth by Suttle, phages destroy up to 40 percent of the bacteria in Earth’s oceans each day.
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The students collected soil from barnyards, gardens, and even the monkey pit at the Bronx Zoo. The scientists then taught the students how to isolate a bacteriophage from the soil by growing the viruses in Mycobacterium smegmatis, a harmless bacterial relative of the microbe that causes tuberculosis. “We guarantee them that the bacteriophage they find will never have been discovered before. We know that because the diversity is so high, and we’ve never isolated the same bacteriophage twice,” says Hatfull.

In the April 18 Cell, Hatfull and his professional and teenage collaborators describe the genomes of 10 soil-dwelling bacteriophages that they had isolated. Of the more than 1,600 genes that the team identified, about half are novel, that is, they don’t match any previously described genes in any other organism.

Science is full of amazing new frontiers. Some other amazing stuff: Thinking Slime Moulds – Tracking the Ecosystem Within Us – Retroviruses – Energy Efficiency of Digestion – One Species’ DNA Discovered Inside Another’s