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Bugs Inside: What Happens When the Microbes That Keep Us Healthy Disappear? by Katherine Harmon
Despite the flood of new data, Foxman laughs when asked if there is any hope for a final report from the Human Microbiome Project any time soon. “This is the very, very beginning,” she says, comparing this project with the NIH’s Human Genome Project, which jump-started a barrage of new genetic research. “There are basic, basic questions that we don’t know the answers to,” she says, such as how different microbiota are between random individuals or family members; how much microbiota change over time; or how related the microbiota are to each other on or inside a person’s body.
Related: Microcosm by Carl Zimmer – Tracking the Ecosystem Within Us – Alligator Blood Provides Strong Resistance to Bacteria and Viruses – Beneficial Bacteria
Interrupting Bacterial Chatter to Thwart Infection
Bassler and her colleagues disrupted these lines of communication by interfering with molecules called acyl-homoserine lactone (AHL) autoinducers, which drive quorum sensing among a kind of bacteria known as Gram-negative bacteria. Gram-negative bacteria include Pseudomonas, E. coli and Salmonella, and other disease-causing microbes. In the study, the team focused on Chromobacterium violaceum, which rarely infects human, but can be lethal to other organisms. C. violaceum lends itself to studies of quorum sensing because it produces a readily detected, bright purple dye when it detects that its population has reached a critical mass.
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The experiment shows that interfering with quorum sensing may provide an alternative to traditional antibiotics, Bassler says, and circumvent the problem of resistance that antibiotics foster by killing off susceptible bacteria but allowing resistant ones to survive and propagate.
Related: Bacteria Communicate Using a Chemical Language (quorum sensing) – Disrupting Bacteria Communication (2007) – Electrolyzed Water Replacing Toxic Cleaning Substances – Gram-negative Bacteria Defy Drug Solutions
Scientists Discover Mechanism to Make Existing Antibiotics More Effective at Lower Doses
NO is a small molecule composed of one atom of oxygen and one of nitrogen. It was known as a toxic gas and air pollutant until 1987, when it was first shown to play a physiological role in mammals, for which a Nobel Prize was later awarded. NO has since been found to take part in an extraordinary range of activities including learning and memory, blood pressure regulation, penile erection, digestion and the fighting of infection and cancer. A few years ago, the Nudler’s group from NYU demonstrated that bacteria mobilize NO to defend against the oxidative stress. The new study from the same group supports the radical idea that many antibiotics cause the oxidative stress in bacteria, often resulting in their death, whereas NO counters this effect. This work suggests scientists could use commercially available inhibitors of NO-synthase, an enzyme producing NO in bacteria and humans, to make antibiotic resistant bacteria like MRSA and ANTHRAX more sensitive to available drugs during acute infection.
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The study by Nudler and his colleagues was funded by a 2006 Pioneer Award from the National Institutes of Health in Bethesda, Maryland. The Pioneer Award, a $2.5 million grant over five years, is designed to support individual scientists of exceptional creativity who propose pioneering and possibly transforming approaches to major challenges in biomedical and behavioral research.
Related: Copper Doorknobs and Faucets Kill 95% of Superbugs – How Bleach Kills Bacteria – Foreign Cells Outnumber Human Cells in Our Bodies – Bacteria Survive On All Antibiotic Diet
Entrepreneurial mycologist Paul Stamets studies mushrooms. The focus of Stamets’ research is the Northwest’s native fungal genome, mycelium, but along the way he has filed 22 patents for mushroom-related technologies, including pesticidal fungi that trick insects into eating them, and mushrooms that can break down the neurotoxins used in nerve gas.
The webcast really gets interesting at minute 9 or so (in my opinion) with 6 specific examples.
Related: Fun Fungi – Thinking Slime Moulds – Microbe Types
Multiple antibiotic-resistant bacteria has emerged as one of the top public health issues worldwide in the last few decades as the overuse of antibiotics and other factors have caused bacteria to become resistant to common drugs. Chuanwu Xi’s group chose to study Acinetobacter because it is a growing cause of hospital-acquired infections and because of its ability to acquire antibiotic resistance.
Xi said the problem isn’t that treatment plants don’t do a good job of cleaning the water—it’s that they simply aren’t equipped to remove all antibiotics and other pharmaceuticals entering the treatment plants.
The treatment process is fertile ground for the creation of superbugs because it encourages bacteria to grow and break down the organic matter. However, the good bacteria grow and replicate along with the bad. In the confined space, bacteria share resistant genetic materials, and remaining antibiotics and other stressors may select multi-drug resistant bacteria.
While scientists learn more about so-called superbugs, patients can do their part by not insisting on antibiotics for ailments that antibiotics don’t treat, such as a common cold or the flu, Xi said. Also, instead of flushing unused drugs, they should be saved and disposed of at designated collection sites so they don’t enter the sewer system.
The next step, said Xi, is to see how far downstream the superbugs survive and try to understand the link between aquatic and human superbugs. This study did not look past 100 yards.
Xi’s colleagues include visiting scholar Yongli Zhang; Carl Marrs, associate professor of public health; and Carl Simon, professor of mathematics.
Xi and colleagues found that while the total number of bacteria left in the final discharge effluent declined dramatically after treatment, the remaining bacteria was significantly more likely to resist multiple antibiotics than bacteria in water samples upstream. Some strains resisted as many as seven of eight antibiotics tested. The bacteria in samples taken 100 yards downstream also were more likely to resist multiple drugs than bacteria upstream.
Related: How Bleach Kills Bacteria – Superbugs, Deadly Bacteria Take Hold – Bacteria Race Ahead of Drugs – New Family of Antibacterial Agents Discovered –
Scientists Learning to Target Bacteria Where They Live
The answer, say researchers, is to find substances that will break up biofilms.
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Melander said “a throwaway sentence in an obscure journal” — the Bulletin of the Chemical Society of Japan — gave them another clue. They isolated a compound from the sponge that disperses biofilms and figured out how to synthesize it quickly and cheaply.
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But dispersing biofilms without understanding all the ramifications could be a “double-edged sword,” Romeo warned, because some bacteria in a biofilm could wreak worse havoc once they disperse.
“Simply inducing biofilm dispersion without understanding exactly how it will impact the bacterium and host could be very dangerous, as it might lead to spread of a more damaging acute infection,” he said.
Related: Entirely New Antibiotic Developed – Soil Could Shed Light on Antibiotic Resistance – How Antibiotics Kill Bacteria
Simple elixir called a ‘miracle liquid’
In Santa Monica, the once-skeptical Sheraton housekeeping staff has ditched skin-chapping bleach and pungent ammonia for spray bottles filled with electrolyzed water to clean toilets and sinks. “I didn’t believe in it at first because it didn’t have foam or any scent,” said housekeeper Flor Corona. “But I can tell you it works. My rooms are clean.”
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It turns out that zapping salt water with low-voltage electricity creates a couple of powerful yet nontoxic cleaning agents. Sodium ions are converted into sodium hydroxide, an alkaline liquid that cleans and degreases like detergent, but without the scrubbing bubbles. Chloride ions become hypochlorous acid, a potent disinfectant known as acid water.
“It’s 10 times more effective than bleach in killing bacteria,” said Yen-Con Hung, a professor of food science at the University of Georgia-Griffin, who has been researching electrolyzed water for more than a decade. “And it’s safe.”
There are drawbacks. Electrolyzed water loses its potency fairly quickly, so it can’t be stored long. Machines are pricey and geared mainly for industrial use. The process also needs to be monitored frequently for the right strength.
Very cool use of science: providing a green cleaning agent that is effective.
Related: Clean Clothes Without Soap – posts on chemical engineering – iRobot Gutter Cleaning Robot – Water From Air
Deadly bacteria defy drugs, alarming doctors by Mary Engel
The three bugs belong to a large category of bacteria called “gram-negative” that are especially hard to fight because they are wrapped in a double membrane and harbor enzymes that chew up many antibiotics. As dangerous as MRSA is, some antibiotics can still treat it, and more are in development, experts say.
But the drugs once used to treat gram-negative bacteria are becoming ineffective, and finding effective new ones is especially challenging.
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For the most part, gram-negative bacteria are hospital scourges — harmless to healthy people but ready to infect already-damaged tissue. The bacteria steal into the body via ventilator tubes, catheters, open wounds and burns, causing pneumonia, urinary tract infections, and bone, joint and bloodstream infections.
Pseudomonas is widely found in soil and water, and rarely causes problems except in hospitals.
Related: Superbugs – Deadly Bacteria Take Hold – CDC Urges Increased Effort to Reduce Drug-Resistant Infections – MRSA Blows Up Defender Cells – posts on antibiotics
In India: A Search for More Effective Tuberculosis Drugs
To create their new compound, Gokhale and his colleagues exploited an evolutionary quirk in the way Mycobacterium tuberculosis builds the lipid layer that coats its surface. Unlike other organisms, M. tuberculosis displays a suite of complex lipids on its outer membrane. Some scientists have suggested that these long lipid molecules contribute to the bacteria’s ability to maintain long-term infections by confusing the host’s immune system.
Related: Fighting Tuberculosis – TB Pandemic Threat – Extensively Drug-resistant Tuberculosis (XDR TB) – Virtually untreatable TB found
Bacteria continue to gain resistance to commonly used antibiotics. In this week’s JBC, one potential new antibotic has been found in the tiny freshwater animal Hydra.
The protein identified by Joachim Grötzinger, Thomas Bosch and colleagues at the University of Kiel (Germany), hydramacin-1, is unusual (and also clinically valuable) as it shares virtually no similarity with any other known antibacterial proteins except for two antimicrobials found in another ancient animal, the leech.
Hydramacin proved to be extremely effective though; in a series of laboratory experiments, this protein could kill a wide range of both Gram-positive and Gram-negative bacteria, including clinically-isolated drug-resistant strains like Klebsiella oxytoca (a common cause of nosocomial infections). Hydramacin works by sticking to the bacterial surface, promoting the clumping of nearby bacteria, then disrupting the bacterial membrane.
Grötzinger and his team also determined the 3-D shape of hydramacin-1, which revealed that it most closely resembled a superfamily of proteins found in scorpion venom; within this large group, they propose that hydramacin and the two leech proteins are members of a newly designated family called the macins.
Source: American Society for Biochemistry and Molecular Biology
Related: Entirely New Antibiotic Developed (platensimycin) – Bacteria Race Ahead of Drugs – How Bleach Kills Bacteria – Antibacterial Products May Do More Harm Than Good
Related: How Bleach Kills Bacteria – Bacteria Survive On All Antibiotic Diet – Soil Could Shed Light on Antibiotic Resistance – Antibiotics Too Often Prescribed for Sinus Woes
Developed more than 200 years ago and found in households around the world, chlorine bleach is among the most widely used disinfectants, yet scientists never have understood exactly how the familiar product kills bacteria. In fact, Hypochlorite, the active ingredient of household bleach, attacks essential bacterial proteins, ultimately killing the bugs.
“As so often happens in science, we did not set out to address this question,” said Jakob, an associate professor of molecular, cellular and developmental biology. “But when we stumbled on the answer midway through a different project, we were all very excited.”
Jakob and her team were studying a bacterial protein known as heat shock protein 33 (Hsp33), which is classified as a molecular chaperone. The main job of chaperones is to protect proteins from unfavorable interactions, a function that’s particularly important when cells are under conditions of stress, such as the high temperatures that result from fever.
“At high temperatures, proteins begin to lose their three-dimensional molecular structure and start to clump together and form large, insoluble aggregates, just like when you boil an egg,” said lead author Jeannette Winter, who was a postdoctoral fellow in Jakob’s lab. And like eggs, which once boiled never turn liquid again, aggregated proteins usually remain insoluble, and the stressed cells eventually die.
Jakob and her research team figured out that bleach and high temperatures have very similar effects on proteins. Just like heat, the hypochlorite in bleach causes proteins to lose their structure and form large aggregates.
These findings are not only important for understanding how bleach keeps our kitchen countertops sanitary, but they may lead to insights into how we fight off bacterial infections. Our own immune cells produce significant amounts of hypochlorite as a first line of defense to kill invading microorganisms. Unfortunately, hypochlorite damages not just bacterial cells, but ours as well. It is the uncontrolled production of hypochlorite acid that is thought to cause tissue damage at sites of chronic inflammation.
How did studying the protein Hsp33 lead to the bleach discovery? The researchers learned that hypochlorite, rather than damaging Hsp33 as it does most proteins, actually revs up the molecular chaperone. When bacteria encounter the disinfectant, Hsp33 jumps into action to protect bacterial proteins against bleach-induced aggregation.
“With Hsp33, bacteria have evolved a very clever system that directly senses the insult, responds to it and increases the bacteria’s resistance to bleach,” Jakob said.
Related: University of Michigan Press release – How do antibiotics kill bacteria? – NPR podcast on the story – Why ‘Licking Your Wounds’ Works – Researchers Learn What Sparks Plant Growth
Copper door handles and taps kill 95% of superbugs in hospitals
Related: Anti-microbial ‘paint’ – Antimicrobial Wipes Often Spread Bacteria – Attacking Bacterial Walls
NFL stars no match for bacteria
Related: CDC Urges Increased Effort to Reduce Drug-Resistant Infections – Antimicrobial Wipes Often Spread Bacteria – Treadmill Desks
Clostridium difficile (C.diff), a bacteria, is increasingly posing health risk. Rising Foe Defies Hospitals’ War On ‘Superbugs’
Related: C.diff deaths double in two years – Killing Germs May Be Hazardous to Your Health – Bacteria Survive On All Antibiotic Diet – Articles on the Overuse of Antibiotics – Good Germs – Clay Versus MRSA Superbug
Superbugs by Jerome Groopman, New Yorker:
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
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