Science and Engineering: Innovation, Research, Education and Economics
Antibiotics and Bacteria Category (also with posts on microbes etc.)
Posts about bacteria, antibiotics, microbes, and the overuse of antibiotics. See also health care related posts.
Recommended posts: How do antibiotics kill bacteria? - CDC Urges Increased Effort to Reduce Drug-Resistant Infections - Entirely New Antibiotic Developed - Antibiotic Discovery Stagnates - Antibiotics Too Often Prescribed for Sinus Woes
Related: Articles on the overuse of antibiotics - Antibiotic Resistance and You
June 19, 2009

Saving the World with Science and Mushrooms

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

May 13, 2009

Waste Treatment Plants Result in Super Bacteria

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.

Full press release

Related: How Bleach Kills Bacteria - Superbugs, Deadly Bacteria Take Hold - Bacteria Race Ahead of Drugs - New Family of Antibacterial Agents Discovered -

March 10, 2009

Scientists Target Bacteria Where They Live

Scientists Learning to Target Bacteria Where They Live

Scientists have learned that bacteria that are vulnerable when floating around as individual cells in what is known as their “planktonic state” are much tougher to combat once they get established in a suitable place — whether the hull of a ship or inside the lungs — and come together in tightly bound biofilms. In that state, they can activate mechanisms like tiny pumps to expel antibiotics, share genes that confer protection against drugs, slow down their metabolism or become dormant, making them harder to kill.

The answer, say researchers, is to find substances that will break up biofilms.

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.

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

March 7, 2009

Electrolyzed Water Replacing Toxic Cleaning Substances

Simple elixir called a ‘miracle liquid’

The stuff is a simple mixture of table salt and tap water whose ions have been scrambled with an electric current. Researchers have dubbed it electrolyzed water

Used as a sanitizer for decades in Russia and Japan, it’s slowly winning acceptance in the United States. A New York poultry processor uses it to kill salmonella on chicken carcasses. Minnesota grocery clerks spray sticky conveyors in the checkout lanes. Michigan jailers mop with electrolyzed water to keep potentially lethal cleaners out of the hands of inmates.

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.”

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

March 1, 2009

Gram-negative Bacteria Defy Drug Solutions

Deadly bacteria defy drugs, alarming doctors by Mary Engel

Acinetobacter doesn’t garner as many headlines as methicillin-resistant Staphylococcus aureus, the dangerous superbug better known as MRSA. But a January report by the Infectious Diseases Society of America warned that drug-resistant strains of Acinetobacter baumannii and two other microbes — Pseudomonas aeruginosa and Klebsiella pneumoniae — could soon produce a toll to rival MRSA’s.

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.

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

February 1, 2009

Searching for More Effective Tuberculosis Drugs

In India: A Search for More Effective Tuberculosis Drugs

The multi-drug regimen is a major problem for several reasons. It requires TB patients to manage taking four drugs exactly as prescribed over six to nine months. If patients don’t take the full course of the medicines, the TB bacteria may develop resistance to the drugs and become even more difficult to treat. To reduce that risk, many countries require that patients go to a clinic so a healthcare professional can watch them take the medication and ensure they are complying with their drug-treatment regimen. This is both expensive and time consuming. Gokhale said that a single drug that targets multiple pathways could save time and money by eliminating the need to take so many drugs over such a long period of time.

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

January 18, 2009

New Family of Antibacterial Agents Discovered

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

December 10, 2008

How Antibiotics Kill Bacteria

How Antibiotics Kill Bacteria

Since the first antibiotics reached the pharmacy in the 1940s, researchers discovered that they target various pieces of machinery in bacterial cells, disrupting the bacteria’s ability to build new proteins, DNA, or cell wall. But these effects alone do not cause death, and a complete explanation of what actually kills bacteria after they are exposed to antibiotics has eluded scientists.

The group found that all bactericidal antibiotics, regardless of their initial targets inside bacteria, caused E. coli to produce unstable chemicals called hydroxyl radicals. These compounds react with proteins, DNA, and lipids inside cells, causing widespread damage and rapid death for the bacteria.

With the results of these two experiments, the researchers were able to identify three major processes implicated in gentamicin-induced cell death: protein transport, a stress response triggered by abnormal proteins in the cell membrane, and a metabolic stress response.

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

November 17, 2008

How Bleach Kills Bacteria

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

October 30, 2008

Copper Doorknobs and Faucets Kill 95% of Superbugs

Copper door handles and taps kill 95% of superbugs in hospitals

A study found that copper fittings rapidly killed bugs on hospital wards, succeeding where other infection control measures failed.

It is thought the metal ’suffocates’ germs, preventing them breathing. It may also stop them from feeding and destroy their DNA. Lab tests show that the metal kills off the deadly MRSA and C difficile superbugs. It also kills other dangerous germs, including the flu virus and the E coli food poisoning bug.

Researcher Professor Peter Lambert, of Aston University, Birmingham, said: ‘The numbers decreased always on copper but not on the steel surfaces.’

The healing power of copper has been recognised for thousands of years. More than 4,000 years ago, the Egyptians used it to sterilise wounds and drinking water and the Aztecs treated skin conditions with the metal. The ancient Greeks also knew of its benefits. Hippocrates, sometimes called ‘the father of medicine’, noted that it could be used to treat leg ulcers.

Related: Anti-microbial ‘paint’ - Antimicrobial Wipes Often Spread Bacteria - Attacking Bacterial Walls

October 29, 2008

NFL Stars no Match for Bacteria

NFL stars no match for bacteria

The problem came to the forefront last week with Cleveland Browns player Kellen Winslow, who recently had his second staph infection. He is reportedly the sixth player to acquire staph among the Browns in five years.

Peyton Manning of the Indianapolis Colts was revealed to have a staph infection, the Indianapolis Star reported Friday. University of North Carolina-Asheville fans also recently learned that Kenny George, the 7-foot-7 center on the basketball team, had a staph infection complication that led to part of his foot being amputated. It’s unclear how these high-profile athletes acquired their infections, but locker rooms have been found to habor staph bacteria in previous outbreaks.

A study on the St. Louis Rams published in the New England Journal of Medicine in 2003 found that during the 2003 football season, there were eight MRSA infections among five of the 58 Rams players.

Related: CDC Urges Increased Effort to Reduce Drug-Resistant Infections - Antimicrobial Wipes Often Spread Bacteria - Treadmill Desks

September 17, 2008

Move over MRSA, C.diff is Here

Clostridium difficile (C.diff), a bacteria, is increasingly posing health risk. Rising Foe Defies Hospitals’ War On ‘Superbugs’

Even as hospitals begin to get control of other drug-resistant infections such as MRSA, a form of staph, rates of C. diff are rising sharply, and a recent, more virulent strain of the bug is causing more severe complications. The Centers for Disease Control and Prevention estimates there are 500,000 cases of C. diff infection annually in the U.S., contributing to between 15,000 and 30,000 deaths. That’s up from roughly 150,000 cases in 2001.

Many patients get C. diff infections as an unintended consequence of taking antibiotics for other illnesses. That’s because bacteria normally found in a person’s intestines help keep C. diff under control, allowing the bug to live in the gut without necessarily causing illness. But when a person takes antibiotics, both bad and good bacteria are suppressed, allowing drug-resistant C. diff to grow out of control.

Only 3% to 5% of healthy, non-hospitalized adults carry C. diff in their gut, but that rate is much higher in hospitals and nursing homes, where carriers can spread the bacteria to others. Studies at several hospitals in recent years have shown that 20% or more of inpatients were colonized with C. diff, and a 2007 study of 73 long-term-care residents showed 55% were positive for C. diff. Even though the majority had no symptoms of disease, spores on the skin of asymptomatic patients were easily transferred to the investigators’ hands.

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

August 17, 2008

Superbugs - Deadly Bacteria Take Hold

Superbugs by Jerome Groopman, New Yorker:

“My basic premise,” Wetherbee said, “is that you take a capable microörganism 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.

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

June 15, 2008

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.

Related: Entirely New Antibiotic Developed - Soil Could Shed Light on Antibiotic Resistance - articles on the Overuse of Antibiotics

April 22, 2008

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.

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.

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.

Related: Androgenesis - Sick spinach: Meet the killer E coli - Parasite Rex

April 8, 2008

Clay Versus MRSA Superbug

“Healing clays” hold promise in fight against MRSA superbug infections and disease

Scientists from Arizona State University report that minerals from clay promise could provide inexpensive, highly-effective antimicrobials to fight methicillin-resistant Staphylococcus aureus (MRSA) infections that are moving out of health care settings and into the community.

Unlike conventional antibiotics routinely administered by injection or pills, the so-called “healing clays” could be applied as rub-on creams or ointments to keep MRSA infections from spreading

In their latest study, funded by the National Institutes of Health, Williams, Haydel and their colleagues collected more than 20 different clay samples from around the world to investigate their antibacterial activities… The researchers identified at least two clays from the United States that kill or significantly reduce the growth of these bacteria

Also listen to a podcast with the researchers, Lynda Williams and Shelly Haydel, that provides much more detail. The Science Studio podcasts from Arizona State University provides great science podcasts.

Related: Soil Could Shed Light on Antibiotic Resistance - Entirely New Antibiotic Developed - Science Webcast Directory - NSF Awards $50 Million for Collaborative Plant Biology Project (University of Arizona)

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