Tag Archives: Antibiotics

Antibiotics Breed Superbugs Faster Than Expected

We continue to endanger ourselves by using antibiotics inappropriately. This is one of many things that happen when the public at large is ignorant about science and ignores scientific evidence. I don’t believe people want to put other people’s lives in danger. But our behavior in the face of the evidence has us doing just that. I believe because we don’t value science rather than because we don’t care about putting others (and ourselves) in danger. Antibiotics Breed Superbugs Faster Than Expected

Bacteria don’t just develop resistance to one drug at a time, but to many — and at accelerated rates. That’s because antibiotics boost bacterial production of free-radical oxygen molecules that damage bacterial DNA. Repairs to the DNA cause widespread mutations, giving bacteria more chances to randomly acquire drug-resistant traits.
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Drug resistance is a serious public health concern. According to the federal Centers for Disease Control and Prevention, 70 percent of 1.7 million infections acquired in hospitals every year are resistant to at least one drug. Those infections annually kill 99,000 Americans — more than double the number that die in car crashes.

Drugs that once destroyed almost any bacteria now kill only a few, or don’t work at all. In the case of some drugs, like Cipro, the decline is dramatic: Where in 1999 it worked against 95 percent of E. coli, it treated only 60 percent by 2006. Against lung infection-causing Acinobacter, its effectiveness fell by 70 percent in just four years.

Though drug resistance is ultimately inevitable, conventional wisdom holds that antibiotics consumed at suboptimum doses hasten the process. Bugs that would have succumbed to a larger dose live to multiply, pushing the strain as a whole closer to resistance. That happens when a prescription goes unfinished, or when antibiotics used on farms enter food and water at low levels.
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Of the 35 million pounds of antibiotics consumed annually in the United States, 80 percent goes to farm animals. Much of it is used to treat diseases spread by industrial husbandry practices, or simply to accelerate growth. As a result, farms have become giant petri dishes for superbugs, especially multidrug-resistant Staphylococcus aureus, or MRSA, which kills 20,000 Americans every year – more than AIDS.

Alarming cases of farm-based MRSA and other diseases led to a proposed Congressional law restricting the use of agricultural antibiotics. That bill, supported by the American Medical Association and American Public Health Association, is opposed by farm lobbyists and remains stuck in committee.

Microbes Flourish In Healthy People

Bugs Inside: What Happens When the Microbes That Keep Us Healthy Disappear? by Katherine Harmon

The human body has some 10 trillion human cells—but 10 times that number of microbial cells. So what happens when such an important part of our bodies goes missing?
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“Someone who didn’t have their microbes, they’d be naked,” says Martin Blaser, a professor of microbiology and chair of the Department of Medicine at New York University Langone Medical Center in New York City.
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Even though it is such an apparently integral and ancient aspect of human health, scientists are still grasping for better ways to study human microbiota—before it changes beyond historical recognition. Borrowing models from outside of medicine has helped many in the field gain a better understanding of this living world within us. “The important concept is about extinctions,” Blaser says. “It’s ecology.”
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The first step in understanding these systems is simply taking stock of what archaea, bacteria, fungi, protozoa and viruses are present in healthy individuals. This massive micro undertaking has been ongoing since 2007 through the National Institutes of Health’s (NIH) Human Microbiome Project. So far it has turned up some surprisingly rich data, including genetic sequencing for some 205 of the different genera that live on healthy human skin.

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.

Disrupting Bacterial Communication to Thwart Them

Interrupting Bacterial Chatter to Thwart Infection

To measure their own numbers, bacteria produce, release, and detect chemical signals called autoinducers. As a population of bacteria grows, it releases more autoinducer into its environment. When individuals detect that a threshold level of autoinducer is present, they change their behavior – by releasing a toxin, for example.

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.

Bacteria Use Nitric Oxide to Resist Antibiotics

Scientists Discover Mechanism to Make Existing Antibiotics More Effective at Lower Doses

Eliminating this NO[nitric oxide]-mediated bacterial defense renders existing antibiotics more potent at lower, less toxic, doses. With infectious diseases the major cause of death worldwide, the study paves the way for new ways of combating bacteria that have become antibiotic resistant.

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.

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

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.
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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.

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
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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.”
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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.

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.
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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.

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 GrÃ¶tzinger, 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.

GrÃ¶tzinger 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

Evolution, Methane, Jobs, Food and More

Photo from May 2005 by NASA’s Mars Exploration Rover Spirit as the Sun sank below the rim of Gusev crater on Mars.

Science Friday is a great National Public Radio show. The week was a great show covering Antimicrobial Copper, Top Jobs for Math and Science, Human-Driven Evolution, Methane On Mars, Fish with Mercury and more. This show, in particular did a great job of showing the scientific inquiry process in action.

“Fishing regulations often prescribe the taking of larger fish, and the same often applies to hunting regulations,” said Chris Darimont, one of the authors of the study. “Hunters are instructed not to take smaller animals or those with smaller horns. This is counter to patterns of natural predation, and now we’re seeing the consequences of this management.” Darimont and colleagues found that human predation accelerated the rate of observable trait changes in a species by 300 percent above the pace observed within purely natural systems, and 50 percent above that of systems subject to other human influences, such as pollution

Very interesting stuff, listen for more details. A part of what happens is those individuals that chose to focus on reproducing early (instead of investing in growing larger, to reproduce later) are those that are favored (they gain advantage) by the conditions of human activity. I am amazed how quickly the scientists says the changes in populations are taking place.

And Methane On Mars is another potentially amazing discovery. While it is far from providing proof of live on Mars it is possibly evidence of life on Mars. Which would then be looked back on as one of the most important scientific discoveries ever. And in any even the podcast is a great overview of scientists in action.

This week astronomers reported finding an unexpected gas — methane — in the Martian atmosphere. On Earth, a major source of methane is biological activity. However, planetary scientists aren’t ready to say that life on Mars is to blame for the presence of the gas there, as geochemical processes could also account for the finding. The find is intriguing especially because the researchers say they have detected seasonal variations of methane emissions over specific locations on the planet.

Martian Methane Reveals the Red Planet is not a Dead Planet
The Mars Methane Mystery: Aliens At Last?