Thursday, 17 September 2009

Sunday, 13 September 2009

Is your beach contaminated with MRSA?




Is your beach contaminated with MRSA?

September 12, 2009 | 11:33 am

Beach1Staphylococcus aureus is a common bug that can cause serious infections. An antibiotic-resistant strain, called MRSA (methicillin-resistant Staphylococcus aureus), has increased dramatically in recent years. It typically spreads in hospitals. But it's also found in healthy people in the community. It spreads from skin-to-skin contact with someone who is infected, or by touching surfaces contaminated with the germ.

Little is known about places in the environment where MRSA can hide. A study presented today, however, is the first to show that public beaches may be reservoirs for the bug. Staph was isolated in marine water and in intertidal beach sand in nine of 10 public beaches in Washington state, and half of the strains were MRSA, according to the study from researchers at the University of Washington. When examined, those strains appeared to be the type that spreads in hospitals rather than community-acquired MRSA.

How beaches are becoming contaminated with hospital-acquired MRSA is unknown, said the lead author of the study, Dr. Marilyn C. Roberts. The study was presented this morning at the Interscience Conference on Antimicrobial Agents and Chemotherapy in San Francisco.

"Where all these organisms are coming from and how they are getting seeded, we don't know," Roberts said. The samples were "grab-and-go" samples, meaning that researchers didn't spend a lot of time thinking about where to collect the samples. And, Roberts said, "the fact that we found these organisms suggests [beach contamination] is much higher than we normally thought."

Another study on beach sand, published in June in the Journal of Epidemiology, found that people who dug in the sand or covered themselves with sand were more likely to have diarrheal illnesses in the following week or two compared with beachgoers who just walked on the beach or lay on the sand. The most likely scenario for MRSA infection, Roberts said, is getting sand in a cut or abrasion. But the risk of getting MRSA at the beach cannot be estimated at this time.

"We don't know what the risk is because nobody's done a good study," she said.

Roberts also tested two beaches in Southern California and did not find MRSA. But that should not reassure beachgoers in California -- or anywhere. Testing of the samples from California beaches was delayed, which may have affected the quality of the test, Roberts said.

The best advice for beachgoers is to cover open skin wounds and wash off sand thoroughly. People who have weakened immune systems because of other illnesses should take special care with open wounds.

"I'm not telling people not to go to the beach," Roberts said. "But if, all of a sudden, you have a skin rash and it doesn't get better, you need to go and be seen."

-- Shari Roan

Photo credit: Allen J. Schaben / Los Angeles Times

Tuesday, 8 September 2009

Deep Inside Bacteria, a Germ of Human Personality










Article Link Here

Deep Inside Bacteria, a Germ of Human Personality

Scientists Hope to Fight Infections by Blocking the Social Creatures' Ability to Sense When They Have Sufficient Numbers to Attack

Bacteria are the oldest living things on earth, and researchers have long felt that they must lead dull, unfussy lives. New discoveries are starting to show just how wrong that notion is.

For a simple, single-cell creature, a bacterium is surprisingly social. It can communicate in two languages. It can tell self from nonself, friend from foe. It thrives in the company of others. It spies on neighbors, spreads misinformation and even commits fratricide.

"Really, they're just stripped-down versions of us," says Bonnie Bassler, microbial geneticist at Princeton University, who has spent two decades peeking at the inner lives of bacteria. Dr. Bassler and other scientists are using this information to devise new ways to fight infections and reduce antibiotic resistance.

Bacterial society is based on a chemical language called quorum sensing. To detect how many of its own species, or members of another bacterial species, are in the immediate vicinity, each bacterium secretes a certain molecule into the environment. The greater the number of molecules it can sense, the more fellow bacteria it knows are out there.

This is often a trigger to act. Some bacteria will attack a person or any other host only after establishing that there is a quorum -- a large-enough army to overcome the host's immune defenses. The strategy helps explain the virulence of a number of human ailments, including cholera, pneumonia and food poisoning.

Dr. Bassler was the first to identify the molecule that bacteria use to communicate with members of other species. She hopes the finding will lead to a new kind of drug that won't succumb to antibiotic resistance.

Resistance is a serious and growing health risk across the world. It occurs because most antibiotics are designed to kill bacteria. But some bugs survive the attack and pass on their resistant genes to their progeny, strengthening future generations and making the antibiotic less effective.

Instead of killing bacteria, Dr. Bassler wants to simply jam their communication lines -- the quorum-sensing mechanism. She figures that if the bugs can't signal each other, they can't properly assess the size of their growing army and might never attack. Another benefit: Because bacteria aren't killed, the approach could delay the onset of resistance.

In a study published in July in the journal Molecular Cell, Dr. Bassler and her colleagues identified a compound that disrupted bacterial small talk. The compound stopped worms from dying from a bug that also infects humans. The next step is to test it on mice. Says Dr. Bassler: "We plan to tinker with the molecule to make it stronger and stronger."

Labs are developing similar drugs to fight other bacterial maladies, including cholera, pneumonia and septicemia. Last year, University of Iowa researchers used a human protein to destroy a particular bacterium's messenger molecule, protecting fruit flies from infection-related death. The bacterium is the same one that causes some infections in hospitalized patients, burn victims and people with cystic fibrosis. Microbiologist Richard Novick of New York University has applied a similar technique for fighting staph infections in animal models. And the U.S. National Institutes of Health's Human Microbiome Project aims to catalog and understand all the microbes humans carry, and their role in nutrition, development and physiology.

Though the drugs are promising, they are a long way from being tried on humans.

At first glance, bacterial life is humdrum. A microbe eats nutrients, doubles in size, then divides in two. The colony grows.

But scientists are learning that microbes interact with humans in complex and often-useful ways. For starters, humans have one trillion cells of their own, but 10 trillion cells of bacteria. "At best," says Dr. Bassler, "you're only 10% human."

While some bacteria cause disease, other "good" bacteria keep people alive. They digest plant products in the gut, educate the immune system, and help to produce vitamins B-12 and K. Some 1,000 species live on human skin alone.

Equally remarkable is how bacteria band together and behave like sophisticated, multicellular animals. They sometimes organize into deeply structured "slime cities," or biofilms. The whitish layer that forms on the teeth every morning is actually a tightknit community of 600 bacterial species. Brush it away, and a new layer will form in exactly the same way by the next morning.

In the 1970s, scientists puzzled over why a colony of bioluminescent bacteria begins to glow only after it reaches a certain size. Over the years, they found the answer. By releasing a chemical into their environment, the bacteria constantly communicate with each other in order to assess the size of their population. Once the chemical level reaches a certain threshold, the bacteria individually -- and simultaneously -- turn on their lights.

In the deep ocean where light is scarce, the angler fish makes clever use of bacteria's ability to shine through quorum-sensing. A spine of the fish's dorsal fin has evolved to stick out like a fishing rod; its tip is home to a colony of bioluminescent bacteria. Attracted by the glowing lure, prey swim towards the angler fish and are devoured in its toothy jaws.

In the early 1990s, Dr. Bassler discovered that bacteria use a second chemical language to talk to other species, a sort-of microbial Esperanto. "The molecule simply says 'I'm the other,'" says Dr. Bassler. "But there must be molecules that tell the bacteria who the other is. We haven't found those yet."

Today, quorum sensing is a fast-growing area of research, with dozens of labs involved and scores of papers published.

During a recent tour of her lab in Princeton, N.J., Dr. Bassler asked a visitor to peer through a microscope. A dozen or so tiny worms, known as c. Elegans, writhed on a glass plate. The worms were the subject of the experiment that was recently reported in Molecular Cell.

In the experiment, Dr. Bassler was looking for a drug that would disrupt a bacteria's quorum-sensing system. As an opponent, she chose a bacterial species, C. violaceum, whose relatives include salmonella and E. coli. Though it rarely infects humans, violaceum can easily kill other creatures, including c. Elegans.

When its population reaches a certain critical mass, E. violaceum produces an easy-to-see purple dye, making it a good subject to study in the lab. To communicate with its brethren, it uses a molecule called acyl-homoserine lactone, or AHL. Dr. Bassler hoped to block AHL.

She had researchers at Broad Institute in Cambridge, Mass., screen 35,000 chemicals to see whether any might do the trick. They narrowed the possibilities to 15 compounds, then picked the most promising one and tweaked its molecular structure to make it more powerful.

It worked. The researchers found that the chemical interfered with the bacteria's quorum-sensing mechanism and prevented infected worms from dying. The worms suffered no noticeable ill effects.

Write to Gautam Naik at gautam.naik@wsj.com


Monday, 7 September 2009

Bedding- Animal Health is the Whole Point


Which bedding is best?


Link to Article Here



With the arrival of autumn, and winter on the horizon, the majority of horses will be spending more time in their stables, which can lead to problems such as RAO, capped hocks and thrush. However, in certain cases, these conditions can be avoided by simply changing your horse's bedding.

Capped hocks and elbows

If a horse has insufficient bedding in his stable, he may suffer from capped hocks and elbows, caused by bruising over the point of the hock or elbow joint, both of which contain lubricating joint fluid.

In serious cases, the joints can become very swollen and sore, and the horse may also be lame. A combination of rubber matting and a covering of additional bedding such as straw or paper usually helps to alleviate the problem.

Colic

Horses who eat their bedding through hunger or boredom may become prone to colic. A common cause of bedding-related colic is a horse eating dry bedding, which then expands in the stomach causing discomfort, inflammation and possibly a blockage. Choosing a non-palatable alternative such as cardboard or shavings should deter the horse from nibbling his bed.

Getting cast

Horses who enjoy rolling may become cast. This can cause injury and swelling to joints and limbs, as well as potential back damage. High banks and a thick layer of light bedding such as straw will go some way to alleviate injury if your horse does become cast.

RAO

Recurrent airway obstruction (RAO), formerly known as chronic obstructive pulmonary disease (COPD), is a common respiratory disease similar to asthma in humans. In most cases, RAO is caused by hypersensitivity to mould spores in the horse's environment. It is a management issue. The horse's respiratory tract responds to allergy-inducing particles with a narrowing of the airways and reduced breathing capacity. Many horses with RAO are kept outdoors, while stabled patients are commonly given rubber flooring and/or dust-extracted bedding to reduce spores.

Urticaria

Some forms of the skin irritation urticaria can be caused by an allergy to bedding or mould, which results in the appearance of rashes or bumps on the horse's body. It is usually a temporary condition, alleviated when the offending bedding is removed and the stable cleaned and disinfected to eradicate mould spores.

Slipping

Shod horses with smooth stable floors and a minimal amount of bedding may be prone to slipping in the stable, resulting in musculoskeletal trauma or strain. Rubber matting is an ideal solution to provide grip for the horse when getting up or lying down, especially if a covering of additional bedding is provided on top.

Stiffness and injury

Some horses with stiff joints, or those with limited mobility through injury, may suit certain types of bedding. For example, rubber matting may not provide enough comfort for the horse who is immobilised for long periods, while some types of bedding can become tangled around limbs or make dressings or wounds messy and unhygienic. Light, clean types of bedding, such as chopped cardboard, are good choices for equine patients.

Thrush

Horses suffering from conditions of the foot, such as thrush, need clean, dry stable bedding in order for the foot to dry out and recover. With this in mind, bedding such as hemp or wood fibre, both of which drain down to the base leaving a dry top layer, may be good options.

Is this a viable market?

www.americanhorsecouncil.org

Highlights of the national study include:

There are 9.2 million horses in the United States.

4.6 million Americans are involved in the industry as horse owners, service providers, employees and volunteers. Tens of millions more participate as spectators.

2 million people own horses.

The horse industry has a direct economic effect on the U.S.of $39 billion annually.

The industry has a $102 billion impact on the U.S.economy when the multiplier effect of spending by industry suppliers and employees is taken into account. Including off-site spending of spectators would result in an even higher figure.

The industry directly provides 460,000 full-time equivalent (FTE) jobs.

Spending by suppliers and employees generates additional jobs for a total employment impact of 1.4 million FTE jobs.

The horse industry pays $1.9 billion in taxes to all levels of government.

Approximately 34% of horse owners have a household income of less than $50,000 and 28% have an annual income of over $100,000. 46% of horse owners have an income of between $25,000 to $75,000.

Over 70% of horse owners live in communities of 50,000 or less.

There are horses in every state. Forty-five states have at least 20,000 horses each.


Numbers of Horses

The study concludes that there are 9.2 million horses in the U.S., including horses used for racing, showing, competition, sport, breeding, recreation and work. This includes horses used both commercially and for pleasure.

Specifically, the number of horses by activity is:

Racing - 844,531
Showing - 2,718,954
Recreation - 3,906,923
Other - 1,752,439
Total - 9,222,847

“Other” activities include farm and ranch work, rodeo, carriage horses, polo, police work, informal competitions, etc.

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