Posts Tagged "Bacteria"

food 2Food expiration dates are generally guidelines rather than hard-and-fast rules.

Obviously, a container of milk won’t sour at precisely 12:01 a.m. on the stamped date. But the dates on labels can be tricky.

The Food and Drug Administration doesn’t regulate expiration dates except on baby formula. Many dates are there for the benefit of the store, not the consumer.

Kristin Kirkpatrick, the manager of nutrition services at the Cleveland Food 1Clinic Wellness Institute, offers a quick guide to label language:

– A “sell by” date indicates how long a store should display a product on its shelves. Foods can still be tasty and are safe for several days longer if stored properly.

– A “use by” or “best if used by” date comes from the manufacturer and refers to taste and texture, not safety.

– An “expiration” date is the only packaging date related to food safety. If this date has passed, throw the food out.

Unfortunately, 30 percent to 40 percent of all harvested food in this country ends up wasted, much of it by consumers who waited too long to eat it, or worried it had gone bad, according to a report last month in PLOS One.

food 3Adding to the confusion: Foods spoil at different rates, depending on their type and growing conditions, as well as how they were harvested, transported and distributed, and how they have been stored after being purchased, said Robert B. Gravani, a professor of food science at Cornell University.

Looking closely at food isn’t a good way to check for spoilage, Dr. Gravani said, because bacteria are largely invisible.

Source: New York Times

Flu Season 3At present, influenza activity is low in the United States but we expect activity to increase in the coming weeks as the U.S. typically experiences peak influenza activity between December and February. Based on our surveillance data we also expect an increase in norovirus in the very near future. In addition to vaccinations, it is also important to emphasize the early use of antivirals in the treatment of influenza. Antivirals are an important second line of defense, particularly for those at high-risk for complications from influenza. Two neuraminidase inhibitor antiviral medications are recommended for use in the United States—oseltamivir (Tamiflu®) and zanamivir (Relenza®). Current national surveillance data has not revealed significant resistance to oseltamivir and zanamivir to date.

Treatment works best when started within the first 48 hours of illness and can shorten the duration of symptoms and reduce Flu Season 2the risk of severe complications and death. Treatment with antiviral medications is recommended for patients with influenza who are hospitalized; have severe, complicated or progressive illness; or are at higher risk for influenza complications. Antiviral treatment may also be considered in other populations, if treatment can be initiated within 48 hours of illness onset. Use of antivirals for the prevention of influenza should be considered for institutional outbreaks (such as in nursing homes or other closed populations) or for those who have contraindications to influenza vaccination. Other preventive health practices that may help decrease the spread of influenza and Flu Season 1other common winter illnesses (such as norovirus), include staying home from work and school when ill, staying away from people who are sick, increasing hand washing, and using cough etiquette and respiratory hygiene practices.

Source: CDC

“The Center has plenty of Quadrivalent Influenza vaccine available.”

Smartphones reflect the personal microbial world of their owners, say US scientists.

More than 80% of the common bacteria that make up our personal bacterial “fingerprints” end up on their screens, a study suggests.

using-smartphone-saidaonlinePersonal possessions, such as phones, might be useful for tracking the spread of bacteria, they report in PeerJ.

They reflect our microbiome – the trillions of different micro-organisms that live in and on our bodies.

Mobile phone users have been found to touch their devices on average 150 times a day.

Scientists have found an overlap between the collection of micro-organisms naturally present on our bodies and those on the screens of smartphones.

They say this could one day be used to track people’s exposure to bacteria.

In the study, biologists from the University of Oregon sequenced the DNA of microbes found on the index fingers and thumbs of 17 people.

They also took swabs of the subjects’ smartphones.

A total of 7,000 different types of bacteria were found in 51 samples.

On average, 22% of bacterial families overlapped on fingers and phones.

Some 82% of the most common bacteria present on participants’ fingers were also found on their phones.

They included three families that are commonly found on the skin or in the mouth – Streptococcus, Staphylococcus and Corynebacterium.

Men and women both shared bacteria with their phones, but the connection was stronger in women.

Lead researcher Dr James Meadow said while the sample size was small, the findings were “revealing”.

“This project was a proof-of-concept to see if our favourite and most closely held possessions microbially resemble us,” he said.

“We are ultimately interested in the possibility of using personal effects as a non-invasive way to monitor our health and our contact with the surrounding environment.”

The researchers say there is no evidence that mobile phones present any more infection risk than any other possession.

But they say our phones might one day be used to study whether people have been exposed to certain bacteria, particularly healthcare workers.

The study confirms that “we share more than an emotional connection with our phones – they carry our personal microbiome”, Dr Meadow added.

There is increasing scientific interest in the human microbiome – the population of trillions of micro-organisms that live in our gut, mouth, skin and elsewhere on our bodies.

Bacteria can be harmful but they can also have beneficial effects, particularly in the gut, by digesting food and making essential nutrients and vitamins.

Stress has long been thought to trigger heart attacks, but the mechanism is unknown. Now, researchers think that bacteria could play a role. A study published today in suggests that stress hormones can break up mats of bacteria growing on the fatty plaques in arteries, releasing the plaques and causing strokes or heart attacks.

Researchers have suspected for years that bacteria infect the plaques of hardened arteries. The plaques form a surface on which bacteria can attach and grow in masses called biofilms, held together in a scaffold. To test this, a team led by bacteriologist David Davies of Binghamton University in New York analyzed arteries from 15 patients with cardiovascular disease. Using fluorescent tags that mark bacterial DNA, they discovered at least 10 species of bacteria clustered tightly around the plaques, including the biofilm-forming Pseudomonas aeruginosa.

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If these biofilms are tightly attached to plaques, they may have an effect on cardiovascular disease, Davies says. Plaques in blood vessels are normally stable, but if they break up and enter the bloodstream, they can trigger blood clots that lead to heart attacks or strokes.

To test this idea, the researchers grew P. aeruginosa in artificial arteries made of silicone tubing and waited for the bacteria to form biofilms. They then flooded the tubes with the stress hormone noradrenaline, which caused the biofilms to break up.

The authors say that stress hormones in the blood trigger the body’s cells to release iron into the bloodstream. The iron causes bacteria such as P. aeruginosa to produce enzymes that sever the polymer bonds that hold the bacteria together in the biofilm matrix and attach the bacteria to the plaque. The plaque is broken up as collateral damage, Davies says. Although he says that much more research in animals and humans is needed, the work “introduces a completely unexpected potential culprit” in the mystery of how plaques trigger heart attacks, he adds.

“It’s quite an intriguing hypothesis,” says microbiologist Primrose Freestone of the University of Leicester, UK. But she adds that the amount of noradrenaline that the authors used in the experiment is much higher than would be present in a human body.

Still, Freestone says, it is possible that noradrenaline levels are somewhat higher at the site of the plaque. And she says that the project could serve as a “springboard” for researchers to think more about the role of bacteria in cardiovascular disease.

Emil Kozarov, a microbiologist at Columbia University in New York, agrees that the idea is interesting. But he says that he would like to see whether noradrenaline breaks up plaques in mice injected with the biofilm bacteria, and whether noradrenaline disperses biofilms formed by other bacterial species.

Davies says that he plans to model the process in mice. He and his team are also planning to determine whether the arteries of healthy people contain biofilm-forming bacteria.

Source: Scientific American

triclosan

In 1978 the Bee Gees ruled the airwaves, Grease topped the box office and the U.S. Food and Drug Administration first proposed a rule on antibacterial hand soaps—a rule that would have eliminated an unnecessary and unsafe ingredient called triclosan. Thirty-five years later many things have changed, but the FDA has not. Just recently it proposed rules on antibacterial soaps that would remove triclosan-containing soap from the shelves—for the third time. Yet because the FDA has failed to finalize any of these proposals, triclosan has proliferated in the marketplace. It is now the most common active ingredient found in antibacterial consumer hand soaps.

It’s also common in our bodies. Triclosan has been measured in amniotic fluid, breast milk, human blood and the urine of 75 percent of Americans sampled over the age of six. Although it does not discriminate by gender or racial/ethnic group, it appears to increase in concentration as income increases. Despite little evidence of their effectiveness to reduce illness, triclosan-containing antibacterial soaps have dominated the market. Soap aside, triclosan can also be found in consumer products as diverse as cutting boards, shoes, lipstick and toothpaste.

In other words, we are continually exposed to triclosan. The problem is that triclosan is not safe. In animal studies it has been shown to interfere with the regulation of thyroid hormones (affecting metabolism and brain development), testosterone synthesis (decreasing sperm counts) and estrogen action (causing early onset of puberty). Exposure to triclosan has been shown to weaken heart muscle, impairing contractions and reducing heart function, and to weaken skeletal muscle, reducing grip strength. In aquatic environments fish exposed to triclosan were unable to swim properly.

Higher urinary levels of triclosan are associated with hay fever, allergies to airborne triggers (like ragweed and cats) and food (peanut, shrimp, dairy) allergies. Triclosan has even been associated with elevated body mass index in adults. Although the mechanism driving this association is not clear, researchers suggest that it could be due to changes in the gut flora or hormones.

There are also concerns about the potential impact of triclosan use on development of antibiotic resistance. Laboratory studies on bacteria exposed to triclosan demonstrate evidence of cross-resistance to critically important antibiotics including erythromycin, ciprofloxacin, ampicillin and gentamicin. Further, there is evidence that resistance to triclosan itself exists in Salmonella enterica, Staphylococcus aureus, streptococcus, Escherichia coli and other species of bacteria. Strains of Mycobacterium tuberculosis tolerant to triclosan have also showed resistance to the drug isoniazid (INH), which is used to treat tuberculosis. Although the overuse of antibiotics in humans and livestock is a greater contributor to the public health crisis of antibiotic-resistant bacteria, the potential increased risk of antibiotic resistance from the use of antimicrobial chemicals is unnecessary.

To add insult to injury, there is no added benefit to using triclosan (or any antibacterial) soaps. Triclosan is intrinsically ineffective against some bacteria like Pseudomonas aeruginosa and fungal infections. The FDA requires that to be considered effective these soaps must do more than remove bacteria; they must “provide a clinical benefit by reducing infections.” But studies show that using soap containing triclosan does not reduce human illnesses or infections any more than using regular soap. There have even been occasional reports of fatal bacterial outbreaks in hospitals using triclosan, including bacterial contamination of triclosan soap containers in a surgical intensive care unit.

Which brings us back to the FDA. In the rule it proposed in 1978 (and again in 1994 and 2013) the FDA said it does not have sufficient information to determine whether triclosan is safe or effective. In the absence of such a determination triclosan cannot be sold in the U.S.—but the FDA’s failure to finalize these proposals allowed the products to remain on the market. Therefore, in 2010 the Natural Resources Defense Council sued the FDA to compel it to finalize its rules. As a result of the settlement, the FDA now has to finish its rules on antibacterial soaps by September 2016. If at that time the FDA still cannot say triclosan is safe and effective, then antibacterial hand soaps can no longer contain triclosan. Until then, antibacterial soaps remain on the market and consumers are left to protect themselves from this harmful chemical.

Source: Scientific American

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