It's summertime and movie companies are once again betting on the draw of the classic fight between good and evil manifested in our love for the superhero and our hatred for the supervillain. From the iconic Superman and his battle with the evil General Zod to Iron Man and his struggles against The Mandarin, epic clashes are packing theatres.
Closer to home, our bodies are being subjected to similar conflicts in which germs are constantly fighting to take over a more important prize: our health.
The supervillains are few, but they are well known and can bring fear to anyone who is aware of them, or worse, has suffered from their evil deeds. While perhaps the worst of them all are the ever dreaded Ebola virus, SARS, and avian influenza, cases of these are few and far between. The real archnemesis is without a doubt Norovirus, which can halt a cruise ship in its tracks and close down hospital wards.
This week, another major enemy of the human state was given the spotlight in the microbiological world. A group led by Dr. Joshua Adkins at the Pacific Northwest National Laboratory in Richland, Washington, took a closer look at Salmonella, the fourth leading cause of foodborne illness. They wanted to see just how infection progressed in the gut. What they found would make even Dr. Doom proud.
As Salmonella enters the gastrointestinal tract, it finds a happy environment that is going about its business in a comfortable manner. But soon, Salmonella starts to make trouble, stealing away valuable nutrients from the happy microbial citizens and vandalizing the lining of the intestines. As the immune system reacts, the normal microbes start to disappear either through the inability to thrive, or worse, from the overreaction of the immune system. As the disruption continues, Salmonella continues to multiply and soon simply outnumbers all the other cells in the area. At the height of the attack, the entire area is worse than a Bane-destroyed Gotham City.
Eventually, as the destruction takes its toll, the evil bacteria start to decrease in number -- their job is over and they have moved on to seek other victims. Much like Gotham, the intestinal city, which could be called "Gutham," will eventually recuperate, but life there may never be the same.
Thankfully, there are a group of superheroes who can help ward off the Salmonella attack. Probiotics, specifically Lactobacillus, have been shown to fight Salmonella at every stage of its attack. They can prevent the bacterium from getting anywhere near the intestinal lining; help to control the immune system's reaction to infection to ensure that the intruder is killed; and they even have the ability to kill the invaders with their own superpowered weapons known as antimicrobial compounds. While probiotics, much like superheroes, cannot stop these invaders entirely, they can help to protect our "Gutham" and even help to fight off the enemies when they come.
This week also saw the unveiling of another supreme battle between the forces of good and evil with a globe at stake. Although in this case, the spherical object isn't the Earth; it's your eye.
Researchers from the University of Pittsburgh and the University of Medicine and Dentistry of New Jersey collaborated on a project that focused on how using two microbial superheroes named Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus can help to protect the eye from the threat of a duo of supervillains.
Infection of the eye, in this case, bacterial keratitis, is an inflammation of the front of the eye causing itching, redness, and pain. If it is untreated, the damage can be severe and even cost a person his or her vision. There are several sight-scaring supervillains but the two examined in this study were Pseudomonas aeruginosa and Serratia marcescens.
The researchers engaged a battle in a petri dish, putting the four bacterial species together. Sure enough, over 48 hours, B. bacteriovorus and M. aeruginosavorus, lived up to the meanings of their names: bacteria and aeruginosa devouring. The predatory nature of these two bacteria was sufficient to reduce the level of both P. aeruginosa and S. marcescens by anywhere from 99 to 99.99%. The superheroes were hungry and they feasted. But while that worked in a petri dish, the researchers also wanted to see if this could be used in the eye itself. Rather than using humans, they had a surrogate, the larvae of the wax moth .
The results were just as impressive; almost all the worms' eyes were saved. There was even an added bonus. The two heroes did not trigger an immune response and as such, the crawlers were able to live naturally without any concern for their sight. The good bacteria were worthy of their heroic title in the lab as well as the insect model.
The battle for the body is a continuous one and there will never be a time when we are not threatened by one of the long list of microbial threats. However, as we realize that we as humans are not alone, we are learning how to work with good germs, such as Lactobacillus, Bdellovibrio, and Micavibrio, as allies in the fight. Although their actions may not be as appealing as what we might see on the big screen, the work of these small defenders deserves our attention and respect. Moreover, while we may know of many at the moment, there is little doubt that with continued research in microbes and their interaction with us, we'll continue to find even more superheroes.
Each of us has more than 1,000 different types of bacteria that live in our digestive tracts, helping us to break down food and absorb nutrients. But when we take antibiotics -- medicine that is designed to kill destructive, illness-causing bacteria -- the drugs can also kill the healthy intestinal flora that helps us digest. About 30 percent of the patients who take antibiotics report suffering from diarrhea or some other form of gastrointestinal distress, according to the recent JAMA study on probiotics and antibiotic-associated diarrhea. As a result, doctors commonly prescribe taking probiotics to "repopulate" the digestive tract with healthful bacteria. The study found that it was a viable solution for many. But probiotics can also help with other types of digestive issues. Research has shown that probiotics can be helpful for people with irritable bowel syndrome, or IBS -- a hard-to-treat condition that can have a range of intestinal symptoms, such as abdominal pain, cramps, bloating, diarrhea and constipation. In one study, female IBS patients experienced some alleviation of symptoms like abdominal pain and irregularity when they were given a supplement of the bacterial strain, Bifidobacterium infantis. Even for those without an urgent problem, probiotics can help with overall digestive management. Challa argues in his book, Probiotics For Dummies, that good bacteria help "crowd out" bad bacteria. That's because the intestine is lined with adherence sites where bacteria latches on. If the sites are populated with good-for-you microbes, there's no place for a harmful bacterium to latch on.
Probiotics make a nice compliment to antibiotics among people who suffer from urinary tract infections, according to the research. What's more, there's emerging evidence that regular probiotics can help prevent bad bacteria from invading the urinary tract by maintaining a population of healthy bacteria on the tract's adherence sites. Infections of the urinary tract are extremely common, especially in women. Most infections disappear with antibiotics, but about 30 to 40 percent might return, according to literature from the University of Maryland Medical Center.
Allergy research is still preliminary, but at least one large, high quality study found a relationship between women taking probiotics during pregnancy and a 30 percent reduction in the instance of childhood eczema (an early sign of allergies) in their infants. Researchers selected women who had a history of seasonal allergies -- or whose partners had histories of allergies. The infants who received probiotics in-vitro also had 50 percent higher levels of tissue inflammation, which is thought to trigger the immune system and reduce allergy incidence.
Just like the digestive tract, the vagina relies on a precarious balance of good and bad bacteria. When that balance is off, it can result in one of two very common, though thoroughly uncomfortable infections: bacterial vaginosis and yeast infections. In fact, bacterial vaginosis can actually lead to a yeast infection. Some small studies have found that L. acidophilius can help prevent infection, manage an already active one or support antibiotics as a treatment, though it's worth noting that the probiotics were taken as vaginal suppositories, rather than orally in food. Probiotics may also have a special role in maternal health, as pregnant women are particularly susceptible to vaginal infections. And bacterial vaginosis has been indicated as a contributing factor to pre-term labor, making probiotics a potential boon for fetal health.
Surprisingly, one of the main functions of healthful bacteria is to stimulate immune response. By eating probiotic-rich foods and maintaining good intestinal flora, a person can also help to maintain a healthy immune system. And that has real world effects: for example, in one small study of students, those who were given a fermented dairy drink (instead of milk) displayed increased production from lymphocytes -- a marker of immune response.
In 2006, Stanford University researchers found that obese people had different gut bacteria than normal-weighted people -- a first indication that gut flora plays a role in overall weight. Some preliminary research shows that probiotics can help obese people who have received weight loss surgery to maintain weight loss. And in a study of post-partum women who were trying to lose abdomnial fat, the addition of lactobacillus and bifidobacterium capsules helped reduce waist circumference. It's still unclear how probiotics play a role in weight loss -- and there is some controversy about how significant the probiotics-associated weight loss is. But as long as the probiotics source is low-calorie and healthful, itself, it is an innocuous method to attempt.
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