Navigation Links
Scientists look to the Bahamas as a model for coral reef conservation

Bacteria are bad. Mothers and doctors, not to mention the cleaning product industry, repeatedly warn of their dangers. But a Stanford University School of Medicine microbiologist is raising the intriguing idea that persistent bacterial and viral infections have benefits.

Stanley Falkow, PhD, the Robert W. and Vivian K. Cahill Professor in Cancer Research, is publishing his thoughts on this topic in an essay in the Feb. 24 issue of the journal Cell, in which he asks, "Is persistent bacterial infection good for your health?" The essay is based on a talk he was invited to give at Cambridge University in November.

Falkow points out that the medical community and those who fund medical research focus on curing disease. He wonders if this single-mindedness might distract researchers from appreciating the beneficial contributions of micro-organisms to the body.

"Organisms that cause disease are usually considered in the context of harm and epidemics and so on," said Falkow. "But the fact is that a great number of organisms that infect humans come in and set up housekeeping as it were. There are no clinical symptoms of anything wrong and people take the organisms with them to their graves."

It's not that the organisms in question - such as the bacteria that cause pneumonia or meningitis - are innocuous, he said. It's just that most of the individuals do not get disease from being infected.

The best recent example of this, said Falkow, is H. pylori. First identified only 25 years ago, the organism earned researchers last year's Nobel Prize in Medicine or Physiology for being implicated as a cause of ulcers and stomach cancer.

As is typical in the world of microbiology, though, it's not a simple equation: being infected = ulcers or cancer. At least 80 percent of the world's population is infected with H. pylori yet has no overt symptoms.

What makes the study of H. pylori even more perplexing is that as such advances as c lean water and pasteurization are adopted, the prevalence of H. pylori infection has declined. On the one hand, this has been accompanied by a drop in the incidence of gastric cancer and ulcers. On the other, there has been an increase in esophageal cancer. H. pylori appear to protect against cancer of the esophagus. "So that says that there might be something about persistent infection that might be protective," said Falkow.

This raises the conundrum: By messing with the microbes, are we just replacing one disease with another?

Falkow's lab has been studying the phenomenon of persistent infection for decades, in particular with H. pylori and Salmonella. He and his colleagues have shown that when infected with these organisms, mice initially show an inflammatory response that then settles down and stays with them for the rest of their lives.

Although very few of these organisms remain in the mice, it is enough to cause the immune system to have an ongoing response. "It's not so much that the immune system has failed," Falkow explained, "but that the organisms have manipulated the immune system in such a way that they can't be cleared." If the infections are cleared by antibiotic intervention, the mice are highly susceptible to re-infection, and the re-infection is more likely to progress to disease than the initial infection.

Furthermore, as many infectious diseases have decreased, autoimmune diseases such as ulcerative colitis, Crohn's disease and diabetes have increased.

"All these observations have been made without necessarily trying to pull it all together," said Falkow. "So what I tried to do in this article is to point out that the continued presence of these organisms in human society may actually be beneficial to the host and that is why they are tolerated by the immune system."

It's an intriguing idea that requires more research in animal models. "We don't know what to look for per se," he said. "But we can g uess that since a persistently infected host is constantly having its immune system stimulated and refined, that may provide it with resistance to other things."

He wondered whether, as seen with H. pylori, humans are also unknowingly causing the disappearance of other things that have been with us for all of our evolution, and that might play some role in our health. "Could it be this that is responsible for some of the things we see such as the failure of the immune system to act appropriately?" he asked.

The only answer to date is: "It's complicated." Instead of a persistent infection, some people get very ill from organisms such as Salmonella, H. pylori, tuberculosis and meningitis. How the immune system responds differently in individuals demands further research.

Falkow credits his colleagues for providing the fodder for his essay.


Source:Stanford University

Related biology news :

1. Scientists ID molecular switch in liver that triggers harmful effects of saturated and trans fats
2. Scientists Replicate Hepatitis C Virus in Laboratory
3. Scientists detect probable genetic cause of some Parkinsons disease cases
4. Scientists find missing enzyme for tuberculosis iron scavenging pathway
5. Scientists seek answers on what activates deadly anthrax spores
6. Yale Scientists Find MicroRNA Regulates Ras Cancer Gene
7. Scientists collaborate to assess health of global environment
8. Scientists decipher genome of fungus that can cause life-threatening infections
9. Scientists discover the cellular roots of graying hair
10. Scientists rid stem cell culture of key animal cells
11. Scientists develop new color-coded test for protein folding
Post Your Comments:

(Date:5/9/2016)... May 9, 2016 Elevay is ... to expanding freedom for high net worth professionals seeking ... today,s globally connected world, there is still no substitute ... ever duplicate sealing your deal with a firm handshake. ... by taking advantage of citizenship via investment programs like ...
(Date:4/26/2016)... DUBLIN , April 27, 2016 ... of the  "Global Multi-modal Biometrics Market 2016-2020"  report ... ) , The analysts forecast ... a CAGR of 15.49% during the period 2016-2020.  ... a number of sectors such as the healthcare, ...
(Date:4/13/2016)... 13, 2016  IMPOWER physicians supporting Medicaid patients in ... new clinical standard in telehealth thanks to a new ... higi platform, IMPOWER patients can routinely track key health ... mass index, and, when they opt in, share them ... to a local retail location at no cost. By ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... ... June 27, 2016 , ... Rolf K. ... the faculty of the University of North Carolina Kenan-Flagler Business School ... entrepreneurship at UNC Kenan-Flagler, with a focus on the school’s international efforts, leading ...
(Date:6/24/2016)... 2016 Epic Sciences unveiled a liquid ... to PARP inhibitors by targeting homologous recombination deficiency ... new test has already been incorporated into numerous ... types. Over 230 clinical trials are ... including PARP, ATM, ATR, DNA-PK and WEE-1. Drugs ...
(Date:6/23/2016)... ... June 23, 2016 , ... UAS LifeSciences, one of ... their brand, UP4™ Probiotics, into Target stores nationwide. The company, which has been ... Target to its list of well-respected retailers. This list includes such fine stores ...
(Date:6/23/2016)... , June 23, 2016 Houston Methodist ... the Cy-Fair Sports Association to serve as their ... agreement, Houston Methodist Willowbrook will provide sponsorship support, ... connectivity with association coaches, volunteers, athletes and families. ... the Cy-Fair Sports Association and to bring Houston ...
Breaking Biology Technology: