Bacteria That Cause Disease In Humans Have ‘Reversible Switching Mechanism’ Allowing Them To Adapt To Environments Lacking Oxygen

 

From the 13 September article at Medical News Today

Bacteria that cause disease in humans have a ‘reversible switching mechanism’ that allows them to adapt to environments lacking oxygen, scientists at the University of East Anglia (UEA) have found.

Published in the journal Proceedings of the National Academy of Sciences USA, the findings provide a new insight into how bacteria sense and adapt to oxygenated atmospheres, and uncover a new ‘antioxidant’ pathway by which certain types of damaged proteins can be repaired. …

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• Reversible oxygen-sensing ‘switching’ mechanism discovered (eurekalert.org)
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• The Mighty Microbes (idyllic.wordpress.com)
• Ward off Dangerous Bacteria with This: Report on Study by DoctorsHealthPress.com (prweb.com)

 

Beneficial Bacteria May Help Ward Off Infection

 

English: Template for Template:Food safety (Photo credit: Wikipedia)

 

From the 19 July 2012 article at Science News Daily

 

While many bacteria exist as aggressive pathogens, causing diseases ranging from tuberculosis and cholera, to plague, diphtheria and toxic shock syndrome, others play a less malevolent role and some are critical for human health.

In a new study, Cheryl Nickerson and her group at ASU’s Biodesign Institute, in collaboration with an international team including Tom Van de Wiele and lead author Rosemarie De Weirdt at Ghent University, Belgium, explore the role of Lactobaccilus reuteri — a natural resident of the human gut — to protect against foodborne infection.

Their results demonstrate that this beneficial or probiotic organism, which produces an antimicrobial substance known as reuterin, may protect intestinal epithelial cells from infection by the foodborne bacterial pathogen Salmonella….

…

Bacterial Blizzard

A swarm of some hundred trillion bacteria occupies the human body, outnumbering human cells by about 10 to 1. Among these are members of the genus Lactobacilli, some of which have been associated with therapeutic, probiotic properties, including anti-inflammatory and anti-cancer activity.

The current study zeros in on Lactobacillus reuteri – one of the more than 180 species of Lactobacilli. The group investigated the potential of this bacterium to inhibit the early stages ofSalmonella infection, seeking to identify plausible mechanisms for such inhibitory effects.

Intestinal infections by non-typhoidal Salmonella strains induce diarrhea and gastroenteritis, and remain a leading source of foodborne illness worldwide. Such infections are acutely unpleasant but self-limiting in healthy individuals. For those with compromised immunity however, they can be deadly and the alarming incidence of multi-drug resistant Salmonellastrains has underlined the necessity of more effective therapeutics.

The use of benign microorganisms offers a promising new approach to treating infection from pathogens like Salmonellaand indeed, L. reuteri has been shown to help protect against gastrointestinal infection and reduce diarrhea in children.

Safeguarding cells

The origin of L. reuteri’s protective role still remains unclear, and the present study investigated whether reuterin, a metabolite produced by L. reuteri during the process of reducing glycerol in the gut, could be one of the keys to protection. While it has been speculated that reuterin acts by regulating immune responses or competing with Salmonella for key binding sites, the current study represents the first in vitro examination of host-pathogen interactions using human intestinal epithelium in the presence of reuterin-producing L. reuteri.

 

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• Probiotics (slideshare.net)
• Genome Project for Food Pathogens Launched by FDA (bespacific.com)
• Tummy Troubles, Colic, and Mama’s Diet (scienceofmom.com)
• FDA plans database for identifying foodborne germs (sfgate.com)
• Genome Project for Food Pathogens Launched (fda.gov)
• Toward an alternative for antibiotics to fight bacterial infections? (eurekalert.org)
• Seeking An Alternative For Antibiotics To Fight Bacterial Infections (medicalnewstoday.com)
• The Surprising Viruses in Our Gut [The Weizmann Wave] (scienceblogs.com)

 

Fighting Malaria By Modifying Friendly Bacteria In Mosquito Gut

Malaria is preventable and curable (Photo credit: Novartis AG)

This method of malarial control is not without controversy***, especially among folks who are against genetic engineering of any kind.

Back in 1980-81 I came down with malaria four times in Liberia where I served as a Peace Corps volunteer. Each time I came down with it on a Tuesday after forgetting to take my weekly preventative (Chloroquine) on Sunday. Thankfully each time it was similar to a mild flu bug and I was back at work the next day.

Since then, Chloroquine is ineffective in Liberia. The malarial strains are much more virulent. Back in the early 80′s the virulent malarial strains in Africa were mostly in East Africa.

From the 17 July 2012 article at Medical News today

By genetically modifying gut bacteria in the malaria mosquito, US researchers have found a potentially powerful way to fight malaria. The modified “friendly” bacteria, which live in the midgut of the mosquito alongside the malaria parasite, produce toxins that are deadly to the parasite but do not harm humans or mosquitoes…

..”In the past, we worked to genetically modify the mosquito to resist malaria, but genetic modification of bacteria is a simpler approach.”..

…The battle against malaria has to be fought on a number of fronts: insect repellent and bed nets can help prevent transmission from mosquitoes to humans, but work like that of Jacobs-Lorena and colleagues helps to find ways to control malaria one step earlier by eliminating infection within the mosquito itself.

In May 2011, another team from Johns Hopkins University reported identifying a class of naturally occurring bacteria that can strongly inhibit malaria parasites in mosquitoes. They found the presence of Enterobacter reduced various developmental stages of P. falciparum, including the stage that is transmitted to humans through a mosquito bite, were reduced by 98 to 99%….

Related Resources

• World Health Organization – Malaria, including
  • Vector Control (specific methods as treated mosquito nets)
  • Information for Travellers
• CDC -Malaria(US Centers for Disease Control and Prevention), including
  • About Malaria
  • How Can I Help?

Related articles

• Malaria fighting bacteria [Life Lines] (scienceblogs.com)
• Genetically engineered bacteria `kills malaria parasite` (news.bioscholar.com)
• Genetically engineered bacteria prevent mosquitoes from transmitting malaria (phys.org)
• Scientists Genetically Modify Bacteria in Mosquitoes for ‘Malaria Control’ (naturalsociety.com)
• Mutant Mosquito May Be The Cure For Malaria (webpronews.com)
• Engineered bacteria kill malaria parasite (futurity.org)
• Genetically engineered bacteria prevent mosquitoes from transmitting malaria (terradaily.com)
• Mosquitoes Prevented From Transmitting Malaria Through Genetic Modification Of Their Gut Bacteria (medicalnewstoday.com)
• Genetically Engineered Bacteria Prevent Mosquitoes From Transmitting Malaria (InnovationToronto.com)
• Engineering mosquito gut bacteria to fight malaria (blogs.discovermagazine.com)
• Fighting Malaria Inside a Mosquito’s Guts (technologyreview.com)

***

• the Organic Review: GM Exterminators Inserted into Intestines to Stop Malaria
  “Those mosquitos that contained genetically modified gut bacteria, alternative to the actual GM mosquitos, have been proven to conquer Plasmodium bacterium in both human and rodent populations by nearly 100%. The question that remains is if such genetic modifications can cause other negative affects to healthy functioning parts or other bacteria in the mosquitos or is spread to other animals or humans. Results after further studying could possibly lead to new circumstances.” 

Harmful Bacteria Live In Healthy Bodies Without Causing Disease

Depiction of the human body and bacteria that predominate     Larger Image at http://www.genome.gov/Images/press_photos/highres/20169-300.jpg(Photo credit: Wikipedia)

Somehow I always felt this to be true…

Many scientists now regard human bodies as “supra-organisms”, collections of communities made up of human and microbial cells coexisting in a whole that is more than the sum of its parts.

From the 14 June 2012 Medical News Today article

Scientists working on a huge project that has mapped all the different microbes that live in and on a healthy human body have made a number of remarkable discoveries, including the fact that harmful bacteria can live in healthy bodies and co-exist with their host and other microbes without causing disease.

This week sees the publication of several papers from the Human Microbiome Project (HMP), including two in Nature and two inPLoS ONE.

The Microbiome

The microbiome is the sum of all the microbes that colonize the body: it comprises trillions of microorganisms that outnumber human cells by 10 to 1. The microbes inhabit every nook and cranny of the body, and most of     the time the relationship is a friendly one, because they help digest food, strengthen the immune system and fight off dangerous pathogens.

Colorado University (CU)-Boulder Associate Professor Rob Knight of the BioFrontiers Institute is co-author on the two Nature papers. He told the press that the microbiome may only make up 1 to 3% of human body mass, but it plays a key role in human health.

One of the fascinating features of the microbiome is that different body sites have different communites of microorganisms that are as different from each other as the differences between microbial communities in oceans and deserts.

Knight said:

“By better understanding this microbial variation we can begin searching for genetic biomarkers for disease.”

Another of the curious features the HMP has discovered is that even healthy people carry low levels of harmful bacteria, but as long as the body remains healthy, they don’t cause disease, they just coexist alongside beneficial microbes. …

…

The HMP researchers established that more than 10,000 microbial species inhabit the human “ecosystem”. Knight said they believe they have now found between 81 and 99% of all genera of microorganisms in healthy adult Americans.

One of the key findings was the stark differences in microbial communities across the human body. For instance, the microbial communities that live on the teeth are different from those in saliva. …

…Another interesting discovery is that of the genes that influence human metabolism, most of them are in the microbiome and not in the human genome…

…gut bacteria do more than break down food and its constituents like proteins, fats and carbohydrates, they also produce beneficial compounds like vitamins and anti-inflammatories.

Related articles

• Human Microbiome Project Decodes Our 100 Trillion Good Bacteria (nytimes.com)

• Mutant Gut Bacteria Reverse Colon Cancer In Lab Models, UF Researchers Find (Medical News Today)
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• NIH Human Microbiome Project defines normal bacterial makeup of the body (eurekalert.org)
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• Man’s microbes help map ‘normal’ in humans (vitals.msnbc.msn.com)
• Human Microbiome Project outlines powerful new methods for cataloging and analyzing microbes (eurekalert.org)
• Normal bacterial makeup has huge implications for health, says CU professor (eurekalert.org)
• Did you know… Your cooties could keep you healthy?! (warmsouthernbreeze.wordpress.com)
• Scientists map bacteria living inside us (cbc.ca)
• 10,000 germ species live in and on healthy people (newsobserver.com)
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• More than 1 way to be healthy: Map of bacterial makeup of humans reveals microbial rare biosphere (eurekalert.org)
• Census of microbes in healthy humans reported (eurekalert.org)
• Gut Microbiota Transplantation May Prevent Development Of Diabetes And Fatty Liver Disease (jflahiff.wordpress.com)
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The Dirtiest Places In The Office

From the 24 May 2012 Medical News Today article

If you think the restroom is the place you are most likely to pick up germs at the office, perhaps you should think again, because new findings from the US suggest the dirtiest places in the office are in break rooms and kitchens, with sink and microwave door handles topping the list of germ “hot spots”…

..
An ATP **count of 300 or more means the surface has a high level of contamination and there is a high risk of illness transmission. When they analyzed the samples, the researchers found ATP counts of 300 and higher on:

• 75% of break room sink faucet (tap) handles,
• 48% of microwave door handles,
• 27% of keyboards,
• 26% of refrigerator door handles,
• 23% of water fountain buttons, and
• 21% of vending machine buttons.

**ATP  (adenosine triphosphate) is the universal energy molecule found in all animal, plant, bacteria, yeast and mold cells. Large amounts are present in food and organic residues, which when left on a surface can harbor and grow bacteria.

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• Where do germs flourish in your office? – CBS News (cbsnews.com)
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Disarming Disease-Causing Bacteria

From the 5 April 2012 Science Daily article

New treatments that combat the growing problem of antibiotic resistance by disarming rather than killing bacteria may be on the horizon, according to a new study.

Published in Nature Structure and Molecular Biology, research led by Monash Universityshowed a protein complex called the Translocation and Assembly Module (TAM), formed a type of molecular pump in bacteria. The TAM allows bacteria to shuttle key disease-causing molecules from inside the bacterial cell where they are made, to the outside surface, priming the bacteria for infection.
Lead author and PhD student Joel Selkrig of the Department of Biochemistry and Molecular Biology at Monash said the work paves the way for future studies to design new drugs that inhibit this process.
“The TAM was discovered in many disease-causing bacteria, from micro-organisms that cause whooping cough and meningitis, to hospital-acquired bacteria that are developing resistance to current antibiotics,” Mr Selkrig said.
“It is a good antibacterial target because a drug designed to inhibit TAM function would unlikely kill bacteria, but simply deprive them of their molecular weaponry, and in doing so, disable the disease process.”
“By allowing bacteria to stay alive after antibiotic treatment, we believe we can also prevent the emergence of antibiotic resistance, which is fast becoming a major problem worldwide.”…

Related articles

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Food Poisoning: Understanding How Bacteria Come Back from the ‘Dead’

 

Image via Wikipedia

From the 3 February 2012 Science Daily article

almonella remains a serious cause of food poisoning in the UK and throughout the EU, in part due to its ability to thrive and quickly adapt to the different environments in which it can grow. New research involving a team of IFR scientists, funded by BBSRC, has taken the first detailed look at what Salmonella does when it enters a new environment, which could provide clues to finding new ways of reducing transmission through the food chain and preventing human illness.

Bacteria can multiply rapidly, potentially doubling every 20 minutes in ideal conditions. However, this exponential growth phase is preceded by a period known as lag phase, where no increase in cell number is seen. Lag phase was first described in the 19th Century, and was assumed to be needed by bacteria to prepare to exploit new environmental conditions. Beyond this, surprisingly little was known about lag phase, other than bacteria are metabolically active in this period. But exactly what are bacteria doing physiologically during this period?

To fill in this knowledge gap researchers at IFR, along with colleagues at Campden BRI, a membership-based organisation carrying out research and development for the food and drinks industry, have developed a simple and robust system for studying the biology ofSalmonella during lag phase. In this system, lag phase lasts about two hours, but the cells sense their new environment remarkably quickly, and within four minutes switch on a specific set of genes, including some that control the uptake of specific nutrients….

Related articles

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Microbial communities on skin affect humans’ attractiveness to mosquitoes – could be basis for antimalarial research

Image via Wikipedia

[Author's note - I came down with malaria at least 3 timeswhile a Peace Corps volunteer in Liberia, West Africa (1980-81). Fortunately malaria was less virulent in West Africa than East Africa at the time. So, each bout was similar to a one day flu bug. Each time I came down with malaria, it was because I forgot to take the weekly preventive and came down with malaria two days later]

From the 29 December 2011 Eureka News Alert

The microbes on your skin determine how attractive you are to mosquitoes, which may have important implications for malaria transmission and prevention, according to a study published Dec. 28 in the online journal PLoS ONE.

Without bacteria, human sweat is odorless to the human nose, so the microbial communities on the skin play a key role in producing each individual’s specific body odor. The researchers, led by Niels Verhulst of Wageningen University in the Netherlands, conducted their experiments with the Anopheles gambiae sensu stricto mosquito, which plays an important role in malaria transmission. They found that individuals with a higher abundance but lower diversity of bacteria on their skin were more attractive to this particular mosquito. They speculate individuals with more diverse skin microbiota may host a selective group of bacteria that emits compounds to interfere with the normal attraction of mosquitoes to their human hosts, making these individuals less attractive, and therefore lower risk to contracting malaria. This finding may lead to the development of personalized methods for malaria prevention.

###

Citation: Verhulst NO, Qiu YT, Beijleveld H, Maliepaard C, Knights D, et al. (2011) Composition of Human Skin Microbiota Affects Attractiveness to Malaria Mosquitoes. PLoS ONE 6(12): e28991. doi:10.1371/journal.pone.0028991

Read the entire news release

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How Bacteria Fight Fluoride in Toothpaste and in Nature

Yale researchers have uncovered the molecular tricks used by bacteria to fight the effects of fluoride, which is commonly used in toothpaste and mouthwash to combat tooth decay. (Credit: © mathom / Fotolia)

From the 22 December 2011 Science News Daily article

Yale researchers have uncovered the molecular tricks used by bacteria to fight the effects of fluoride, which is commonly used in toothpaste and mouthwash to combat tooth decay.

In the Dec. 22 online issue of the journal Science Express, the researchers report that sections of RNA messages called riboswitches — which control the expression of genes — detect the build-up of fluoride and activate the defenses of bacteria, including those that contribute to tooth decay.

“These riboswitches are detectors made specifically to see fluoride,” said Ronald Breaker, the Henry Ford II Professor and chair of the Department of Molecular, Cellular and Developmental Biology and senior author of the study.

Fluoride in over-the-counter and prescription toothpastes is widely credited with the large reduction in dental cavities seen since these products were made available beginning in the 1950s. This effect is largely caused by fluoride bonding to the enamel of our teeth, which hardens them against the acids produced by bacteria in our mouths. However, it has been known for many decades that fluoride at high concentrations also is toxic to bacteria, causing some researchers to propose that this antibacterial activity also may help prevent cavities.

The riboswitches work to counteract fluoride’s effect on bacteria. “If fluoride builds up to toxic levels in the cell, a fluoride riboswitch grabs the fluoride and then turns on genes that can overcome its effects,” said Breaker…

Read the entire news article

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Beating superbugs with a high-tech cleanser

Beating superbugs with a high-tech cleanser

From the 9 December Science News Daily article

According to the World Health Organization, antibiotic-resistant bacteria are one of the top three threats to human health. Patients in hospitals are especially at risk, with almost 100,000 deaths due to infection every year in the U.S. alone.

Now Dr. Udi Qimron of the Department of Clinical Microbiology and Immunology at Tel Aviv University’s Sackler Faculty of Medicine has developed an efficient and cost-effective liquid solution that can help fight antibiotic-resistant bacteria and keep more patients safe from life-threatening infections. The solution is based on specially designed bacteriophages — viruses that infect bacteria — that can alter the genetic make-up of antibiotic-resistant bacteria. “We have genetically engineered the bacteriophages so that once they infect the bacteria, they transfer a dominant gene that confers renewed sensitivity to certain antibiotics,” explains Dr. Qimron.

The solution, recently detailed in the journal Applied and Environmental Microbiology, could be added to common antibacterial cleansers used on hospital surfaces, turning resistant bacteria into sensitive bacteria. It’s easy to prepare, easy to apply, and non-toxic, Dr. Qimron notes. He estimates that one liter of the growth medium — the liquid in which the bacteriophages are grown — will cost just a few dollars.

 …

Two steps to disarming bacteria

Added to cleansers, Tellurite represents the second step in a two-part process. A Tellurite compound, which is toxic to bacteria, would also be spread on all surfaces to wipe out the bacteria that had not been rendered sensitive, and thus the entire population of the surface bacteria would be sensitized. The combination is designed to first disarm, and then kill dangerous bacteria.

Next, the solution will be tested in pre-clinical animal trials to ensure its safety before being made available for wider use at hospitals…

.

Related articles

• Beating superbugs with a high-tech cleanser (eurekalert.org)
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• Bacteriophages mobilize the antibiotic resistance of bacteria in the environment (sciencedaily.com)
• Drug-Resistant Superbugs Sweeping Across Europe (science.slashdot.org)
• New paper calls for strong steps to tackle antibiotic resistance (eurekalert.org)
• Some Superbugs Are Even More Super Than We Thought | 80beats (blogs.discovermagazine.com)