Featured Research

from universities, journals, and other organizations

Bacteria In Urinary Tract Infections Caught Making Burglar's Tools

Date:
February 20, 2009
Source:
Washington University School of Medicine
Summary:
Bacteria that cause urinary tract infections make more tools for stealing from their host than friendly versions of the same bacteria found in the gut, researchers have found. The tools help the bad bacteria to survive and reproduce. But they also provide a potential way to target them without adversely affecting the good strains.

Differences in the way they use their genes cause different strains of the E. coli bacterium to take on different hues. The beaker in the foreground contains strains of bacteria linked to urinary tract infections, while the background beaker holds more benign strains of bacteria isolated from the gut. Scientists are hoping to develop drugs that specifically target infection-causing strains of bacteria like those in the foreground beaker.
Credit: Michael Purdy/Washington University School of Medicine in St. Louis

Bacteria that cause urinary tract infections (UTIs) make more tools for stealing from their host than friendly versions of the same bacteria found in the gut, researchers at Washington University School of Medicine in St. Louis and the University of Washington have found.

The tools, compounds called siderophores, allow the bad bacteria to steal iron from their hosts, making it easier for the bacteria to survive and reproduce. But they also provide a potential way to target the bad strains of bacteria for eradication without adversely affecting the good strains, researchers report.

"When we treat an infection with antibiotics, it's like dropping a bomb—nearly everything gets wiped out, regardless of whether it's helpful or harmful," says lead author Jeff Henderson, M.D., Ph.D., a Washington University infectious disease specialist who treats patients with UTIs at Barnes-Jewish Hospital. "We'd like to find ways to target the bad bacteria and leave the good bacteria alone, and these siderophores are a great lead in that direction."

UTIs are one of the most common infections, causing around $1.6 billion in medical expenses every year in the United States. Half of all women will experience a UTI at some point in their lives, and recurrent UTIs affect 20 to 40 percent of these patients. Scientists believe 90 percent of all UTIs are caused by the bacterium Escherichia coli (E. coli).

The E. coli that cause UTIs may come from the human gut, where several strains of the bacteria reside. Scientists think some of those strains help their human hosts by aiding digestion and blocking other infectious organisms. To study how friendly and infection-causing E. coli strains differ, Henderson and colleagues at the Center for Women's Infectious Disease Research at Washington University used a new approach called metabolomics. Instead of examining genes, metabolomics analyzes all the chemicals produced by a cell, which includes bacterial growth signals, toxins and waste products.

"This allows us to look at the end products of many genes working together," says senior author Scott Hultgren, Ph.D., the Helen L. Stoever Professor of Molecular Microbiology. "We assess what all the various assembly lines are producing and which products disease-causing bacteria prefer to make, such as certain siderophores."

Bacteria studied in the experiment came from recurrent UTI patients treated at the University of Washington. Researchers cultured both E. coli from stool samples and urine samples. They found that the strains from urine made more yersiniabactin and salmochelin, two siderophores that help bacteria scavenge iron to support their own survival.

Iron is an important nutrient typically kept under tight control by the host, and there's evidence that a back-and-forth contest centered on iron has been raging for millennia between disease-causing microbes and the hosts they exploit. For example, studies suggest that humans may make a protein that specifically blocks particular bacterial siderophores.

There may be multiple ways to take advantage of the infectious bacterial strains' reliance on siderophores. Researchers will try to block or disrupt the activity of the proteins that make siderophores, but they also may use what Henderson calls a "Trojan horse" strategy.

"To steal iron, siderophores have to be sent out from the cell, bind to the iron, and then be taken back into the cell," he explains. "If we can design an antibiotic that looks like a siderophore, we might be able to trick only disease-causing bacteria into taking up the drug while leaving other bacteria alone."


Story Source:

The above story is based on materials provided by Washington University School of Medicine. Note: Materials may be edited for content and length.


Journal Reference:

  1. Henderson JP, Crowley JR, Pinkner JS, Walker JN, Tsukayama P, Stamm WE, Hooton TM, Hultgren SJ. Quantitative metabolomics reveals an epigenetic blueprint for iron acquisition in uropathogenic Escherichia coli. PLoS Pathogens, 5(2): e1000305 DOI: 10.1371/journal.ppat.1000305

Cite This Page:

Washington University School of Medicine. "Bacteria In Urinary Tract Infections Caught Making Burglar's Tools." ScienceDaily. ScienceDaily, 20 February 2009. <www.sciencedaily.com/releases/2009/02/090219202725.htm>.
Washington University School of Medicine. (2009, February 20). Bacteria In Urinary Tract Infections Caught Making Burglar's Tools. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2009/02/090219202725.htm
Washington University School of Medicine. "Bacteria In Urinary Tract Infections Caught Making Burglar's Tools." ScienceDaily. www.sciencedaily.com/releases/2009/02/090219202725.htm (accessed July 25, 2014).

Share This




More Plants & Animals News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How to Make Single Serving Smoothies: Howdini Hacks

How to Make Single Serving Smoothies: Howdini Hacks

Howdini (July 24, 2014) Smoothies are a great way to get in lots of healthy ingredients, plus they taste great! Howdini has a trick for making the perfect single-size smoothie that will save you time on cleanup too! All you need is a blender and a mason jar. Video provided by Howdini
Powered by NewsLook.com
Boy Attacked by Shark in Florida

Boy Attacked by Shark in Florida

Reuters - US Online Video (July 24, 2014) An 8-year-old boy is bitten in the leg by a shark while vacationing at a Florida beach. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Newsy (July 24, 2014) A new study claims a set of prehistoric T-Rex footprints supports the theory that the giant predators hunted in packs instead of alone. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins