Featured Research

from universities, journals, and other organizations

Bacterium That Causes Kidney Stones And Complicated Urinary Tract Infections Gives Up Its Genetic Secrets

Date:
May 24, 2006
Source:
University of Michigan Health System
Summary:
Scientists now have inside information to use in the fight against Proteus mirabilis -- a nasty bacterium that can cause kidney stones, as well as hard-to-treat urinary tract infections.

Proteus mirabilis can cause kidney stones and urinary tract infections.
Credit: Xin Li, University of Michigan Medical School

Scientists now have inside information to use in the fight against Proteus mirabilis -- a nasty bacterium that can cause kidney stones, as well as hard-to-treat urinary tract infections.

Data from the first complete genome sequence for P. mirabilis, which includes at least 3,693 genes and 4.063 megabases of DNA, will be presented at the 106th general meeting of the American Society of Microbiology taking place in Orlando from May 21-25.

Melanie M. Pearson, Ph.D., a research fellow in microbiology and immunology at the University of Michigan Medical School, is the first scientist to perform an in-depth analysis of the genome sequence. She will present her initial findings in an ASM poster presentation beginning at 9 a.m. on May 23.

"Access to the full genome sequence will help scientists determine the virulence factors produced by the organism and learn how it causes disease," Pearson says. "Part of our goal is finding potential targets for new vaccines that could protect people from infection."

"E. coli causes urinary tract infections in otherwise healthy individuals, but P. mirabilis causes more infections in those with 'complicated' urinary tracts. In cases where stones form, the bacteria can become resistant to antibiotics," says Harry L.T. Mobley, Ph.D., professor and chair of microbiology and immunology in the U-M Medical School. "It is particularly prevalent in nursing home residents with indwelling catheters."

Mobley is an expert on urease, an enzyme produced by P. mirabilis, which breaks down urea in the urinary tract, reduces the acidity of urine and leads to the formation of kidney or bladder stones. Once a stone begins to form, bacteria stick to the stone and live within its layers, where they are protected from antibiotics.

When Pearson examined the genomic sequence data for Proteus mirabilis, she discovered an explanation for the bacterium's "stickiness."

"This bacterium has an unusually high number of genes that encode for 15 different adherence factors or fimbriae on its surface," Pearson explains. "All these different fimbriae help the bacterium stick to bladder cells, catheters, kidney stones or each other.

It's not unusual for bacteria to have several ways of attaching to surfaces, but I've never heard of one with 15 different adherence factors before."

"Over the course of 20-plus years of laboratory research, we had painstakingly identified four P. mirabilis fimbriae," says Mobley. "Suddenly, here were 11 more predicted in the genome sequence data. We couldn't believe it."

Pearson also discovered what she calls a "pathogenicity island" in the P. mirabilis genome made up of 24 genes that encode components of a system used to inject bacterial proteins into host cells.

"Until we reviewed the sequence data, we had no idea P. mirabilis had these genes," Mobley says. "When Melanie analyzed the sequences of these 24 genes, she noticed that they have smaller amounts of two of the four nucleotides in DNA -- guanine and cytosine -- than are present in the overall genome. This implies that another bacterium contributed this little piece of DNA to P. mirabilis at some point during its evolution."

In future research, Pearson will use gene microarrays to identify the Proteus mirabilis genes that are turned on, or expressed, during the infection stage. Genes involved in the infection process will be prime targets for future vaccine development, according to Pearson, although she says that years of additional research will be needed before vaccines could be commercially available.

Mohammed Sebaihia and Julian Parkhill, scientists at the Wellcome Trust Sanger Institute in Cambridge, UK, were responsible for the sequencing process. The sequenced strain was P. mirabilis HI4320, a strain commonly used in laboratory research, which was cultured in the Mobley laboratory from the urine of a nursing home patient with a long-term indwelling catheter.

The research was supported by the National Institute of Diabetes and Digestive and Kidney Diseases, in collaboration with the Sanger Institute.


Story Source:

The above story is based on materials provided by University of Michigan Health System. Note: Materials may be edited for content and length.


Cite This Page:

University of Michigan Health System. "Bacterium That Causes Kidney Stones And Complicated Urinary Tract Infections Gives Up Its Genetic Secrets." ScienceDaily. ScienceDaily, 24 May 2006. <www.sciencedaily.com/releases/2006/05/060524125023.htm>.
University of Michigan Health System. (2006, May 24). Bacterium That Causes Kidney Stones And Complicated Urinary Tract Infections Gives Up Its Genetic Secrets. ScienceDaily. Retrieved September 15, 2014 from www.sciencedaily.com/releases/2006/05/060524125023.htm
University of Michigan Health System. "Bacterium That Causes Kidney Stones And Complicated Urinary Tract Infections Gives Up Its Genetic Secrets." ScienceDaily. www.sciencedaily.com/releases/2006/05/060524125023.htm (accessed September 15, 2014).

Share This



More Health & Medicine News

Monday, September 15, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

EU Ministers and Experts Meet to Discuss Ebola Reponse

EU Ministers and Experts Meet to Discuss Ebola Reponse

AFP (Sep. 15, 2014) The European Commission met on Monday to coordinate aid that the EU can offer to African countries affected by the Ebola outbreak. Duration: 00:58 Video provided by AFP
Powered by NewsLook.com
FDA Eyes Skin Shocks Used at Mass. School

FDA Eyes Skin Shocks Used at Mass. School

AP (Sep. 15, 2014) The FDA is considering whether to ban devices used by the Judge Rotenberg Educational Center in Canton, Massachusetts, the only place in the country known to use electrical skin shocks as aversive conditioning for aggressive patients. (Sept. 15) Video provided by AP
Powered by NewsLook.com
Respiratory Virus Spreads To Northeast, Now In 21 States

Respiratory Virus Spreads To Northeast, Now In 21 States

Newsy (Sep. 14, 2014) The respiratory virus Enterovirus D68, which targets children, has spread from the Midwest to 21 states. Video provided by Newsy
Powered by NewsLook.com
Shocker: Journalists Are Utterly Addicted To Coffee

Shocker: Journalists Are Utterly Addicted To Coffee

Newsy (Sep. 13, 2014) A U.K. survey found that journalists consumed the most amount of coffee, but that's only the tip of the coffee-related statistics iceberg. 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