Featured Research

from universities, journals, and other organizations

Researchers Discover New Disease-causing Bacterium In Patients With Rare Immune Disorder

Date:
April 14, 2006
Source:
NIH/National Institute of Allergy and Infectious Diseases
Summary:
Scientists at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), have discovered a new bacterium and determined that it can cause serious lymph node infections in patients with chronic granulomatous disease (CGD) -- a rare immune disorder that leaves individuals susceptible to frequent and sometimes life-threatening fungal and bacterial infections. Details of the discovery are described in the April 14 issue of PLoS Pathogens.

Scientists at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), have discovered a new bacterium and determined that it can cause serious lymph node infections in patients with chronic granulomatous disease (CGD)--a rare immune disorder that leaves individuals susceptible to frequent and sometimes life-threatening fungal and bacterial infections. Details of the discovery are described in the April 14 issue of PLoS Pathogens.

Researchers found the novel bacterium--which they named Granulobacter bethesdensis in recognition of Bethesda, Md., the location of NIH headquarters--in the inflamed lymph nodes of a patient with CGD. The bacterium is part of the Acetobacteraceae family that includes several types of bacteria prevalent in the environment and used industrially to produce vinegar. This is the first time, however, that any member of that bacterial family has been known to cause invasive human disease. Moreover, it represents yet another infection concern for people with CGD, and possibly other individuals as well.

"The discovery of new bacteria is not uncommon, but discovering an organism that causes human illness is certainly unique and warrants further research," says NIH Director Elias A. Zerhouni, M.D.

"This finding is an important discovery both in understanding new human pathogens and in revealing a new source of illness in a patient population particularly vulnerable to bacterial infections," notes NIAID Director Anthony S. Fauci, M.D.

CGD, which affects one in 250,000 people worldwide, is one of 80 inherited immune disorders known collectively as primary immune deficiencies. The disease is caused by a genetic defect in an enzyme called phagocyte NADPH oxidase. Certain white blood cells called neutrophils use this enzyme to generate hydrogen peroxide that the cells need to kill bacteria and fungi. Because people with CGD cannot effectively fight off bacterial and fungal invaders, these individuals are at greater risk of developing serious infections of the skin, lungs, lymph nodes and bones. People with CGD also are prone to developing obstructions in the digestive and urinary tracts caused by swollen areas of inflamed tissues known as granulomas.

In July 2003, a 39-year old man with CGD was referred to NIH after experiencing three months of unexplainable fever, chills, fatigue, night sweats and a 10-pound weight loss. Doctors first gave him two different antibiotics, which did not alleviate his symptoms. Two months later, he developed a painful swelling of the lymph nodes at the base of his neck. Because the infection did not respond to the antimicrobial medications and because there was no clear diagnosis for his symptoms, the doctors removed several lymph nodes for examination. The lymph nodes revealed extensive infection. Tests performed on three of the lymph nodes confirmed a bacterial presence.

Using genetic sequencing, the researchers eventually determined that the bacteria most closely resembled a member of the Acetobacteraceae family. Other tests revealed that the patient's immune system responded to the organism, indicating that it had been exposed to and hence recognized the bacterium, and confirmed that the newly discovered bacterium was indeed a pathogen.

To determine whether the bacterium specifically caused infection in connection with CGD, the researchers inoculated healthy mice and mice genetically altered to carry CGD with various amounts of the newly identified bacterium. Lymph nodes recovered from the CGD mice revealed a similar condition to those of the CGD patient. The lymph nodes of the disease-free mice appeared normal. Spleens recovered from both types of mice showed evidence of the new bacterium but in much greater amounts in the CGD mice. Genetic sequencing confirmed that the bacterium found in the mice was identical to the organism isolated from the patient. The bacterium was not fatal in the CGD patient nor the infected mice.

Since the initial acceptance of this study for publication, NIAID researchers have isolated Granulobacter bethesdensis bacteria from two additional patients with CGD who were experiencing clinical symptoms similar to those of the initial CGD patient.

"Until recently, about 50 percent of infections in people with CGD could not be diagnosed. Some of these patients were treated empirically with surgery and broad spectrum drugs. Other infections were never successfully treated," says Steven M. Holland, M.D., chief of NIAID's Laboratory of Clinical Infectious Diseases. "This newly identified organism could help us identify the source of those infections and allow for the development of targeted and curative therapies."

According to the study's lead author David E. Greenberg, M.D., a clinical fellow in NIAID's Laboratory of Clinical Infectious Diseases, further studies will be needed to

  • Compare the immune response to the new bacterium in healthy people and in those with CGD
  • Determine how the bacterium causes infection in people with CGD
  • Explore the bacterium's importance, if any, for the population at large

"The fact that the CGD mice survived the infection raises the question, What is the critical component of the host's immune defense, and which patients other than those with CGD are most vulnerable to this newly discovered microbe?" Dr. Holland adds. "I suspect the bacterium has been around as long as we have and that we'll find it has been busier than we knew in terms of disease activity over the years."

Researchers from the NIH Clinical Center and the National Cancer Institute, additional components of NIH, also contributed to the research.


Story Source:

The above story is based on materials provided by NIH/National Institute of Allergy and Infectious Diseases. Note: Materials may be edited for content and length.


Cite This Page:

NIH/National Institute of Allergy and Infectious Diseases. "Researchers Discover New Disease-causing Bacterium In Patients With Rare Immune Disorder." ScienceDaily. ScienceDaily, 14 April 2006. <www.sciencedaily.com/releases/2006/04/060414013952.htm>.
NIH/National Institute of Allergy and Infectious Diseases. (2006, April 14). Researchers Discover New Disease-causing Bacterium In Patients With Rare Immune Disorder. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2006/04/060414013952.htm
NIH/National Institute of Allergy and Infectious Diseases. "Researchers Discover New Disease-causing Bacterium In Patients With Rare Immune Disorder." ScienceDaily. www.sciencedaily.com/releases/2006/04/060414013952.htm (accessed July 31, 2014).

Share This




More Plants & Animals News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com
Peace Corps Pulls Workers From W. Africa Over Ebola Fears

Peace Corps Pulls Workers From W. Africa Over Ebola Fears

Newsy (July 30, 2014) The Peace Corps is one of several U.S.-based organizations to pull workers out of West Africa because of the Ebola outbreak. Video provided by Newsy
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
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