Published: <a style="color: rgb(102, 102, 102); text-decoration: none;" href="http://www.ucfnews.com/main.cfm/include/displayIssueArticles/issue_date/20041007.html">Thursday, October 7, 2004 </a><span class="storytextstyle"></span> Microbiologists at UCF may be one step closer to tracing the origins of a rare intestinal disease after identifying bacteria from the blood of afflicted patients.
Saleh Naser, an associate professor in the Department of Molecular Biology and Microbiology, was the first to extract bacteria called MAP (Mycobacterium avium subspecies paratuberculosis) from victims of Crohn's disease - a feat that hasn't been achieved since the first reported isolation of the bacteria 20 years ago.
Crohn's disease is a bowel disease that causes inflammation in the small intestine, leading to abdominal pain, diarrhea and other digestive problems. It is a relatively rare disease, occurring in about one to five people in every 10,000, according to the Life Extension Foundation.
More than 1 million people worldwide are inflicted with the debilitating disease. There is still no effective and permanent treatment for their condition and the origin of the disease remains controversial.
Naser's study, which made the cover of the Sept. 18 issue of the prestigious British medical journal Lancet, is the first to "report that this bacterium exists in blood," Naser said. These results could open new doors to treatments for Crohn's disease, which currently include temporary relief by anti-inflammatory drugs and surgical removal of parts of the intestine.
It has been shown that "the MAP is present in the environment more than we think," Naser said. "But not everyone who's exposed to it will develop [Crohn's] disease, unless they have a genetic susceptibility to it."
About 20 percent of people with Crohn's disease have a blood relative with an inflammatory bowel disease, most often a sibling and sometimes a parent or child.
The bacteria MAP has been known to cause a similar intestinal condition known as Johne's disease in cattle, sheep and goats, but scientists have not been able to prove that the same bacteria causes Crohn's disease in humans, since culturing and isolating MAP in the laboratory setting has proved to be extremely difficult.
Researchers have successfully isolated the bacteria from the intestinal tissue of Crohn's disease patients, but their finding "is debatable, because many bacteria live in the intestines," Naser said.
MAP was first identified in the blood of a person with Crohn's disease 20 years ago. However, culturing the bacteria took six months, and no one succeeded in replicating the experiment to isolate the bacteria from the patient's blood.
Part of this difficulty is caused by MAP's behavior inside the human body. In an effort to escape attack by immune system defenses, MAP sheds its cell wall once it enters humans, making it harder for scientists to grow the bacteria in the laboratory.
To counter this problem, Naser and his colleagues, who have also grown MAP from intestinal tissue and breastmilk in people with Crohn's disease, developed a new culture in which the bacteria successfully and quickly reproduced in a matter of eight to 12 weeks.
Finding the bacteria in the blood is significant because "blood is free of bacteria and is a sterile environment, and presence of MAP [in blood] suggests that the bacteria is pathogenic, not opportunistic, and it can go all over the body," Naser said. Most bacteria living in the human intestine are labeled as opportunistic and will not travel and infect different body organs or blood.
Naser identified MAP in the blood of 14 of the 28 Crohn's disease patients, two of the nine ulcerative colitis patients, but in none of 15 participants who did not have an inflammatory bowel disease.
"[The results] tell all the skeptics that [correlation of] this bacterium [to Crohn's disease] cannot be denied," Naser said.
Concurrent with Naser's research, a team of Australian scientists are in the final stages of a placebo-controlled antibiotic trial for Crohn's patients. The results of their study are expected to be published soon, but "it is still too early to advocate the routine use of antibiotic treatment directed against MAP," read a statement from Warwick Selby, a researcher and professor at the University of Sydney's Gastroenterology and Liver Centre at the Royal Prince Alfred Hospital. Selby also explained the need to replicate the experiment in other laboratories.
Naser said his results show a "conservative estimation," but said he was certain that he would continue extracting and studying bacteria from the blood of more Crohn's disease patients. By Naseem Sowti UCF News Florida |
