Featured Research

from universities, journals, and other organizations

New Research May Overturn Conventional Wisdom On Drug-resistant Tuberculosis

Date:
February 21, 2007
Source:
Infectious Diseases Society of America
Summary:
A newly released study suggests that the majority of cases of drug-resistant tuberculosis (TB) among patients undergoing treatment for the disease may be due to new infections, not acquired resistance. If confirmed in future studies the research, in the March 15 issue of the Journal of Infectious Diseases, may drive a major shift in strategy for controlling TB.

A newly released study suggests that the majority of cases of drug-resistant tuberculosis (TB) among patients undergoing treatment for the disease may be due to new infections, not acquired resistance. If confirmed in future studies the research, in the March 15 issue of The Journal of Infectious Diseases, may drive a major shift in strategy for controlling TB.

Related Articles


A major difficulty in treating patients with pulmonary TB is that the organism can become progressively resistant to standard therapy. This resistance was long thought to be acquired through mutations in the infecting strain when the treatment regimen was inadequate or the patient did not comply with it. More recently, studies of the genetic make-up of Mycobacterium tuberculosis (M. tuberculosis) strains have shown that resistance can also result from re-infection with a new strain that is already drug-resistant, sometimes against multiple drugs.

The authors of the new study, Qian Gao, PhD, and coworkers in Shanghai, China and elsewhere, used molecular genetics and drug susceptibility testing to investigate patients with TB who were treated in Shanghai hospitals during 1999-2004. They focused on 38 patients from whom samples were available before and during treatment. The researchers found that the strains of TB in the samples taken before treatment were genetically different from those taken during treatment in 87 percent (33 out of 38) of patients.

To determine the relative proportion of drug resistance caused by re-infection or mutation, the authors excluded six patients who were initially infected with resistant TB and then became drug-susceptible or resistant to fewer drugs. In the remaining 32 patients, the initial sample was drug-susceptible or resistant to at least one drug and the subsequent sample resistant to one or more drugs. Of these patients, 84 percent (27 patients) had before-and-during samples with different genetic patterns and only 16 percent (5 patients) had identical patterns. Thus, there were more than 5 times as many cases caused by re-infection compared to mutation.

"It was surprising to find a high rate of primary drug-resistant strains among treated patients," said Dr.Gao. "This overturned the common belief that drug resistance among treated patients is always acquired."

The investigators also noted that two patients in the study had multidrug-resistant strains in both their first and second sample, and that 10 others had multidrug-resistant strains in their second sample; genetic testing showed that 9 of the 10 patients had a different strain in the second sample. The most serious kind of drug-resistant disease therefore accounted for about a third of patients with drug resistance.

Limitations of the study included the exclusion of many patients without sample results, reliance on previously collected data in which some patients might have been misclassified, use of computerized drug susceptibility data, and the unknown contribution of mixed infections. Nevertheless, the findings are a warning. Although better diagnostics, drugs, and effective vaccines for TB are clearly needed, the authors said, "Our findings highlight the urgency of accelerating efforts to interrupt the transmission of drug-resistant tuberculosis." The research shows improved methods of preventing TB transmission may be needed in the very facilities and communities where TB patients are treated.

Fast Facts

  • Tuberculosis (TB) is one of the world's top killer diseases, claiming roughly 2 million lives each year.
  • Drug-resistant TB is a growing problem worldwide. Most resistance is believed to derive from inefficient treatment, leading to mutations.
  • This study found that 33 of 38 patients had a different strain of TB during treatment than before treatment.
  • Improved methods of preventing TB transmission may be needed in the very facilities and communities where TB patients are treated.

Story Source:

The above story is based on materials provided by Infectious Diseases Society of America. Note: Materials may be edited for content and length.


Cite This Page:

Infectious Diseases Society of America. "New Research May Overturn Conventional Wisdom On Drug-resistant Tuberculosis." ScienceDaily. ScienceDaily, 21 February 2007. <www.sciencedaily.com/releases/2007/02/070220132018.htm>.
Infectious Diseases Society of America. (2007, February 21). New Research May Overturn Conventional Wisdom On Drug-resistant Tuberculosis. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2007/02/070220132018.htm
Infectious Diseases Society of America. "New Research May Overturn Conventional Wisdom On Drug-resistant Tuberculosis." ScienceDaily. www.sciencedaily.com/releases/2007/02/070220132018.htm (accessed October 25, 2014).

Share This



More Health & Medicine News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

IKEA Desk Converts From Standing to Sitting With One Button

IKEA Desk Converts From Standing to Sitting With One Button

Buzz60 (Oct. 24, 2014) IKEA is out with a new convertible desk that can convert from a sitting desk to a standing one with just the push of a button. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Ebola Protective Suits Being Made in China

Ebola Protective Suits Being Made in China

AFP (Oct. 24, 2014) A factory in China is busy making Ebola protective suits for healthcare workers and others fighting the spread of the virus. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com
WHO: Millions of Ebola Vaccine Doses by 2015

WHO: Millions of Ebola Vaccine Doses by 2015

AP (Oct. 24, 2014) The World Health Organization said on Friday that millions of doses of two experimental Ebola vaccines could be ready for use in 2015 and five more experimental vaccines would start being tested in March. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Doctor in NYC Quarantined With Ebola

Doctor in NYC Quarantined With Ebola

AP (Oct. 24, 2014) An emergency room doctor who recently returned to the city after treating Ebola patients in West Africa has tested positive for the virus. He's quarantined in a hospital. (Oct. 24) Video provided by AP
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:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

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