Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New research may overturn conventional wisdom on drug-resistant tuberculosis

22.02.2007
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 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.

Steve Baragona | EurekAlert!
Further information:
http://www.idsociety.org

More articles from Studies and Analyses:

nachricht The personality factor: How to foster the sharing of research data
06.09.2017 | ZBW – Leibniz-Informationszentrum Wirtschaft

nachricht Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Comet or asteroid? Hubble discovers that a unique object is a binary

21.09.2017 | Physics and Astronomy

Cnidarians remotely control bacteria

21.09.2017 | Life Sciences

Monitoring the heart's mitochondria to predict cardiac arrest?

21.09.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>