Navigation Links
New research may overturn conventional wisdom on drug-resistant tuberculosis

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 id entical 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 need ed in the very facilities and communities where TB patients are treated.

'"/>

Source:Infectious Diseases Society of America


Related biology news :

1. Columbia research lifts major hurdle to gene therapy for cancer
2. U of M researcher examines newly emerging deadly disease
3. NYU researchers simulate molecular biological clock
4. First atlas of key brain genes could speed research on cancer, neurological diseases
5. New research questions basic tenet of neuron function
6. Vital step in cellular migration described by UCSD medical researchers
7. ASU researchers finds novel chemistry at work to provide parrots vibrant red colors
8. UCSD researchers maintain stem cells without contaminated animal feeder layers
9. Why do insects stop breathing? To avoid damage from too much oxygen, say researchers
10. New protein discovered by Hebrew University researchers
11. First real-time view of developing neurons reveals surprises, say Stanford researchers
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:4/15/2016)... , April 15, 2016  A new ... make more accurate underwriting decisions in a fraction ... timely, competitively priced and high-value life insurance policies ... screenings. With Force Diagnostics, rapid testing ... lifestyle data readings (blood pressure, weight, pulse, BMI, ...
(Date:3/31/2016)...  Genomics firm Nabsys has completed a financial  restructuring ... , M.D., who returned to the company in October ... team, including Chief Technology Officer, John Oliver , ... and Vice President of Software and Informatics, Michael ... Dr. Bready served as CEO of Nabsys from 2005-2014 ...
(Date:3/21/2016)... March 22, 2016 Unique ... passcodes for superior security   ... provider of secure digital communications services, today announced it ... and offer enterprise customers, particularly those in the Financial ... and voice authentication within a mobile app, alongside, and ...
Breaking Biology News(10 mins):
(Date:5/2/2016)... , May 2, 2016 Q ... its technology partner Mannin Research Inc. will be attending ... which takes place from May 1-5, 2016 in ... be meeting with its vendors and research partners. The ... development goals and other collaborative opportunities for the MAN-01 ...
(Date:5/2/2016)... ... 2016 , ... F.E.E.D. Co., the Feline Environmental Enrichment Design ... product for indoor cats. The NoBowl Feeding System replaces the bowl with the ... nature intended. NoBowls make cats happy and healthy. , Since being introduced on ...
(Date:4/29/2016)... ... April 29, 2016 , ... Amendia, Inc., a leading ... today announced the completion of a significant transaction and partnership that positions Amendia ... and partners. Kohlberg & Company, L.L.C. (“Kohlberg”), a leading private equity firm ...
(Date:4/29/2016)... KY and San Diego, CA (PRWEB) , ... April 29, 2016 ... ... National Stem Cell Foundation (NSCF) to support the development of a patient-specific stem cell ... Dr. Andrés Bratt-Leal in the lab of Dr. Jeanne Loring at The Scripps Research ...
Breaking Biology Technology: