Genetic test for resistant tuberculosis bacteria

Tuberculosis: Improved genetic test to improve surveillance

02/13/2013

Tuberculosis is still one of the most dangerous diseases worldwide. Every year, millions of people suffer from the bacterial infectious disease, many do not survive the disease ... Based on the genome of bacteria causing tuberculosis researchers want to monitor future outbreaks better and identify antibiotic-resistant tuberculosis bacteria. The World Health Organization (WHO) has the number of new tuberculosis cases for the year 2011 in its „Global Tuberculosis Report 2012“ estimated at 8.7 million cases worldwide. According to the WHO, 1.4 million people died of tuberculosis in 2011.

A team of experts from public health institutions, research institutes and universities in Germany and France around Stefan Niemann from the Borstel Research Center at the Leibniz Center for Medicine and Biosciences in Borstel has evaluated the results of two different genetic tests on Mycobacterium tuberculosis isolates and his findings in the journal „PLoS Medicine“ released. In total, the data from 2,301 patients from Schleswig-Holstein and Hamburg were collected over a period of about thirteen years (1997 to 2010), write Stefan Niemann and colleagues in the journal.

During population-based epidemiological surveillance, a major outbreak was identified with that of classical strain typing, which was initially attributed to the strain of the Haarlem lineage of Mycobacterium tuberculosis. However, the recent genome-wide sequencing methods would have yielded significantly more precise results and demonstrated that it was actually a „Hamburg clone“ of the bacterial strain that presumably developed between 1993 and 1997. The novel genetic tests will help control the development and spread of tuberculosis bacteria in the future, the researchers said.

Monitor tuberculosis infection chains with new genetic tests
Previous genetic tests used for the analysis of tuberculosis bacteria, according to the scientists capture only a small proportion of the genome, which will significantly reduce the precision. Here the complete sequencing of the bacterial genes offers clear advantages. In this way, let a possible outbreak much better monitor you. Because of the exact genetic assignment, the occurring diseases can be easily connected to each other. So far, according to the report of a tuberculosis patient at the health authorities in its environment „after further cases and possible infection chains“, explained Niemann. This will remain essential in the future, but the exact genetic assignment can greatly facilitate the identification of the infection chains.

Track antibiotic-resistant tuberculosis bacteria
In addition, has „the genome-based study is of great importance in detecting and spreading the tuberculosis bacteria that have become resistant to multiple antibiotics“, explained Stefan Niemann. To date, tuberculosis is usually treated with antibiotics, usually a combination of different preparations over a period of about six months is applied. However, as the prevalence of multidrug-resistant bacteria has increased significantly in recent years, tuberculosis therapy with standard drugs is proving increasingly difficult today. The pathogens hardly respond to common antibiotics and the treatment can be massively delayed. To monitor the spread of multidrug-resistant tuberculosis bacteria, "the new genetic tests are much better suited than conventional genetic tests," the researchers report.

Tuberculosis is the world's deadliest infectious disease
While tuberculosis is a rather rare disease in Germany (4,268 diseases reported by the Robert Koch Institute for the year 2012), less developed countries, in particular, often struggle with outright epidemics. Although global strategies to reduce tuberculosis infections have been effective in recent years, tuberculosis (also known as tuberculosis) remains the world's deadliest infectious disease, according to the WHO. In fact, however, only a fraction of the infected get sick. People with a weakened immune system are at particular risk, for example due to HIV infection.

Recognize signs of tuberculosis
The disease course of tuberculosis is generally divided into several stages. For example, a distinction is made between primary tuberculosis and secondary tuberculosis. As a typical sign of tuberculosis in the initial stages are constant mild cough, fatigue, loss of appetite and a corresponding weight loss, mild fever and swollen lymph nodes. If the pathogens spread through the bloodstream in the patient's organism, a particularly serious course of the disease, the so-called miliary tuberculosis, threatens. At worst, this can lead to life-threatening meningitis (meningitis). People with extremely weakened immune systems may also experience potentially fatal blood poisoning (sepsis) in the course of the disease. Improving the monitoring of possible tuberculosis outbreaks with the help of novel genetic tests could make a significant contribution to the prevention of tuberculosis. (Fp)