British scientists have developed an advanced method of diagnosing tuberculosis (TB), one of the top 10 leading causes of death worldwide.
Researchers from Oxford and Birmingham were able to isolate numerous strains of the TB bacteria with the help of genome sequencing.
This means patients who may have waited months to get the right TB drugs can be diagnosed in just a few days, giving them a greater chance of recovery.
It also reduces the chances of spreading the disease. The scientists were able to determine DNA of different samples in a little more than a week. The CRyPTIC study was published in the Journal of Clinical Microbiology. While it has sufficiently been able to differentiate between the strains, it has also picked up a worrying pattern in relation to drug resistance.
Tim Jinks, the head of the drug-resistant infection department at The Wellcome Trust, a research charity based in London, said: “New tools for faster and more accurate diagnosis of infections are vital, so patients get the most appropriate and most effective treatment, and to help us track and stop drug-resistant infections from spreading.”
The study found one in five global cases of the disease is now resistant to at least one major treatment drug. “Using the MiniSeq System, the workflow from patient sample to results can be completed in 44/16 hours at a reagent cost of £96 (Sh12,416) and £198 (Sh25,608) per sample,” read an abstract of the study.
PENDING APPROVAL AND VALIDATION
Symptoms of TB include a chronic cough accompanied by blood-tinged sputum, fever, sweating at night and weight loss.
The disease, ranked the fourth frequent cause of death in Kenya, is transmitted by people, and the organism cannot survive in the environment. It thrives in crowded conditions such as prisons, refugee camps and slums. The news comes when the world has stepped up efforts to eliminate a disease that infects 10 million people and kills 1.5 million every year.
In 2015, an estimated 480,000 people worldwide developed multidrug-resistant TB (MDR-TB). A survey carried out last year showed that the number of Kenyans with TB had doubled since 2015, with more men than women being affected. According to the study, 558 out of 100,000 people have TB, almost double the World Health Organisation (WHO) estimate of 233 cases for 100,000.
The highest TB infections were reported among men aged 25 to 34, followed by women over 65. Dr Enos Masini, who heads the National Tuberculosis, Leprosy and Lung Disease Programme, said it was still too early to tell if the new diagnostic tool would be introduced in Kenya. “We only consider a drug or a diagnostic tool based on WHO approval and validation,” said Dr Masini.
He, however, said gene sequencing is used as a second-opinion diagnostic test when two testing tools give conflicting results.
“If for instance, you have two diagnostic kits, say, the Gene Xpert and the sputum culture test and one shows there is drug resistance and the other does not, then we have to do genome sequencing,” he said. Dr Grace Smith, a microbiologist involved in the study, said:
“We are able to provide information on the species of the organism and the drugs to which it may be resistant if it is TB.” According to Public Health England — an agency in the Department of Health in the UK — this is the first time anyone has applied the technique on such a large scale.