Vital TB diagnosis breakthrough

Radiographer Akhona Masebeni working inside a mobile X-ray clinic, as TB, the biggest killer worldwide, was said to have taken a backseat during and immediately after Covid-19. Picture Henk Kruger/Independent Media

Radiographer Akhona Masebeni working inside a mobile X-ray clinic, as TB, the biggest killer worldwide, was said to have taken a backseat during and immediately after Covid-19. Picture Henk Kruger/Independent Media

Published Aug 11, 2024

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A NEW study has produced groundbreaking diagnostic results for Tuberculosis (TB) which remains among the country’s – and the world’s – biggest killers.

The new results have shown a 23-hour turnaround time, compared to 15 days before.

Saying the median turnaround time for diagnosis included resistance testing to the most important TB drugs, the Open Forum Infectious Diseases journal called it an advancement, representing a significant leap forward in the fight against TB.

The study, co-led by Helen Cox, a professor in the division of medical microbiology at the University of Cape Town (UCT), is entitled "Reflex Xpert MTB/XDR testing of residual rifampicin-resistant specimens; a clinical laboratory-based diagnostic accuracy and feasibility study in South Africa".

It was funded by the European and Developing Countries Clinical Trials Partnership.

In the journal, the researchers said globally, the largest barrier to providing effective treatment for the 410 000 individuals estimated to develop multidrug or rifampicin-resistant TB annually was rapid and effective diagnosis.

“Only two in five are diagnosed with rifampicin resistance and receive any second-line TB treatment. Additionally, providing the most effective second-line treatment for multi- and other drug-resistant TB and preventing the emergence of further drug resistance requires knowledge of resistance to isoniazid and key second-line TB drugs included in currently recommended regimens.”

This, as South Africa suffers from a high burden of multi-drug resistant and rifampicin-resistant TB, with 11 000 individuals estimated to develop such resistance last year.

“The World Health Organization (WHO)-endorsed tests have been rolled out widely in South Africa and elsewhere, providing rapid Mycobacterium tuberculosis complex (MTBC) detection as well as rifampicin-resistance mutation detection for all individuals investigated for TB,” the journal said.

Current testing for resistance to isoniazid and second-line TB drugs, they said, relied on line-two types of drug susceptibility testing which resulted in incomplete results and delays in diagnosis.

“The new approach from the study eliminated the need for a second sputum sample and significantly reduced the time required to determine drug resistance. The new test was much faster, providing results in 23 hours compared to 15 days with routine testing.”

They explained that the new method increased the availability of results and drastically cut down the turnaround time. Said study’s co-author and research coordinator in UCT’s faculty of health sciences, Dr Widaad Zemanay: “Faster diagnosis of TB drug resistance allows for the more rapid initiation of effective treatment and, therefore, improves patient outcomes, while reducing further transmission of drug-resistant TB.”

The study formed part of one arm of a process that aimed to provide evidence for impactful implementation of TB and TB/HIV co-infection diagnostic strategies, including drug-susceptibility testing through a series of trials in Tanzania, Mozambique and South Africa.

This, as TB remained high in the country despite all efforts to fight it, with almost 300 000 being diagnosed with it last year, with the most at risk being foreign-born people, including children, who had immigrated within five years from areas that had a high TB incidence, the WHO said.

“Residents and employees of settings like prisons, nursing homes, homeless shelters, drug treatment facilities, and healthcare facilities were also high risk,” the Department of Health said.

And, as in across the world, people with diabetes, who had had a gastrectomy or jejunoileal bypass, those with a low body weight, and those who used and abused substances were high risk, as were those with HIV.

It has also been found in people of any age and has been diagnosed in newborns who acquired it from their ill mother's placenta, and older children who were infected by parents and/or caregiver.

Adults and pregnant women, in rich and in poor communities, were also on the list of people suffering from TB worldwide.

Cox said the information derived from the study had the potential to greatly impact national TB programmes globally.

“Additionally, data collected through this study has allowed ongoing investigation around resistance to the new TB drugs currently used in South Africa,” she said.

The health sector noted that TB could have been neglected during the Covid-19 treatment period, becoming more common post-Covid and, in South Africa, potentially leading to a TB outbreak.

Cox said: “This collaborative effort exemplifies the power of international partnerships in advancing public health initiatives.”

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