Nav: Home

Prevalence of drug-resistant tuberculosis in West Africa higher than previously thought

November 02, 2016

Multidrug-resistant tuberculosis (TB) could become a serious public health threat in West Africa unless effective surveillance and control measures are implemented, according to a study published in the open access journal BMC Medicine. Researchers from the West-African Network of Excellence for TB, AIDS and Malaria (WANETAM) found the prevalence of multidrug-resistant tuberculosis (MDR-TB) to be unexpectedly high in eight West-African countries.

Professor Martin Antonio, Principal Investigator at the Medical Research Council Unit The Gambia (MRCG), who led WANETAM's TB-related activities, said: "To our surprise, we found that multidrug-resistant and pre-extensively drug-resistant tuberculosis strains are already widely circulating and that drug resistance is a much bigger problem in West Africa than previously anticipated. WHO estimates the prevalence of multidrug resistance in new and retreatment cases to be 2% and 17% respectively but we found that it is 6% and 35% respectively."

Professor Antonio added: "We recommend that efforts be put in place for containment of a potential West African TB epidemic at the earliest possible stage. This is especially important as West Africa with its 245 million inhabitants is one of the poorest regions globally, whose fragile health systems can easily be overwhelmed by infectious disease epidemics, as seen in the recent Ebola outbreak."

Analysis of 974 bacterial samples collected from patients with TB revealed that 39% were resistant to at least one first-line drug and 22% were multidrug-resistant. Pre-extensively drug-resistant TB isolates were found to be present at all study sites with Ghana showing the highest proportion, where 35% of MDR samples were pre-extensively drug-resistant.

Multidrug-resistant bacteria are resistant to two or more of the first-line drugs used for the treatment of a disease. Pre-extensively drug-resistant bacteria are on the verge of developing into extensively drug-resistant bacteria, which are resistant to the second-line drugs that are used if first-line treatment fails. MDR-TB prevalence was highest among patients previously treated for TB in Bamako, Mali (59%) and in Ibadan (39%) and Lagos (66%), Nigeria. Bacteria isolated from these retreatment patients were four times more likely to be resistant to one or more first-line drugs when compared to bacteria isolated from new patients.

Dr Florian Gehre, a postdoctoral researcher and first author of the paper said: "In Lagos, 32% of new TB patients tested positive for the MDR-TB strains. Even when considering a potential sampling bias in the study, it is uncommon for new patients to acquire MDR-TB, except if patients with MDR-TB strains transmit these strains directly to new patients or new patients infect each other."

This study is the first to achieve a comprehensive overview of drug resistance in the region. Professor Antonio said: "Due to poor laboratory infrastructure and inadequate capacity, at the start of WANETAM, data on drug-resistant TB prevalence in West Africa were scarce so prevalence was assumed to be comparably low and not considered a major public health problem. Our data shows that this may not be the case."

In order to take steps to remedy the lack of laboratory infrastructure and to generate comprehensive data on drug resistance prevalence in West Africa, WANETAM - which was founded in 2008 and comprises nine study sites in Burkina Faso, The Gambia, Ghana, Guinea-Bissau, Mali, Nigeria, Senegal and Togo - trained local laboratory staff to perform routine diagnostics, such as standardized smear microscopy and mycobacterial culture.

Professor Souleymane Mboup, head of the Bacteriology Virology Department at the University Hospital Le Dantec, University of Dakar, Senegal and the overall principle investigator for the WANETAM project said: "This is the first time that leading scientists and research institutes in West Africa joined forces to create a research network that provides research opportunities, fosters collaborations, builds capacity and trains members in basic and advanced laboratory techniques to independently conduct TB drug resistance surveys."

The infrastructure built by WANETAM will help countries in West Africa to respond effectively to emerging public health threats and to conduct trials to address local health needs and inform health policies. Although more data is needed to fully assess the risk of a drug-resistant TB epidemic in West Africa, the results from this study should prompt the implementation of continuous surveillance of all retreatment patients in participating countries, according to the researchers.

Professor Umberto D'Alessandro, MRCG Unit Director, said: "Besides building infrastructures and training local research teams, WANETAM has been able to produce highly relevant and high quality information for the control of TB in West Africa. I hope WANETAM will continue to provide a major contribution to the fight against diseases of public health importance in Africa."
-end-
Media Contact

Anne Korn
Press Officer
BioMed Central
T: +44 (0)20 3192 2744
E: anne.korn@biomedcentral.com

1. The emerging threat of pre-extensively drug-resistant tuberculosis in West Africa: preparing for large-scale tuberculosis research and drug resistance surveillance Gehre et al.

BMC Medicine 2016

DOI: 10.1186/s12916-016-0704-5

For an embargoed copy of the research article, please contact Anne Korn at BioMed Central.

After the embargo lifts, the article will be available at the journal website here: https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-016-0704-5

Please name the journal in any story you write. If you are writing for the web, please link to the article. All articles are available free of charge, according to BioMed Central's open access policy.

2. An infographic that illustrates the findings is available from Anne Korn at BioMed Central.

3. BMC Medicine is an open access, open peer-reviewed general medical journal publishing outstanding and influential research in all areas of clinical practice, translational medicine, public health, policy, and general topics of interest to the biomedical research community. As the flagship medical journal of the BMC series, we also publish stimulating debates and reviews as well as unique forum articles and concise tutorials.

4. BioMed Central is an STM (Science, Technology and Medicine) publisher which has pioneered the open access publishing model. All peer-reviewed research articles published by BioMed Central are made immediately and freely accessible online, and are licensed to allow redistribution and reuse. BioMed Central is part of Springer Nature, a major new force in scientific, scholarly, professional and educational publishing, created in May 2015 through the combination of Nature Publishing Group, Palgrave Macmillan, Macmillan Education and Springer Science+Business Media. http://www.biomedcentral.com

5. This study was possible thanks to the support provided by the European Developing Countries Clinical Trial Partnership (EDCTP) to WANETAM. Besides building infrastructures and training local research teams, WANETAM has been able to produce highly relevant and high quality information for the control of TB in West Africa.

BioMed Central

Related Drug Resistance Articles:

Fast test can monitor drug resistance in hookworms
More than 2 billion people around the world are infected with intestinal helminths, parasitic worms that can cause disease, complicate pregnancies, and stunt the growth of children.
Resistance to drug of last resort found in farm animals in US
Carbapenems are one of the most important classes of antibiotics used in humans, and are an important agent against multi-drug resistant bacteria.
A cinematic approach to drug resistance
In a creative stroke inspired by Hollywood wizardry, scientists from Harvard Medical School and Technion-Israel Institute of Technology have designed a simple way to observe how bacteria move as they become impervious to drugs.
Salmonella protein reduces drug resistance in tumors
A surprising result in an experiment on Salmonella bacteria has led to a discovery that may make drug resistant cancer cells more treatable by conventional chemotherapies.
Deciphering the mutations behind drug resistance
Antimicrobial resistance in disease-causing microbes has garnered attention in recent years, but another persistent area of drug resistance is the ability for tumors to evade chemotherapy drugs.
More Drug Resistance News and Drug Resistance Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Erasing The Stigma
Many of us either cope with mental illness or know someone who does. But we still have a hard time talking about it. This hour, TED speakers explore ways to push past — and even erase — the stigma. Guests include musician and comedian Jordan Raskopoulos, neuroscientist and psychiatrist Thomas Insel, psychiatrist Dixon Chibanda, anxiety and depression researcher Olivia Remes, and entrepreneur Sangu Delle.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...