Multi Drug Resistant TB Still a Menace

Diana Wangari, CNS Correspondent 
(First published in The Star News in Kenya on 15 March 2014)
Tuberculosis is ranked second among the infectious agents with highest mortality rates. According the WHO, 8.7 million people were infected with TB in 2011 with 1.4million deaths. This can be translated to approximately 1,500 deaths every day where 10% of these are children. Despite the high incidence rate, there appeared to be a silver lining after investigations showed a decrease in new infections and an estimated 85% success rate in treatment.

Then there was the emergence of multi-drug resistant tuberculosis (MDR-TB) and the same drugs that were once effective became worthless against this strain of tuberculosis. MDR-TB is caused by organisms that are resistant to the first line anti-TB drugs, both isoniazid and rifampicin. This reduced the number of drugs that can safely treat patients with this strain of TB.

Mismanagement of TB treatment is the primary cause of resistance. For tuberculosis treatment, a strict six month drug regimen is provided to patients with support and supervision to ensure adherence. However, with lack of adherence and ineffective formulations being circulated, resistance developed. New strains that proved too clever for the two most powerful first line drugs emerged. And once again, incidence of tuberculosis infection began to rise.  In Kenya, 2300 patients were reported to have MDR-TB. Globally, 3.7% of new TB infections were multi-drug resistant whereas 20% relapsed with the new strain.

The nature of MDR-TB is so insidious that the stop TB Partnership Goal Plan estimates that there will be one million MDR-TB patients between 2011 and 2015 who will be diagnosed and placed on treatment. What happens to the undetected cases? They will probably continue to transmit the infection as a person only needs to inhale a few of these organisms to become infected. In fact, about one third of the world’s population has latent TB which means they have been infected with TB but aren’t (at least not yet) ill with the disease. The good news is that if you do not have the disease, you cannot transmit the infection.  In as much as Kenya was ranked 13th in the list of high TB burden countries worldwide, we have doubled our efforts in the fight against the TB epidemic.

This was evidenced by the launch of the KEMRI/CDC lab in Nyanza which was the first lab to undertake TB culture testing apart from the Central Reference lab based in Nairobi. The decentralization was a much needed change as Dr. Joseph Sitienei, Director of the National Leprosy and TB control Programme (NLTP) explained, “The emergence of multi drug resistant TB is posing a great threat to TB treatment especially in Nyanza where TB cases are on the increase.”

He went on to reveal that Kenya is the first country in East and Central Africa to detect Extensively Drug Resistant TB (XDR-TB). Thus, a new concept is introduced. XDR-TB is a form of TB caused by organisms that are resistant to isoniazid and rifampicin as well as any fluoroquinolone and any of the second line injectable anti-TB drugs. Yes, just as we were beginning to combat MDR-TB, the strain of XDR-TB emerges with a 9% worldwide incidence rate. In addition, 4 new cases of a Totally Drug Resistant TB (TDR-TB) have been reported in India, though it is yet to be clearly described.

Regardless, these forms of TB do not respond to the standard TB treatment course and can take up to three years to treat with more toxic, more expensive and less potent drugs. As far as TB treatment goes, appropriate use and international standards must be maintained as the infection could outsmart us. 

Diana Wangari, Citizen News Service - CNS 
April 2014