Plasmodium falciparum

WHO/TDR/Taylor-Robinson

[NEW DELHI] A new antibiotic has shown promise in fighting malaria and could eventually supplement traditional antimalarials to combat multidrug-resistant malaria, say researchers.

Tigecycline belongs to a new class of antibiotics effective against bacteria that develop resistance to the common antibiotic tetracycline, which is used to supplement traditional antimalarials such as artemisinin in some countries including Bangladesh.

It shows substantial antimalarial activity and has potential use in combination with other faster-acting antimalarials, researchers based in Bangladesh and Austria report in the September 2009 issue of Antimicrobial Agents and Chemotherapy.

They tested the effects of tigecycline on 66 blood samples from men and non-pregnant women in Bangladesh infected with Plasmodium falciparum malaria, and found the antibiotic was six times more effective against the malaria parasite than the common antibiotic doxycycline — also used in malaria treatment in Bangladesh — and delayed death.

"[Tigecycline] is an interesting step forward and shows significant antimalarial activity on its own. It may also be effective against multidrug-resistant falciparum malaria when administered in combination with faster-acting antimalarial drugs [for example artemisinin or quinine], says Wasif Ali Khan, associate scientist at the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B) and one of the authors of the paper.

Varinder Singh Chauhan, director of the International Centre for Genetic Engineering and Biotechnology (ICGEB) and one of India's top malaria researchers says that a large number of antibiotics do have "fairly decent antimalarial activity".

But for a drug to be used as an antimalarial in humans, it needs to be much more potent and specific, Chauan told SciDev.Net. Naturally occurring compounds like curcumin (turmeric extract) and many others have decent antimalarial activity, but need further development to be used as antimalarials.

Chauhan says that although the new finding is an interesting step forward, so far no antibiotic has been found to be potent enough, and without adverse side effects, to be used to treat malaria.

Link to abstract in Antimicrobial Agents and Chemotherapy