A new study suggests that tigecycline, the first member of a new class of antibiotics, shows significant antimalarial activity on its own and may also be effective against multi drug-resistant malaria when administered in combination with traditional antimalarial drugs.
The researchers from the Medical University of Vienna, Austria; Malaria Research Initiative Bandarban, Bangladesh; and the International Center for Diarrheal Disease Research, Dhaka, Bangladesh report their findings in the September 2009 issue of the journal Antimicrobial Agents and Chemotherapy.
Increasing resistance of Plasmodium falciparum to existing drugs has resulted in the search for new antimalarial therapies. Tigecycline belongs to a novel class of antibiotics called glycylcyclines which exhibit unique and novel methods of action against bacteria and are specifically designed to overcome two mechanisms of tetracycline resistance. Clinical studies of tigecycline have shown it is easy to administer and is generally well tolerated with a twice-daily dosing regimen.
In the study blood samples were collected from male and nonpregnant female patients in Bangladesh infected by P. falciparum. Specifically excluded from the study were pregnant or breastfeeding women and patients who had received malaria drug therapy up to 30 days prior. When tested with 66 isolates tigecycline showed one the highest activities of all antibiotics against P. falciparum. Additionally, tigecycline was up to 6 times more active against P. falciparum than doxycycline, however, when tested in conjunction with doxycycline, a significant activity correlation was noted. Finally, further testing of tigecycline confirmed earlier studies indicating that tigecycline may induce a delayed-death response and also that it has a relatively long half-life making it simpler to administer than tetracycline and doxycycline.
"We conclude that tigecycline has substantial antimalarial activity on its own and may be a potential candidate for exploring its clinical efficacy in combination with faster-acting antimalarials in the parenteral treatment of multidrug-resistant P. falciparum malaria in seriously ill patients," say the researchers.
(P. Starzengruber, K. Thriemer, R. Haque, W.A. Khan, H.P. Fuehrer, A. Siedl, V. Hofecker, B. Ley, W.H. Wernsdorfer, H. Noedl. 2009. Antimalarial activity of tigecycline, a novel glycylcycline antibiotic. Antimicrobial Agents and Chemotherapy, 53. 9: 4040-4042.)
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