Quinine resistant falciparum malaria acquired in east Africa
Jelinek, T.; Schelbert, P.; Löscher, T.; Eichenlaub, D.
Tropical Medicine and Parasitology Official Organ of Deutsche Tropenmedizinische Gesellschaft and of Deutsche Gesellschaft für Technische Zusammenarbeit 46(1): 38-40
1995
ISSN/ISBN: 0177-2392 PMID: 7631126 Document Number: 442152
A 43 year old man with falciparum malaria acquired in East Africa was treated with quinine intravenously at a loading dose of 500 mg and subsequently 500 mg tid. Within 42 hours after initiation of treatment the parasitaemia increased from 2% to 16%. A RIII-resistance against quinine was suspected and therapy was switched to oral administration of halofantrine (500 mg at 6 hourly intervals) which led to complete recovery. Blood samples were cultured for malaria parasites 42 hours after start of therapy with quinine but before initiation of therapy with halofantrine. In vitro resistance testing was performed with samples directly derived from the patient and after 24 and 48 hours of culturing. In repeated tests an in vitro resistance to quinine could be confirmed (IC 50: 25.6 times 10-6 mol/l, IC99: gt 51.2 times 10-6 mol/l) while the strain was fully susceptible to chloroquine (IC 50: lt 0.4 times 10-6 mol/l, IC 99: 1.6 times 10-6 mol/l), mefloquine (IC 50: lt 0.4 times 10-6 mol/l, IC99: 3.2 times 10-6 mol/1), tetracycline (IC 50: 0.16 times 10-6 mol/l, IC 99: 0.32 times 10-6 mol/l) and halofantrine (IC 50: 0.02 times 10-6 mol/l, IC99: 0.04 times 10-6 mol/l). Increased susceptibility to quinine after addition of verapamil was noted. The presence of a specific mutation, on the pfmdr1-gene on chromosome 5, previously associated with chloroquine drug resistance, could be confirmed by polymerase chain reaction. To our knowledge a R III-in vivo and in vitro resistance of Plasmodium falciparum to quinine has not been described yet in East Africa. P. falciparum strains with isolated resistance to quinine like the strain described here might have been overlooked previously due to their full susceptibility to other commonly used antimalarial drugs.