Chemosusceptibility analysis of Plasmodium falciparum imported malaria in Italy.
A constant surveillance of susceptibility to antimalarials allows to optimize prevention and treatment of malaria in nonendemic countries. In vitro susceptibility of imported Plasmodium falciparum isolates to chloroquine, quinine, mefloquine, halofantrin, pyronaridine, and amodiaquine was analyzed by WHO Micro-test Mark III; IC50 and IC90 were calculated by WHO Log-probit. Sixty-seven tests were performed. All the infections were acquired in Africa: 14.9% in East Africa and 85.1% in West Africa (WA). IC50 and IC90 (micromol/L) were chloroquine: 0.129 and 0.648; amodiaquine: 1.134 and 5.445; mefloquine: 0.38 and 0.868; quinine: 0.193 and 0.478; halofantrin: 3.27 and 25.35; pyronaridine: 11.504 and 51.996. Higher IC50 and IC90 were observed in East Africa versus West Africa strains. All strains were susceptible to quinine and mefloquine; chloroquine resistance, 14%; amodiaquine resistance, 33%, with cross-resistance to chloroquine (r = 0.93; P < .0001); halofantrin resistance, 3.6%, no cross-resistance with chloroquine; low susceptibility to pyronaridine (66.7%), with cross-resistance with chloroquine (r = 0.38, P < 0.05). Lower levels of chloroquine resistance were observed in 2000-2003 as compared with prior data; thus, the reemergence of chloroquine susceptibility in Africa may be hypothesized.
Caramello
Pietro
P
Divisione A di Malattie Infettive, Dipartimento di Malattie Infettive, Ospedale Amedeo di Savoia, Turin, Italy. pcarame@tin.it
Canta
Francesca
F
Cavecchia
Ilaria
I
Sergi
Giuseppina
G
Balbiano
Rosanna
R
Ariaudo
Silvia
S
Audagnotto
Sabrina
S
Di Perri
Giovanni
G
D000293:Adolescent; D000328:Adult; D000349:Africa / Q000208:ethnology; D000368:Aged; D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D004351:Drug Resistance; D005260:Female; D006801:Humans; D020128:Inhibitory Concentration 50; D007558:Italy; D016778:Malaria, Falciparum / Q000208:ethnology / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification; D011446:Prospective Studies
D000962:Antimalarials