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Antimicrobial Agents and Chemotherapy, June 2007, p. 2280-2281, Vol. 51, No. 6
0066-4804/07/$08.00+0 doi:10.1128/AAC.01532-06
First Case of Emergence of Atovaquone Resistance in Plasmodium falciparum during Second-Line Atovaquone-Proguanil Treatment in South America 

LETTER
The atovaquone-proguanil combination (Malarone) has been introduced
in French Guiana for prophylaxis and second-line treatment for
Plasmodium falciparum malaria in 2002. We report here a treatment
failure in a patient who was given a second-line atovaquone-proguanil
treatment. A nonimmune
P. falciparum patient was infected during
a 5-day visit without prophylaxis in Maripasoula, a region of
malaria endemicity, and while residing in a malaria-free area,
the patient experienced three malaria episodes on day 0 (treated
with halofantrine [Halfan]), day 25 (treated with atovaquone-proguanil),
and day 49 (treated with quinine-doxycline). All treatments
were well tolerated. Plasma atovaquone concentration, measured
1 day after atovaquone-proguanil administration, was 1.45 µg/ml,
indicating adequate drug absorption (
8).
In vitro susceptibility tests, performed on blood samples from day 0 and day 49 (no blood sample was collected before atovaquone-proguanil administration), showed an increased 50% inhibitory concentration (IC50) value for atovaquone on day 49 compared to that on day 0 (Table 1). Genotyping of the parasites from days 0, 26, and 49, using four microsatellite loci (C4M69, 7A11, C4M79, and Pf2802) (1), msp2, and glurp (6), showed identical alleles for each locus in the three samples. The sequencing of cyt b, the atovaquone target (4, 9, 11), showed a wild-type 268 codon in the day 0 and day 26 samples and a 268S mutation in the day 49 sample. The sequencing of Pfdhfr-ts (the target of proguanil) (3) showed the same C50R N51I S108N triple mutant in the three samples, which furthermore had an increased copy number (two gene copies). In brief, the parasite genotypes of the three episodes were indistinguishable for all loci except cyt b. These data indicate that the second and third episodes were recrudescences due to successive treatment failures.
The day 49 parasites presented elevated IC
50 levels for atovaquone
and a 268S mutant Cyt
b, a mutation consistently associated
with in vitro resistance to atovaquone and therapeutic failures
(
2,
4,
5,
8,
10). The resistance mutation was undetected in
both pretreatment samples, indicating the emergence of resistant
parasites during the course of the atovaquone-proguanil treatment.
The presence of the 268S
cyt b mutation was associated with
a significantly lower IC
50 level for atovaquone than for some
atovaquone-proguanil treatment failures associated with the
same mutation (
2,
8). This result may suggest, in light of lack
of
cyt b mutation in an atovaquone-proguanil failure (
12), additional
targets for atovaquone-proguanil. However, a similar moderate
increase in IC
50 has been reported for recrudescent isolates
from Thai patients treated with atovaquone-proguanil (
7). Both
in Thailand and in French Guiana, therapeutic failure may involve
reduced susceptibility to both proguanil and atovaquone. In
vitro resistance to cycloguanil, the major metabolite of proguanil,
is very high in French Guiana (close to 100% prevalence in 2000
with a mean IC
50 of >4,100 nM). The mutant
Pfdhfr-ts and
cyt b genotypes observed in our atovaquone-proguanil therapeutic
failure are consistent with combined resistance to both proguanil
and atovaquone.
The observation of this first indigenous case of atovaquone-proguanil treatment failure in South America, due to drug resistance, shows the need for increased vigilance in the follow-up of patients treated with atovaquone-proguanil and in the reinforced surveillance of the parasite population.

ACKNOWLEDGMENTS
This project was supported by the French Ministry of Health
(InVS agency, Paris) and the EU commission-funded program RESMALCHIP
(QLK2-CT-2002-01503).
We thank B. Maubert (Biomedical Unit, Institut Pasteur de la Guyane, Cayenne, French Guiana) for providing the blood samples.

FOOTNOTES

Published ahead of print on 16 April 2007.

Present address: Unité d'Immunologie Moléculaire des Parasites, CNRS URA 2581, Institut Pasteur, 75724 Paris Cedex 15, France. 

REFERENCES
1 - Bogreau, H., F. Renaud, H. Bouchiba, P. Durand, S.-B. Assi, M.-C. Henry, E. Garnotel, B. Pradines, T. Fusai, B. Wade, E. Adehossi, P. Parola, M. Ali Kamil, O. Mercereau-Puijalon, and C. Rogier. 2006. Genetic diversity and structure of African Plasmodium falciparum populations in urban and rural areas. Am. J. Trop. Med. Hyg. 74:953-959.[Abstract/Free Full Text]
2 - Fivelman, Q. L., G. A. Butcher, I. S. Adagu, D. C. Warhurst, and G. Pasvol. 2002. Malarone treatment failure and in vitro confirmation of resistance of Plasmodium falciparum isolate Lagos, Nigeria. Mal. J. 1:1-4.[CrossRef]
3 - Foote, S. J., D. Galatis, and A. F. Cowman. 1990. Amino acids in the dihydrofolate reductase-thymidylate synthase gene of Plasmodium falciparum involved in cycloguanil resistance differ from those involved in pyrimethamine resistance. Proc. Natl. Acad. Sci. USA 87:3014-3017.[Abstract/Free Full Text]
4 - Korsinczky, M., N. Chen, B. Kotecka, A. Saul, K. Rieckmann, and Q. Cheng. 2000. Mutations in Plasmodium falciparum cytochrome b that are associated with atovaquone resistance are located at a putative drug-binding site. Antimicrob. Agents Chemother. 44:2100-2108.[Abstract/Free Full Text]
5 - Kuhn, S., M. J. Gill, and K. C. Kain. 2005. Emergence of atovaquone-proguanil resistance during treatment of Plasmodium falciparum malaria acquired by a non-immune North American traveller to West Africa. Am. J. Trop. Med. Hyg. 72:407-409.[Abstract/Free Full Text]
6 - Legrand, E., B. Volney, A. Lavergne, C. Tournegros, L. Florent, D. Accrombessi, M. Guillotte, O. Mercereau-Puijalon, and P. Esterre. 2005. Molecular analysis of two local falciparum malaria outbreaks on the French Guiana coast confirms the msp1 B-K1/varD genotype association with severe malaria. Mal. J. 4:26.[CrossRef]
7 - Looareesuwan, S., C. Viravan, H. K. Webster, D. E. Kyle, D. B. Hutchinson, and C. K. Canfield. 1996. Clinical studies of atovaquone, alone or in combination with other antimalarial drugs, for treatment of acute uncomplicated malaria in Thailand. Am. J. Trop. Med. Hyg. 54:62-66.[Abstract/Free Full Text]
8 - Musset, L., B. Pradines, D. Parzy, R. Durand, P. Bigot, and J. Le Bras. 2006. Apparent absence of atovaquone/proguanil resistance in 477 Plasmodium falciparum isolates from untreated French travellers. J. Antimicrob. Chemother. 57:110-115.[Abstract/Free Full Text]
9 - Sabchareon, A., P. Attanath, P. Phanuaksook, P. Chanthavanich, Y. Poonpanich, D. Mookmanee, T. Chongsuphajaisiddhi, B. M. Sadler, Z. Hussein, C. J. Canfield, and D. B. A. Hutchinson. 1998. Efficacy and pharmacokinetics of atovaquone and proguanil in children with multidrug-resistant Plasmodium falciparum malaria. Trans. R. Soc. Trop. Med. Hyg. 92:201-206.[CrossRef][Medline]
10 - Schwöbel, B., M. Alifrangis, A. Salanti, and T. Jelinek. 2003. Different mutation patterns of atovaquone resistance to Plasmodium falciparum in vitro: rapid detection of codon 268 polymorphisms in the cytochrome b as potential in vivo resistance marker. Mal. J. 2:1-7.[CrossRef]
11 - Srivastava, I., H. Rottenberg, and A. Vaidya. 1997. Atovaquone, a broad spectrum antiparasitic drug, collapses mitochondrial membrane potential in a malarial parasite. J. Biol. Chem. 272:3961-3962.[Abstract/Free Full Text]
12 - Wichmann, O., M. Muehlen, H. Gruss, F. P. Mockenhaupt, N. Suttorp, and T. Jelinek. 2004. Malarone treatment failure not associated with previously described mutations in the cytochrome b gene. Mal. J. 3:1-3.[CrossRef]
| | | | | |
Eric Legrand*
Centre National de Référence sur la Chimiorésistance du Paludisme dans la région Antilles-Guyane Institut Pasteur de la Guyane BP 6010 F-97306 Cayenne-Cedex, French Guiana
Magalie Demar
Laboratoire Hospitalo-Universitaire de Parasitologie et Mycologie Faculté de Médecine Antilles-Guyane et Centre Hospitalier de Cayenne Equipe EA 3593 Cayenne, French Guiana
Béatrice Volney
Centre National de Référence sur la Chimiorésistance du Paludisme dans la région Antilles-Guyane Institut Pasteur de la Guyane BP 6010 F-97306 Cayenne-Cedex, French Guiana
Marie-Thérèse Ekala
Unité d'Immunologie Moléculaire des Parasites CNRS URA 2581 Institut Pasteur 25 rue du Docteur Roux 75724 Paris Cedex 15, France
Marc Quinternet
Centre National de Référence sur la Chimiorésistance du Paludisme dans la région Antilles-Guyane Institut Pasteur de la Guyane BP 6010 F-97306 Cayenne-Cedex, French Guiana
Christiane Bouchier
Pasteur Genopole Ile de France Institut Pasteur 25 rue du Docteur Roux 75724 Paris Cedex 15, France
Thierry Fandeur
Faculté de Pharmacie UFR sciences pharmaceutiques UMR INRA-Université d'Immunologie Parasitaire et de Vaccinologie Tours, France
Christophe Rogier
Unité de recherche en Biologie et Epidémiologie Parasitaire Institut de Medecine Tropicale du Service de Santé des Armées Marseille, France
Bernard Carme
Laboratoire Hospitalo-Universitaire de Parasitologie et Mycologie Faculté de Médecine Antilles-Guyane et Centre Hospitalier de Cayenne Equipe EA 3593 Cayenne, French Guiana
Odile Mercereau Puijalon
Unité d'Immunologie Moléculaire des Parasites CNRS URA 2581 Institut Pasteur 25 rue du Docteur Roux 75724 Paris Cedex 15, France
Philippe Esterre
Centre National de Référence sur la Chimiorésistance du Paludisme dans la région Antilles-Guyane Institut Pasteur de la Guyane BP 6010 F-97306 Cayenne-Cedex, French Guiana
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* Phone: 594 29 26 12 Fax: 594 31 80 83 E-mail: elegrand{at}pasteur-cayenne.fr |
Antimicrobial Agents and Chemotherapy, June 2007, p. 2280-2281, Vol. 51, No. 6
0066-4804/07/$08.00+0 doi:10.1128/AAC.01532-06
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