Emergence of P. vivax resistance to chloroquine in French Guiana.

The objective of this study was to collect data on chloroquine resistance in French Guiana by associating a retrospective evaluation of the therapeutic efficacy and an analysis of recurrent parasitemia from any patients.Patients with P. vivax infection, confirmed by microscopy and temperature ≥37.5°C, were retrospectively identified at Cayenne Hospital between 2009 and 2015. Follow-up and treatment responses were performed according to the World Health Organization protocol. Parasite resistance was confirmed after dosage of plasmatic concentration of chloroquine and microsatellite characterization. The pvmdr1 and pvcrt-o genes were analysed for sequence and gene copy-number variation.Among the 172 patients followed for 28 days, 164 presented adequate clinical and parasitological responses. Eight cases of treatment failures were identified (4.7%, n=8/172), all after 14 days. The therapeutic efficacy of chloroquine was estimated at 95.3% (95% CI 92.5-98.1, n=164/172). Among the eight failures, five were characterized: two cases were true P. vivax chloroquine resistance (1.2%, 95% CI 0-2.6, n=2/172) and three cases were found with subtherapeutic concentrations of chloroquine. No particular polymorphism in the Plasmodium vivax pvmdr1 and pvcrt-o genes was identified in the resistant parasites.This identified level of resistance of P. vivax to chloroquine in French Guiana does not require a change in therapeutic recommendations. However, primaquine should be administered more f...

Source: Antimicrobial Agents and Chemotherapy - September 2, 2019 Category: Microbiology Authors: Musset L, Heugas C, Naldjinan R, Blanchet D, Houze P, Abboud P, Volney B, Walter G, Lazrek Y, Epelboin L, Pelleau S, Ringwald P, Legrand E, Demar M, Djossou F Tags: Antimicrob Agents Chemother Source Type: research