RESUMEN
The goal of the present study was to assess the evolution of the in vitro chloroquine resistance and also the prevalence of pfcrt T76 and pfmdr1 Y86 mutations in Pikine from 2000 while chloroquine (CQ) was the first-line treatment of malaria to 2009 when artemisinin-based combination therapies (ACTs) are in use. We genotyped pfcrt K76T and pfmdr1 N86Y polymorphisms by PCR-RFLP and assessed in vitro CQ susceptibility by double-site enzyme-linked pLDH immunodetection (DELI) assay in Plasmodium falciparum isolates collected in Pikine, Senegal. The proportions of the pfcrt T76 allele in the light of the three different treatment policies were 72.4 % before CQ withdrawal (2000 to 2003), 47.2% while amodiaquine plus Fansidar was the first-line treatment (2004 to 2005), and 59.5 % since the ACT use was implemented (2006 to 2009). The prevalence of pfcrt T76 decreased significantly after CQ was stopped [X (2) = 6.54, P = 0.01 (2000-2003 versus 2004-2005)] and then slightly since ACTs have been implemented [X(2) = 1.12, P = 0.28 (2000-2003 versus 2006-2009)]. There were no significant differences on the prevalence of pfmdr1 Y86 throughout the three treatment policies. The DELI assay was carried out episodically in 2000 (n = 36), 2001 (n = 47), and 2009 (n = 37). The mean IC(50)s of the isolates to CQ in 2000 versus 2009 and 2001 versus 2009 are significantly different (P < 0.05). The Fisher exact test found a significant association between the presence of the pfcrt T76 mutant allele and in vitro resistance in 2000/2001 (P = 0.023), while in 2009 there were no association between both variables (P = 0.274). Mutant pfcrt T76 and pfmdr1 Y86 alleles and in vitro CQ-resistant strains are still circulating in Pikine. The official discontinuation of CQ use is not completely followed by its total withdrawal from private drug sellers, and the molecule still exerts pressure on local P. falciparum populations.
Asunto(s)
Cloroquina/farmacología , Resistencia a Medicamentos , Proteínas de Transporte de Membrana/genética , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/genética , Mutación Missense , Plasmodium falciparum/efectos de los fármacos , Plasmodium falciparum/genética , Proteínas Protozoarias/genética , Antimaláricos/farmacología , ADN Protozoario/genética , Utilización de Medicamentos/estadística & datos numéricos , Frecuencia de los Genes , Humanos , Malaria Falciparum/parasitología , Pruebas de Sensibilidad Parasitaria , Plasmodium falciparum/aislamiento & purificación , Mutación Puntual , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , SenegalRESUMEN
In the context of early infant diagnosis (EID) decentralization in sub-Saharan Africa, dried blood spot (DBS) is now widely used for HIV proviral DNA detection in resource-limited settings. A new version of CAP/CTM (version 2) has been introduced, recently by Roche Diagnosis as a new real-time PCR assay to replace previous technologies on qualitative detection of HIV-1 DNA using whole blood and DBS samples. The objective of this study was to evaluate CAP/CTM version 2 compared to CAP/CTM version 1 and Amplicor on DBS. A total of 261 DBS were collected from children aged 4 weeks to 17 months born from HIV-seropositive mothers and tested by the three techniques. CAP/CTM version 2 showed 100% of agreement with Amplicor including 74 positive results and 187 negative results. CAP/CTM version 2 versus CAP/CTM version 1 as well as CAP/CTM version 1 versus Amplicor showed two discordant results giving a sensitivity of 98.6%, specificity of 99.5%, positive predictive value of 98.6% and negative predictive value of 99.5%. The concordance was 99.12% (95% of confidence interval) giving a Kappa coefficient of 0.97 (p<0.001). These findings confirmed the expected good performance of CAP/CTM version 2 for HIV-1 EID.
Asunto(s)
Sangre/virología , ADN Viral/análisis , Infecciones por VIH/diagnóstico , VIH-1/aislamiento & purificación , Técnicas de Diagnóstico Molecular/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Manejo de Especímenes/métodos , África del Sur del Sahara , ADN Viral/genética , Desecación , VIH-1/genética , Humanos , Lactante , Valor Predictivo de las Pruebas , Sensibilidad y Especificidad , Carga Viral/métodosRESUMEN
In 2003, the high level of chloroquine (CQ) treatment failure for uncomplicated Plasmodium falciparum malaria cases has led Senegal to adopt a new combination therapy with sulfadoxine-pyrimethamine and amodiaquine (SP-AQ). From September through November 2004, we used the 14-day World Health Organization follow-up protocol to assess the therapeutic response in patients with uncomplicated P. falciparum malaria in an area of high prevalence of pfcrt T76 mutant allele and SP resistance mutations. Of the 82 patients who were recruited, 68 (82.9%) completed follow-up. The response of the patients to treatment was adequate clinical response for 63 out of 68 patients (92.6%), while five (7.4%) clinical failures were recorded, four early treatment failures, and one late treatment failure. The prevalence of the pfcrt T76 allele at day 0 was 59.5%. The two-sided Fisher's exact test did not show an association between pfcrt T76 allele and treatment failure (p=0.167). The transitory treatment is effective and safe. However, the presence of high levels of mutant alleles points out the need to closely monitor the new therapeutic regimen.