Assessment of malaria in vitro drug combination screening and mixed-strain infections using the malaria Sybr green I-based fluorescence assay.
Antimicrob Agents Chemother
; 53(6): 2557-63, 2009 Jun.
Article
en En
| MEDLINE
| ID: mdl-19349518
Several drug development strategies, including optimization of new antimalarial drug combinations, have been used to counter malaria drug resistance. We evaluated the malaria Sybr green I-based fluorescence (MSF) assay for its use in in vitro drug combination sensitivity assays. Drug combinations of previously published synergistic (atovaquone and proguanil), indifferent (chloroquine and azithromycin), and antagonistic (chloroquine and atovaquone) antimalarial drug interactions were tested against Plasmodium falciparum strains D6 and W2 using the MSF assay. Fifty percent inhibitory concentrations (IC(50)s) were calculated for individual drugs and in fixed ratio combinations relative to their individual IC(50)s. Subsequent isobologram analysis and fractional inhibitory concentration determinations demonstrated the expected drug interaction pattern for each combination tested. Furthermore, we explored the ability of the MSF assay to examine mixed parasite population dynamics, which are commonly seen in malaria patient isolates. Specifically, the capacity of the MSF assay to discern between single and mixed parasite populations was determined. To simulate mixed infections in vitro, fixed ratios of D6 and W2 strains were cocultured with antimalarial drugs and IC(50)s were determined using the MSF assay. Dichotomous concentration curves indicated that the sensitive and resistant parasites composing the genetically heterogeneous population were detectable. Biphasic analysis was performed to obtain subpopulation IC(50)s for comparison to those obtained for the individual malaria strains alone. In conclusion, the MSF assay allows for reliable antimalarial drug combination screening and provides an important method to discern between homogenous and heterogeneous parasite populations.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Plasmodium falciparum
/
Pruebas de Sensibilidad Parasitaria
/
Evaluación Preclínica de Medicamentos
/
Antimaláricos
Tipo de estudio:
Diagnostic_studies
/
Screening_studies
Límite:
Animals
Idioma:
En
Revista:
Antimicrob Agents Chemother
Año:
2009
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos