In vitro activities of quinine and other antimalarials and pfnhe polymorphisms in plasmodium isolates from Kenya
Resistance to the amino alcohol quinine has been associated with polymorphisms in pfnhe, a sodium hydrogen exchanger. We investigated the role of this gene in quinine resistance in vitro in isolates from Kenya. We analyzed pfnhe whole-gene polymorphisms, using capillary sequencing, and pfcrt at codo...
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| Main Authors: | , , , , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
1 June 2010
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| In: |
Antimicrobial agents and chemotherapy
Year: 2010, Volume: 54, Issue: 8, Pages: 3302-3307 |
| ISSN: | 1098-6596 |
| DOI: | 10.1128/aac.00325-10 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1128/aac.00325-10 Verlag, lizenzpflichtig, Volltext: https://journals.asm.org/doi/10.1128/AAC.00325-10 
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| Author Notes: | John Okombo, Steven M. Kiara, Josea Rono, Leah Mwai, Lewa Pole, Eric Ohuma, Steffen Borrmann, Lynette Isabella Ochola, and Alexis Nzila |
| Summary: | Resistance to the amino alcohol quinine has been associated with polymorphisms in pfnhe, a sodium hydrogen exchanger. We investigated the role of this gene in quinine resistance in vitro in isolates from Kenya. We analyzed pfnhe whole-gene polymorphisms, using capillary sequencing, and pfcrt at codon 76 (pfcrt-76) and pfmdr1 at codon 86 (pfmdr1-86), using PCR-enzyme restriction methodology, in 29 isolates from Kilifi, Kenya, for association with the in vitro activities of quinine and 2 amino alcohols, mefloquine and halofantrine. In vitro activity was assessed as the drug concentration that inhibits 50% of parasite growth (IC50). The median IC50s of quinine, halofantrine, and mefloquine were 92, 22, and 18 nM, respectively. The presence of 2 DNNND repeats in microsatellite ms4760 of pfnhe was associated with reduced susceptibility to quinine (60 versus 227 nM for 1 and 2 repeats, respectively; P < 0.05), while 3 repeats were associated with restoration of susceptibility. The decrease in susceptibility conferred by the 2 DNNND repeats was more pronounced in parasites harboring the pfmdr1-86 mutation. No association was found between susceptibility to quinine and the pfcrt-76 mutation or between susceptibility to mefloquine or halofantrine and the pfnhe gene and the pfcrt-76 and pfmdr1-86 mutations. Using previously published data on the in vitro activities of chloroquine, lumefantrine, piperaquine, and dihydroartemisinin, we investigated the association of their activities with pfnhe polymorphism. With the exception of a modulation of the activity of lumefantrine by a mutation at position 1437, pfnhe did not modulate their activities. Two DNNND repeats combined with the pfmdr1-86 mutation could be used as an indicator of reduced susceptibility to quinine. |
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| Item Description: | Gesehen am 03.07.2023 |
| Physical Description: | Online Resource |
| ISSN: | 1098-6596 |
| DOI: | 10.1128/aac.00325-10 |