TABLE 2.
Comparison of peripheral blood and placental Plasmodium falciparum dihydrofolate reductase genotypes
| Placental dhfr genotype of samplea | No. of samples with indicated peripheral blood dhfr genotypea
|
Total (%) | |||||||
|---|---|---|---|---|---|---|---|---|---|
| 51 59 108 | 51 59 108 | 51 59 108 | 51 59 108 | 51 59 108 | 51 59 108 | 51 59 108 | Nontypeable | ||
| 51 59 108 | 12 | 2 | 2 | 1 | 17 (5.7) | ||||
| 51 59 108 | 5 | 2 | 2 | 9 (3.0) | |||||
| 51 59 108 | 1 | 1 (0.3) | |||||||
| 51 59 108 | 2 | 1 | 3 (1.0) | ||||||
| 51 59 108 | 7 | 3 | 10 (3.3) | ||||||
| 51 59 108 | 1 | 1 | 1 | 81 | 14 | 2 | 100 (33.3) | ||
| 51 59 108 | 1 | 5 | 6 | 141 | 1 | 154 (51.3) | |||
| Nontypeable | 4 | 2 | 6 (2.0) | ||||||
| Total (%) | 15 (5.0) | 7 (2.3) | 3 (1.0) | 2 (0.7) | 16 (5.3) | 93 (31.0) | 161 (53.7) | 3 (1.0) | |
a
Mutated codons are displayed in bold. The concordance of alleles between matched placental and peripheral samples was high for codon 108 (97.6%; 284/291), lower for codon 59 (94.2%; 274/291), and lowest for codon 51 (90%; 262/291) (P = 0.0007). Of 20 discordant peripheral isolates with the dhfr triple mutation, 17 matching placental genotypes exhibited double mutations, and 1 was of the wild type. Contrariwise, of the 13 placental isolates with dhfr triple mutation not identified as such by peripheral genotyping, 11 showed double dhfr mutations.