Plasmodium falciparum DHFR and DHPS Mutations Are Associated With HIV-1 Co-Infection and a Novel DHPS Mutation I504T Is Identified in Western Kenya

Abstract

Antifolate resistance is significant in Kenya and presumed to result from extensive use and cross-resistance between antifolate antimalarials and antibiotics, including cotrimoxazole/Bactrim used for HIV-1 chemotherapy. However, little is known about antifolate-resistant malaria in the context of newly diagnosed HIV-1 co-infection prior to administration of HIV-1 chemotherapy. Blood samples from a cross-sectional study of asymptomatic adult Kenyans enrolled during voluntary HIV testing were analyzed by PCR for Plasmodium spp. More than 95% of volunteers with identifiable parasite species (132 HIV-1 co-infected) were infected with Plasmodium falciparum alone or P. falciparum with Plasmodium ovale and/or Plasmodium malariae. Deep sequencing was used to screen for mutations in P. falciparum dihydrofolate reductase (dhfr) (N51I, C59R, S108N, I164L) and dihydropteroate synthase (dhps) (S436H, A437G, K540E, A581G) from 1133 volunteers. Individual mutations in DHPS but not DHFR correlated with HIV-1 status. DHFR haplotype diversity was significantly different among volunteers by gender and HIV-1 status. DHPS haplotype diversity by HIV-1 status was significantly different between volunteers paired by age and gender, indicating that patterns of resistance were independent of these variables. Molecular simulations for a novel DHPS mutation (I504T) suggested that the mutated protein has increased affinity for the endogenous ligand DHPPP and decreased affinity for drug binding. A sub-group of monoclonal infections revealed that age and parasitemia were not correlated and enabled identification of a rare septuple-mutant haplotype (IRNL-HGEA). In our study, adult Kenyans newly diagnosed with HIV-1 infection were predominantly infected with moderately resistant P. falciparum, with patterns of infecting parasite genotypes significantly associated with HIV-1 status. Together with the discovery of DHPS I504T, these data indicate that antifolate resistance continues to evolve in Kenya. Further, they highlight the need to understand the effects of associated mutations on both fitness and resistance of P. falciparum in the context of HIV-1 co-infection to better inform treatment for asymptomatic malaria.

HIV-1 Impact on Malaria Transmission: A Complex and Relevant Global Health Concern

“…Contrary to parasitemia data above, asymptomatic individuals infected with HIV-1 have been shown to have a significantly higher risk of being gametocyte positive, and with a higher relative gametocyte density, compared to HIV-1-negative individuals (Stiffler et al, 2020). Further, HIV-1 co-infection is associated with significant differences in P. falciparum dhfr and dhps haplotypes in the same patient population, suggesting that HIV-1 co-infection could impact the spread of drug resistance (Torrevillas et al, 2020). These observations are concerning in the context of transmission reduction, especially considering the high prevalence of asymptomatics in varying endemnicities (Alves et al, 2005;Bousema et al, 2014;Sattabongkot et al, 2018;Tadesse et al, 2018) and areas with seasonal transmission.…”

Asymptomatic falciparum and Non-falciparum Malarial Parasitemia in Adult Volunteers with and without HIV-1 Coinfection in a Cohort Study in Western Kenya

“…34 In other studies of our volunteers published elsewhere, we observed that HIV-1-infected individuals had an increased risk of carrying gametocytes relative to HIV-1-uninfected individuals. 35 Furthermore, we observed that P. falciparum mutation haplotypes for the folate pathway genes dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) were significantly associated with volunteer HIV-1 status, 36 observations that collectively suggest that asymptomatic coinfected reservoirs in Western Kenya could be fueling transmission of drug-resistant parasites.…”

HIV-1 Infection Is Associated With Increased Prevalence and Abundance of Plasmodium falciparum Gametocyte-Specific Transcripts in Asymptomatic Adults in Western Kenya

“…), 1,116 had adequate remaining DBS for gametocyte transcript analysis by qPCR. Samples collected for this study were also analyzed for the prevalence of antifolate resistance makers in the context of HIV-1 co-infection (Torrevillas et al, 2020).…”