AUTHOR=Ajibaye Olusola , Olukosi Yetunde Adeola , Oriero Eniyou C. , Oboh Mary Aigbiremo , Iwalokun Bamidele , Nwankwo Ikechukwu Chidiebere , Nnam Chinaza Favour , Adaramoye Olawunmi Victoria , Chukwemeka Somadina , Okanazu Judith , Gabriel Eniafe , Balogun Emmanuel Oluwadare , Amambua-Ngwa Alfred 

TITLE=Detection of novel Plasmodium falciparum coronin gene mutations in a recrudescent ACT-treated patient in South-Western Nigeria

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=14

YEAR=2024

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2024.1366563

DOI=10.3389/fcimb.2024.1366563

ISSN=2235-2988

ABSTRACT=<sec><title>Background</title><p>Routine surveillance for antimalarial drug resistance is critical to sustaining the efficacy of artemisinin-based Combination Therapies (ACTs). <italic>Plasmodium falciparum kelch-13 (Pfkelch-13)</italic> and non-<italic>Pfkelch-13</italic> artemisinin <italic>(</italic>ART) resistance-associated mutations are uncommon in Africa. We investigated polymorphisms in <italic>Plasmodium falciparum</italic> actin-binding protein (Pfcoronin<italic>)</italic> associated with <italic>in vivo</italic> reduced sensitivity to ART in Nigeria.</p></sec><sec><title>Methods</title><p>Fifty-two <italic>P. falciparum</italic> malaria subjects who met the inclusion criteria were followed up in a 28-day therapeutic efficacy study of artemether-lumefantrine in Lagos, Nigeria. Parasite detection was done by microscopy and molecular diagnostic approaches involving PCR amplification of genes for <italic>Pf</italic>18S rRNA, <italic>var</italic>ATS, telomere-associated repetitive elements-2 (TARE-2). <italic>Pfcoronin</italic> and <italic>Pfkelch-13</italic> genes were sequenced bi-directionally while clonality of infections was determined using 12 neutral <italic>P. falciparum</italic> microsatellite <italic>loci</italic> and <italic>msp2</italic> analyses. Antimalarial drugs (sulfadoxine-pyrimethamine, amodiaquine, chloroquine and some quinolones) resistance variants (DHFR_51, DHFR_59, DHFR_108, DHFR_164, MDR1_86, MDR1_184, DHPS_581 and DHPS_613) were genotyped by high-resolution melting (HRM) analysis.</p></sec><sec><title>Results</title><p>A total of 7 (26.92%) cases were identified either as early treatment failure, late parasitological failure or late clinical failure. Of the four post-treatment infections identified as recrudescence by <italic>msp2</italic> genotypes, only one was classified as recrudescence by multilocus microsatellites genotyping. Microsatellite analysis revealed no significant difference in the mean allelic diversity, <italic>He</italic>, (P = 0.19, Mann-Whitney test). Allele sizes and frequency per locus implicated one isolate. Genetic analysis of this isolate identified two new <italic>Pfcoronin</italic> SNVs (I68G and L173F) in addition to the P76S earlier reported. Linkage-Disequilibrium as a standardized association index, <italic>I<sub>A</sub><sup>S</sup></italic>, between multiple <italic>P. falciparum</italic> loci revealed significant LD (<italic>I<sub>A</sub><sup>S</sup></italic> = 0.2865, <italic>P</italic>=0.02, Monte-Carlo simulation) around the neutral microsatellite loci. The <italic>pfdhfr/pfdhps/pfmdr1</italic> drug resistance-associated haplotypes combinations, (108<bold><sub>T/N</sub></bold>/51<bold><sub>I/</sub></bold>164<bold><sub>L</sub></bold>/59<bold><sub>R</sub></bold>/581<bold><sub>G</sub></bold>/86<bold><sub>Y</sub></bold>/184<bold><sub>F</sub></bold>), were observed in two samples.</p></sec><sec><title>Conclusion</title><p><italic>Pfcoronin</italic> mutations identified in this study, with potential to impact parasite clearance, may guide investigations on emerging ART tolerance in Nigeria, and West African endemic countries.</p></sec>