Resistance-mediating polymorphisms of <i>Plasmodium falciparum</i> among isolates from children with severe malaria in Kumasi, Ghana

Abstract

SUMMARYBackground: Antimalarial drug resistance has been a major contributor to the failure of the battle against malaria in many developing countries. The P. falciparum genes, pfcrt and pfmdr-1, have been implicated in chloroquine resistance. The objective of this study was to determine the presence of mutant alleles of these chloroquine resistance genes among isolates of P. falciparum from children presenting with severe malaria in Ghana. Methods: Venous blood samples were taken from patients, and plasma chloroquine levels measured. P. falciparum chromosomal DNA was isolated from the blood samples, and subjected to PCR, restriction digestion and sequencing. Resulting data were analysed using the STATA statistical software. Results: Of 140 children recruited into the study, 109 (77.9%) had detectable pre-treatment chloroquine levels. PCR and restriction digestion analysis of the pfcrt gene indicated that 124 (88.6%) had the mutant T76 gene, and that this correlated with higher chloroquine levels. Sequence analysis of these showed consistent genetic sequences for chloroquine resistant and sensitive parasites with respect to Pfcrt codons 72 through 76.The Pfcrt T76 mutation was found in 88.4% of isolates having the Pfmdr-1Y86 mutation. The Pfmdr-1 Y86 mutation was found in 67.6% of isolates having the Pfcrt T76 mutation. Conclusion: The study affirms Pfcrt as a better chloroquine resistance marker. Both mutations are independently selected by chloroquine levels and that one mutation (Y86) might modify/increase the effect of the other (T76). This study also depicts the muchoverlooked antimalarial drug resistance situation in the area and emphasizes the need for a proper treatment strategy.

Use of proscribed chloroquine is associated with an increased risk of pfcrt T76 mutation in some parts of Ghana

“…Various studies since the change in malaria treatment policy in Ghana have reported different levels in prevalence of the mutant pfcrt T76 in P. falciparum isolates collected from different parts of the country [ 4 , 5 , 16 ]. CQ pressure is driven by high CQ usage in an area and it is a major determinant of selection and spread of CQ resistance genes among P. falciparum population [ 17 - 19 ].…”

“…Earlier, Abruquah and colleagues had reported 88.6% K76T prevalence in Kumasi [4], while Kwansa-Bentum and colleagues reported 51.6% K76T prevalence in southern part of Ghana [5]. A study conducted in 2004 by Duah and colleagues reported different T76 mutations among the various sentinel sites for their studies [12].…”

“…Based on reports of high chloroquine (CQ) treatment failure in Ghana and the recommendations of the World Health Organization (WHO) [ 1 - 3 ], CQ was replaced with artemisinin-based combination therapy (ACT) in 2004. Interestingly, high prevalence of CQ resistant mutants have been reported in different parts of the country by several researchers after the change in the malaria treatment policy [ 4 , 5 ] though others have reported decreased trend in prevalence and resistance in vitro [ 6 , 7 ].…”

“…In a retrospective study conducted from 2003 to 2010 by Duah and colleagues, they showed that there is decrease in T76, although the prevalence varies from study site to study site [ 6 ]. Earlier, Abruquah and colleagues had reported 88.6% K76T prevalence in Kumasi [ 4 ], while Kwansa-Bentum and colleagues reported 51.6% K76T prevalence in southern part of Ghana [ 5 ]. A study conducted in 2004 by Duah and colleagues reported different T76 mutations among the various sentinel sites for their studies [ 12 ].…”

Transcriptomic analyses of differentially expressed genes, micro RNAs and long-non-coding RNAs in severe, symptomatic and asymptomatic malaria infection

“…The recent World Health Malaria Report estimated about 241 million malaria cases and 627,000 deaths, and 95% of the cases and deaths are from sub-Saharan Africa (WHO, 2021). As a result of the growing threat of parasite and vector resistance to antimalarial drug and insecticides (Abruquah et al, 2010; Adams et al, 2018; Alam et al, 2011; Awolola et al, 2018; Diallo et al, 2022; Fukuda et al, 2021; Hawkes et al, 2015; Oboh et al, 2018; Patel et al, 2017; Straimer et al, 2022; Tacoli et al, 2016; Traoré et al, 2019; Tumwebaze et al, 2021), attention is now focused, more than ever on other control measures that can be deployed for malaria control. Unfortunately, vaccine development has also not been spared from parasite evasive mechanisms.…”