Emergence of artemisinin-based combination treatment failure in patients returning from sub-Saharan Africa with P. falciparum malaria

Background Artemisinin-based combination therapies (ACTs) are recommended as first-line treatment against uncomplicated Plasmodium falciparum infection. Mutations in the PfKelch13 (PF3D7_1343700) gene led to resistance to artemisinin in Southeast Asia. Mutations in the Pfcoronin (PF3D7_1251200) gene confer reduced artemisinin susceptibility in vitro to an African Plasmodium strain, but their role in clinical resistance has not been established.Methods We conducted a retrospective observational study of Israeli travellers returning from sub-Saharan Africa with P. falciparum malaria, including patients with artemether-lumefantrine (AL) failure. Blood samples from all malaria-positive patients are delivered to the national Parasitology Reference Laboratory along with personal information. Confirmation of malaria, species identification and comparative parasite load analysis were performed using real-time PCR. DNA extractions from stored leftover samples were analysed for the presence of mutations in Pfkelch13 and Pfcoronin. Age, weight, initial parasitaemia level and Pfcoronin status were compared in patients who failed treatment vs responders.Results During 2009-2020, 338 patients had P. falciparum malaria acquired in Africa. Of those, 15 (24-69 years old, 14 males) failed treatment with AL. Four were still parasitemic at the end of treatment, and 11 had malaria recrudescence. Treatment failure rates were 0% during 2009-2012, 9.1% during 2013-2016 and 17.4% during 2017-2020. In all patients, the Pfkelch13 propeller domain had a wild-type sequence. We did find the P76S mutation in the propeller domain of Pfcoronin in 4/15 (28.6%) of the treatment-failure cases compared to only 3/56 (5.5%) in the successfully treated patients (P = 0.027).Conclusion AL treatment failure emergence was not associated with mutations in Pfkelch13. However, P76S mutation in the Pfcoronin gene was more frequently present in the treatment-failure group and merits further investigation. The increase of malaria incidence in sub-Saharan-Africa partly attributed to the COVID-19 pandemic might also reflect a wider spread of ACT resistance.

Automated summary

A study on artemisinin resistance genes in Southeast Asia and Africa found that the P76S mutation in the Pfcoronin gene is associated with treatment failure of the antimalarial drug AL, while mutations in the Pfkelch13 gene are not associated with treatment failure.