Ngangue-Siewe Idriss Nasser, Ndjeunia-Mbiakop Paulette, Kala-Chouakeu Nelly Armanda, Bamou Roland, Talipouo Abdou, Djamouko-Djonkam Landre, Vontas John, Mavridis Konstantinos, Tombi Jeannette, Tchuinkam Timoléon, Mbida-Mbida Jean Arthur, Antonio-Nkondjio Christophe
Laboratory of Animal Biology and Physiology, University of Douala, Douala P.O. Box 24157, Cameroon.
Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé P.O. Box 288, Cameroon.
Pathogens. 2022 Jul 23;11(8):824. doi: 10.3390/pathogens11080824.
The spread of pyrethroid resistance in malaria vectors is a major threat affecting the performance of current control measures. However, there is still not enough information on the resistance profile of mosquitoes to carbamates and organophosphates which could be used as alternatives. The present study assessed the resistance profile of Anopheles gambiae s.l. to bendiocarb and malathion, at the phenotypic and molecular levels, in different eco-epidemiological settings in Cameroon. Anopheles gambiae s.l. mosquitoes were collected from four eco-epidemiological settings across the country and their susceptibility level to bendiocarb and malathion was determined using WHO tubes bioassays. The ace-1 target site G119S mutation was screened by PCR. Reverse Transcription quantitative PCR 3-plex TaqMan assays were used to quantify the level of expression of eight genes associated with metabolic resistance. Resistance to malathion and/or bendiocarb was recorded in all study sites except in mosquitoes collected in Kaélé and Njombé. The Ace-1 (G119S) mutation was detected in high frequencies (>40%) in Kékem and Santchou. Both An. gambiae and An. coluzzii were detected carrying this mutation. The cytochrome P450s gene Cyp6p3 associated with carbamate resistance and the glutathione S-transferase gene Gste2 associated with organophosphate resistance were found to be overexpressed. Genes associated with pyrethroid (Cyp6m2, Cyp9k1, Cyp6p3) and organochlorine (Gste2, Cyp6z1, Cyp6m2) and cuticle resistance (Cyp4g16) were also overexpressed. The rapid spread of resistance to organophosphates and carbamates could seriously compromise future control strategies based on IRS. It is therefore becoming important to assess the magnitude of bendiocarb and malathion resistance countrywide.
拟除虫菊酯抗性在疟疾媒介中的传播是影响当前控制措施效果的一个主要威胁。然而，关于蚊子对可用作替代品的氨基甲酸酯类和有机磷酸酯类的抗性情况，目前仍缺乏足够信息。本研究在喀麦隆不同的生态流行病学环境中，从表型和分子水平评估了冈比亚按蚊复合组对残杀威和马拉硫磷的抗性情况。从该国四个生态流行病学环境中收集冈比亚按蚊复合组蚊子，并使用世卫组织试管生物测定法确定它们对残杀威和马拉硫磷的易感性水平。通过聚合酶链反应筛选ace-1靶位点G119S突变。使用逆转录定量聚合酶链反应三重TaqMan测定法来量化与代谢抗性相关的八个基因的表达水平。除了在卡埃莱和恩琼贝收集的蚊子外，在所有研究地点都记录到了对马拉硫磷和/或残杀威的抗性。在凯凯姆和桑舒，Ace-1（G119S）突变的检测频率很高（>40%）。检测到冈比亚按蚊和科氏按蚊都携带这种突变。发现与氨基甲酸酯抗性相关的细胞色素P450s基因Cyp6p3和与有机磷酸酯抗性相关的谷胱甘肽S-转移酶基因Gste2过度表达。与拟除虫菊酯（Cyp6m2、Cyp9k1、Cyp6p3）、有机氯（Gste2、Cyp6z1、Cyp6m2）和表皮抗性（Cyp4g16）相关的基因也过度表达。对有机磷酸酯类和氨基甲酸酯类抗性的迅速传播可能会严重损害基于室内滞留喷洒的未来控制策略。因此，评估全国范围内残杀威和马拉硫磷抗性的程度变得很重要。
