Aponte Angélica, Penilla R Patricia, Rodríguez Américo D, Ocampo Clara B
Centro Internacional de Entrenamiento e Investigaciones Médicas CIDEIM, Carrera 125 N 19-225, Cali, Colombia.
Centro Regional de Investigación en Salud Pública- Instituto Nacional de Salud Pública de México, Avenida 4 Norte 19 calle poniente, CP 307000, Chiapas, Tapachula, Mexico.
Acta Trop. 2019 Mar;191:146-154. doi: 10.1016/j.actatropica.2018.12.021. Epub 2018 Dec 12.
In Colombia Aedes (Stegomyia) aegypti is the main vector of urban arboviruses such as dengue, chikungunya and Zika. This urban mosquito has a well-established capacity to develop insecticide resistance to different types of insecticides (pyrethroids, organochlorides, organophosphates), using multiple resistance mechanisms. An understanding of ongoing resistance mechanisms is critical to determining the activities of vector control programs. In order to identify the biochemical and molecular mechanisms associated with pyrethroid resistance in Colombia, three laboratory-selected strains resistant to DDT, Propoxur and lambdacyhalothrin, and 7 field-collected strains were evaluated. CDC bioassays were performed to measure the susceptibility status to pyrethroid type I (permethrin) and II (deltamethrin and lambdacyhalothrin), and potential cross-resistance to different types of insecticides; organochlorine (DDT), carbamates (propoxur) and organophosphates (malathion). The enzymatic activity of esterases, glutathione S-transferases (GST) and P monooxygenases were biochemically determined. Frequencies of kdr mutations Val1016Ile and Phe1534cys were determined through real-time PCR. The Rockefeller strain of Aedes (Stegomyia) aegypti was used as the susceptible control. The laboratory-selected strains "propoxur" and "lambdacyhalothrin" and one field population (Medellín (BF) F were resistant to all evaluated pyrethroids. Six of the seven field populations as well as the laboratory- selected "DDT" strain were resistant to permethrin. All the evaluated strains were resistant to DDT. Cross-resistance between lambdacyhalothrin and propoxur was observed in the laboratory-selected strains; however, all field-collected strains were susceptible to propoxur and no evidence of malathion resistance was found. The main biochemical mechanism for resistance observed in the field-collected strains was related to the enzyme GST. Further, the frequencies of kdr mutations alleles associated with insecticide resistance were high and ranged from 0.02 to 0.72 for Ile1016 and from 0.44 to 0.99 for Cys1534. Strains with high frequencies of both kdr mutations were resistant to both type I and II pyrethroids. These results suggest that Ae. aegypti from Colombia have developed multiple resistance mechanisms associated with pyrethroid resistance; therefore a resistance management strategy against these field populations of Ae. Aegypti, incorporating these findings is strongly recommended.
在哥伦比亚，埃及伊蚊（白纹伊蚊）是登革热、基孔肯雅热和寨卡等城市虫媒病毒的主要传播媒介。这种城市蚊子利用多种抗性机制，对不同类型的杀虫剂（拟除虫菊酯、有机氯、有机磷）产生抗药性的能力很强。了解当前的抗性机制对于确定病媒控制计划的成效至关重要。为了确定哥伦比亚与拟除虫菊酯抗性相关的生化和分子机制，对三个实验室选育的对滴滴涕、残杀威和高效氯氟氰菊酯具有抗性的品系以及7个野外采集的品系进行了评估。进行了疾控中心生物测定，以测量对I型拟除虫菊酯（氯菊酯）和II型拟除虫菊酯（溴氰菊酯和高效氯氟氰菊酯）的易感性状况，以及对不同类型杀虫剂的潜在交叉抗性；有机氯（滴滴涕）、氨基甲酸酯（残杀威）和有机磷（马拉硫磷）。通过生化方法测定了酯酶、谷胱甘肽S-转移酶（GST）和P单加氧酶的酶活性。通过实时聚合酶链反应确定了kdr突变Val1016Ile和Phe1534cys的频率。埃及伊蚊（白纹伊蚊）的洛克菲勒品系用作敏感对照。实验室选育的“残杀威”和“高效氯氟氰菊酯”品系以及一个野外种群（麦德林（BF）F）对所有评估的拟除虫菊酯均具有抗性。7个野外种群中的6个以及实验室选育的“滴滴涕”品系对氯菊酯具有抗性。所有评估的品系对滴滴涕均具有抗性。在实验室选育的品系中观察到高效氯氟氰菊酯和残杀威之间存在交叉抗性；然而，所有野外采集的品系对残杀威敏感，未发现马拉硫磷抗性的证据。在野外采集的品系中观察到的主要抗性生化机制与GST酶有关。此外，与杀虫剂抗性相关的kdr突变等位基因频率很高，Ile1016的频率范围为0.02至0.72，Cys1534的频率范围为0.44至0.99。同时具有高频率kdr突变的品系对I型和II型拟除虫菊酯均具有抗性。这些结果表明，来自哥伦比亚的埃及伊蚊已经形成了与拟除虫菊酯抗性相关的多种抗性机制；因此，强烈建议针对这些埃及伊蚊野外种群制定一项纳入这些研究结果的抗性管理策略。
