Departamento de Entomologia, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz. Av. Moraes Rego s/n, Cidade Universitária, CEP: 50670-420, Recife PE, Brazil.
Acta Trop. 2010 Feb;113(2):180-9. doi: 10.1016/j.actatropica.2009.10.015. Epub 2009 Oct 30.
Insecticide resistance is one of the main problems in vector control programs. Because insects have developed resistance to all classes of available chemical insecticides, a proper surveillance and management of resistance in areas where these compounds are being utilized is crucial for the success of control programs. Since the mechanisms and molecular bases of resistance are various, they must be characterized to allow efficient monitoring strategies. Here we report the establishment of an Aedes aegypti strain resistant to temephos, named RecR, selected under laboratory conditions. The parental A. aegypti population was obtained from eggs collected in an area where temephos had been used for 8 years, and presented a baseline resistance ratio (RR) of 7. After 17 generations under selective pressure, the RR has increased to 180. Biochemical assays indicate that metabolic mechanisms are involved on temephos resistance in the selected strain. These experiments showed that, compared to the susceptible colony Rockefeller, RecR present higher activity of glutathione S-transferases (GSTs), alpha- and beta-esterases, and, to a lesser degree, mixed function oxidases (MFO). At the 14th or 17th generations, there was no cross resistance of these insects to deltamethrin, cypermethrin and malathion, while a low resistance level (RR=3) was observed for pyriproxyfen, a juvenile hormone analogue. Experiments on resistance reversal, performed through three different field simulated schemes using the resistant strain, showed that temephos susceptibility can be recovered. The establishment of an A. aegypti colony resistant to temephos is extremely valuable for a deeper understanding of resistance mechanisms and thus for further improvements in control strategies against this vector. With the urgent need on improving methodologies to monitor resistance, molecular studies such as microarrays, and resistant colonies such as RecR will certainly hasten such studies.
昆虫抗药性是病媒控制项目中的主要问题之一。由于昆虫已经对所有可用的化学杀虫剂产生了抗药性，因此在使用这些化合物的地区，对其进行适当的监测和管理对于控制项目的成功至关重要。由于抗药性的机制和分子基础各不相同，因此必须对其进行特征描述，以允许采用有效的监测策略。在这里，我们报告了一种对硫磷具有抗性的埃及伊蚊（Aedes aegypti）品系的建立，该品系命名为 RecR，是在实验室条件下选择的。亲代埃及伊蚊种群是从已使用硫磷 8 年的地区收集的卵中获得的，其基线抗性比（RR）为 7。在选择性压力下经过 17 代后，RR 增加到 180。生化测定表明，代谢机制参与了所选菌株对硫磷的抗性。这些实验表明，与敏感品系洛克菲勒相比，RecR 中谷胱甘肽 S-转移酶（GSTs）、α-和β-酯酶的活性更高，混合功能氧化酶（MFO）的活性略低。在第 14 或 17 代时，这些昆虫对氯菊酯、氯氰菊酯和马拉硫磷没有交叉抗性，而对保幼激素类似物吡丙醚的抗性水平较低（RR=3）。使用抗性品系进行的三种不同现场模拟方案的抗药性逆转实验表明，硫磷的敏感性可以恢复。建立对硫磷具有抗性的埃及伊蚊品系对于深入了解抗药性机制非常有价值，从而可以进一步改进针对这种病媒的控制策略。由于迫切需要改进监测抗药性的方法，因此分子研究（例如微阵列）和类似 RecR 的抗性品系肯定会加速这些研究。
