Limoee M, Enayati A A, Khassi K, Salimi M, Ladonni H
Department of Public Health and Health Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran.
Trop Biomed. 2011 Apr;28(1):111-8.
The development of insecticide resistance in the German cockroach, Blattella germanica (L.) is a serious problem in controlling this medically important household pest. The insecticide resistance status in three hospital-collected strains of the German cockroach using four commonly used insecticides from different classes (permethrin, cypermethrin, bendiocarb and chlorpyrifos) was detected by topical bioassay method and preliminary information on possible involvement of monooxygenases in permethrin resistant strains employing synergist piperonyl butoxide (PBO) was obtained. For each insecticide, four to six concentrations resulting in >0% and <100% mortality were used. Three to six replicates of 10 cockroaches per concentration were conducted. For synergism studies, 100 μg PBO per gram body weight of cockroach as the maximum sublethal dose was administered to the first abdominal segment 1 h before insecticide treatment. The differences between LD50 (μg/g) values were considered statistically significant only when the 95% confidence intervals did not overlap. The resistance ratio and synergism ratio were calculated for each insecticide. All three hospital-collected strains of the German cockroach showed different levels of resistance to permethrin and cypermethrin based on resistance ratios compared with SUS strain. Permethrin and cypermethrin resistance ratios ranged from 11.61 to 17.64 and 11.45 to 26.45 at LD50 levels, respectively. Low to moderate levels of bendiocarb resistance and low level of chlorpyrifos resistance were also observed in the hospital-collected strains under study. The synergist piperonyl butoxide (PBO) significantly enhanced the toxicity of permethrin to all strains with different degrees of synergist ratio, 2.45-, 1.87-, 2.51- and 2.38-fold, suggesting monooxygenase involvement in permethrin resistance.
德国小蠊（Blattella germanica (L.)）对杀虫剂产生抗性是控制这种具有重要医学意义的家庭害虫的一个严重问题。采用点滴生物测定法检测了从医院收集的三个德国小蠊品系对四种不同类型常用杀虫剂（氯菊酯、氯氰菊酯、仲丁威和毒死蜱）的抗药性状况，并利用增效剂胡椒基丁醚（PBO）获得了关于单加氧酶可能参与氯菊酯抗性品系的初步信息。对于每种杀虫剂，使用了四至六个导致死亡率>0%且<100%的浓度。每个浓度进行三至六次重复试验，每次重复10只蟑螂。在增效作用研究中，在杀虫剂处理前1小时，以每克蟑螂体重100μg PBO作为最大亚致死剂量施用于第一腹节。只有当95%置信区间不重叠时，LD50（μg/g）值之间的差异才被认为具有统计学意义。计算了每种杀虫剂的抗性比和增效比。与敏感品系相比，基于抗性比，从医院收集的所有三个德国小蠊品系对氯菊酯和氯氰菊酯均表现出不同程度的抗性。在LD50水平下，氯菊酯和氯氰菊酯的抗性比分别为11.61至17.64和11.45至26.45。在所研究的从医院收集的品系中还观察到对仲丁威的低至中等水平抗性和对毒死蜱的低水平抗性。增效剂胡椒基丁醚（PBO）显著增强了氯菊酯对所有品系的毒性，增效比不同程度提高，分别为2.45倍、1.87倍、2.51倍和2.38倍，表明单加氧酶参与了氯菊酯抗性。
