氨基甲酸酯类农药残留对生食果蔬表面细菌抗生素抗性的影响及其机理研究

The direct toxic effect of pesticide residuces in raw fruits and vegetables on humans has been well studied, while the indirect threat to human health through affecting the microorganism on the surface of fresh produce has rarely been reported. Carbamate pesticides (CMs), which are frequently-used in the cultivation of fruits and vegetables, have been shown to induce the production of DNA adduct and result in genetic mutation. And genetic mutation is the fundamental mechanism for bacterial antibiotic resistance (BAR) acquisition. Based on these facts, a hypothesis is proposed that CMs may induce bacteria genetic mutation and lead bacteria to resistance to antibiotics. The following will be investigated: the qualitative and quantitative analysis of the effect of CMs on BAR, and in the fruit and vegetable production base, the influence of CMs residues on microbiological ecology and BAR on the surface of raw fruits and vegetables; the roles of environmental factors and mixed pesticides in the process of the BAR inducement by CMs; the molecular ecology mechanism of this effect. The results will reveal the mechanism and the risk of antibiotic resistance acquisition for pathogens induced by CMs residues on the surface of raw fruits and vegetables. This study will establish a newly linkage between the pesticide residues problem and microbiological risk of raw fruits and vegetables, which will offer scientific foundation and novel visual angle for comprehensively and systematically control of raw fruits and vegetables quality safety.

生食果蔬中农药残留对人体的直接毒害作用研究较多，而其对果蔬表面微生物作用进而威胁人类健康的研究鲜见报道。果蔬生产中常用的氨基甲酸酯类(CMs)农药已被证实能够诱导DNA加合物产生，引起基因突变，而基因突变是细菌抗生素抗性（BAR）产生的根本途径。本项目由此提出CMs农药可能诱导细菌发生基因抗性突变而产生抗生素抗性的假设，并将研究CMs农药对BAR的定性和定量影响，以及实际果蔬生产中，CMs农药对果蔬表面微生物的生态结构和BAR的影响；探讨环境因素及农药混配等对CMs农药诱导BAR作用的影响；并分析该诱导作用的分子生态学机理等。研究结果将揭示CMs农药残留诱导果蔬表面致病菌获得抗生素抗性的机理及其风险，建立起生食果蔬的农药残留问题和微生物学风险之间的联系，为更全面系统地控制生食果蔬质量安全提供科学依据和新思路。

生食果蔬中农药残留对人体的直接毒害作用研究较多，而其对果蔬表面微生物作用进而威胁人类健康的研究鲜见报道。本项目根据细菌产生抗生素抗性的途径和氨基甲酸酯类(CMs)农药被证实能够诱导基因突变的发现，提出CMs农药可能诱导细菌发生基因抗性突变而产生抗生素抗性的假设，并对该假设进行了系统的证明及其机理的探讨。研究表明，CMs农药确实会引起阴沟肠杆菌（Enterobacter cloacae）对抗生素抗性的提高，其中涕灭威和抗蚜威对抗性提高作用最为显著。另外，CMs同样对大肠杆菌（Escherichia coli）和沙门氏菌（Salmonella enterica）抗生素抗性具有诱导作用，说明CMs可能诱导果蔬中其他细菌包括致病菌对抗生素的抗性。全基因组重测序分析证实了CMs农药处理菌株中突变的发生，尤其是染色体与质粒、质粒与质粒间的基因易位，会影响抗性的传播和扩散。另外，对种植基地、市场上的草莓进行调查发现，包括异丙威和乙霉威在内的52种农药残留及多种致病菌有检出，抗生素抗性基因多样性较高且具有传播风险。本研究揭示了果蔬表面细菌获得抗生素抗性的一条被忽略的途径，建立起生食果蔬的农药残留问题和微生物学风险之间的联系，证实农药残留会加剧果蔬的微生物学风险，为更全面系统地保障生食果蔬质量安全提供了科学依据和新思路。