摘要

    作为一种腐生昆虫，黑水虻可以以环保的方式高效消化有机废物。然而，这种昆虫的能力和效率，以及所涉及的微生物降解抗生素的机制在很大程度上是未知的。为了在黑水虻幼虫（幼虫）降解 OTC（土霉素）过程中获得更多细节，研究了肠道细菌群落的变化。在幼虫肠道内发现了 ARG（抗生素抗性基因）和 MGE（移动遗传元件）。在降解期末，当初始浓度分别为 100、1000 和 2000 mg kg-1（干重）时，82.7%、77.6% 和 69.3% 的 OTC 被幼虫降解，远高于降解效率 (19.3–22.2%) 没有幼虫。 OTC对幼虫的发育无明显影响。虽然幼虫肠道微生物受到 OTC 的影响，但它们适应了改变的环境。肠道中的肠球菌、Ignatzschineria、Providencia、摩根氏菌、Paenalcaligenes 和放线菌对抗生素暴露有强烈反应。有趣的是，发现了许多 ARG（特别是 180 个 ARG 和 10 个 MGE），并且与幼虫肠道中的整合子整合酶基因和转座酶显着相关。在所有检测到的 ARG 中，四环素抗性基因的表达水平较高，占 ARG 总数的 67%。特别是，肠球菌、伊格纳茨氏菌、博德特氏菌、普罗维登西亚菌和变形杆菌都是肠道中四环素酶修饰基因的宿主，能够有效降解 OTC。这些发现表明 OTC 可以有效降解，并证明幼虫增强了抗生素污染的生物修复。此外，形成的大量 ARG 和 MGE 应受到关注，并在环境健康风险评估系统中予以考虑。

     As a saprophytic insect, the black soldier fly can digest organic waste efficiently in an environmentally friendly way. However, the ability and efficiency of this insect, and the microbial mechanisms involved, in the degradation of antibiotics are largely uncharacterized. To obtain further details during the degradation of OTC (oxytetracycline) by black soldier fly larvae (larvae), the changes in intestinal bacterial communities were examined. Both ARGs (antibiotic resistance genes) and MGEs (mobile genetic elements) were found within the larval guts. At the end of the degradation period, 82.7%, 77.6% and 69.3% of OTC was degraded by larvae when the initial concentrations were 100, 1000 and 2000 mg kg−1 (dry weight), respectively, which was much higher than the degradation efficiencies (19.3–22.2%) without larvae. There was no obvious effect of OTC on the development of the larvae. Although the larval gut microorganisms were affected by OTC, they adapted to the altered environment. Enterococcus, Ignatzschineria, Providencia, Morganella, Paenalcaligenes and Actinomyces in the gut responded strongly to antibiotic exposure. Interestingly, numerous ARGs (specifically, 180 ARGs and 10 MGEs) were discovered, and significantly correlated with those of both integron-integrase gene and transposases in the larval gut. Of all the detected ARGs, tetracycline resistance genes expressed at relatively high levels and accounted for up to 67% of the total ARGs. In particular, Enterococcus, Ignatzschineria, Bordetella, Providencia and Proteus were all hosts of enzymatic modification genes of tetracycline in the guts that enabled effective degradation of OTC. These findings demonstrate that OTC can be degraded effectively and prove that the bioremediation of antibiotic contamination is enhanced by larvae. In addition, the abundance of ARGs and MGEs formed should receive attention and be considered in environmental health risk assessment systems.

    https://www.sciencedirect.com/science/article/pii/S016041202031789X