摘要

       黑水虻幼虫（BSFL）已成功应用于处理各种有机废物。然而，人们对重金属对 BSFL 肠道抗生素耐药性的影响知之甚少。在这里，我们研究了铜（暴露浓度为 0、100 和 800 mg/kg）对 BSFL 肠道中抗生素和金属耐药性的影响。在幼虫肠道样本中共观察到 83 个抗生素抗性基因 (ARGs)、18 个移动遗传元件 (MGEs) 和 6 个金属抗性基因 (MRGs)。暴露于铜显着降低了 ARGs 和 MGEs 的多样性，但显着增加了肠道相关 ARGs 和 MRGs 的丰度。与 CK 相比，Cu 暴露后 MRGs copA、czcA 和 pbrT 的水平显着增强（增加了 2.8-13.5 倍）。肠球菌属是多种 ARG、MGE 和 MRG 亚型的最主要潜在宿主。同时，高铜暴露加剧了 BSFL 肠道中潜在病原体的富集，尤其是大肠杆菌、肠球菌和沙门氏菌。壁炉架测试和 procrustes 分析表明，肠道微生物群落可能是抗生素和金属耐药性的关键决定因素。然而，在 MGEs 和 ARGs 或 MRGs 之间没有观察到显着的正相关，这可能表明 MGEs 在 Cu 胁迫下对 BSFL 肠道中的 ARGs 或 MRGs 的形成没有发挥关键作用。这些发现扩展了我们对重金属对 BSFL 肠道相关抗生素和金属抵抗组影响的理解。

       The black soldier fly larvae (BSFL) have been successfully applied to treat various organic wastes. However, the impacts of heavy metals on antibiotic resistance in the BSFL guts are poorly understood. Here, we investigated the effect of copper (exposure concentrations of 0, 100 and 800 mg/kg) on the antibiotic and metal resistance profiles in BSFL guts. A total of 83 antibiotic resistance genes (ARGs), 18 mobile genetic elements (MGEs) and 6 metal resistance genes (MRGs) were observed in larval gut samples. Exposure to Cu remarkably reduced the diversity of ARGs and MGEs, but significantly enhanced the abundances of gut-associated ARGs and MRGs. The levels of MRGs copA, czcA and pbrT were dramatically strengthened after Cu exposure as compared with CK (increased by 2.8–13.5 times). Genera Enterococcus acted as the most predominant potential host of multiple ARG, MGE and MRG subtypes. Meanwhile, high exposure to Cu aggravated the enrichment of potential pathogens in BSFL guts, especially for Escherichia, Enterococcus and Salmonella species. The mantel test and procrustes analysis revealed that the gut microbial communities could be a key determinant for antibiotic and metal resistance. However, no significant positive links were observed between MGEs and ARGs or MRGs, possibly suggesting that MGEs did not play a crucial role in shaping the ARGs or MRGs in BSFL guts under the stress of Cu. These findings extend our understanding on the impact of heavy metals on the gut-associated antibiotic and metal resistome of BSFL.

https://www.sciencedirect.com/science/article/abs/pii/S1001074221000528