环丙沙星胁迫猪粪生物转化中抗性基因微生物响应分析

Microbial Response to Antibiotic Resistance Genes in Manure Biotransformation Under Ciprofloxacin Stress

  • 摘要: 抗性基因(Antibiotic Resistance Genes,ARGs)是一种新兴污染物,持续累积会引发环境健康风险,也可通过水平转移诱导耐药细菌产生,从而危害人类健康与国家生物安全.当前关于ARGs的研究多集中于水、土壤、大气等环境介质,固体废弃物领域ARGs研究尚局限于其丰度变化与影响因素方面,对抗生素-ARGs剂量-效应关系、导致ARGs丰度变化的微生物响应机制仍有待深入研究.基于此,开展了不同浓度水平环丙沙星(Ciprofloxacin,CIP)胁迫下猪粪堆肥试验,环丙沙星添加量分别为25 mg/kg(A25)、50 mg/kg(A50)、100 mg/kg(A100),同时设置空白对照0 mg/kg(CK).采用分子生物学手段、网络分析、统计学分析等方法,解析了不同浓度环丙沙星胁迫猪粪好氧堆肥过程中喹诺酮类ARGs丰度变化的微生物响应关系,并重点探讨了潜在宿主菌中致病菌的分布及其与ARGs的相关性.结果表明:①经堆肥处理,CK、A25和A100堆体中喹诺酮类ARGs总丰度均受到不同程度削减,A50堆体中ARGs总丰度未被削减(升高2.73倍).而高温期除CK外,3个处理组中ARGs丰度均显著降低(P < 0.05),表明堆肥高温期或是削减ARGs的关键阶段.②狭义梭菌属(Clostridium_sensu_stricto_1)、水微菌属(Aquamicrobium)、乳杆菌属(Lactobacillus)及交替赤杆菌属(Altererythrobacter)既是堆肥环境中优势菌属,也是喹诺酮类ARGs潜在宿主微生物,主要分布在厚壁菌门(Firmicutes)和变形菌门(Proteobacteria).③丰度较高的致病菌Clostridium_sensu_stricto_1和链球菌(Streptococcus)是喹诺酮类ARGs的潜在宿主菌,且至堆肥腐熟期,仍有部分致病菌均未被完全去除,可见猪粪堆肥过程中存在ARGs向致病菌转移的环境健康风险.研究显示,加强高温期干预调控,是有效阻控ARGs环境污染行为的关键节点,研究可为固废资源化过程中ARGs环境健康风险防控提供参考.

     

    Abstract: Antibiotic resistance genes (ARGs), an emerging pollutant, cause health risks by accumulation in environment. It also induces the production of resistant bacteria through gene horizontal transfer, endangering human health and national biosecurity. Currently, research on ARGs is concentrated on wastewater, soil, and aerosol. However, scientific issues such as microbial driving mechanisms are still unclear, and the microbial response to abundance of ARGs remains to be further studied. Herein, manure composting experiments were conducted at four concentration levels (0, 25, 50, 100 mg/kg) of Ciprofloxacin stress. The response mechanism of ARGs abundance and microbial community structure was analyzed based on molecular biology, network analysis and statistical analysis. The distribution of pathogenic bacteria in potential host bacteria and their correlation with ARGs were discussed. The results showed that after composting, the total abundance of quinolones ARGs in CK, A25 and A100 all decreased to varying degrees, but the total abundance of ARGs in A50 did not decrease. During high temperature composting, in addition to CK, the abundance of ARGs in the treatment groups decreased significantly (P < 0.05). Clostridium_sensu_stricto_1, Aquamicrobium, Lactobacillus and Altererythrobacter were the dominant genus of bacteria in manure compost. They were also potential host microorganisms for quinolones ARGs, mainly distributed in Firmicutes and Proteobacteria. Highly abundance pathogenic bacteria Clostridium_sensu_stricto_1 and Streptococcus were potential host bacteria for quinolones ARGs. The pathogenic bacteria in the four composts were not removed completely on the 46th day of composting maturity. In summary, there is an environmental health risk of transferring ARGs to pathogenic bacteria in a pig manure composting environment. The high-temperature period is a key stage to control the environmental pollution of ARGs.

     

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