生物质炭与噬菌体联用阻控与灭活土壤–生菜体系中抗生素抗性致病细菌

Combined Biochar and Bacteriophage to Control and Inactivate Antibiotic Resistance Pathogenic Bacteria in Soil-Lettuce System

农田土壤-蔬菜体系中残留和滋生的多种抗生素抗性致病细菌已对人体健康和生态环境安全造成较严重的隐患,因此开展针对性的风险管控技术研究十分迫切。生物质炭阻控与农业噬菌体疗法联用靶向灭活土壤-蔬菜体系中抗生素抗性致病细菌,为解决此类污染土壤问题提供了全新途径。本研究以自主制备的抗生素抗性致病细菌(携带四环素抗性基因tetW的大肠杆菌K12,携带氯霉素抗性基因ampC的铜绿假单胞菌PAO1)污染农田土壤为盆栽用土,开展生菜土培试验60 d。设置单独或同时添加生物质炭和接种广宿主型噬菌体(YSZ 5K)的不同处理,以土壤-生菜体系中K12、PAO1数量变化及tetW、ampC丰度消减程度表征联合修复的效果。结果表明,针对土壤-生菜体系中残留K12、PAO1和tetW、ampC消减程度变化,判断不同处理效果,依次为:BP(生物质炭与噬菌体联用)>B(单独施用生物质炭)>P(单独接种噬菌体)>CK(对照),其中BP处理条件下,K12与PAO1在土壤和生菜叶片中数量较之对照处理下降了2.1~3.1个数量级,tetW和ampC丰度较之对照处理下降了2.2~3.3个数量级。此外,在BP处理条件下,生菜收获后,土壤微生物群落结构与功能多样性和稳定性指数也得到显著提升,证明该联合治理方式是一种较为环境友好的修复技术。本研究结果可为降低土壤–蔬菜体系中抗性致病细菌的残留风险提供科学的理论依据和有效的管控技术。

Ubiquitous existence of antibiotic resistant pathogens(ARP)in the agricultural land and vegetation system has posed great threat against public health and environmental safety,making it essential to develop targeted controlling technologies.In this work,biochar and bacteriophage combined technology was investigated for its effectiveness in targeted inactivating the ARP in the soil-lettuce system.Biochar and polyvalent phage YSZ 5K were applied to the ARP(tetracycline resistant Escherichia coli K12 and chloramphenicol resistant Pseudomonas aeruginosa PAO1)contaminated soil.The residual K12 and PAO1 counts and antibiotic resistance genes(tetW and ampC)abundances were determined after 60 days of incubation.The results showed that the combined technology was proved most effective,followed by sole application of biochar,sole inoculation of YSZ 5K,and the control.For the combined treatment,the counts of K12/PAO1 decreased by 2.1-3.1 magnitudes and the abundances of tetW/ampC decreased by 2.2-3.3 magnitudes in the soil and lettuce leaves,respectively.In addition,the structural and functioning diversity of soil microbial community was improved significantly after the combined treatment.The results obtained here demonstrate the combined application of biochar and polyvalent phage YSZ 5K an environmentally-friendly technology that could effectively decrease the ARP in the soil-lettuce system.