Xia Longji, Wang Jiaping, Chen Min, Li Guiying, Wang Wanjun, An Taicheng
Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
J Hazard Mater. 2025 Jan 5;481:136554. doi: 10.1016/j.jhazmat.2024.136554. Epub 2024 Nov 17.
Over 95 % of bacteria on water supply pipeline surfaces exist in biofilms, which are hotspots for antibiotic resistance gene (ARG) transmission. This study established mixed biofilm culture systems on a metal iron substrate using Escherichia coli: antibiotic-sensitive bacteria (ASB) and antibiotic-resistant bacteria (ARB). The growth rate and extracellular polymeric substances (EPS) content of mixed biofilm surpassed single-species biofilms due to synergistic interactions among different bacteria. However, the composition of mixed biofilms formed by ASB and ARB became unstable after 72 h, linked to reduced polysaccharide proportions in EPS and inter-bacterial competition. The bacterial composition and conjugative transfer frequency of ARGs in mixed biofilms indicate that biofilm formation significantly enhances horizontal transfer of ARGs. Notably, the conjugative transfer frequency of the mixed biofilm formed by two ARB increased 100-fold within five days. In contrast, the conjugative transfer frequency in the mixed biofilm formed by ASB and ARB was unstable; inter-bacterial competition led to plasmid loss associated with horizontal transfer of ARGs, ultimately resulting in biofilm shedding. Furthermore, genes associated with ARG transfer and biofilm growth up-regulated by 1.5 - 6 and 2 - 7 times, respectively, in mixed biofilm. These findings highlight a mutually reinforcing relationship between biofilm formation and horizontal ARG transmission, with significant environmental implications.
供水管道表面超过95%的细菌以生物膜形式存在，而生物膜是抗生素抗性基因（ARG）传播的热点。本研究使用大肠杆菌：抗生素敏感菌（ASB）和抗生素耐药菌（ARB）在金属铁基质上建立了混合生物膜培养系统。由于不同细菌之间的协同相互作用，混合生物膜的生长速率和胞外聚合物（EPS）含量超过了单物种生物膜。然而，ASB和ARB形成的混合生物膜组成在72小时后变得不稳定，这与EPS中多糖比例降低和细菌间竞争有关。混合生物膜中细菌组成和ARGs的接合转移频率表明，生物膜形成显著增强了ARGs的水平转移。值得注意的是，由两种ARB形成的混合生物膜的接合转移频率在五天内增加了100倍。相比之下，ASB和ARB形成的混合生物膜中的接合转移频率不稳定；细菌间竞争导致与ARGs水平转移相关的质粒丢失，最终导致生物膜脱落。此外，与ARG转移和生物膜生长相关的基因在混合生物膜中分别上调了1.5 - 6倍和2 - 7倍。这些发现突出了生物膜形成与ARGs水平转移之间相互促进的关系，具有重要的环境意义。
