近日，广东工业大学环境健康与污染控制研究院、环境科学与工程学院安太成教授团队题为《Biofilm formation mechanisms of mixed antibiotic-resistant bacteria in water: Bacterial interactions and horizontal transfer of antibiotic-resistant plasmids》的学术论文在Journal of Hazardous Materials (2025, 481: 136554; https://doi.org/10.1016/j.jhazmat.2024.136554)杂志上发表。论文的第一作者为博士生夏隆基、硕士毕业生王佳萍，通讯作者为安太成教授。该研究主要关注水体中不同金属介质表面耐药菌形成不同混合菌剂生物膜的形成机理，深入讨论了混合生物膜内不同细菌之间的相互作用和耐药基因水平转移对混合生物膜形成过程的作用机制。该研究可为理解和调控水生环境中不同介质表面混合生物膜的污染与防控提供有效的支持。

论文DOI: https://doi.org/10.1016/j.jhazmat.2024.136554

自来水供水管道表面95%以上的细菌是以生物膜的形式存在的，同时生物膜也是抗生素耐药基因（Antibiotic resistance gene，ARG）传播的热点。本研究利用大肠杆菌、抗生素敏感菌（Antibiotic-sensitive bacteria，ASB）和抗生素耐药菌（Antibiotic-resistant bacteria，ARB）在不同的金属基质上构建了不同菌种的混合生物膜培养体系。混合生物膜的生长速度和胞外聚合物（Extracellular polymeric substances，EPS）含量均超过单种生物膜，这是由于不同细菌之间的协同作用导致的。然而，实验发现由ASB和ARB形成的混合生物膜的组成在72h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ARGs的细菌组成和共轭转移频率表明：生物膜的形成显著促进了ARGs的水平转移。值得注意的是，两种ARB形成的混合生物膜的共轭转移频率在5天内增加了100倍。相反，ASB和ARB形成的混合生物膜中的共轭转移频率不稳定；这可能是因为细菌间竞争导致与ARGs水平转移相关的质粒丢失所导致，最终也可能会导致生物膜从基质上的脱落。此外还发现与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。这些发现均强调了生物膜形成和水平ARG传播之间存在相互加强的关系，这样的结果可能对水环境中的病原微生物的防控具有非常重要的意义。

图片摘要：

论文的英文摘要附如下：

ABSTRACT:

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.

项目资助：本研究得到国家自然科学基金（42330702, 42122056和 42077333）和粤桂联合基金重点项目(2020B1515420002）的大力支持。