MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China.
Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300401, China.
J Environ Manage. 2024 Mar;355:120402. doi: 10.1016/j.jenvman.2024.120402. Epub 2024 Feb 29.
Interactions of microplastics (MPs) biofilm with antibiotic resistance genes (ARGs) and antibiotics in aquatic environments have made microplastic biofilm an issue of keen scholarly interest. The process of biofilm formation and the degree of ARGs enrichment in the presence of antibiotic-selective pressure and the impact on the microbial community need to be further investigated. In this paper, the selective pressure of ciprofloxacin (CIP) and illumination conditions were investigated to affect the physicochemical properties, biomass, and extracellular polymer secretion of polyvinyl chloride (PVC) microplastic biofilm. In addition, relative copy numbers of nine ARGs were analyzed by real-time quantitative polymerase chain reaction (qPCR). In the presence of CIP, microorganisms in the water and microplastic biofilm were more inclined to carry associated ARGs (2-3 times higher), which had a contributing effect on ARGs enrichment. The process of pre-microplastic biofilm formation might have an inhibitory effect on ARGs (total relative abundance up to 0.151) transfer and proliferation compared to the surrounding water (total relative abundance up to 0.488). However, in the presence of CIP stress, microplastic biofilm maintained the abundance of ARGs (from 0.151 to 0.149) better compared to the surrounding water (from 0.488 to 0.386). Therefore, microplastic biofilm act as abundance buffer island of ARGs stabilizing the concentration of ARGs. In addition, high-throughput analyses showed the presence of antibiotic-resistant (Pseudomonas) and pathogenic (Vibrio) microorganisms in biofilm under different conditions. The above research deepens our understanding of ARGs enrichment in biofilm and provides important insights into the ecological risks of interactions between ARGs, antibiotics, and microplastic biofilm.
微塑料生物膜与抗生素抗性基因（ARGs）和抗生素在水生环境中的相互作用使得微塑料生物膜成为一个备受关注的学术问题。在抗生素选择性压力存在的情况下，生物膜形成的过程以及 ARGs 的富集程度，以及对微生物群落的影响都需要进一步研究。本文研究了环丙沙星（CIP）的选择性压力和光照条件对聚氯乙烯（PVC）微塑料生物膜的理化性质、生物量和胞外聚合物分泌的影响。此外，通过实时定量聚合酶链反应（qPCR）分析了 9 个 ARGs 的相对拷贝数。在 CIP 的存在下，水中和微塑料生物膜中的微生物更倾向于携带相关的 ARGs（高 2-3 倍），这对 ARGs 的富集有促进作用。与周围水体相比（总相对丰度高达 0.488），预微塑料生物膜形成过程对 ARGs 的转移和增殖可能具有抑制作用（总相对丰度高达 0.151）。然而，在 CIP 胁迫下，微塑料生物膜中 ARGs 的丰度（从 0.151 到 0.149）比周围水体（从 0.488 到 0.386）更好地维持。因此，微塑料生物膜作为 ARGs 的丰度缓冲岛，稳定 ARGs 的浓度。此外，高通量分析显示，在不同条件下生物膜中存在抗生素抗性（假单胞菌）和致病性（弧菌）微生物。上述研究加深了我们对生物膜中 ARGs 富集的认识，并为 ARGs、抗生素和微塑料生物膜相互作用的生态风险提供了重要的见解。
