Tang Kuok Ho Daniel, Li Ronghua
Department of Environmental Science, College of Agriculture, Life & Environmental Sciences, The University of Arizona (UA), Tucson, AZ 85721, USA.
School of Natural Resources and Environment, UA Microcampus, Northwest A&F University (NWAFU), Yangling 712100, China.
Antibiotics (Basel). 2024 Oct 6;13(10):941. doi: 10.3390/antibiotics13100941.
Microplastic aging affects the dynamics of antibiotic resistance genes (ARGs) on microplastics, yet no review presents the effects of microplastic aging on the associated ARGs. This review, therefore, aims to discuss the effects of different types of microplastic aging, as well as the other pollutants on or around microplastics and the chemicals leached from microplastics, on the associated ARGs. It highlights that microplastic photoaging generally results in higher sorption of antibiotics and ARGs due to increased microplastic surface area and functional group changes. Photoaging produces reactive oxygen species, facilitating ARG transfer by increasing bacterial cell membrane permeability. Reactive oxygen species can interact with biofilms, suggesting combined effects of microplastic aging on ARGs. The effects of mechanical aging were deduced from studies showing larger microplastics anchoring more ARGs due to rough surfaces. Smaller microplastics from aging penetrate deeper and smaller places and transport ARGs to these places. High temperatures are likely to reduce biofilm mass and ARGs, but the variation of ARGs on microplastics subjected to thermal aging remains unknown due to limited studies. Biotic aging results in biofilm formation on microplastics, and biofilms, often with unique microbial structures, invariably enrich ARGs. Higher oxidative stress promotes ARG transfer in the biofilms due to higher cell membrane permeability. Other environmental pollutants, particularly heavy metals, antibacterial, chlorination by-products, and other functional genes, could increase microplastic-associated ARGs, as do microplastic additives like phthalates and bisphenols. This review provides insights into the environmental fate of co-existing microplastics and ARGs under the influences of aging. Further studies could examine the effects of mechanical and thermal MP aging on their interactions with ARGs.
微塑料老化会影响微塑料上抗生素抗性基因（ARGs）的动态变化，但尚无综述介绍微塑料老化对相关ARGs的影响。因此，本综述旨在探讨不同类型的微塑料老化以及微塑料上或其周围的其他污染物和从微塑料中浸出的化学物质对相关ARGs的影响。研究强调，微塑料光老化通常会因微塑料表面积增加和官能团变化而导致对抗生素和ARGs的吸附增加。光老化会产生活性氧，通过增加细菌细胞膜通透性促进ARGs转移。活性氧可与生物膜相互作用，这表明微塑料老化对ARGs具有综合影响。机械老化的影响是从一些研究中推断出来的，这些研究表明，由于表面粗糙，较大的微塑料能固定更多的ARGs。老化产生的较小微塑料可深入渗透到更小的地方，并将ARGs输送到这些地方。高温可能会减少生物膜数量和ARGs，但由于研究有限，热老化微塑料上ARGs的变化情况仍不清楚。生物老化会导致微塑料上形成生物膜，而生物膜通常具有独特的微生物结构，总是会富集ARGs。较高的氧化应激由于细胞膜通透性较高而促进生物膜中ARGs的转移。其他环境污染物，特别是重金属、抗菌剂、氯化副产物和其他功能基因，以及邻苯二甲酸盐和双酚等微塑料添加剂，都可能增加与微塑料相关的ARGs。本综述深入探讨了老化影响下微塑料和ARGs共存的环境归宿。进一步的研究可以考察机械老化和热老化微塑料对其与ARGs相互作用的影响。
