Sulfadiazine proliferated antibiotic resistance genes in the phycosphere of Chlorella pyrenoidosa: Insights from bacterial communities and microalgal metabolites

• Published in: Journal of hazardous materials 2024-07, Vol.473, p.134679-134679, Article 134679
• Main Authors: Gao, Ziqi, Cao, Manman, Ma, Shuai, Geng, Huanhuan, Li, Junhong, Xu, Qing, Sun, Ke, Wang, Fei
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - pharmacology; Antibiotic resistance genes; Bacteria - drug effects; Bacteria - genetics; Bacteria - metabolism; Bacterial community; Chlorella - drug effects; Chlorella - genetics; Chlorella - metabolism; Drug Resistance, Bacterial - genetics; Drug Resistance, Microbial - genetics; Genes, Bacterial; Microalgae - drug effects; Microalgae - genetics; Microalgae - metabolism; Microalgae-bacteria symbiotic systems; Microbiota - drug effects; Phycosphere; RNA, Ribosomal, 16S - genetics; Sulfadiazine; Sulfadiazine - pharmacology
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2024.134679

The phycosphere is an essential ecological niche for the proliferation of antibiotic resistance genes (ARGs). However, how ARGs’ potential hosts change and the driving mechanism of metabolites under antibiotic stress in the phycosphere have seldom been researched. We investigated the response of Chlorella pyrenoidosa and the structure and abundance of free-living (FL) and particle-attached (PA) bacteria, ARGs, and metabolites under sulfadiazine by using real-time quantitative PCR, 16 S rRNA high-throughput. The linkage of key bacterial communities, ARGs, and metabolites through correlations was established. Through analysis of physiological indicators, Chlorella pyrenoidosa displayed a pattern of "low-dose promotion and high-dose inhibition" under antibiotic stress. ARGs were enriched in the PA treatment groups by 117 %. At the phylum level, Proteobacteria, Bacteroidetes, and Actinobacteria as potential hosts for ARGs. At the genus level, potential hosts included Sphingopyxis, SM1A02, Aquimonas, Vitellibacter, and Proteiniphilum. Middle and high antibiotic concentrations induced the secretion of metabolites closely related to potential hosts by algae, such as phytosphingosine, Lysophosphatidylcholine, and α-Linolenic acid. Therefore, changes in bacterial communities indirectly influenced the distribution of ARGs through alterations in metabolic products. These findings offer essential details about the mechanisms behind the spread and proliferation of ARGs in the phycosphere. [Display omitted] •The antibiotics proliferated the colonization of ARGs in the phycosphere.•PA bacteria in the phycosphere enriched the ARGs.•The bacterial community in the phycosphere was significantly changed under sulfadiazine stress.•Metabolites secreted under antibiotic stress affect ARGs’ potential hosts.