Cyanobacterial blooms contribute to the diversity of antibiotic-resistance genes in aquatic ecosystems

Abstract

Cyanobacterial blooms are a global ecological problem that directly threatens human health and crop safety. Cyanobacteria have toxic effects on aquatic microorganisms, which could drive the selection for resistance genes. The effect of cyanobacterial blooms on the dispersal and abundance of antibiotic-resistance genes (ARGs) of concern to human health remains poorly known. We herein investigated the effect of cyanobacterial blooms on ARG composition in Lake Taihu, China. The numbers and relative abundances of total ARGs increased obviously during a Planktothrix bloom. More pathogenic microorganisms were present during this bloom than during a Planktothrix bloom or during the non-bloom period. Microcosmic experiments using additional aquatic ecosystems (an urban river and Lake West) found that a coculture of Microcystis aeruginosa and Planktothrix agardhii increased the richness of the bacterial community, because its phycosphere provided a richer microniche for bacterial colonization and growth. Antibiotic-resistance bacteria were naturally in a rich position, successfully increasing the momentum for the emergence and spread of ARGs. These results demonstrate that cyanobacterial blooms are a crucial driver of ARG diffusion and enrichment in freshwater, thus providing a reference for the ecology and evolution of ARGs and ARBs and for better assessing and managing water quality.

Gammaproteobacteria, a core taxon in the guts of soil fauna, are potential responders to environmental concentrations of soil pollutants

“…Proteobacteria are facultative anaerobic bacteria, whose unique oxygen consumption affects the gut environment, making it conducive to colonization by many types of anaerobic bacteria and destroys the stability of the original gut microbial community. The phylum Proteobacteria is generally considered to be comprised of 116 validated bacterial families and has the largest phylogenetic composition, with highly diverse morphological and physiological functions for maintaining a competitive advantage in adapting to complex and diverse ecological niches (e.g., soil [ 36 ], plants [ 41 ], freshwater [ 42 ], seawater [ 43 ], and the atmosphere [ 44 ]). In particular, one group of Proteobacteria, the Gammaproteobacteria, often aggressively occupies the ecological niche of the symbiotic relationship between plants and insects [ 45 , 46 ].…”

Seasonal Dynamics Are the Major Driver of Microbial Diversity and Composition in Intensive Freshwater Aquaculture

“…In this regard, the enrichment of nine ASVs belonging to the family Saprospiracae clade during the dry season is intriguing, as this clade is thought to be associated with the hydrolysis and utilization of complex carbon sources as well as with active predation on bacteria and algae, including Microcystis ( Ashton and Robarts, 1987 ). Additionally, both Saprospiracae and another group enriched in the dry season, the genus Haliscomenobacter , has been suggested to be associated with the presence of both cyanobacterial blooms and antibiotic resistance genes in Lake Taihu ( Zhang et al, 2020 ). While antibiotics are not used directly in the three sampled water bodies, they are used prophylactically at DARU at the beginning of the fish fattening cycle (beginning of dry season), including in additional fishponds connected to the system ( Patil et al, 2016 , 2020 ).…”

“…For example, environmental microorganisms can form the initial inocula for fish eggs or larvae, and pathogens can be transferred through the water, especially when fish biomass/density is very high. Therefore, significant effort has been invested in studying the aquatic microbiome in some aquaculture types, with the aim of using these measurements to understand fish health, to identify biomarkers/early markers of emerging diseases, or to explore the use of probiotics ( Dawood et al, 2019 ; Kuebutornye et al, 2019 ; Kolda et al, 2020 ; Zhang et al, 2020 ). In our dataset, we identify several bacterial lineages known as fish pathogens, including the genera Aeromonas , Vibrio , and Enterobacter , in agreement with previous studies from DARU ( Patil et al, 2016 , 2020 ).…”

Healthier Communities of Phytoplankton and Bacteria Achieved via the Application of Modified Clay in Shrimp Aquaculture Ponds

“…In addition, most marine phytoplankton are unicellular organisms and sensitive to environmental changes [ 38 ]. The variations in phytoplankton can reflect not only the health state of the aquaculture water ecosystem, but also the structure and function of the aquatic ecosystem [ 39 ].…”