Search

Climate warming multiplies the threat of antibiotic resistance genes (ARGs) to public health, but whether temperature may predict antibiotic resistomes in water environment remain unknown. Here, by metagenomic sequencing, we investigated the changes of resistome at five different temperature gradients (23, 26, 29, 32, and 35 °C) in polluted water by animal cadaver. Thirty ARG types including 668 subtypes were observed in our samples. Temperature significantly influenced ARG profiles and showed a negative correlation with ARG diversity. The ARG assembly process was dominated by a deterministic process (63.32%–95.08%) but showed a peak pattern with temperature. Notably, temperature may predict approximately 21% of ARGs and 36% of mobile genetic elements (MGEs), while most other ARGs or MGEs were insensitive to temperature. Three types (carbapenem, dicyclomycin, and diaminopyrimidine antibiotic) and 63 subtypes of ARGs that positively correlated with temperature were identified in the polluted water. Notably, we screened 21 subtypes of high-risk ARGs (bacA , mdtA , tetM , etc.) and 22 opportunistic pathogens (Aeromonas , Clostridium , Bacteroides , etc.) and found their positive co-occurrence with temperature, implying these potential biological or genetic pollutants may probably go up under global warming. Our study reveals the predictability of temperature on antibiotic resistance genes, providing a suitable approach to track the fate and spread of ARGs in water environment under climate warming. [Display omitted] • Temperature may predict approximately 21% of ARGs and 36% of MGEs. • Temperature had a negative correlation with ARG diversity. • The ARG assembly process was dominated by deterministic processes. • High-risk ARGs related to cadaver decay pose potential risks to public health. • Proteobacteria and Actinobacteria were the main hosts of ARGs after carcass decay. [ABSTRACT FROM AUTHOR]

Many contaminants were carried by dust, a common environment media that is easy to contact with human beings, and antibiotic resistance genes (ARGs) as an emergency pollutant also harbor in dust and pose serious threats to human health especially those carried by opportunistic pathogens because inactivation of antibiotics caused by ARGs may enhance pathogenicity. Considering there is a gap of investigation of dust ARGs, 16 S rRNA gene sequences and high-throughput quantitative PCR were employed to obtain information of microbial communities and accumulated ARGs in dust from different urban places, including the malls, hospitals, schools and parks, to investigate the distribution and influencing factors of ARGs and discover the potential hosts of ARGs in dust. Here, 9 types of ARGs such as sulfonamide, tetracycline, and beta-lactamase and 71 subtypes of ARGs like sul1 , tetM-01 , and drfA1 were detected in dust. ARGs had varying distribution in different public places and seasons in dust. The abundances of total ARGs, MLSB and tetracycline genes were higher in spring than summer. The diversity of ARGs was highest in malls, follow by hospitals, schools, and parks. Additionally, multi-drug resistance genes in dust were more abundant in hospitals than in schools and parks. The microbes were distinguished as the most important driving factors for ARGs in dust, followed by the mobile genetic elements (MGEs) and different places, while dust physicochemical parameters only exert a negligible impact. Notably, several opportunistic pathogens like the Streptococcus , Vibrio , and Pseudomonas were inferred as potential hosts of high-risk ARGs such as mecA , tetM-02 , and tetO-01 in dust because of strongly positive co-occurrence. These results imply that dust is likely an important reservoir of ARGs. We should realize that ARGs may be harbored in some opportunistic pathogens occur in dust and endanger human health because of dust contacting to human easily. [Display omitted] • Many common ARGs harbored in dust from various public places. • Diversity of dust ARGs were higher in spring than those in summer. • Microbiome was the leading driving factors of ARGs, followed by different places and MGEs. • Some high-risk ARGs and opportunistic pathogens were found in dust. • Several high-risk ARGs presented positive correlations with opportunistic pathogens. [ABSTRACT FROM AUTHOR]

Suspended particles in water can shelter both microorganisms and contaminants. However, the emerging pollutants antibiotic resistance genes (ARGs) in free-living (FL) or particle-attached (PA) bacteria in aquatic environments are less explored. In this study, we compared the free-living and particle-attached ARGs during four seasons in the Yellow River using high-throughput quantitative PCR techniques and 16S rRNA gene sequencing. Our results demonstrated that both the free-living water and particles were dominated by tetracycline and beta-lactamase resistance genes. The PA-ARGs had a higher absolute abundance than FL-ARGs in the Yellow River, regardless of the season. Both PA-ARGs and FL-ARGs had the highest absolute abundance and diversity during winter. Mobile genetic elements (MGEs) were the dominant driver for both size-fractionated ARGs. However, the microbiome had less influence on PA-ARG profiles than the FL-ARG profiles, while the effects of the heavy metals on ARGs were negligible. The community assembly of both FL-ARG and PA-ARG can be explained by neutral processes. Several opportunistic pathogens (e.g., Escherichia coli) associated with human health exhibited a higher relative abundance in the particles than during a free-living lifestyle. Parts of these pathogens were potential ARG hosts. As such, it is important to monitor the ARGs and opportunistic pathogens from size-fractionated bacteria and develop targeted strategies to manage ARG dissemination and opportunistic pathogens to ensure public health. [Display omitted] • The PA-ARGs in the Yellow River had higher diversity and abundance than FL-ARGs. • The effects of the heavy metals on size-fractionated ARGs were negligible. • Both FL-ARG and PA-ARG community assembly can be explained by neutral processes. • Opportunistic pathogens Escherichia coli had higher abundance in particles. [ABSTRACT FROM AUTHOR]

The prevalence and transmission of antibiotic resistance genes (ARGs) and opportunistic pathogens in water environments can pose great threat to public health. However, the dissemination of ARGs and opportunistic pathogens from water environments to humans has been poorly explored. Here, we employed 16S rRNA gene sequencing and high-throughput quantitative PCR techniques to explore the seasonal distribution of ARGs and opportunistic pathogens in the Yellow River water (source water) and tap water, as well as their relationships with healthy humans at Lanzhou, China. Physiochemical analysis was applied to detect water quality parameters and heavy metal contents. The absolute abundance and diversity of ARGs in the Yellow River and tap water demonstrated distinct seasonal patterns. In winter, the Yellow river water had the highest ARG abundance and diversity, while tap water owned the lowest. Mobile genetic elements (MGEs) were the predominant driver of ARG profiles in both the Yellow river and tap water. Null model analysis showed that ARG assembly in the Yellow River was more influenced by stochastic processes than tap water and this was independent of seasons. Total organic carbon and arsenic contents exhibited positive correlations with many ARGs. Opportunistic pathogens Aeromonas and Pseudomonas may be potential hosts for ARGs. Approximately 80% of detected ARGs were shared between water samples and the human gut. These persistent ARGs could not be entirely eliminated through drinking water treatment processes. Thus, it is crucial to protect sources of tap water from anthropogenic pollution and improve water treatment technologies to reduce the dissemination of ARGs and ensure drinking-water biosafety for human health. [Display omitted] • The ARG profiles in the Yellow River and tap water had distinct seasonal patterns. • MGEs were the key driver for ARG profiles in the Yellow River and tap water. • ARGs assembly in the Yellow River had more stochastic processes. • Opportunistic pathogens Aeromonas and Pseudomonas may be potential hosts for ARGs. • Persistent ARGs cannot be entirely eliminated via drinking water treatment process. [ABSTRACT FROM AUTHOR]

As a common natural phenomenon, corpse decomposition may lead to serious environmental pollution such as nitrogen pollution. However, less is known about antibiotic resistance genes (ARGs), an emerging contaminant, during corpse degradation. Here, ARGs and microbiome in three soil types (black, red and yellow soil) have been investigated between experimental and control groups based on next-generation sequencing and high-throughput quantitative PCR techniques. We found that the absolute abundance of total ARGs and mobile genetic elements (MGEs) in the experimental groups were respectively enriched 536.96 and 240.60 times in different soil types, and the number of ARGs in experimental groups was 7–25 more than that in control groups. For experimental groups, the distribution of ARGs was distinct in different soil types, but sulfonamide resistance genes were always enriched. Corpse decomposition was a primary determinant for ARGs profiles. Microbiome, NH 4 + concentrates and pH also significantly affected ARGs profiles. Nevertheless, soil types had few effects on ARGs. For soil microbiome, some genera were elevated in experimental groups such as the Ignatzschineria and Myroides. The alpha diversity is decreased in experimental groups and microbial community structures are different between treatments. Additionally, the Escherichia and Neisseria were potential pathogens elevated in experimental groups. Network analysis indicated that most of ARGs like sulfonamide and multidrug resistance genes presented strong positively correlations with NH 4 + concentrates and pH, and some genera like Ignatzschineria and Dysgonomonas were positively correlated with several ARGs such as aminoglycoside and sulfonamide resistance genes. Our study reveals a law of ARGs' enrichment markedly during corpse decomposing in different soil types, and these ARGs contaminant maintaining in environment may pose a potential threat to environmental safety and human health. [Display omitted] • Corpse decomposition changes soil environment. • Corpse decomposition causes the accumulation of ARGs in all soil types. • Soil types have few impact on ARGs. • Treatment, microbiome, NH 4 + concentrates and pH are primary determinants. • ARGs are correlated with integrons, NH 4 +, pH and microbes during corpse decay. [ABSTRACT FROM AUTHOR]

Contamination of antibiotic resistomes due to animal carcass decay has become a serious environmental concern. However, the relationship between main metabolite compounds of corpse decomposition (i.e., putrescine and cadaverine) and antibiotic resistomes remains unclear. To tackle this issue, the response of antibiotic resistance genes (ARGs) and microbiome in aquatic environment to excess putrescine, cadaverine and a mixture of both based on laboratory simulation experiment was investigated by high-throughput quantitative PCR and amplicon sequencing methods. Our results showed putrescine and cadaverine led to the increasing of TC (total carbon) and TN (total nitrogen) both in water and sediment. Under the exposure of putrescine and cadaverine, the total abundance of mobile genetic elements (MGEs) and most ARGs in water was higher than in sediment. In particular, putrescine and cadaverine caused significantly different decreases in alpha diversity of microbial community in water and sediment compared with the control group. Microbial community structures both in water and sediment were also significantly affected by cadaverine and putrescine. Furthermore, putrescine and cadaverine led to different degrees of increases of high-risk ARGs (like mecA) and opportunistic pathogens (like Delftia) in sediment, promoting the prevalence of antibiotic resistant bacteria. In conclusion, our findings revealed the influences of main metabolites of carcass decay on microbiome and resistomes, providing references for risk assessment and pollution management. • The response of resistomes to putrescine and cadaverine was investigated for the first time. • Putrescine and cadaverine influenced resistomes in aquatic environment. • Putrescine and cadaverine led to the increasing of high-risk resistomes in sediment. [ABSTRACT FROM AUTHOR]

Animal carcass decay produces many poisonous metabolites and chemical pollutants, which pose potential ecological risks to the aquatic environment and human health. However, the effects of animal cadaver decomposition on high-risk antibiotic resistance genes (ARGs) and potential pathogens in different water types are still unknown. In this study, fifteen freshwater economic fish (Carassius auratus) corpses were put into three types of water (i.e., pond water, tap water, and domestic sewage) for a 100-day decomposition. Next generation sequencing and HT-qPCR were used to illustrate how corpse decomposition affected microbial communities and ARG profiles. Our results revealed that fish corpse degradation caused similar resistomes and microbiome in different water types. MLSB (Macrolide-Lincosamide-Streptogramin B), β-lactamase, sulfonamide, tetracycline resistance genes and transposase genes in the experimental groups were increased. Among them, tetracycline resistance genes were enriched by 224 to 136,218-fold during the process of corpse degradation. Furthermore, high-risk ARGs (ermB , floR and dfrA1), which resist to MLSB, multidrug and sulfonamide respectively, were significantly enriched in the cadaver groups and had co-occurrence patterns with opportunistic pathogens, such as Bacteroidetes , which was more than 37 times in carcass groups than that in control groups. The study is able to draw a general conclusion that cadaver decomposition of freshwater economic fish deteriorates the aquatic environment by affecting high-risk ARGs and pathogenic microorganisms regardless of water types, which poses potential threats to human health. Therefore, timely management and treatment of animal carcasses is of great significance to the protection of water environment. [Display omitted] • Fish corpse degradation caused similar resistomes and microbiome in different water types. • Fish cadaver decomposition led to enrichment of opportunistic pathogens and high-risk ARGs. • Corpse decay, microbiomes, MGEs and environment factors primarily affect ARG profiles. • Timely management and treatment of animal carcasses is of great significance to the protection of water environment. [ABSTRACT FROM AUTHOR]

Serious concerns have been raised regarding resistomes caused by corpse decomposition in the aquatic environment, which has posed threats to the water environment and human health. However, antibiotic resistance genes (ARGs) in large-volume tap water and their temporal stability during corpse decay are poorly explored. Here, high-throughput quantitative polymerase chain reaction (HT-qPCR) and amplicon sequencing were applied to profile ARGs and bacterial communities in experimental and control groups containing 50 L of tap water at 7th, 15th and 100th day during corpse decomposition. Our results suggested that most of the ARGs in experimental group had higher abundance compared with the control group independent of time. Some ARGs' absolute abundance like tetracycline and beta-lactamase was even enriched by 259 – 413,640-folds during corpse decay. Twelve opportunistic pathogens, especially Burkholderia , Legionella and Halomonas , remarkably increased as decomposition proceeded. Furthermore, network analysis showed that opportunistic pathogens were significantly associated with ARGs. Our results emphasize that corpse decay increases the abundance and diversity of ARGs in large-volume drinking water independent of time while exhibiting temporal persistence of ARGs, thereby uncovering the harmful effects of animal cadavers. Our study also provides valuable suggestions for the risk assessment and management of source water caused by corpse decay. [Display omitted] ∙ Corpse decay increases the abundance of ARGs in large-volume drinking water ∙ Most of the ARGs remains relative stable abundance over decomposition time. ∙ Twelve opportunistic pathogens were significantly associated with ARGs. ∙ Treatment, dissolve oxygen (DO) and pH were important factors influencing ARGs' spread. [ABSTRACT FROM AUTHOR]