Application of nematicide avermectin enriched antibiotic-resistant bacteria and antibiotic resistance genes in farmland soil

Variations in antibiotic resistomes associated with archaeal, bacterial, and viral communities affected by integrated rice-fish farming in the paddy field ecosystem

Antibiotic resistance genes (ARGs) serving as a newly recognized pollutant that poses potential risks to global human health, which in the paddy soil can be potentially altered by different agricultural production patterns. To elucidate the impacts and mechanisms of the widely used and sustainable agricultural production pattern, namely integrated rice-fish farming, on the antibiotic resistomes, we applied metagenomic sequencing to assess ARGs, mobile genetic elements (MGEs), bacteria, archaea, and viruses in paddy soil. There were 20 types and 359 subtypes of ARGs identified in paddy soil. The integrated rice-fish farming reduced the ARG and MGE diversities and the abundances of dominant ARGs and MGEs. Significantly decreased ARGs were mainly antibiotic deactivation and regulator types and primarily ranked level IV based on their potential threat to human health. The integrated rice-fish farming decreased the alpha diversities and altered microbial community compositions. MGEs, bacteria, archaea, and virus exhibited significant correlations with ARGs, while integrated rice-fish farming effectively changed their interrelationships. Viruses, bacteria, and MGEs played crucial roles in affecting the ARGs by the integrated rice-fish farming. The most crucial pathway by which integrated rice-fish farming affected ARGs was through the modulation of viral communities, thereby directly or indirectly influencing ARG abundance. Our research contributed to the control and restoration of ARGs pollution from a new perspective and providing theoretical support for the development of clean and sustainable agricultural production.

Urbanization influences the indoor transfer of airborne antibiotic resistance genes, which has a seasonally dependent pattern

Over the last few years, the cumulative use of antibiotics in healthcare institutions, as well as the rearing of livestock and poultry, has resulted in the accumulation of antibiotic resistance genes (ARGs). This presents a substantial danger to human health worldwide. The characteristics of airborne ARGs, especially those transferred from outdoors to indoors, remains largely unexplored in neighborhoods, even though a majority of human population spends most of their time there. We investigated airborne ARGs and mobile genetic element (MGE, IntI1), plant communities, and airborne microbiota transferred indoors, as well as respiratory disease (RD) prevalence using a combination of metabarcode sequencing, real-time quantitative PCR and questionnaires in 72 neighborhoods in Shanghai. We hypothesized that (i) urbanization regulates ARGs abundance, (ii) the urbanization effect on ARGs varies seasonally, and (iii) land use types are associated with ARGs abundance. Supporting these hypotheses, during the warm season, the abundance of ARGs in peri-urban areas was higher than in urban areas. The abundance of ARGs was also affected by the surrounding land use and plant communities: an increase in the proportion of gray infrastructure (e.g., residential area) around neighborhoods can lead to an increase in some ARGs (mecA, qnrA, ermB and mexD). Additionally, there were variations observed in the relationship between ARGs and bacterial genera in different seasons. Specifically, Stenotrophomonas and Campylobacter were positively correlated with vanA during warm seasons, whereas Pseudomonas, Bacteroides, Treponema and Stenotrophomonas positively correlated with tetX in the cold season. Interstingly, a noteworthy positive correlation was observed between the abundance of vanA and the occurrence of both rhinitis and rhinoconjunctivitis. Taken together, our study underlines the importance of urbanization and season in controlling the indoor transfer of airborne ARGs. Furthermore, we also highlight the augmentation of green-blue infrastructure in urban environments has the potential to mitigate an excess of ARGs.

Silybin mitigates chronic Avermectin exposure-induced intestinal damage and growth inhibition in carp

Avermectins, as a new type of environmental pollutant, have received significant attention in recent years. Previous research has shown that acute exposure to avermectins can induce oxidative stress and inflammation in non-target fish species, such as carp. Flavonoid lignans, particularly Silybin, have demonstrated promising biological activities, including regulation of non-alcoholic fatty liver and cerebral ischemia-reperfusion injury. This study aims to investigate the impact of dietary supplementation with Silybin on the intestinal damage in carp caused by chronic exposure to avermectins and to improve the health status and production of carp in aquaculture. Silybin was used as a dietary supplement by adding it to the experimental feed, and an animal experimental model was utilized to assess its effects on oxidative stress, inflammation, and cell apoptosis in carp intestine. Additionally, intestinal barrier integrity, digestive capacity, and fish growth were evaluated. The results indicated that dietary supplementation with Silybin effectively alleviated the oxidative stress induced by chronic exposure to avermectins in carp intestine. Furthermore, Silybin improved intestinal barrier integrity and digestive capacity by modulating the Nrf2/Keap1 pathway. This study demonstrates that dietary supplementation with Silybin can effectively mitigate the intestinal damage caused by chronic exposure to avermectins in carp, providing a sustainable solution for the aquaculture industry to enhance the overall health and production of cultured fish. The research expands our understanding of avermectin environmental pollution and offers a potential remediation approach.

Whole-transcriptome analysis after the acquisition of antibiotic resistance of Cronobacter sakazakii: Mechanisms of antibiotic resistance and virulence changes

The emergence of antibiotic-resistant bacteria led to the misuse of antibiotics, resulting in the emergence of more resistant bacteria and continuous improvement in their resistance ability. Cronobacter sakazakii (C. sakazakii) has been considered a pathogen that harms infants. Incidents of C. sakazakii contamination have continued globally, several studies have indicated that C. sakazakii is increasingly resistant to antibiotics. A few studies have explored the mechanism of antibiotic resistance in C. sakazakii, and some have examined the antibiotic resistance and changes in virulence levels. We aimed to investigate the antibiotic resistance mechanism and virulence differences in C. sakazakii. The level of virulence factors of C. sakazakii was modified after induction by antibiotics compared with the antibiotic-sensitive strains, and the XS001-Ofl group had the strongest capacity to produce enterotoxin (85.18 pg/mL) and hemolysin (1.47 ng/mL). The biofilm formation capacity after induction significantly improved. The number of bases and mapped reads in all groups accounted for more than 55 % and 70 %, as detected by transcriptomic analysis. The resistance mechanism of different antibiotics was more common in efflux pumps, cationic antimicrobial peptides, and biofilm formation pathways. The level of antibiotic resistance mainly affected the expression of virulence genes associated with flagella assembly and synthesis.