Tire wear particles (TWPs) attract attention because of their harmful impact on the soil ecosystem. Nevertheless, there is limited understanding regarding how aging affects the toxicity of TWPs to soil microorganisms. Herein, a microcosm experiment was performed to compare the toxicity of pristine and UV-aged TWPs on the soil microbial community. After 28 days operation, more holes and cracks appeared on the surface of the UV-aged TWPs compared with the pristine TWPs. The diversity and community structure of soil microorganisms changed under the pristine and UV-aged TWPs exposure, with the UV-aged TWPs significantly altered nirK-type soil denitrifying bacteria. Streptomyces played an important role in connecting the nirK-type bacterial community and promoting the denitrification process under the UV-aged TWPs exposure. The soil microorganisms further promoted the membrane transport of metabolites to resist the toxic effects of UV-aged TWPs by up-regulating the ATP-binding cassette (ABC) transporters, which consumed lots of energy and led to interference in energy metabolism. Furthermore, UV-aged TWPs further stimulated the accumulation of reactive oxygen species (ROS), stimulated the soil microorganisms to secrete more extracellular polymers substances (EPS) and activated the antioxidant defense system against oxidative damage caused by UV-aged TWPs, however, the activation of SOS response in turn increased the risk of antibiotic resistance genes (ARGs) transmission.

Pyroligneous acids (PAs) amendments could reduce soil antibiotic resistance genes (ARGs) pollution, but their impacts on horizontal transformation of extracellular ARGs (eARGs) remain unclear. Here, a wood residues derived PA was selected to investigate its effect on ARG dissemination via transformation using a soil microcosm experiment and an in vitro transformation system. The PA application effectively decreased the abundances of representative ARGs and mobile genetic elements, demonstrating that the weakened horizontal gene transfer alleviated ARG pollution in the soil. PA showed an amount-dependent inhibition on the transformation as well as the three distilled fractions and chemical components, proving that their important roles in inhibiting eARG transformation. The relatively low-amount (1 mu L mL-1) of PA suppressed the transformation mainly by destroying the plasmid pBR322 structure, while the high-amount (10-100 mu L mL-1) of PA inhibited the transformation due to the inactivation of recipient Escherichia coli DH5 alpha by inducing oxidative stress and destroying cell membrane, and damages of plasmid by reducing eARGs abundance and broking the base deoxyribose, and phosphate skeletons. These findings expand the understanding of PA amendments mitigating ARG pollution in agricultural soils via inhibiting horizontal gene transformation, and also provide a practical strategy to remediate soil ARG pollution.

Background:A shallow active layer of soil above the permafrost thaws during the summer months which promotes microbial growth and releases previously confined pathogens which result in bacterial epidemics in circumpolar regions. Furthermore, these permafrost sources harbor several antibiotic resistance genes (ARGs) which may disseminate and pose a challenge for pharmacologists worldwide.Aims:The authors examined the potential association between climate change-induced permafrost thawing, and the resulting release of antibiotic-resistant pathogens, as well as the potential impact this can have on global healthcare systems in the long run.Methodology:A cursory abstract screening was done to rule out any articles that did not have to do with viral pathogens caused by melting permafrost. Articles that were not available in English or that our institutions library did not have full-text access were weeded out by a secondary screen.Results:A comprehensive analysis of 13 relevant studies successfully revealed a wide variety of bacterial genera, including Staphylococcus spp., Pseudomonas spp., Acinetobacter spp., and Achromobacter spp., along with a total of 1043 antibiotic resistance genes (ARGs), with most pertaining to aminoglycosides and beta-lactams, offering resistance via diverse mechanisms such as efflux pumps and enzymatic modifications, within the permafrost isolates. Additionally, mobile genetic elements (MGEs) housing antibiotic resistance genes (ARGs) and virulence factor genes (VFGs), including plasmids and transposons, were also discovered.Conclusion:Permafrost thawing is an underrated healthcare challenge warranting the need for further articles to highlight it alongside concerted efforts for effective mitigation.

Continuous use of antibiotics in poultry feed as growth promoters poses a grave threat to humanity through the emergence of antibiotic resistance, necessitating the exploration of novel and sustainable alternatives. The present study was carried out to evaluate the performance of postbiotics derived from Lactobacillus acidophilus in broiler birds. The postbiotics were harvested by culturing probiotic bacteria from the stock cultures at the required temperature and duration under laboratory conditions and supplemented to broilers via feed. For experimentation, 480-day-old CARI-Bro Dhanraja (slow-growing broiler) straight-run chicks were randomly split up into six groups. Treatment groups diets are as follows: T1- Basal diet (BD)+0.2%(v/w) MRS Broth/ uninoculated media; T2 - BD + Antibiotic (CTC); T3- BD + Probiotic; T4, T5 & T6 - BD + postbiotics supplementation of 0.2%, 0.4% and 0.6% (v/w) respectively. The chicks were raised under an intensive, deep litter system with standard protocol for 6 weeks. Results showed that 0.2% of postbiotics (T4) had significantly (P < 0.001) higher body weight (1677.52 g) with better FCR (1.75) and immune response. Postbiotic supplementation altered various serum attributes positively, in this study. Significant (P < 0.001) reductions in total plate counts (TPC), coliform counts, and maximum Lactobacillus counts were recorded in all postbiotic-supplemented groups. The villus height (1379.25 mu m), width (216.06 mu m) and crept depth (179.25 mu m) showed significant (P < 0.001) improvement among the treatment groups on the 21st and 42nd day of the experimental trial, with the highest value in the T4 group (0.2% postbiotic supplementation). Jejunal antioxidant values also noted significantly (P < 0.001) higher values in T4 group. The study concludes that 0.2% postbiotic supplementation can act as a substitute to antibiotic growth promoters and also combat the disfavour activity of probiotics in broilers.

Background: Bacillus cereus is a widespread environmental Gram-positive bacterium which is especially common in soil and dust. It produces two types of toxins that cause vomiting and diarrhea. At present, foodborne outbreaks due to Bacillus cereus group bacteria (especially Bacillus cereus sensu stricto) are rising, representing a serious problem in the agri-food supply chain. Methods: In this work, we analyzed 118 strains belonging to the Bacillus cereus group, isolated from several food sources, for which in vitro and in silico antibiotic resistance assessments were performed. Results: Many strains showed intermediate susceptibility to clindamycin, erythromycin, and tetracycline, suggesting an evolving acquisition of resistance against these antibiotics. Moreover, one strain showed intermediate resistance to meropenem, an antibiotic currently used to treat infections caused by Bacillus cereus. In addition to the phenotypic antimicrobial resistance profile, all strains were screened for the presence/absence of antimicrobial genes via whole-genome sequencing. There was inconsistency between the in vitro and in silico analyses, such as in the case of vancomycin, for which different isolates harbored resistance genes but, phenotypically, the same strains were sensitive. Conclusions: This would suggest that antibiotic resistance is a complex phenomenon due to a variety of genetic, epigenetic, and biochemical mechanisms.

Nanoplastics (NPs), identified as emerging pollutants, pose a great risk to environment and global public health, exerting profound influences on the prevalence and dissemination of antibiotic resistance genes (ARGs). Despite evidence suggesting that nano-sized plastic particles can facilitate the horizontal gene transfer (HGT) of ARGs, it is imperative to explore strategies for inhibiting the transfer of ARGs. Currently, limited information exists regarding the characteristics of environmentally aged NPs and their impact on ARGs propagation. Herein, we investigated the impact of photo-aged NPs on the transfer of ARG-carrying plasmids into Escherichia coli (E. coli) cells. Following simulated sunlight irradiation, photo-aged nano-sized polystyrene plastics (PS NPs) exhibited multiple enzyme-like activities, including peroxidase (POD) and oxidase (OXD), leading to a burst of reactive oxygen species (ROS). At relatively low concentrations (0.1, 1 mu g/mL), both pristine and aged PS NPs facilitated the transfer of pUC19 and pHSG396 plasmids within E. coli due to moderate ROS production and enhanced cell membrane permeability. Intriguingly, at relatively high concentrations (5, 10 mu g/mL), aged PS NPs significantly suppressed plasmids transformation. The non-unidirectional impact of aged PS NPs involved the overproduction of ROS (center dot OH and center dot O-2(-)) via nanozyme activity, directly degrading ARGs and damaging plasmid structure. Additionally, oxidative damage to bacteria resulted from the presence of much toxic free radicals, causing physical damage to cell membranes, reduction of the SOS response and restriction of adenosine-triphosphate (ATP) supply, ultimately leading to inactivation of recipient cells. This study unveils the intrinsic multienzyme-like activity of environmentally aged NPs, highlighting their potential to impede the transfer and dissemination of ARGs.

More information is needed to fully comprehend how acid mine drainage (AMD) affects the phototransformation of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in karst water and sewage -irrigated farmland soil with abundant carbonate rocks (CaCO 3 ) due to increasing pollution of AMD formed from pyrite (FeS 2 ). The results showed FeS 2 accelerated the inactivation of ARB with an inactivation of 8.7 log. Notably, extracellular and intracellular ARGs and mobile genetic elements (MGEs) also experienced rapid degradation. Additionally, the pH of the solution buffered by CaCO 3 significantly influenced the photo -inactivation of ARB. The Fe 2 + in neutral solution was present in Fe(II) coordination with strong reducing potential and played a crucial role in generating center dot OH (7.0 mu M), which caused severe damage to ARB, ARGs, and MGEs. The center dot OH induced by photo -Fenton of FeS 2 posed pressure to ARB, promoting oxidative stress response and increasing generation of reactive oxygen species (ROS), ultimately damaging cell membranes, proteins and DNA. Moreover, FeS 2 contributed to a decrease in MIC of ARB from 24 mg/L to 4 mg/L. These findings highlight the importance of AMD in influencing karst water and sewage -irrigated farmland soil ecosystems. They are also critical in advancing the utilization of FeS 2 to inactivate pathogenic bacteria.

Antibiotic resistance, along with its dynamics in different environments, has attracted increasing attention because of the potential for resistance gene transfer into human pathogens. Therefore, several researchers have focused on combating the increasing prevalence of antibiotic resistance genes (ARGs) in diverse environments, using various carbon-based amendments to resolve issues regarding emerging contaminants. However, information on systematic knowledge regarding carbon-based material performance and mechanisms for alleviating ARGs remains lacking. To this end, we summarize carbon-based materials that are used as additives, amendments, adsorbents, and other functional materials in compost, soil, and water environments. The underlying mechanisms of alleviating ARG pollution using carbon-based materials are mainly related to 1) environmental factor improvement, 2) microbial community structure alteration, 3) chemical contaminant-caused co-selective pressure reduction, 4) mobile genetic element (mediating horizontal gene transfer processes) reduction, and 5) direct adsorption and/or damage to extracellular DNA. This review aimed to enrich our understanding of the functional roles of carbon-based materials and provide a basis for management strategy development to mitigate ARG pollution.

Antibiotic resistance and heavy metal contamination are two worldwide environmental concerns. Especially in soil, the interaction between these two pollutants may exacerbate the problem of antibiotic resistance genes (ARGs) entering the food chain, which can have severe consequences on the environment and the wellness of humankind. This study investigated the influences of cadmium (Cd) and copper (Cu) pollution on ARG profiles in the soil rhizosphere and endogenous microbiome of roots and leaves in pakchoi. We further determined the impact of these heavy metals and various environmental factors on the accumulation of ARGs in leaves and discussed the possible transfer pathways of ARGs in the soil-plant system. Our results showed that Cd-Cu stress increased the relative abundance of most target genes in the samples, especially the sulfonamide resistance genes sul1 and sul3, the quinolone resistance gene qepA, and the Class 1 integron integrase gene intI1. Variance partitioning analysis indicated that the Cd-Cu contents primarily contributed (45.7%) to ARG variations in leaves. Cadmium and Cu led to a pollution-induced community tolerance phenomenon in microbial communities, enriching Cd- and Cu-tolerant bacteria. ARGs were highly correlated with mobile genetic elements (e.g., intI1) and metal resistance genes, increasing the co-selection of metals on ARGs. Structural equation modeling showed that metal resistance genes and intI1 in leaves had significant direct positive effects on the relative abundances of ARGs (p < 0.05). Higher Cu concentrations facilitated the migration of most target ARGs from soil to leaves.

As an emerging contaminant, antibiotic resistance genes (ARGs) are raising concerns about its significant threat to public health. Meanwhile, graphene oxide (GO), which also has a potential ecological damage with increasingly entering the environment, has a great influence on the transfer of ARGs. However, little is known about the effects mechanisms of GO on the migration of antibiotic resistance genes (ARGs) from bacteria into plants. In this study, we investigated the influence of GO on the transfer of ARGs carried by RP4 plasmids from Bacillus subtilis into rice plants. Our results showed that the presence of GO at concentrations ranging from 0 to 400 mg L-1 significantly reduced the transfer of ARGs into rice roots by 13-71 %. Moreover, the migration of RP4 from the roots to aboveground parts was significantly impaired by GO. These effects may be attributed to several factors. First, higher GO concentrations led to low pH in the culture solution, resulting in a substantial decrease in the number of antibiotic-resistant bacteria. Second, GO induced oxidative stress in rice, as indicated by enhanced Evans blue dye staining, and elevated levels of malondialdehyde, nitric oxide, and phenylalanine ammonia-lyase activity. The oxidative stress negatively affected plant growth, as demonstrated by the reduced fresh weight and altered lignin content in the rice. Microscopic observations confirmed the entry of GO into root cells but not leaf mesophyll cells. Furthermore, potential recipients of RP4 plasmid strains in rice after co-cultivation experiments were identified, including Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus cereus. These findings clarify the influence of GO on ARGs in the bacteria-plant system and emphasize the need to consider its potential ecological risks.