Antibiotic Resistance In Environment Research Articles

An Antibiotic-Degrading Engineered Biofilm Platform to Combat Environmental Antibiotic Resistance.

The presence of antibiotics in natural water bodies is a growing problem regarding the occurrence of antibiotic resistance among various species. This is mainly caused by the excessive use of medical and veterinary antibiotics as well as the lack of effective treatment processes for eliminating residual antibiotics from wastewaters. In this study, we introduce a genetically engineered biomaterial as a solution for the effective degradation of one of the dominantly found antibiotics in natural water bodies. Our biomaterial harnesses laccase-type enzymes, which are known to attack specific types of antibiotics, i.e., fluoroquinolone-type synthetic antibiotics, and as a result degradation occurs. The engineered biomaterial is built using Escherichia coli biofilm protein CsgA as a scaffold, which is fused separately to two different laccase enzymes with the SpyTag-SpyCatcher peptide-protein duo. The designed biofilm materials were successful in degrading ciprofloxacin, as demonstrated with the data obtained from mass spectrometry analysis and cell viability assays.

Contrasting Dynamics of Intracellular and Extracellular Antibiotic Resistance Genes in Response to Nutrient Variations in Aquatic Environments

The propagation of antibiotic resistance in environments, particularly aquatic environments that serve as primary pathways for antibiotic resistance genes (ARGs), poses significant health risks. The impact of nutrients, as key determinants of bacterial growth and metabolism, on the propagation of ARGs, particularly extracellular ARGs (eARGs), remains poorly understood. In this study, we collected microorganisms from the Yangtze River and established a series of microcosms to investigate how variations in nutrient levels and delivery frequency affect the relative abundance of intracellular ARGs (iARGs) and eARGs in bacterial communities. Our results show that the relative abundance of 7 out of 11 representative eARGs in water exceeds that of iARGs, while 8 iARGs dominate in biofilms. Notably, iARGs and eARGs consistently exhibited opposite responses to nutrient variation. When nutrient levels increased, iARGs in the water also increased, with the polluted group (COD = 333.3 mg/L, COD:N:P = 100:3:0.6, m/m) and the eutrophic group (COD = 100 mg/L, COD:N:P = 100:25:5, m/m) showing 1.2 and 3.2 times higher levels than the normal group (COD = 100 mg/L, COD:N:P = 100:10:2, m/m), respectively. In contrast, eARGs decreased by 6.7% and 8.4% in these groups. On the other hand, in biofilms, higher nutrient levels led to an increase in eARGs by 1.5 and 1.7 times, while iARGs decreased by 17.5% and 50.1% in the polluted and eutrophic groups compared to the normal group. Moreover, while increasing the frequency of nutrient delivery (from 1 time/10 d to 20 times/10 d) generally did not favor iARGs in either water or biofilm, it selectively enhanced eARGs in both. To further understand these dynamics, we developed an ARGs-nutrient model by integrating the Lotka–Volterra and Monod equations. The results highlight the complex interplay of bacterial growth, nutrient availability, and mechanisms such as horizontal gene transfer and secretion influencing ARGs’ propagation, driving the opposite trend between these two forms of ARGs. This contrasting response between iARGs and eARGs contributes to a dynamic balance that stabilizes bacterial resistance levels amid nutrient fluctuations. This study offers helpful implications regarding the persistence of bacterial resistance in the environment.

Global analysis of the RNA-RNA interactome in Acinetobacter baumannii AB5075 uncovers a small regulatory RNA repressing the virulence-related outer membrane protein CarO.

Acinetobacter baumannii is an opportunistic Gram-negative pathogen that infects critically ill patients. The emergence of antimicrobial resistant A. baumannii has exacerbated the need to characterize environmental adaptation, antibiotic resistance and pathogenicity and their genetic regulators to inform intervention strategies. Critical to adaptation to changing environments in bacteria are small regulatory RNAs (sRNAs), however, the role that sRNAs play in the biology of A. baumannii is poorly understood. To assess the regulatory function of sRNAs and to uncover their RNA interaction partners, we employed an RNA proximity ligation and sequencing method (Hi-GRIL-seq) in three different environmental conditions. Forty sRNAs were ligated to sRNA-RNA chimeric sequencing reads, suggesting that sRNA-mediated gene regulation is pervasive in A. baumannii. In-depth characterization uncovered the sRNA Aar to be a post-transcriptional regulator of four mRNA targets including the transcript encoding outer membrane protein CarO. Aar initiates base-pairing with these mRNAs using a conserved seed region of nine nucleotides, sequestering the ribosome binding sites and inhibiting translation. Aar is differentially expressed in multiple stress conditions suggesting a role in fine-tuning translation of the Aar-target molecules. Our study provides mechanistic insights into sRNA-mediated gene regulation in A. baumannii and represents a valuable resource for future RNA-centric research endeavours.

Ketoprofen promotes the conjugative transfer of antibiotic resistance among antibiotic resistant bacteria in natural aqueous environments

The emergence and spread of antibiotic resistance in the environment pose a serious threat to global public health. It is acknowledged that non-antibiotic stresses, including disinfectants, pharmaceuticals and organic pollutants, play a crucial role in horizontal transmission of antibiotic resistance genes (ARGs). Despite the widespread presence of non-steroidal anti-inflammatory drugs (NSAIDs), notably in surface water, their contributions to the transfer of ARGs have not been systematically explored. Furthermore, previous studies have primarily concentrated on model strains to investigate whether contaminants promote the conjugative transfer of ARGs, leaving the mechanisms of ARG transmission among antibiotic resistant bacteria in natural aqueous environments under the selective pressures of non-antibiotic contaminants remains unclear. In this study, the Escherichia coli (E. coli) K12 carrying RP4 plasmid was used as the donor strain, indigenous strain Aeromonas veronii containing rifampicin resistance genes in Taihu Lake, and E. coli HB101 were used as receptor strains to establish inter-genus and intra-genus conjugative transfer systems, examining the conjugative transfer frequency under the stress of ketoprofen. The results indicated that ketoprofen accelerated the environmental spread of ARGs through several mechanisms. Ketoprofen promoted cell-to-cell contact by increasing cell surface hydrophobicity and reducing cell surface charge, thereby mitigating cell-to-cell repulsion. Furthermore, ketoprofen induced increased levels of reactive oxygen species (ROS) production, activated the DNA damage-induced response (SOS), and enhanced cell membrane permeability, facilitating ARG transmission in intra-genus and inter-genus systems. The upregulation of outer membrane proteins, oxidative stress, SOS response, mating pair formation (Mpf) system, and DNA transfer and replication (Dtr) system related genes, as well as the inhibition of global regulatory genes, all contributed to higher transfer efficiency under ketoprofen treatment. These findings served as an early warning for a comprehensive assessment of the roles of NSAIDs in the spread of antibiotic resistance in natural aqueous environments.

Antibiotic resistance risk assessment in Mymensingh, Bangladesh: Current scenario from human-animal-environmental interfaces viewpoint

The imprudent use of antibiotics increases the environmental microflora's resistance to various drugs, particularly antibiotics. Prescription data is crucial for understanding antibiotic usage frequency and dosage. This health-focused study aims to analyze antibiotic prescription patterns in human and veterinary practices to identify emerging trends in environmental antibiotic resistance.For this survey, A total of 6550 prescriptions were randomly collected from hospitals and pharmacies in Mymensingh sadar upazila, Bangladesh, between August and October 2022. Of these, 5123 (78 %) were for human cases and 1427 (22 %) for veterinary purposes. Photos of the prescriptions were taken and analyzed to understand prescribing habits. Additionally, 30 water samples from rivers, ponds, sewage, and households in Mymensingh City Corporation were collected to assess environmental antibiotic levels and resistance patterns of microorganisms.The analysis showed that Cephalosporins were the most prescribed antibiotics, found in 570 (56.27 %) of human prescriptions and 230 (42.99 %) of veterinary prescriptions. Aminoglycosides had the lowest frequency, with 13 (1.2 %) for humans and 46 (8.6 %) for animals. Macrolides (12.24 %), carboxylic acids (1.87 %), and rifamycins (1.28 %) were only found in human prescriptions, while sulfa drugs (10.84 %), tetracyclines (5.42 %), and combinations of antibiotics (14.77 %) were only in animal prescriptions. Quinolones were prescribed 4.06 times more for humans, while aminoglycosides were used 3.54 times more for animals. Environmental samples showed E. coli had the highest resistance (MAR Value: 0.625) against eight antibiotics.This study illuminates the human-animal prescription patterns that are influenced by environmental factors which drive antibiotic stewardship in Bangladesh. It is imperative for practitioners to exercise caution and adhere to guidelines when prescribing antibiotics, both in human and veterinary practices, given the alarming trend of antibiotic resistance. Additionally, measures must be taken to restrict the influx of antibiotics residue into the environment.

Bacterial and Genetic Features of Raw Retail Pork Meat: Integrative Analysis of Antibiotic Susceptibility, Whole-Genome Sequencing, and Metagenomics.

The global antibiotic resistance crisis, driven by overuse and misuse of antibiotics, is multifaceted. This study aimed to assess the microbiological and genetic characteristics of raw retail pork meat through various methods, including the isolation, antibiotic susceptibility testing (AST), whole-genome sequencing (WGS) of selected indicator bacteria, antibiotic residue testing, and metagenomic sequencing. Samples were purchased from 10 pre-selected retail stores in Gauteng, South Africa. The samples were aseptically separated, with portions sent to an external laboratory for isolating indicator bacteria and testing for antibiotic residues. Identification of the isolated bacteria was reconfirmed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). AST was performed using the Microscan Walkaway system (Beckman Coulter, Brea, CA, USA). WGS and metagenomic sequencing were performed using the Illumina NextSeq 550 instrument (San Diego, CA, USA). The isolated E. coli and E. faecalis exhibited minimal phenotypic resistance, with WGS revealing the presence of tetracycline resistance genes. Both the isolated bacteria and meat samples harboured tetracycline resistance genes and the antibiotic residue concentrations were within acceptable limits for human consumption. In the metagenomic context, most identified bacteria were of food/meat spoilage and environmental origin. The resistome analysis primarily indicated beta-lactam, tetracycline and multidrug resistance genes. Further research is needed to understand the broader implications of these findings on environmental health and antibiotic resistance.

Genome characterization of a multi-drug resistant Escherichia coli strain, L1PEag1, isolated from commercial cape gooseberry fruits (Physalis peruviana L.).

Foodborne infections, which are frequently linked to bacterial contamination, are a serious concern to public health on a global scale. Whether agricultural farming practices help spread genes linked to antibiotic resistance in bacteria associated with humans or animals is a controversial question. This study applied a long-read Oxford Nanopore MinION-based sequencing to obtain the complete genome sequence of a multi-drug resistant Escherichia coli strain (L1PEag1), isolated from commercial cape gooseberry fruits (Physalis peruviana L.) in Ecuador. Using different genome analysis tools, the serotype, Multi Locus Sequence Typing (MLST), virulence genes, and antimicrobial resistance (AMR) genes of the L1PEag1 isolate were determined. Additionally, in vitro assays were performed to demonstrate functional genes. The complete genome sequence of the L1PEag1 isolate was assembled into a circular chromosome of 4825.722 Kbp and one plasmid of 3.561 Kbp. The L1PEag1 isolate belongs to the B2 phylogroup, sequence type ST1170, and O1:H4 serotype based on in silico genome analysis. The genome contains 4,473 genes, 88 tRNA, 8 5S rRNA, 7 16S rRNA, and 7 23S rRNA. The average GC content is 50.58%. The specific annotation consisted of 4,439 and 3,723 genes annotated with KEEG and COG respectively, 3 intact prophage regions, 23 genomic islands (GIs), and 4 insertion sequences (ISs) of the ISAs1 and IS630 families. The L1PEag1 isolate carries 25 virulence genes, and 4 perfect and 51 strict antibiotic resistant gene (ARG) regions based on VirulenceFinder and RGI annotation. Besides, the in vitro antibiotic profile indicated resistance to kanamycin (K30), azithromycin (AZM15), clindamycin (DA2), novobiocin (NV30), amikacin (AMK30), and other antibiotics. The L1PEag1 isolate was predicted as a human pathogen, matching 464 protein families (0.934 likelihood). Our work emphasizes the necessity of monitoring environmental antibiotic resistance, particularly in commercial settings to contribute to develop early mitigation techniques for dealing with resistance diffusion.

Effect of meddling ARBs on ARGs dynamics in fungal infested soil and their selective dispersal along spatially distant mycelial networks

During the recent times, environmental antibiotic resistance genes (ARGs) and their potential transfer to other bacterial hosts of pathogenic importance are of serious concern. However, the dissemination strategies of such ARGs are largely unknown. We tested that saprotrophic soil fungi differentially enriched antibiotic resistant bacteria (ARBs) and subsequently contributed in spatial distribution of selective ARGs. Wafergen qPCR analysis of 295 different ARGs was conducted for manure treated pre-sterilized soil incubated or not with selected bacterial-fungal consortia. The qPCR assay detected unique ARGs specifically found in the mycosphere of ascomycetous and basidiomycetous fungi. Both fungi exerted potentially different selection pressures on ARBs, resulting in different patterns of ARGs dissemination (to distant places) along their respective growing fungal highways. The relative abundance of mobile genetic elements (MGEs) was significantly decreased along fungal highways compared to the respective inoculation points. Moreover, the decrease in MGEs and ARGs (along fungal highways) was more prominent over time which depicts the continuous selection pressure of growing fungi on ARBs for enrichment of particular ARGs in mycosphere. Such data also indicate the potential role of saprotrophic soil fungi to facilitate horizontal gene transfer within mycospheric environmental settings. Our study, therefore, advocates to emphasize the future investigations for such (bacteria-fungal) interactive microbial consortia for potential (spatial) dissemination of resistance determinants which may ultimately increase the exposure risks of ARGs.

Profiles of Antibiotic Resistance Genes in the Coastal Aquatic Environment of Xiamen City

The coastal areas and the adjacent islands are the hotspots of human economic and social activities, including urbanization, industrialization, and agricultural practices, which have profound impacts on the ecological environment of the coastal environment. Antibiotic resistance genes （ARGs）, as emerging contaminants, have become hot topics in water ecological security and public concern. However, the profiles of antibiotic resistome in the costal water remain largely unknown, impeding resistome risk assessment associated with coastal environments. In this study, the high-throughput quantitative PCR technique was used to investigate the abundance and distribution of ARGs in the coastal environment of Xiamen City. Combined with the 16S rDNA gene amplicon sequencing method, the structure and composition of the microbial community in a water environment were investigated, and the influencing factors and associated mechanism of ARGs in seawater were deeply explained. The results of this study showed that a total of 187 ARGs were detected in the coastal water environment, and the abundance level was up to 1.29×1010 copies·L-1. Multidrug resistance, aminoglycosides, and β lactamase resistance genes were the three main classes of antibiotic resistance genes in the water environment of the Xiamen coastal zone. On the whole, the profile of ARGs was of high abundance, great diversity, and common co-existence, and the coastal water environment was an important hot area and reservoir for antibiotic resistance genes. Twenty-two microbes, including Nautella, Candidatus, Tenacibaculum, Rubripirellula, and Woeseia, were potential carriers of the corresponding 16 antibiotic resistance genes. The mobile genetic elements （MGEs） and microbial community structure accounted for 93.9% of the variation in environmental resistance genes in water. Therefore, microbial community and its mobile genetic elements were the most important driving forces for the occurrence and evolution of ARGs in coastal waters. Based on the results, it is implied that the environmental antibiotic resistance genes in the waters near Xiamen Island have potential risks to water ecological security and human health and highlight the necessity for comprehensive surveillance of ARGs associated with microbial contamination in the coastal aquatic environment.

Antibiotic Resistance in the Farming Environment

Bacterial resistance to antibiotics is now an extremely important safety and health issue. Much of the research on this phenomenon focuses on its clinical aspects, while current findings confirm that it is only one of a number of potential sources of bacteria and genes responsible for drug resistance. There are many indications that one of the main contributors to this issue is currently agriculture and that this applies virtually worldwide. Increased awareness of issues of rational use of antibiotics in husbandry practice entails increased interest in phenomena related to the spread of antibiotic resistance in the environment, their specifics, and the scale of the existing threat. This work, based on current research, analyzed selected aspects of the use of antibiotics in animal production, the presence of antibiotic-resistant microorganisms in farm animals and in waste from agricultural production, in particular from animal breeding farms, the determinants of antibiotic resistance in farming practices and the potential threats related to emissions and spread of antibiotic resistance factors in the environment, including the possibility of transfer of resistant bacteria and resistance genes to humans.

Ubiquitous nanocolloids suppress the conjugative transfer of plasmid-mediated antibiotic resistance in aqueous environment

Nanocolloids (Nc) are widespread in natural water environment, whereas the potential effects of Nc on dissemination of antibiotic resistance remain largely unknown. In this study, Nc collected from the Yellow River in Henan province was tested for its ability to influence the conjugative transfer of resistant plasmid in aqueous environment. The results revealed that the conjugative transfer of RP4 plasmid between Escherichia coli was down-regulated by 52%–91% upon exposure to 1–10 mg/L Nc and the reduction became constant when the dose became higher (20−200 mg/L). Despite the exposure of Nc activated the anti-oxidation and SOS response in bacteria through up-regulating genes involved in glutathione biosynthesis and DNA recombination, the inhibition on the synthesis and secretion of extracellular polysaccharide induced the prevention of cell-cell contact, leading to the reduction of plasmid transfer. This was evidenced by the decreased bacterial adhesion and lowered levels of genes and metabolites relevant to transmembrane transport and D-glucose phosphorylation, as clarified in phenotypic, transcriptomics and metabolomics analysis of E. coli. The significant down-regulation of glycolysis/gluconeogenesis and TCA cycle was associated with the shortage of ATP induced by Nc. The up-regulation of global regulatory genes (korA and trbA) and the reduction of plasmid genes (trfAp, trbBp, and traG) expression also contributed to the suppressed conjugation of RP4 plasmid. The obtained findings remind that the role of ubiquitous colloidal particles is nonnegligible when practically and comprehensively assessing the risk of antibiotic resistance in the environment.

Bacterial dynamics of the plastisphere microbiome exposed to sub-lethal antibiotic pollution

BackgroundAntibiotics and microplastics are two major aquatic pollutants that have been associated to antibiotic resistance selection in the environment and are considered a risk to human health. However, little is known about the interaction of these pollutants at environmental concentrations and the response of the microbial communities in the plastisphere to sub-lethal antibiotic pollution. Here, we describe the bacterial dynamics underlying this response in surface water bacteria at the community, resistome and mobilome level using a combination of methods (next-generation sequencing and qPCR), sequencing targets (16S rRNA gene, pre-clinical and clinical class 1 integron cassettes and metagenomes), technologies (short and long read sequencing), and assembly approaches (non-assembled reads, genome assembly, bacteriophage and plasmid assembly).ResultsOur results show a shift in the microbial community response to antibiotics in the plastisphere microbiome compared to surface water communities and describe the bacterial subpopulations that respond differently to antibiotic and microplastic pollution. The plastisphere showed an increased tolerance to antibiotics and selected different antibiotic resistance bacteria (ARB) and antibiotic resistance genes (ARGs). Several metagenome assembled genomes (MAGs) derived from the antibiotic-exposed plastisphere contained ARGs, virulence factors, and genes involved in plasmid conjugation. These include Comamonas, Chryseobacterium, the opportunistic pathogen Stenotrophomonas maltophilia, and other MAGs belonging to genera that have been associated to human infections, such as Achromobacter. The abundance of the integron-associated ciprofloxacin resistance gene aac(6’)-Ib-cr increased under ciprofloxacin exposure in both freshwater microbial communities and in the plastisphere. Regarding the antibiotic mobilome, although no significant changes in ARG load in class 1 integrons and plasmids were observed in polluted samples, we identified three ARG-containing viral contigs that were integrated into MAGs as prophages.ConclusionsThis study illustrates how the selective nature of the plastisphere influences bacterial response to antibiotics at sub-lethal selective pressure. The microbial changes identified here help define the selective role of the plastisphere and its impact on the maintenance of environmental antibiotic resistance in combination with other anthropogenic pollutants. This research highlights the need to evaluate the impact of aquatic pollutants in environmental microbial communities using complex scenarios with combined stresses.3sW_WiGiki6wh61j1XWikeVideo

Effect of polyethylene microplastics on antibiotic resistance genes: A comparison based on different soil types and plant types

Microplastics (MPs) and antibiotic resistance genes (ARGs) are two types of contaminants that are widely present in the soil environment. MPs can act as carriers of microbes, facilitating the colonization and spread of ARGs and thus posing potential hazards to ecosystem safety and human health. In the present study, we explored the microbial networks and ARG distribution characteristics in different soil types (heavy metal (HM)-contaminated soil and agricultural soil planted with different plants: Bidens pilosa L., Ipomoea aquatica F., and Brassica chinensis L.) after the application of MPs and evaluated environmental factors, potential microbial hosts, and ARGs. The microbial communities in the three rhizosphere soils were closely related to each other, and the modularity of the microbial networks was greater than 0.4. Moreover, the core taxa in the microbial networks, including Actinobacteriota, Proteobacteria, and Myxococcota, were important for resisting environmental stress. The ARG resistance mechanisms were dominated by antibiotic efflux in all three rhizosphere soils. Based on the annotation results, the MP treatments induced changes in the relative abundance of microbes carrying ARGs, and the G1–5 treatment significantly increased the abundance of MuxB in Verrucomicrobia, Elusimicrobia, Actinobacteria, Planctomycetes, and Acidobacteria. Path analysis showed that changes in MP particle size and dosage may indirectly affect soil enzyme activities by changing pH, which affects microbes and ARGs. We suggest that MPs may provide surfaces for ARG accumulation, leading to ARG enrichment in plants. In conclusion, our results demonstrate that MPs, as potentially persistent pollutants, can affect different types of soil environments and that the presence of ARGs may cause substantial environmental risks.

Rapid and sensitive parallel on-site detection of antibiotics and resistance genes in aquatic environments using evanescent wave dual-color fluorescence fiber-embedded optofluidic nanochip

Environmental antibiotics and antibiotic resistance genes (ARGs) pose considerable threat to humans and animals; thus, the rapid and sensitive parallel detection of these pollutants from a single sample is urgently required. However, traditional multiplexed analytic technologies detect only one type of target (e.g., small molecules or nucleic acids) per assay. To address this issue, Evanescent wave Dual-color fluorescence Fiber-embedded Optofluidic Nanochip (EDFON) was fabricated by integrating a fiber-embedded optofluidic nanochip with evanescent wave dual-color fluorescence technology. The EDFON was used for the parallel quantitative detection of sulfamerazine (SMR) and MCR-1 with high sensitivity and specificity by combining a heterogeneous immunoassay with a homogenous hybridization chain reaction based on time-resolved effects. LODs of 0.032 μg/L and 35 pM was obtained for SMR and MCR-1, respectively, within 20 min. To our best knowledge, the EDFON is the first device for the simultaneous detection of two type of targets in each test, which is highly valuable to prevent the global threats of antibiotics and ARGs. Comparison with liquid chromatography-mass spectrometry showed a strong linear relationship (R2 = 0.998) for SMR pollution in the Qinghe River, with spiked SMR and MCR-1 negative surface and wastewater samples showing recovery rates of 91.8–113.4%. These results demonstrate the excellent accuracy and reliability of the EDFON, with features such as multi-analyte detection, field-deployment, and minimal-equipment, rendering it revolutionary for environmental monitoring, food safety, and medical diagnostics.

Chlorite and bromate alter the conjugative transfer of antibiotic resistance genes: Co-regulation of oxidative stress and energy supply

The widespread use of disinfectants during the global response to the 2019 coronavirus pandemic has increased the co-occurrence of disinfection byproducts (DBPs) and antibiotic resistance genes (ARGs). Although DBPs pose major threats to public health globally, there is limited knowledge regarding their biological effects on ARGs. This study aimed to investigate the effects of two inorganic DBPs (chlorite and bromate) on the conjugative transfer of RP4 plasmid among Escherichia coli strains at environmentally relevant concentrations. Interestingly, the frequency of conjugative transfer was initially inhibited when the exposure time to chlorite or bromate was less than 24 h. However, this inhibition transformed into promotion when the exposure time was extended to 36 h. Short exposures to chlorite or bromate were shown to impede the electron transport chain, resulting in an ATP shortage and subsequently inhibiting conjugative transfer. Consequently, this stimulates the overproduction of reactive oxygen species (ROS) and activation of the SOS response. Upon prolonged exposure, the resurgent energy supply promoted conjugative transfer. These findings offer novel and valuable insights into the effects of environmentally relevant concentrations of inorganic DBPs on the conjugative transfer of ARGs, thereby providing a theoretical basis for the management of DBPs.

Examining Antimicrobial Resistance in Escherichia coli: A Case Study in Central Virginia's Environment.

While environmental factors may contribute to antimicrobial resistance (AMR) in bacteria, many aspects of environmental antibiotic pollution and resistance remain unknown. Furthermore, the level of AMR in Escherichia coli is considered a reliable indicator of the selection pressure exerted by antimicrobial use in the environment. This study aimed to assess AMR variance in E. coli isolated from diverse environmental samples, such as animal feces and water from wastewater treatment plants (WWTPs) and drainage areas of different land use systems in Central Virginia. In total, 450 E. coli isolates obtained between August 2020 and February 2021 were subjected to susceptibility testing against 12 antimicrobial agents approved for clinical use by the U.S. Food and Drug Administration. Approximately 87.8% of the tested isolates were resistant to at least one antimicrobial agent, with 3.1% showing multi-drug resistance. Streptomycin resistance was the most common (73.1%), while susceptibility to chloramphenicol was the highest (97.6%). One isolate obtained from WWTPs exhibited resistance to seven antimicrobials. AMR prevalence was the highest in WWTP isolates, followed by isolates from drainage areas, wild avians, and livestock. Among livestock, horses had the highest AMR prevalence, while cattle had the lowest. No significant AMR difference was found across land use systems. This study identifies potential AMR hotspots, emphasizing the environmental risk for antimicrobial resistant E. coli. The findings will aid policymakers and researchers, highlighting knowledge gaps in AMR-environment links. This nationally relevant research offers a scalable AMR model for understanding E. coli ecology. Further large-scale research is crucial to confirm the environmental impacts on AMR prevalence in bacteria.

A database on the abundance of environmental antibiotic resistance genes

Antimicrobial resistance (AMR) poses a severe threat to global health. The wide distribution of environmental antibiotic resistance genes (ARGs), which can be transferred between microbiota, especially clinical pathogens and human commensals, contributed significantly to AMR. However, few databases on the spatiotemporal distribution, abundance, and health risk of ARGs from multiple environments have been developed, especially on the absolute level. In this study, we compiled the ARG occurrence data generated by a high-throughput quantitative PCR platform from 1,403 samples in 653 sampling sites across 18 provinces in China. The database possessed 291,870 records from five types of habitats on the abundance of 290 ARGs, as well as 8,057 records on the abundance of 30 mobile genetic elements (MGEs) from 2013 to 2020. These ARGs conferred resistance to major common types of antibiotics (a total of 15 types) and represented five major resistance mechanisms, as well as four risk ranks. The database can provide information for studies on the dynamics of ARGs and is useful for the health risk assessment of AMR.

Cephalexin interaction with biosolids-derived dissolved organic matter: binding mechanism and implications for adsorption by biochar and clay

The antibiotic cephalexin binds to DOM under environmentally-relevent solution conditions through π–π bonding. Under conditions where cephalexin–DOM binding occurs, cephalexin adsorption by biochar and clay is impeded by DOM addition.

The microbiome, resistome, and their co-evolution in sewage at a hospital for infectious diseases in Shanghai, China.

The emergence of antibiotic-resistant bacteria (ARB) caused by the overuse of antibiotics severely threatens human health. Hospital sewage may be a key transmission hub for ARB. However, the complex link between the microbiome and resistomeresistance in hospital sewage remains unclear. In this study, metagenomic assembly and binning methods were used to investigate the microbial community, resistome, and association of antibiotic resistance genes (ARGs) with ARB in sewage from 10 representative sites (outpatient building, surgery building, internal medicine buildings [IMB1-4], staff dormitory, laboratory animal building, tuberculosis building [TBB], and hospital wastewater treatment plant) of a hospital in Shanghai from June 2021 to February 2022. A total of 252 ARG subtypes, belonging to 17 antibiotic classes, were identified. The relative abundance of KPC-2 was higher at IMBs and TBB than at other sites. Of the ARG-carrying contigs, 47.3%-62.6% were associated with mobile genetic elements, and the proportion of plasmid-associated ARGs was significantly higher than that of chromosome-associated ARGs. Although a similar microbiome composition was shared, certain bacteria were enriched at different sites. Potential pathogens Enterococcus B faecium and Klebsiella pneumoniae were primarily enriched in IMB2 and IMB4, respectively. The same ARGs were identified in diverse bacterial hosts (especially pathogenic bacteria), and accordingly, the latter possessed multiple ARGs. Furthermore, gene flow was frequently observed in the sewage of different buildings. The results provide crucial information on the characterization profiles of resistomes in hospital sewage in Shanghai.IMPORTANCEEnvironmental antibiotic resistance genes (ARGs) play a critical role in the emergence and spread of antimicrobial resistance, which poses a global health threat. Wastewater from healthcare facilities serves as a significant reservoir for ARGs. Here, we characterized the microbial community along with the resistome (comprising all antibiotic resistance genes) in wastewater from a specialized hospital for infectious diseases in Shanghai. Potential pathogenic bacteria (e.g., Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterococcus B faecium) were frequently detected in hospital wastewater and carried multiple ARGs. A complex link between microbiome and resistome was observed in the wastewater of this hospital. The monitoring of ARGs and antibiotic-resistant bacteria (ARB) in hospital wastewater might be of great significance for preventing the spread of ARB.

Epinephrine Stimulates Mycobacterium tuberculosis Growth and Biofilm Formation.

The human stress hormones catecholamines play a critical role in communication between human microbiota and their hosts and influence the outcomes of bacterial infections. However, it is unclear how M. tuberculosis senses and responds to certain types of human stress hormones. In this study, we screened several human catecholamine stress hormones (epinephrine, norepinephrine, and dopamine) for their effects on Mycobacterium growth. Our results showed that epinephrine significantly stimulated the growth of M. tuberculosis in the serum-based medium as well as macrophages. In silico analysis and molecular docking suggested that the extra-cytoplasmic domain of the MprB might be the putative adrenergic sensor. Furthermore, we showed that epinephrine significantly enhances M. tuberculosis biofilm formation, which has distinct texture composition, antibiotic resistance, and stress tolerance. Together, our data revealed the effect and mechanism of epinephrine on the growth and biofilm formation of M. tuberculosis, which contributes to the understanding of the environmental perception and antibiotic resistance of M. tuberculosis and provides important clues for the understanding of bacterial pathogenesis and the development of novel antibacterial therapeutics.