Overuse Of Antibiotics Research Articles

Marine Microorganisms as Potential Source of Quorum-Sensing Inhibitory Compounds

Antibiotics are extensively utilized globally, and the rate of antibiotic resistance is increasing more rapidly than ever. Since the introduction of antibiotics, the overuse of antibiotics caused selection pressure, and almost all pathogenic bacteria have developed resistance against commonly used antibiotics, which is particularly known as antimicrobial resistance (AMR). It has proven challenging to combat and resolve the issue of microbial resistance. A growing number of microorganisms have developed different resistance mechanisms and turned into "superbugs". The identification of quorum-sensing systems has given researchers a new hope for understanding drug resistance processes. The quorum-sensing system controls a number of cellular functions, including the expression of pathogenic genes, the synthesis of toxins, and the synthesis of extracellular polysaccharides. To targeting QS systems marine bacterial samples were collected by different coastal sites of Gujarat, like Mandvi, Dwarka and Diu. A total of 52 marine isolates were obtained, out of which 16 were associated with various marine macro-organisms like sponges and algae, whereas 36 were free-living. The study has done by screening those marine isolates shown potential to inhibiting the quorum sensing molecule by co culture study against Chromobacter violaceium, followed by growth inhibition assay. The G14 and G82 isolate shows highest degradation of N-acyl homoserine lactone by AHL study. The QSI compounds were extracted using ethyl acetate extraction method. Biofilm inhibition assay with Pseudomonas aeruginosa shows potent inhibitory effect of extract. These results prove that marine microorganism have potential to inhibits quorum sensing and virulence factors regulated by Quorum Sensing phenomenon.

The clinical importance of metagenomic next-generation sequencing in detecting disease-causing microorganisms in cases of sepsis acquired in the community or hospital setting

ObjectivesAlthough metagenomic next-generation sequencing (mNGS) is commonly used for diagnosing infectious diseases, clinicians face limited options due to the high costs that are not covered by basic medical insurance. The goal of this research is to challenge this bias through a thorough examination and evaluation of the clinical importance of mNGS in precisely identifying pathogenic microorganisms in cases of sepsis acquired in the community or in hospitals.MethodsA retrospective observational study took place at a tertiary teaching hospital in China from January to December 2021. Data on 308 sepsis patients were collected, and the performance of etiological examination was compared between mNGS and traditional culture method.ResultsTwo hundred twenty-nine cases were observed in the community-acquired sepsis (CAS) group and 79 cases in the hospital-acquired sepsis (HAS) group. In comparison with conventional culture, mNGS showed a significantly higher rate of positivity in both the CAS group (88.21% vs. 25.76%, adj.P < 0.001) and the HAS group (87.34% vs. 44.30%, adj.P < 0.001), particularly across various infection sites and specimens, which were not influenced by factors like antibiotic exposure or the timing and frequency of mNGS technology. Sepsis pathogens detected by mNGS were broad, especially viruses, Mycobacterium tuberculosis, and atypical pathogens, with mixed pathogens being common, particularly bacterial-viral co-detection. Based on the optimization of antimicrobial therapy using mNGS, 58 patients underwent antibiotic de-escalation, two patients were switched to antiviral therapy, and 14 patients initiated treatment for tuberculosis, resulting in a reduction in antibiotic overuse but without significant impact on sepsis prognosis. The HAS group exhibited a critical condition, poor prognosis, high medical expenses, and variations in etiology, yet the mNGS results did not result in increased medical costs for either group.ConclusionsmNGS demonstrates efficacy in identifying multiple pathogens responsible for sepsis, with mixed pathogens of bacteria and viruses being prevalent. Variability in microbiological profiles among different infection setting underscores the importance of clinical vigilance. Therefore, the adoption of mNGS for microbiological diagnosis of sepsis warrants acknowledgment and promotion.

Dual-Track Multifunctional Bimetallic Metal-Organic Frameworks for Antibiotic Enrichment and Detection.

The improper use and overuse of antibiotics have led to significant burdens and detrimental effects on the environment, food supply, and human health. Herein, a magnetic solid-phase extraction program and an optical immunosensor based on bimetallic Ce/Zr-UiO 66 for the detection of antibiotics are developed. A magnetic Fe3O4@SiO2@Ce/Zr-UiO 66 metal-organic framework (MOF) is prepared to extract and enrich chloramphenicol from fish, wastewater, and urine samples, and a horseradish peroxidase (HRP)-Ce/Zr-UiO 66@bovine serum protein-chloramphenicol probe is used for the sensitive detection of chloramphenicol based on the dual-effect catalysis of Ce and HRP. In this manner, the application of Ce/Zr-UiO 66 in integrating sample pretreatment and antibiotic detection is systematically investigated and the associated mechanisms are explored. It is concluded that Ce/Zr-UiO 66 is a versatile dual-track material exhibiting high enrichment efficiency (6.37mg g-1) and high sensitivity (limit of detection of 51.3 pg mL-1) for chloramphenicol detection and serving as a multifunctional MOF for safeguarding public health and hygiene.

Bacteriophage therapy: An introduction and revitalized therapy for <i>Klebsiella spp</i> and <i>Pseudomonas aeruginosa</i> infections

We are living in a microbial world and microbes like bacteria are affecting our lives in positive and also negative ways they are commensals in our bodies they play key roles in sustaining our environments and they are causing diseases. Bacteriophage therapy once considered a promising alternative to antibiotics is now being revitalized as a potential treatment for infections caused by Klebsiella spp and Pseudomonas aeruginosa. In recent years the rise of multidrug-resistant bacteria has become a major concern in healthcare settings. Antibiotic-resistant bacterial strains have emerged as a result of antibiotic abuse making it more and more difficult to treat illnesses. Bacteriophages that specifically target and infect bacteria offer a potential solution to combat these drug-resistant infections. This review article provides an introduction to bacteriophage therapy and highlights its potential use in treating infections caused by Klebsiella spp and Pseudomonas aeruginosa. The article addresses the urgent need for alternative strategies to antibiotics and explores the use of bacteriophages as biocontrol agents.

Biofunctional lipid nanoparticles for precision treatment and prophylaxis of bacterial infections.

The lack of bacterial-targeting function in antibiotics and their prophylactic usage have caused overuse of antibiotics, which lead to antibiotic resistance and inevitable long-term toxicity. To overcome these issues, we develop neutrophil-bacterial hybrid cell membrane vesicle (HMV)-coated biofunctional lipid nanoparticles (LNP@HMVs), which are designed to transport antibiotics specifically to bacterial cells at the infection site for the effective treatment and prophylaxis of bacterial infection. The dual targeting ability of HMVs to inflammatory vascular endothelial cells and homologous Gram-negative bacterial cells results in targeted accumulation of LNP@HMVs in the site of infections. LNP@HMVs loaded with the antibiotic norfloxacin not only exhibit enhanced activity against planktonic bacteria and bacterial biofilms in vitro but also achieve potent therapeutic efficacy in treating both systemic infection and lung infection. Furthermore, LNP@HMVs trigger the activation of specific humoral and cellular immunity to prevent bacterial infection. Together, LNP@HMVs provide a promising strategy to effectively treat and prevent bacterial infection.

The one-step synthesis of Fe-N co-doped peony pod-based porous carbon for the removal of tetracycline

The peony pod is a component of the cash crop oil peony (Paeonia suffruticosa Andr.), it accounts for more than half of the quality of the peony seed. However, indiscriminate disposal leads to resource waste. In addition, the pollution caused by the overuse of antibiotics and the evolution of resistance have been a conundrum. There is an urgent need to find a pollutant removal method that conforms to the current concept of sustainable development. In this study, the biomass porous carbon (PCN,Fe-0.5) was prepared and modified by one-step synthesis method using the by-product peony pod as carbon precursor, urea as nitrogen source, and steel slag as magnetic material. The utilization of biomass waste solved resources waste caused by the unreasonable disposal of agricultural solid waste. The doped materials were cheap and easy to obtain, and they improved the structure and function of porous carbon. The maximum adsorption capacity of PCN,Fe-0.5 reached 726.4 mg·g−1 with 100 mg·L−1 of tetracycline (TC). The adsorption mechanism was summarized as pore filling, van der Waals force, π-π EDA, surface complexation, hydrogen bonding and chemisorption. A low-budget tetracycline (TC) removal method was explored through the investigation on the adsorption performance and recovery capability of PCN,Fe-0.5, which was also conducive to realizing the recycling of biomass waste and industrial waste.

Gram-negative bacteria recognition and photodynamic elimination by Zn-DPA based sensitizers

The abuse and overuse of antibiotics let drug-resistant bacteria emerges. Antibacterial photodynamic therapy (APDT) has shown outstanding merits to eliminate the drug-resistant bacteria via cytotoxic reactive oxygen species produced by irradiating photosensitizer. However, most of photosensitizers are not effective for Gram-negative bacteria elimination. Herein conjugates of NBS, a photosensitizer, linked with one (NBS-DPA-Zn) or two (NBS-2DPA-Zn) equivalents of zinc-dipicolylamine (Zn-DPA) have been designed to achieve the functional recognition of different bacteria. Due to the cationic character of NBS and metal transfer channel effect of Zn-DPA, NBS-DPA-Zn exhibited the first regent to distinguish P. aeruginosa from other Gram-negative bacteria. Whereas NBS-2DPA-Zn showed broad-spectrum antibacterial effect because the two arm of double Zn-DPA enhanced interactions with anionic membranes of bacteria, led the bacteria aggregation and thus provided the efficacy of APDT to bacteria and corresponding biofilm. In combination with a hydrogel of Pluronic, NBS-2DPA-Zn@gel shows promising clinical application in mixed bacterial diabetic mouse model infection. This might propose a new method that can realize functional identification and elimination of bacteria through intelligent regulation of Zn-DPA, and shows excellent potential for antibacterial application.

Methacrylated gelatin hydrogel conjugated with ε-polylysine and enriched with platelet-rich plasma for chronically infected wounds

While numerous hydrogel dressings are available for treating chronically infected wounds, their clinical application is impeded by intricate preparation processes, low mechanical strength, and frequent reliance on exogenous antimicrobial agents. The latter often leads to antibiotic misuse and compromises the bioactivity of cell growth-promoting substances. Therefore, the field of therapeutic treatment is faced with a pressing need to prepare high-mechanical-strength hydrogels through a facile procedure, achieving endogenous antibacterial characteristics and long-term healing abilities for chronically infected wounds. In this study, employing the Michael addition reaction principle, we conducted the conjugate addition of the natural antimicrobial poly amino acid, ε-polylysine (ε-PL), to gelatin methacrylate. This not only augmented the hydrogel’s mechanical strength but also preserved its antimicrobial efficacy. Subsequently, platelet-rich plasma (PRP), capable of releasing diverse growth factors, was introduced. Injectable and degradable hydrogels with high mechanical strength and water absorption were prepared through UV curing while retaining PRP bioactivity. The combination of PRP and ε-PL substantiated the enhanced antimicrobial properties and promotion of human umbilical vein endothelial cell growth, as validated through bacterial inhibition experiments, such as live-dead bacterial staining and cellular assays, including cell proliferation. Therefore, the as-developed PL-PRP hydrogel presents as a promising hydrogel dressing for the treatment of chronically infected wounds.

Antibiotic Susceptibility and Biofilm Production among Coagulase Negative Staphylococci Isolated from Clinical Samples at Tertiary Care Hospital.

Coagulase Negative Staphylococci have been widely associated with medical device implant treatment and immune-compromised patients. Despite having increasing interest in Coagulase Negative Staphylococci, few studies from Nepal have reported the association of these organisms with urinary tract infections, conjunctivitis, high vaginal swabs, and cerebrospinal fluid. This study was carried out to determine antibiotic susceptibility pattern and biofilm production among Coagulase Negative Staphylococci isolated from clinical samples at tertiary care hospital. This study was a hospital based cross-sectional study in which 3690 clinical samples were included. Isolation and identification of isolates was done following standard microbiological protocol. Coagulase Negative Staphylococci were identified phenotypically on the basis of gram staining, slide and tube coagulase test and by various sugar fermentation tests. Antibiotic susceptibility test was done following Kirby Bauer disk diffusion method (Clinical and Laboratory Standards Institute 2020). Biofilm production was determined by Tissue Culture Plate technique. A total of 113 isolates of Coagulase Negative Staphylococci were detected. Among them S. epidermidis (45.1%), S. saprophyticus (23.9%), S. haemolyticus (16.8%), S. hominis (5.3%), S. capitis (2.7%), -----S. cohini (1.8%), S. lugdunensis (1.8%) and S. sciuri (2.7%) were identified phenotypically. All isolates were found to be resistant against Ampicillin and 111 (98.2%) were sensitive against Linezolid.23.9% of CoNS were strong biofilm producers, 19.5% moderate and 56.6 % were non/weak biofilm producers. It requires susceptibility test for prescribing antibiotics against Coagulase Negative Staphylococci in hospital and the misuse of antibiotics should be prevented.

The synergistic effect of periodate/ferrate (VI) system on disinfection of antibiotic resistant bacteria and removal of antibiotic resistant genes: The dominance of Fe (IV)/Fe (V)

The proliferation of antibiotic resistant genes (ARGs) and antibiotic resistant bacteria (ARB) caused by antibiotic abuse has raised concerns about the global infectious-disease crisis. This study employed periodate (PI)/ferrate (VI) (Fe (VI)) system to disinfect Gram-negative ARB (Escherichia coli DH5α) and Gram-positive bacteria (Bacillus subtilis ATCC6633). The PI/Fe (VI) system could inactivate 1 × 108 CFU/mL of Gram-negative ARB and Gram-positive bacteria by 4.0 and 2.8 log in 30 min. Neutral and acidic pH, increase of PI dosage and Fe (VI) dosage had positive impacts on the inactivation efficiency of ARB, while alkaline solution and the coexistence of 10 mM Cl-, NO3-, SO42- and 20 mg/L humic acid had slightly negative impacts. The reactive species generated by PI/Fe (VI) system could disrupt the integrity of cell membrane and wall, leading to oxidative stress and lipid peroxidation. Intracellular hereditary substance, including DNA and ARGs (tetA), would leak into the external environment through damaged cells and be degraded. The electron spin resonance analysis and quenching experiments indicated that Fe (IV)/Fe (V) played a leading role in disinfection. Meanwhile, PI/Fe (VI) system also had an efficient removal effect on sulfadiazine, which was expected to inhibit the ARGs transmission from the source.

Validation of Thermal Imaging and the ALT-70 Prediction Model to Differentiate Cellulitis From Pseudocellulitis

Cellulitis is misdiagnosed in up to 30% of cases due to mimic conditions termed pseudocellulitis. The resulting overuse of antibiotics is a threat to patient safety and public health. Surface thermal imaging and the ALT-70 (asymmetry, leukocytosis, tachycardia, and age ≥70 years) prediction model have been proposed as tools to help differentiate cellulitis from pseudocellulitis. To validate differences in skin surface temperatures between patients with cellulitis and patients with pseudocellulitis, assess the optimal temperature measure and cut point for differentiating cellulitis from pseudocellulitis, and compare the performance of skin surface temperature and the ALT-70 prediction model in differentiating cellulitis from pseudocellulitis. This prospective diagnostic validation study was conducted among patients who presented to the emergency department with acute dermatologic lower extremity symptoms from October 11, 2018, through March 11, 2020. Statistical analysis was performed from July 2020 to March 2021 with additional work conducted in September 2023. Temperature measures for affected and unaffected skin were obtained. Cellulitis vs pseudocellulitis was assessed by a 6-physician, independent consensus review. Differences in temperature measures were compared using the t test. Logistic regression was used to identify the temperature measure and associated cut point with the optimal performance for discriminating between cellulitis and pseudocellulitis. Diagnostic performance characteristics for the ALT-70 prediction model, surface skin temperature, and both combined were also assessed. The final sample included 204 participants (mean [SD] age, 56.6 [16.5] years; 121 men [59.3%]), 92 (45.1%) of whom had a consensus diagnosis of cellulitis. There were statistically significant differences in all skin surface temperature measures (mean temperature, maximum temperature, and gradients) between cellulitis and pseudocellulitis. The maximum temperature of the affected limb for patients with cellulitis was 33.2 °C compared with 31.2 °C for those with pseudocellulitis (difference, 2.0 °C [95% CI, 1.3-2.7 °C]; P < .001). The maximum temperature was the optimal temperature measure with a cut point of 31.2 °C in the affected skin, yielding a mean (SD) negative predictive value of 93.5% (4.7%) and a sensitivity of 96.8% (2.3%). The sensitivity of all 3 measures remained above 90%, while specificity varied considerably (ALT-70, 22.0% [95% CI, 15.8%-28.1%]; maximum temperature of the affected limb, 38.4% [95% CI, 31.7%-45.1%]; combination measure, 53.9% [95% CI, 46.5%-61.2%]). In this large diagnostic validation study, significant differences in skin surface temperature measures were observed between cases of cellulitis and cases of pseudocellulitis. Thermal imaging and the ALT-70 both demonstrated high sensitivity, but specificity was improved by combining the 2 measures. These findings support the potential of thermal imaging, alone or in combination with the ALT-70 prediction model, as a diagnostic adjunct that may reduce overdiagnosis of cellulitis.

Antimicrobial resistance burden pre and post-COVID-19 pandemic with mapping the multidrug resistance in Egypt: a comparative cross-sectional study

Overuse of antibiotics during coronavirus disease 2019 (COVID-19) in an attempt to reduce COVID-19 mortality in the short term may have contributed to long-term mortality from antimicrobial resistance (AMR). The aim of this study was to evaluate the impact of the COVID-19 pandemic on AMR in Egypt and map the distribution of multidrug-resistant (MDR) and extensive drug-resistant (XDR) across Egypt. Through a multicenter cross-sectional study 2430 culture results were collected in 2019 and 2022 pre and post-COVID-19 pandemic in Egypt, including 400 Klebsiella pneumoniae, 760 Escherichia coli, 650 Acinetobacter baumannii, and 620 Methicillin-resistantstaphylococcus aureus (MRSA) culture results. MDR and XDR culture results distribution across Egypt was highlighted through the geographic information system. Mixed effect logistic regression models and sub-group analysis were performed according to the type of specimens to test the impact of COVID-19 on resistance. Adjusted analysis demonstrated K. pneumoniae resistance has increased against quinolones and carbapenems (P < 0.001). Resistance of E. coli has increased significantly against imipenem and meropenem. While E.coli susceptibility has increased to cefoxitin, levofloxacin, and ciprofloxacin. A. baumannii resistance has increased more than double against ceftazidime, cefepime, and piperacillin-tazobactam (P < 0.001). MRSA reserved its susceptibility to vancomycin and linezolid. MDR K. pneumoniae and A. baumannii have increased post-COVID-19 from 67% to 94% and from 79% to 98%, respectively (P < 0.001). XDR K. pneumoniae and A. baumannii have increased from 6% to 46%, and from 47% to 69%, respectively (P < 0.001). COVID-19 has changed the profile of AMR in Egypt so that urgent action is required to mitigate this threat and preserve our capacity to face infections in future decades.

Space-confined nanozyme with cascade reaction based on PCN-224 for synergistic bacterial infection treatment and NIR fluorescence imaging of wound bacterial infections

The rapid development of bacterial infections has become a significant global health challenge. The overuse or prolonged use of antibiotics is considered a major contributor to the development of bacterial resistance. Therefore, there is an urgent need to develop a new therapeutic approach to combat infectious diseases caused by bacteria. In this study, we demonstrate the effectiveness of a novel strategy for synergistic antibacterial therapy and fluorescence imaging of wound bacterial infections through the nano-confined construction of LL-37-HA-Au-Pt@PCN-224 nanozymes. The nanozyme is composed of Au NPs and Pt NPs confined to PCN-224 through in situ reduction, with its outer layer modified with HA and LL-37. The nanozyme catalyzes the conversion of low-concentration H2O2 into O2 and •OH, with the generated O2 further catalyzed into 1O2 by PCN-224. In vivo imaging experiments demonstrate that LL-37-HA-Au-Pt@PCN-224 labeled with near-infrared fluorescent dye MPA can effectively realize fluorescence imaging of wound bacterial infections and real-time monitoring of the wound healing process. In vitro and in vivo antibacterial experiments reveal that LL-37-HA-Au-Pt@PCN-224 enhances the healing efficiency of bacteria-infected wounds due to its synergistic antibacterial effect. The multifunctional nanozyme offers various synergistic antibacterial therapies, including antimicrobial peptides, peroxide nanozymes, hydrogen peroxide nanozymes, and photodynamic therapy. Moreover, it provides real-time wound imaging and monitoring of the wound healing process, while maintaining high biocompatibility. Overall, this study presents a promising perspective on the potential use of nanozymes as antibacterial agents against wound bacterial infections in the future.

Abstract 2806: A single dose of perioperative cefazolin disrupts the gut microbiome and immunity in patients (pts) with early-stage melanoma

Abstract Background: Perioperative antibiotic prophylaxis is routinely utilized to reduce surgical site infections (SSIs). However, the rate of SSIs following a clean surgical procedure is &amp;lt;3%. Overuse of antibiotics is associated with potential adverse effects, including disruption of the composition and function of the native gut microbiota. Numerous studies have shown a negative impact of antibiotics on response and survival in patients with cancer treated with immune checkpoint blockade. The primary objective of this study was to determine the impact of a single dose of perioperative cefazolin on the gut microbiome and immunity. Methods: In this pilot trial (NCT04875728), 22 eligible pts diagnosed with clinical stage I or II melanoma undergoing wide excision with or without sentinel lymph node biopsy were enrolled between October 2021 and January 2023. Pts were randomized 1:1 to receive a single dose of cefazolin as standard-of-care (ABX, n=11) or no antibiotics (No ABX, n=11) at the time of surgery. Stool samples were collected before surgery, on post-operative day (POD) 14 and POD90 for metagenomic sequencing (WMS). Bulk RNA-sequencing of peripheral blood mononuclear cells (PBMCs) collected at the same timepoints was performed and data processed using DESeq2, log-transformed, and standardized for subsequent analysis. Immune pathway enrichment scores were calculated using GSVA for each sample with gene lists from 3 immune pathways (ADAPTIVE_IMMUNE_SYSTEM, INNATE_IMMUNE_SYSTEM, and CYTOKINE_SIGNALING_IN_IMMUNE_SYSTEM) from REACTOME (https://reactome.org) and immune cell gene signatures from Danaher P et al, 2017. Results: Treatment with a single dose of perioperative cefazolin was associated with a decrease in the alpha diversity of the gut microbiome 2 weeks postoperatively in pts who received perioperative cefazolin versus those who did not receive antibiotics (p=0.057, R2=0.0526); this persisted to POD90 (p=0.021, R2=0.0948). WMS showed prominent and persistent decreases in Akkermansia muciniphila (POD14: Log2FC=-8.38, q&amp;lt;0.001) and Alistipes communis (POD90: Log2FC=-4.47, q&amp;lt;0.001) in the ABX group compared to No ABX, respectively. RNA-seq analysis of PBMCs from pts revealed differences in immune subsets at POD90 between ABX and No ABX groups including decreased IFN-γ signatures (p=0.02) in pts who received perioperative cefazolin. Conclusions: Perioperative antibiotic prophylaxis is associated with profound and persistent reduction in microbiome diversity and composition, particularly of bacterial species associated with protective metabolic and inflammatory effects. Further studies will seek to assess the functional impact of this reduction on the immune response in a murine model, evaluate the generalizability of our findings across broader cohorts of patients undergoing surgery, and apply these findings to guide clinical management decisions. Citation Format: Estefania Fernandez, Samuel Cass, Yongwoo D. Seo, Ashish V. Damania, Xiaolong Meng, Pranoti V. Sahasrabhojane, Jiun Sheng Liu, Wenbin Liu, Yulong Chen, Roland L. Bassett, Samuel Shelburne, Hsiu-Yin Chang, Kinjal R. Somaiya, Kristi S. Mungovan, Jared C. Malke, Brenna Matejka, Sarah B. Fisher, Anthony Lucci, Jeffrey E. Lee, Merrick I. Ross, Jeffrey E. Gershenwald, Padmanee Sharma, Nadim J. Ajami, Christina L. Roland, Jennifer A. Wargo, Emily Z. Keung. A single dose of perioperative cefazolin disrupts the gut microbiome and immunity in patients (pts) with early-stage melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2806.

A magnetic nanozyme platform for bacterial colorimetric detection and chemodynamic/photothermal synergistic antibacterial therapy.

Rapid, convenient, and sensitive detection of bacteria and development of novel antibacterial materials are conducive to accurate treatment of bacterial infection and reducing the generation of drug-resistant bacteria caused by overuse of antibiotics. A dual-function magnetic nanozyme, Fc-MBL@rGO@Fe3O4, has been constructed with broad-spectrum bacterial affinity and good peroxidase-like activity. Detection signal amplification was realized in the presence of 3,3',5,5'-tetramethylbenzidine (TMB) with a detection limit of 26 CFU/mL. In addition, the excellent photothermal properties of Fc-MBL@rGO@Fe3O4 could realize synergistic chemodynamic/photothermal antibacterial therapy. Furthermore, the good bacterial affinity of Fc-MBL@rGO@Fe3O4 enhances the accurate and rapid attack of hydroxyl radical (·OH) on the bacterial membrane and achieves efficient sterilization (100%) at low concentration (40µg/mL) and mild temperature (47℃). Notably, Fc-MBL@rGO@Fe3O4 has a broad spectrum of antibacterial activity against Gram-negative, Gram-positive, and drug-resistant bacteria. The magnetic nanoplatform integrating detection-sterilization not only meets the need for highly sensitive and accurate detection in different scenarios, but can realize low power density NIR-II light-responsive chemodynamic/photothermal antibacterial therapy, which has broad application prospects.

Isolation and Characterization of a Novel Virulent Phage ASG01 of Aeromonas salmonicida and Its Cell Wall Hydrolase Activity.

Aeromonas salmonicida is an important pathogen that causes furunculosis in trout and salmon with high morbidity and mortality, resulting in significant economic losses in aquaculture. Overuse of antibiotics has led to the continuous emergence of drug-resistant strains. Hence, there is an urgent need to find an alternative environmentally friendly antimicrobial agent. In this study, we isolated a virulent phage of A. salmonicida, named ASG01, which belongs to the Myoviridae family and maintains lytic activity at a pH value range from 4 to 12 and in the temperature range from 30 °C to 60 °C. The whole genomic sequence of ASG01 showed 82% similarity to Aeromonas phage pAh6-C. The cell wall hydrolase (Cwh)-encoding gene from the genome of ASG01 was predicted and heterologously expressed. Notably, in the absence of additional phage genes, endogenous expression of Cwh could lyse E. coli cells and greatly inhibit the growth of tested fish pathogenic bacteria. The lytic activity of Cwh was eliminated when the predicted active site was mutated. These results indicate that Cwh of ASG01 possessed excellent lytic activity and a wide antibacterial spectrum, suggesting its potential as an effective enzybiotic.

Prescribing antimicrobials effectively in Dentistry; Resources to support the role of the dentist in antimicrobial stewardship

Background The discovery of antibiotics revolutionised modern medicine and extended the average human lifespan by 23 years.1 Antimicrobial resistance threatens to reverse the progress that has been made. In 2019, there were 4.95 million deaths globally associated with drug-resistant bacterial infections.2 That figure may rise to as many as 50 million by 2050, making this an unprecedented global public health problem.3 The threat of a post-antibiotic era has prompted the publication of Ireland’s One Health National Action Plan on Antimicrobial Resistance (2021-2025).4 This National Action Plan advocates for the judicious use of antimicrobials to limit any unintended consequences and antimicrobial resistance. This is commonly known as Antimicrobial Stewardship. Antibiotic resistance is largely driven by the overuse and misuse of antibiotics in people, animals and in the environment.4 Dentists are responsible for approximately 10% of antibiotic prescribing in humans globally.5 With several international studies of dental antibiotic prescribing demonstrating that overprescribing occurs frequently5, dentists have an opportunity to contribute significantly to slowing the development and spread of antibiotic resistance by optimising prescribing. This article aims to show how dentists can support good antimicrobial stewardship in their practice.

Blood cellular membrane-coated Au/polydopamine nanoparticle-targeted NIR-II antibacterial therapy

Bacterial infections are the primary causes of infectious diseases in humans. In recent years, the abuse of antibiotics has led to the widespread enhancement of bacterial resistance. Concerns have been raised about the identification of a common treatment platform for bacterial infections. In this study, a composite nanomaterial was used for near-infrared II (NIR-II) photothermal antibacterial treatment. Red blood cell membrane was peeled and coated onto the surface of the Au/polydopamine nanoparticle-containing aptamer. The composite nanomaterials based on Au/polydopamine exhibit highest photothermal conversion capability. Moreover, these assembled nanoparticles can quickly enter the body’s circular system with a specific capability to recognise bacteria. In vivo experiments demonstrated that the composites could kill bacteria from infected blood while significantly reducing the level of bacteria in various organs. Such assemblies offer a paradigm for the treatment of bacterial infections caused by the side effects of antibiotics.

Antibiotic resistance genes in Bacteroides isolated from faeces of Philippine ducks, Anas luzonica and Anas platyrhynchos domesticus

The problem of antimicrobial resistance (AMR) has severely afflicted the livestock industry because antibiotics are indiscriminately used for treating infectious diseases and for nontherapeutic purposes. Unfortunately, compared with human AMR research, livestock AMR research is lagging. Thus, this study aimed to contribute to the dearth of knowledge regarding livestock AMR by detecting 10 antibiotic resistance genes (ARGs) in Bacteroides isolated from duck faeces. The 10 ARGs were tetQ, linA, bexA, msrSA, mefA, nim, cfiA, cepA, cfxA, and ermF. In total, 32 isolates were grown, and their DNAs were extracted and subjected to polymerase chain reaction. All isolates were ARG-positive for 1–3 different genes. The ARG-positive genes were linA (21/32), mefA (20/32), and bexA (1/32). Of the 32 isolates, 25 (78%) contained 2–3 ARGs. Although all isolates were ARG-positive, AMR may not be that prevalent in the duck livestock industry because only a maximum of 3/10 ARGs were detected. This is possibly because the duck livestock industry is still a small-scale backyard industry; hence, the use of antibiotics in this industry is not that rampant. However, some reports have shown that Bacteroides exhibit extensive horizontal transfer of resistance and virulence genes. The prevalence of these genes may increase if the misuse of antibiotics in the duck industry is not addressed early.  

Prevalence of antibiotics, antibiotic resistance genes, and their associations in municipal wastewater treatment plants along the Yangtze River basin, China

The overuse and misuse of antibiotics have resulted in the pollution of antibiotics and antibiotic resistance genes (ARGs) in municipal wastewater treatment plants (WWTPs), posing threats to ecological security and human health. Thus, a comprehensive investigation was conducted to assess the occurrence, removal efficiency, and ecological risk of antibiotics, along with the diversity, abundance, and co-occurrence of ARGs, and their correlations in 13 WWTPs along the Yangtze River Basin. Among 35 target antibiotics, 23 antibiotics within 6 categories were detected in all the samples. Amoxicillin (AMO), ofloxacin (OFL), and pefloxacin (PEF) were predominant in influents, while AMO exhibited dominance with the highest concentration of 1409 ng/L in effluents. Although antibiotic removal performance varied among different WWTPs, a significant decrease in each antibiotic category and overall antibiotics was observed in effluents compared with that in influents (p < 0.05). Remarkably, ecological risk assessment revealed high risks associated with AMO and ciprofloxacin (CIP) and medium risks linked to several antibiotics, notably including OFL, roxithromycin (ROX), clarithromycin (CLA), and tetracycline (TC). Furthermore, 96 ARG subtypes within 12 resistance types were detected in this study, and the total absolute abundance and diversity of ARGs were significantly decreased from influents to effluents (p < 0.05). Enrichment of 38 ARGs (e.g., blaNDM, ermA, vatA, mexA, and dfrA25) in effluents indicated potential health risks. Various mobile genetic elements (MGEs), exhibited significant correlations with a majority of ARGs in both influents and effluents, such as intⅠ1, tnpA1, tnpA5, and tp614, underscoring the important role of MGEs in contributing to the ARG dissemination. Many antibiotics displayed lower correlations with corresponding ARGs, but exhibited higher correlations with other ARGs, suggesting complex selective pressures influencing ARG propagation. Overall, the incomplete elimination of antibiotics and ARGs in WWTPs is likely to pose adverse impacts on aquatic ecosystems in the Yangtze River Basin.