Nanoporous Research Articles

Dense and Nanoporous Glasses as Host Matrices to Grow Quantum Dots for Optical and Photonic Applications.

Quantum dots (QDs)grown within inorganic glasses (hereafter referred to as "QD glasses") arepromising candidates for an expanding list of applications such as nonlinear optical (NLO) devices. However, lots of research into NLO properties of QDs still uses polymer-based matrices, whose low laser damage threshold hinders practical applications. This can be explained by the difficulties typically encountered by researchers wishing to grow QDs within glass matrices. Fortunately, much progress has been made, not only as regards dense glass but also in the use of nanoporous (NP) glass which is prepared and explored as a macro-matrix in the growth of QDs. In situ growth techniques for the preparation of QD glasses are more appealing than ex situ methods, as the formercan effectively avoid agglomeration of the QDs and the need for application of prior treatments such as ligand exchange. Here, a review of advances in growth techniques of QDs in both dense and NP glasses is provided, with a discussion on the effect of glasses on the emission nature of the grown QDs, the routes to tune emission, enhancing optical performance and, finally, potential applications of QD glasses. The overview of directions and future challenges of this area are also presented.

Fabrication of Graphene Polyhedra: Unveiling New Structures, Forms, and Properties

AbstractA hybrid nanoporous carbon alloy material is synthesized using a core–shell structure based on metal–organic frameworks, revealing a novel graphene polyhedral form. The presence of carbon and metal as doped cobalt carbides based on morphed graphene within the graphene polyhedra is confirmed through a combination of X‐ray diffraction, X‐ray photoelectron spectroscopy, transmission electron microscopy, and Raman spectroscopy analyses. These novel graphene polyhedra exhibit magnetoelectric coupling properties at room temperature. The magnetic state control is verified using a magnetic probe; the changes in the magnetic state increased with a higher applied bias, and the poling direction of the magnetic phase is reversed based on the scanning direction of the probe. This discovery holds promise for future applications in ultrafast devices and carbon‐based spintronics research.

Tunable 1D-2D Carbon Nanomaterials for Broadband and High-Performance Microwave Absorption via Ultrasonic Spray Ice Template.

Polymer-based one- and two-dimensional (1D-2D) carbon nanomaterials are considered promising microwave-absorbing materials (MAMs) due to their high atomic utilization efficiency and tunable microscopic/macroscopic morphology. The tunable design of 1D-2D carbon nanomaterials through a facile method to meet the requirements of advanced MAMs remains a challenge. In this work, the environmentally friendly processing method of ultrasonic spray ice template (USIT) is employed to fabricate porous carbon nanomaterials based on Kapton-type polyimide, which exhibit the intriguing morphology of both 1D nanowires and 2D nanosheets. Under subsequent carbonization at 700 and 800 °C, the obtained carbon nanomaterials inherit the original morphology. Furthermore, the 1D or 2D nanomorphology can be readily controlled by adjusting the concentration of the precursor solution. For samples fabricated with lower precursor concentrations (0.1%), 1D nanowire structures are predominant. Interconnected conductive networks and heterogeneous interfaces are formed by intertwining and stacking nanowires, thereby enhancing the conductivity loss. Additionally, the abundant porous structure provides an effective channel for electromagnetic wave entrance, significantly improving the impedance matching ability. The results show that the 1D nanowire-dominated samples (700 °C carbonization) show excellent electromagnetic microwave absorption performance. The reflection loss minimum (RLmin) is -67.2 dB at 8.1 GHz and 4.65 mm, and the maximum effective absorption bandwidth (<-10 dB) is 7.7 GHz at 3.03 mm. Exemplified by MAMs, the USIT strategy has broad prospects, providing enormous potential for various practical applications and bridging the gap between polymer precursors and 1D/2D tunable carbon nanomaterials.

A CACTA-like transposon in the Anthocyanidin synthase 1 (Ans-1) gene is responsible for apricot fruit colour in the raspberry (Rubus idaeus) cultivar 'Varnes'.

Cultivated raspberries (Rubus idaeus L.) most commonly bear small, red, highly aromatic fruits. Their colour is derived predominantly from anthocyanins, water soluble polyphenolic pigments, but as well as red forms, there exist cultivars that display yellow- and apricot-coloured fruits. In this investigation, we used a multi-omics approach to elucidate the genetic basis of the apricot fruit colour in raspberry. Using metabolomics, we quantified anthocyanins in red and apricot raspberry fruits and demonstrated that, in contrast to red-fruited raspberries, fruits of the apricot cultivar 'Varnes' contain low concentrations of only a small number of anthocyanin compounds. By performing RNASeq, we revealed differential expression patterns in the apricot-fruited 'Varnes' for genes in the anthocyanin biosynthesis pathway and following whole genome sequencing using long-read Oxford Nanopore Technologies sequencing, we identified a CACTA-like transposable element (TE) in the second exon of the Anthocyanidin synthase (Ans) gene that caused a truncated predicted ANS protein. PCR confirmed the presence in heterozygous form of the transposon in an unrelated, red-fruited cultivar 'Veten', indicating apricot fruit colour is recessive to red and that it may be widespread in raspberry germplasm, potentially explaining why apricot forms appear at regular intervals in modern raspberry breeding populations.

Evaluation of a next generation sequencing assay for Hepatitis B antiviral drug resistance on the oxford nanopore system.

Next-generation sequencing (NGS) for Hepatitis B virus (HBV) antiviral resistance (AVR) testing is a highly sensitive diagnostic method, able to detect low-level mutant subpopulations. Our clinical virology laboratory previously transitioned from DNA hybridization (INNO-LiPA) to NGS, initially with the GS Junior System and subsequently the MiSeq. The Oxford Nanopore Technology (ONT) sequencing system was evaluated for HBV resistance testing, with regards to sequencing accuracy and turn-around time. We performed amplicon sequencing of the HBV polymerase gene from patient plasma and external quality assessment (EQA) samples on the MiSeq Reagent Nano Kit v2 and GridION ONT with R10.4.1 flowcells. Mutational analysis and genotyping were performed by DeepChek®Assay-HBV (version 2.0). A total of 49 patient samples and 15 EQA samples were tested on both the MiSeq and ONT. There was high agreement for both patient and EQA samples between the MiSeq and ONT systems, with regards to total drug resistance mutations detected and total patient sample agreement, 68/70 (97 %) and 47/49 (96 %), respectively. The ONT NGS platform provided accurate HBV AVR results, with improved turn-around times. Sequencing error rates at AVR codons were below 1 %.

Layer-by-Layer Nanoarchitectonics: A Method for Everything in Layered Structures

The development of functional materials and the use of nanotechnology are ongoing projects. These fields are closely linked, but there is a need to combine them more actively. Nanoarchitectonics, a concept that comes after nanotechnology, is ready to do this. Among the related research efforts, research into creating functional materials through the formation of thin layers on surfaces, molecular membranes, and multilayer structures of these materials have a lot of implications. Layered structures are especially important as a key part of nanoarchitectonics. The diversity of the components and materials used in layer-by-layer (LbL) assemblies is a notable feature. Examples of LbL assemblies introduced in this review article include quantum dots, nanoparticles, nanocrystals, nanowires, nanotubes, g-C3N4, graphene oxide, MXene, nanosheets, zeolites, nanoporous materials, sol–gel materials, layered double hydroxides, metal–organic frameworks, covalent organic frameworks, conducting polymers, dyes, DNAs, polysaccharides, nanocelluloses, peptides, proteins, lipid bilayers, photosystems, viruses, living cells, and tissues. These examples of LbL assembly show how useful and versatile it is. Finally, this review will consider future challenges in layer-by-layer nanoarchitectonics.

Advancements in the development of porous nanomaterials for CO2 capture of deep decarbonization: Pore structure and chemical group optimization

Advancements in the development of porous nanomaterials for CO2 capture of deep decarbonization: Pore structure and chemical group optimization

Electron paramagnetic resonance spectroscopy: toward the path of dihydrogen isotopologue detection in porous materials.

Electron paramagnetic resonance (EPR) spectroscopy is a powerful method to characterize the local framework structure of nanoporous materials during the dihydrogen isotopologue adsorption process. It also allows for exploring the adsorption sites of the dihydrogen isotopes and monitoring their desorption characteristics on the microscopic scale. The paramagnetic spin probes in the form of transition metal ions or organic radicals are required for EPR spectroscopy and are introduced either at the framework lattice position or in the pores of the metal-organic frameworks. This review highlights current advancements within the field of dihydrogen isotopologue detection as well as key findings related to the versatility of in situ continuous wave EPR and pulsed EPR experiments as toolkits for monitoring the adsorption-desorption process of dihydrogen isotopologues from the perspective of the framework as well as studying the host-guest interactions based on high-resolution advantages offered by using a pulsed EPR approach.

Enhancing nanopore adaptive sampling for PromethION using readfish at scale.

A unique feature of Oxford Nanopore Technologies sequencers, adaptive sampling, allows precise DNA molecule selection from sequencing libraries. Here we present enhancements to our tool, readfish, enabling all features for the industrial scale PromethION sequencer, including standard and "barcode-aware" adaptive sampling. We demonstrate effective coverage enrichment and assessment of multiple human genomes for copy number and structural variation on a single PromethION flow cell.

P-1498. Contezolid is Active against Methicillin-Resistant Staphylococcus aureus in Experimental Rat Foreign Body Osteomyelitis

Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of orthopedic implant-associated infection, where S. aureus can survive intracellularly and form biofilms. Vancomycin has poor activity against staphyloccoccal biofilms. Although rifampin is effective against staphylococcoal biofilms and has intracellular activity, resistance may develop when it is used as a single agent. Contezolid is a novel oxazolidinone with reported activity against S. aureus in vitro and in vivo in both murine systemic and thigh infection models. Here, we assessed the in vivo activity of contezolid, with and without rifampin, in a rat model of foreign body osteomyelitis. Figure 1. Quantities of MRSA IDRL-6169 recovered from A. tibia B. K-wire. Circles represent values from individual animals; horizontal lines represent mean values. Compared to no treatment: *p=0.0186 **p&amp;lt;0.0002 Methods The left tibia of 60 male Wister rats were inoculated with arachidonic acid (sclerosing agent) and 106 cfu MRSA IDRL-6169 and a K-wire implanted. After four weeks, rats received either no treatment, contezolid (50 mg/kg orally, every 12 h), rifampin (10 mg/kg intraperitoneally every 12 h), rifampin plus contezolid, or vancomycin (75 mg/kg intraperitoneally, every 12 h) plus rifampin for 21 days. Following treatment, tibiae were harvested and cyropulverized. Tibiae and K-wires were cultured separately, and results reported as log10 cfu/gram of bone or K-wire (limit of detect 0.1 log10), respectively. Wilcoxon rank-sum test and false discovery rates were performed and p&amp;lt; 0.05 considered significant. Results Results are shown in Figure 1. MRSA was recovered from tibiae and K-wires of all untreated animals, at means of 5.1 log10 cfu/bone and 3.0 log10 cfu/K-wire, respectively. There was a 1.0 log10 cfu/g mean reduction in MRSA recovered from the tibiae of contezolid-treated rats compared to untreated rats (p=0.0186), and a 0.2 log10 reduction on K-wires. No MRSA was recovered from the tibiae or K-wires in animals receiving rifampin, whether alone or in combination with contezolid or vancomycin. Conclusion Contezolid was active against MRSA in a rat model of foreign body osteomyelitis, reducing bacterial loads in bone, albeit not on K-wires, unless co-administered with rifampin. Disclosures Robin Patel, MD, a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, a: See above|MicuRx Pharmaceuticals and BIOFIRE: Grant/Research Support|PhAST, Day Zero Diagnostics, Abbott Laboratories, Sysmex, DEEPULL DIAGNOSTICS, S.L., Netflix, Oxford Nanopore Technologies and CARB-X: Advisor/Consultant|Up-to-Date and the Infectious Diseases Board Review Course.: Honoraria

P-1091. Hydrogen peroxide generating electrochemical bandage for the treatment of wound biofilm infections - preliminary demonstration of device safety on healthy human skin

Abstract Background Wound biofilm infections impact ∼2% of the United States and at-risk individuals often have underlying morbidities such as diabetes. Antibiotics and topical approaches like debridement or silver dressings have had limited success, underscoring a need for strategies that efficiently target pathogens in wound beds. Methods We developed a hydrogen peroxide (H2O2) generating electrochemical bandage (e-bandage) composed of carbon fabric electrodes separated by cotton fabric with an Ag/AgCl reference electrode (RE) placed between cotton fabric layers. The e-bandage is controlled by a wearable micropotentiostat (MP); H2O2 is generated by O2 + 2H++ 2e- → H2O2. O2 is dissolved on a primary working electrode with negative polarity compared to the RE while a positively polarized secondary counter electrode generates H+ and e-. The H2O2 e-bandage/MP device has in vitro activity against mono- and dual-species bacterial and fungal biofilms. We showed that the H2O2 e-bandage decreased the burden of methicillin-resistant Staphylococcus aureus and/or Pseudomonas aeruginosa with difficult-to-treat resistance in a murine wound infection model. Given this, we initiated a H2O2 e-bandage safety assessment on healthy human skin. Here, testing of a non-polarized, circular (2 cm diameter) device pre-loaded with biocompatible hydrogel containing 0.9% NaCl is reported. Sterilized e-bandages assessed in a shelf-life study retained activity for two weeks. Adults with intact forearm skin were then recruited to the Clinical Research Trials Unit at the Mayo Clinic. Consented individuals had a non-polarized e-bandage covered by Tegaderm placed on their forearm. A MP enclosed in a biocompatible case was connected to the e-bandage and secured using skin tape. One day later, the device was removed and a follow-up phone call made six days later to assess for adverse effects. Results Three volunteers wearing a non-polarized H2O2 e-bandage experienced no discomfort, irritation, allergic reaction, or skin discoloration after device removal and seven days post device placement. Conclusion These preliminary studies combined with the previously performed murine bacterial biofilms work support further studies of this novel device for treating wound infections caused by antimicrobial resistant pathogens. Disclosures Robin Patel, MD, a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, a: See above|MicuRx Pharmaceuticals and BIOFIRE: Grant/Research Support|PhAST, Day Zero Diagnostics, Abbott Laboratories, Sysmex, DEEPULL DIAGNOSTICS, S.L., Netflix, Oxford Nanopore Technologies and CARB-X: Advisor/Consultant|Up-to-Date and the Infectious Diseases Board Review Course.: Honoraria

Cost-Effective Detection of SNPs and Structural Variations in Full-Length Genes of Wheat and Sunflower Using Multiplex PCR and Rapid Nanopore Kit

The rapid identification of allele variants in target genes is crucial for accelerating marker-assisted selection (MAS) in plant breeding. Although current high-throughput genotyping methods are efficient in detecting known polymorphisms, they are limited when multiple variant sites are scattered along the gene. This study presents a target amplicon sequencing approach using Oxford Nanopore Technologies (ONT-TAS) to rapidly sequence full-length genes and identify allele variants in sunflower and wheat collections. This procedure combines multiplex PCR and a rapid sequencing kit, significantly reducing the time and cost compared to previous methods. The efficiency of the approach was demonstrated by sequencing four genes (Ahasl1, Ahasl2, Ahasl3, and FAD2) in 40 sunflower genotypes and three genes (Ppo, Wx, and Lox) in 30 wheat genotypes. The ONT-TAS revealed a complete picture of SNPs and InDels distributed over the individual alleles, enabling rapid (4.5 h for PCR and sequencing) characterization of the genetic diversity of the target genes in the germplasm collections. The results showed a significant diversity of the Ahasl1/Ahasl3 and Wx-A/Lox-B genes in the sunflower and wheat collections, respectively. This method offers a high-throughput, cost-effective (USD 3.4 per gene) solution for genotyping and identifying novel allele variants in plant breeding programs.

P-66. Comparison of Periprosthetic Tissue and Cement Spacer Sonicate Fluid Cultures at the Second Stage of Two-Stage Hip and Knee Revision Arthroplasty Surgery for Periprosthetic Joint Infection

Abstract Background Chronic periprosthetic joint infection is commonly managed with two-stage exchange. Clinically, evaluation for persistent infection at the second stage of exchange may inform management. The aim of this study was to evaluate the yield of periprosthetic tissue and antimicrobial-containing cement spacer sonicate fluid cultures at the second stage of two-stage exchange surgeries. Methods Periprosthetic tissue and sonicate fluid cultures of hip and knee cement spacers removed at the second stage of two-stage exchange surgeries between January 2010 and December 2020 were studied. Two or more positive tissue cultures yielding the same organism were considered positive. For sonicate culture, ≥20 CFU/10 ml of sonicate fluid was considered positive. Persistent infection was defined by the presence of at least one of the following: intraoperative purulence, sinus tract, histopathology showing acute inflammation, or clinical signs of infection. Cement spacers were removed as part of spacer exchange if persistent infection was suspected or for insertion of a new implant if infection was not suspected. Results 172 cultures were evaluated, 69% from knees and 31% from hips. Median patient age was 64 years; 53% were men. 38/172 (22%) of cement spacers were removed as part of a spacer exchange and 134/172 (78%) for insertion of a new implant. Persistent infection was present in 49/172 (28%). 18/172 (10%) received antibiotics 2 weeks before culture, including 8/18 (44%) undergoing spacer exchange. For persistent infections, tissue and sonicate culture were positive in 11/49 and 5/49, respectively. In the 123 without persistent infection, no tissue or sonicate cultures were positive. When a new implant was placed, persistent infection was observed in 18/134 (13%), and tissue and sonicate cultures were positive in 4/18 and 1/18, respectively. When a new implant was placed (116) and no infection was found, all tissue and sonicate cultures were negative. After spacer exchange, persistent infection was present in 31/38 (81%), and tissue and sonicate cultures were positive in 8/31 and 3/31, respectively; in the 7 without infection, there were no positive cultures. Conclusion Sonication culture of cement spacers and periprosthetic tissue cultures have low sensitivities for persistent infection. Disclosures Matthew Abdel, MD, Stryker: Advisor/Consultant|Stryker: Royalties Nicholas Bedard, MD, Stryker: Advisor/Consultant Robin Patel, MD, a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, a: See above|MicuRx Pharmaceuticals and BIOFIRE: Grant/Research Support|PhAST, Day Zero Diagnostics, Abbott Laboratories, Sysmex, DEEPULL DIAGNOSTICS, S.L., Netflix, Oxford Nanopore Technologies and CARB-X: Advisor/Consultant|Up-to-Date and the Infectious Diseases Board Review Course.: Honoraria

300. Clinical Experience with 16S Ribosomal RNA Gene PCR and Sequencing of Normally Sterile Body Fluids and Tissues in Pediatric Patients

Abstract Background 16S ribosomal RNA (rRNA) gene PCR and sequencing may serve as an adjunctive diagnostic tool in complex infections, identifying bacteria in patients on antibiotics whose cultures may be negative. Data on the optimal clinical settings for utilizing this type of testing are limited. This study reviews a single center's 16S rRNA PCR/sequencing experience in children to identify clinical syndromes and optimize specimen choice for higher yield, leading to testing of appropriate patients. Methods A retrospective study was performed at Mayo Clinic, Rochester involving children aged 0 to 18 years whose normally sterile tissue or fluid samples underwent 16S rRNA gene PCR/sequencing. The assay involved an up-front real-time PCR assay, reported as negative or submitted to Sanger or next-generation sequencing depending on Ct values. Data was collected on patient characteristics and results of 16S rRNA gene PCR/sequencing and conventional tests. Impact on clinical decision-making was assessed as to whether the advanced molecular diagnostic changed antimicrobial therapy. Results A total of 162 tests were performed on 124 patients, including 47% females (58/124) with a median age of 9.6 (range, 2.2-15.0) years. Overall, 33/162 (20%) of tests were positive in 24/124 (19%) patients. 58% of positive tests (19/33) were from samples with negative bacterial cultures. Cerebrospinal fluid was the most common specimen tested (n=38; 31%). Positive results were more likely from fluid compared to tissue samples (OR [95% CI]: 3.1 [1.3, 7.1], p=.007; OR [95% CI]: 0.3 [0.1, 0.8], p=.007, respectively). Testing was positive in 5/10 (50%) pleural fluids tested, a higher positivity rate than any other specimen type (OR [95% CI]: 5 [1.3, 19.0], p=.011). No significant changes in antibiotics were made within 24 hours of reporting positive 16S rRNA gene PCR/sequencing results. Conclusion This study highlights the importance of selecting appropriate sample types for 16S rRNA gene PCR/sequencing in pediatric patients. The assay is most likely to yield positive results in children with pleural effusion and in other fluid samples such as subdural and synovial fluid. Further implementation science research is needed to achieve impact on clinical practice. Disclosures Robin Patel, MD, a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, a: See above|MicuRx Pharmaceuticals and BIOFIRE: Grant/Research Support|PhAST, Day Zero Diagnostics, Abbott Laboratories, Sysmex, DEEPULL DIAGNOSTICS, S.L., Netflix, Oxford Nanopore Technologies and CARB-X: Advisor/Consultant|Up-to-Date and the Infectious Diseases Board Review Course.: Honoraria

P-1542. Determining Pseudomonas aeruginosa antibiotic resistance by leveraging methylation risk scores

Abstract Background The increasing prevalence of antibiotic-resistant bacteria poses a significant threat to global health, necessitating innovative approaches to predict and manage resistance. Traditional methods for detecting antibiotic resistance primarily rely on phenotypic assays or short-read sequencing techniques, which often overlook the intricate epigenetic modifications that can influence bacterial behavior and resistance mechanisms. One such modification, DNA methylation, has emerged as a critical regulator in bacterial gene expression and pathogenicity. The emergence of long-read sequencing technologies offers a unique opportunity to comprehensively map methylation patterns across bacterial genomes, potentially unveiling novel insights into the mechanisms underlying antibiotic resistance. Methods We systematically sequenced 133 Pseudomonas aeruginosa bacterial isolates using Oxford nanopore technology and profiled their methylation characteristics. Results We detected 3.38 million common methylation sites (average methylation larger than 1%, occurred in more than 10% samples). By applying methylation association analysis, we discovered 10 methylated sites that are statistically associated with resistance to 12 antibiotics. Based on these results, we developed LASSO regression models using novel weighted methylation risk scores. We benchmarked MRSs using cross validation and observed MRS prediction models have high prediction performance for phenotypic resistance to 9 antibiotics across multiple drug classes. Conclusion In all, this work demonstrated that long-read derived methylation can serve as a powerful predictor of antibiotic resistance, potentially transforming the field of microbial resistance research. Disclosures David E. Greenberg, MD, Jannsen: DSMB member|Sarepta Therapeutics: Advisor/Consultant|Shionogi: Grant/Research Support

P-647. Comparative efficacy of antibiotic regimens against Ureaplasma species with varying antibiotic resistance profiles in a mouse model of lung infection

Abstract Background Lung transplant recipients (LTRs) can experience hyperammonemia syndrome (HS) correlated with lung infection by ammonia-producing Ureaplasma species. HS in LTRs can be managed by Ureaplasma-directed antibiotic therapy; however, Ureaplasma species lack a cell wall, limiting treatment options. Precise guidelines for Ureaplasma-directed antibiotic therapy in LTRs is lacking, and antibiotic resistance may complicate treatment. Here, levofloxacin (LEV), azithromycin (AZM), and doxycycline (DOX) were tested against isolates of U. urealyticum and U. parvum with varying antibiotic resistance profiles, and efficacies compared.Fig 1.Antibiotic prophylaxis of murine infection by antibiotic resistant Ureaplasma isolates. Mice were prophylaxed with levofloxacin (LEV; 100 mg/kg SQ), azithromycin (AZM; 100 mg/kg PO), or doxycycline (DOX; 100 mg/kg IP) 12 hours prior to infection with isolates of Ureaplasma parvum or Ureaplasma urealyticum resistant to one or none of the antibiotics. 18 hours after infection, mice were sacrificed and lungs harvested, with resulting Ureaplasma loads quantified (color changing units: CCU). Control animals (CTRL) were given no antibiotics. Significance between groups was determined via Kruskal-Wallis tests with Dunn’s multiple comparison tests. * p ≤0.05, **p ≤0.01, ***p ≤0.001. Methods Mice were immunosuppressed using a combination of tacrolimus (1.2 mg/kg daily), mycophenolate mofetil (40 mg/kg daily), and methylprednisolone (20 mg/kg weekly) to mimic immunosuppression given to LTRs. Prophylactic antibiotics were given 12 hours prior to infection, including either LEV (100 mg/kg subcutaneously), AZM (100 mg/kg orally), or DOX (100 mg/kg intraperitoneally). Mice were then infected with Ureaplasma isolates resistant to one or none of the antibiotics, including U. parvum IDRL-10774 (fully susceptible), U parvum IDRL-10774R (IDLR-10774 with evolved AZM resistance; serial passage in sub-MIC AZM), U. parvum IDRL-11160 (LEV resistant), and U. urealyticum ATCC-33175 (DOX resistant). Mice were euthanized 18 hours post-infection, and lung bacterial loads (color changing units; CCU/gram) quantified. Results The effect of various antibiotic treatments against mouse lung infections with the four Ureaplasma isolates is displayed in Fig 1. Infection with IDRL-10774 (fully susceptible) and IDRL-11160 (LEV resistant) was only prevented by doxycycline (p=0.09 and p=0.01, respectively). For IDRL-10774, insignificant mean reductions (possibly due to a high standard deviation in the controls) were observed for both LEV (-106.9 CCU/g) and AZM (-105.25 CCU/g). IDRL-10774R (evolved AZM resistance) showed a complete loss of susceptibility to AZM compared to unevolved IDRL-10774. ATCC-33175 (DOX resistant) was not reduced by any antibiotics tested. Conclusion DOX was the most effective antibiotic tested, preventing lung infection by all isolates, except a DOX resistant isolate. Disclosures Robin Patel, MD, a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, a: See above|MicuRx Pharmaceuticals and BIOFIRE: Grant/Research Support|PhAST, Day Zero Diagnostics, Abbott Laboratories, Sysmex, DEEPULL DIAGNOSTICS, S.L., Netflix, Oxford Nanopore Technologies and CARB-X: Advisor/Consultant|Up-to-Date and the Infectious Diseases Board Review Course.: Honoraria

P-2225. Interactions between phage and host bacteria in immunized rabbit serum

Abstract Background Phage therapy is being evaluated to treat bacterial infections. Host-related factors that might abrogate phage efficacy remain incompletely characterized. Phage aggregation has been hypothesized to protect phages in harsh environments. Herein, effects of immunized rabbit sera on phage aggregation were assessed. Methods Three New Zealand rabbits were immunized weekly for 3 weeks by intramuscular injection of phage K. Serum samples were collected weekly at times 0, 7, 14, 21 and 28. Development of an antibody response was confirmed by ELISA. Phage K was exposed to immunized serum with or without heat-inactivated host bacterium (Staphylococcus aureus ATCC 19685) as follows. 45 µl of phage K (1010±1 plaque forming units/mL [pfu/ml]) was mixed with 5 µl immunized serum diluted 1:1000 with or without heat-inactivated bacterial host in phosphate buffered saline (PBS). After incubation, exposed phage was visualized using transmission electron microscopy (TEM, JEOL) at 80kV. Results Phage K immunization elicited a strong IgG response. Exposure to immunized serum led to a decrease in viable phage over time, abrogated by adding heat-inactivated bacteria (Fig 1). TEM imaging showed phage clustering with exposure to immunized serum (Fig 2A); clusters appeared disorganized with concomitant exposure to heat-inactivated host bacteria (Fig 2B). Exposure of phage to heat-inactivated bacteria without serum yielded evenly distributed phage, with minimal clustering (Fig 2C). Conclusion Phage K exposure elicited a neutralizing immune response associated with decreased phage survival in immunized serum, prolonged by adding heat-inactivated host bacteria. TEM imaging showed phage K clustering in different ways depending on the microenvironment encountered. Biological relevance and mechanistic underpinnings of these phenomena need further characterization. Disclosures Robin Patel, MD, a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, a: See above|MicuRx Pharmaceuticals and BIOFIRE: Grant/Research Support|PhAST, Day Zero Diagnostics, Abbott Laboratories, Sysmex, DEEPULL DIAGNOSTICS, S.L., Netflix, Oxford Nanopore Technologies and CARB-X: Advisor/Consultant|Up-to-Date and the Infectious Diseases Board Review Course.: Honoraria

P-1829. Genomic Characterization of Clinically Significant Isolates and Its Effects on Clinical Outcomes, 2022 to 2024

Abstract Background Antimicrobial resistance has evolved into a complex global issue involving many clinically relevant organisms. Among these pathogens, carbapenem-resistant organisms (CROs) are of particular concern due to their limited treatment options and high mortality rates. In collaboration with Solu, whole-genome sequencing (WGS) was performed on clinical isolates recovered from our patient population to gain a better insight into resistance mechanisms present and their direct effect on clinical outcomes. Methods For genomic characterization (WGS), a total of 109 carbapenem resistant isolates across three clinically relevant bacterial groups (Enterobacterales, Pseudomonas aeruginosa and Acinetobacter baumannii complex) were sequenced. Solu utilized a hybrid assembly approach utilizing both long reads generated with Oxford Nanopore Technologies (ONT) complemented by Illumina short reads for the reconstruction of bacterial genomes. Results Multilocus sequence typing (MLST) revealed genetic diversity among all three groups of bacterial isolates. Among members of the family Enterobacterales, there were eight distinct sequence types: ST-131, ST-1431, ST-167, ST-2155, ST-361, ST-410, ST-685 and ST-405. A. baumannii complex strains mostly comprised of ST-2 and ST-1022. The presence of numerous sequence types was observed with the P. aeruginosa isolates, highlighting the biocomplexity within our patient population. Furthermore, genomic analysis of these isolates disclosed a broad range of antimicrobial resistance genes that span across several classes of antibiotics. Isolates across all genera harbored plasmid-mediated carbapenemase genes bla-NDM-5, bla-NDM1, bla-OXA-48 and bla-OXA23. Interestingly, cefiderocol resistance was primarily associated with the Escherichia coli ST-405 strain containing AMR gene bla-NDM5. Patients associated with a carbapenemase-producing strain were observed to have higher mortality rates (12.8%) and longer length of hospital stay (25.6%). Conclusion By having a comprehensive insight into the genomic composition of isolates that make up our patient population, we can provide a more targeted medical treatment approach and investigate and better prevent transmission events. Disclosures All Authors: No reported disclosures

Sequali: Efficient and Comprehensive Quality Control of Short- and Long-Read Sequencing Data

Abstract Motivation Quality control of sequencing data is the first step in many sequencing workflows. Short- and long-read sequencing technologies have many commonalities with regards to quality control. Several quality control programs exist, however none possess a feature set that is adequate for both technologies. Quality Control programs aimed at Oxford Nanopore Technologies sequencing lack vital features such as adapter searching, overrepresented sequence analysis and duplication analysis. Results Sequali was developed to provide sequencing quality control for both short- and long-read sequencing technologies. It features adapter search, overrepresented sequence analysis and duplication analysis and supports FASTQ and uBAM inputs. It is significantly faster than comparable sequencing quality control programs for both short- and long-read sequencing technologies. Availability and Implementation Sequali is an open source Python application using C extensions and is freely available under the AGPL-3.0 license at https://github.com/rhpvorderman/sequali. The source code for each release is archived at zenodo: https://zenodo.org/doi/10.5281/zenodo.10822485.

A One Health approach for the genomic characterization of antibiotic-resistant Campylobacter isolates using Nanopore whole-genome sequencing

In response to the growing threat posed by the spread of antimicrobial resistance in zoonotic Campylobacter, a One Health approach was used to examine the genomic diversity, phylogenomic relationships, and the distribution of genetic determinants of resistance (GDR) in C. jejuni and C. coli isolates from humans, animals (ruminants, swine, and chickens), and avian food products collected during a regionally (Basque Country, Spain) and temporally (mostly 2021–2022) restricted sampling. Eighty-three C. jejuni and seventy-one C. coli isolates, most exhibiting resistance to ciprofloxacin and/or erythromycin, were whole-genome sequenced using Oxford Nanopore Technologies long-fragment sequencing (ONT). Multilocus sequence typing (MLST) analysis identified a high genomic diversity among isolates. Phylogenomic analysis showed that clustering based on the core genome was aligned with MLST profiles, regardless of the sample source. In contrast, accessory genome content sometimes discriminated isolates within the same STs and occasionally differentiated isolates from different sources. The majority of the identified GDRs were present in isolates from different sources, and a good correlation was observed between GDR distribution and phenotypic susceptibility profiles (based on minimum inhibitory concentrations interpreted according to the EUCAST epidemiological cutoff values). Genotypic resistance profiles were independent of genotypes, indicating no apparent association between resistance and phylogenetic origin. This study demonstrates that ONT sequencing is a powerful tool for molecular surveillance of bacterial pathogens in the One Health framework.