bluuebunny/crossref_metadata_2025 huggingface dataset:
Chromosome length genome assembly of the stone marten (Martes foina, Mustelidae): a new view on one of the cornerstones in carnivore cytogenetics
Authors: Tomarovsky Andrey , Khan Ruqayya , Dudchenko Olga , Totikov Azamat , Serdyukova Natalia A , Weisz David , Vorobieva Nadejda V , Bulyonkova Tatiana , Abramov Alexei V , Nie Wenhui , Wang Jinhuan , Romanenko Svetlana A , Proskuryakova Anastasiya A , Cherkasov Nikolay , Ferguson-Smith Malcolm A , Yang Fengtang , Balanovskaya Elena , Gilbert M Thomas P , Graphodatsky Alexander S , Aiden Erez Lieberman , Powell Roger , Koepfli Klaus-Peter , Perelman Polina L , Kliver Sergei
Published: January 2025

The stone marten (Martes foina) is an important species for cytogenetic studies in the order Carnivora. ZooFISH probes created from its chromosomes provided a strong and clean signal in chromosome painting experiments and were valuable for studying the evolution of carnivoran genome architecture. The research revealed that the stone marten chromosome set is similar to the presumed ancestral karyotype of the Carnivora, which added an additional value for the species. Using linked-read and Hi-C sequencing, we generated a chromosome-length genome assembly of a male stone marten (Gansu province, China) from a primary cell line. The stone marten assembly had a length of 2.42 Gbp, scaffold N50 of 144 Mbp, and a 96.2% BUSCO completeness score. We identified 19 chromosomal scaffolds (2n=38) and assigned them chromosome ids based on chromosome painting data. Annotation identified 20,087 protein-coding gene models, of which 18,283 were assigned common names. Comparison of the stone marten assembly with the cat, dog, and human genomes revealed several small syntenic blocks absent on the published painting maps. Finally, we assessed the heterozygosity and its distribution over the chromosomes. The detected low heterozygosity level (0.4 hetSNPs/kbp) and the presence of long RoHs require further research and a new evaluation of the conservation status of the stone marten in China. Combined with available carnivoran genomes in large scale synteny analysis, the stone marten genome will highlight new features and events in carnivoran evolution, hidden from cytogenetic approaches.
Tubular retractor-assisted minimally invasive parafascicular approach for dermoid cyst
Authors: Lee Keng Siang , Kalyal Nida , Mthunzi Engelbert , Marchi Francesco , Elhag Ali , Bodi Istvan , Bhangoo Ranjeev , Vergani Francesco , Ashkan Keyoumars , Gullan Richard , Lavrador Jose Pedro
Published: January 2025

Intracranial dermoid cysts are benign lesions that may be diagnosed incidentally or present symptomatically due to mass effect—focal neurological deficits, seizures and/or hydrocephalus—or chemical meningitis secondary to spontaneous rupture. The use of tubular retractors in minimally invasive parafascicular surgery (tsMIPS) has been described extensively as a technique to preserve neurological function whilst safely maximizing the extent of resection. The authors present the first use of the tsMIPS approach for removal of a dermoid cyst in a 68-year-old female who presented with abulia and seizures due to a large Sylvian fissure dermoid cyst. This approach minimized trauma to surrounding cortical–subcortical structures, as supported by connectome analyses, without sacrificing visualization of the operative field. Additionally, itavoided manipulation of the lenticulostriate arteries attached to the walls of the dermoid cyst. The use of an endoscope ensured complete drainage of the cyst components and therefore the effectiveness of the procedure.
Phototropin 2 mediates daily cold priming to promote light responses in Arabidopsis
Authors: Noguchi Minoru , Keino Issei , Takahashi Hitomi , Yamauchi Shota , Fujisawa Mami , Haga Ken , Sakai Tatsuya , Takemiya Atsushi , Kodama Yutaka
Published: January 2025

Organisms adapt to predictable environmental changes via a biological mechanism called priming. Phototropin (phot) is a plant-specific blue light photoreceptor that mediates daily light-induced responses, such as chloroplast relocation, stomatal opening, and phototropism, to optimize photosynthesis. Phot also functions as a thermosensor for chloroplast relocation that may sense daily temperature decreases at night, thereby modulating light-induced responses at dawn; however, this hypothesis has not yet been fully explored. Here, we reveal that phot mediates daily cold priming to promote stomatal opening and phototropism in Arabidopsis (Arabidopsis thaliana) under dawn-mimicking conditions. A cold pretreatment in the dark enhanced subsequent blue light–induced stomatal opening and phototropism at normal temperatures, suggesting that daily cold priming is involved in these physiological responses. Arabidopsis has two phot proteins (phot1 and phot2), and we show that phot2 clearly mediates the cold priming of stomatal opening and phototropism. Cold priming appears to be based on phot-mediated thermosensing just before dawn, which plants use to optimize their light-induced responses in anticipation of dawn.
Intermittent fasting inhibits platelet activation and thrombosis through the intestinal metabolite indole-3-propionate
Authors: Qi Zhiyong , Zhou Luning , Dai Shimo , Zhang Peng , Zhong Haoxuan , Zhou Wenxuan , Zhao Xin , Xu Huajie , Zhao Gang , Wu Hongyi , Ge Junbo
Published: January 2025

Platelet hyperreactivity contributes significantly to thrombosis in acute myocardial infarction and stroke. While antiplatelet drugs are used, residual ischemic risk remains. Intermittent fasting (IF), a dietary pattern characterized by alternating periods of eating and fasting, has shown cardiovascular benefits, but its effect on platelet activation is unclear. This study demonstrates that IF inhibits platelet activation and thrombosis in both patients with coronary artery disease and apolipoprotein E (ApoE) knockout (ApoE−/−) mice, by enhancing intestinal flora production of indole-3-propionic acid (IPA). Mechanistically, elevated IPA in plasma directly attenuates platelet activation by binding to the platelet pregnane X receptor (PXR) and suppressing downstream signaling pathways, including Src/Lyn/Syk and LAT/PLCγ/PKC/Ca2+. Importantly, IF alleviates myocardial and cerebral ischemia-reperfusion injury in ApoE−/− mice. These findings suggest that IF mitigates platelet activation and thrombosis risk in coronary atherosclerosis by enhancing intestinal flora production of IPA, which subsequently activates the platelet PXR-related signaling pathway.
A practical approach to investigating nosocomial acquisition of Aspergillus
Authors: Meijer Eelco F J , Marek Aleksandra , Ramage Gordon , Chowdhary Anuradha , Bagrade Linda , Voss Andreas , Bal Abhijit M
Published: January 2025

Invasive mould disease (IMD) has a high mortality in immunosuppressed patients. Invasive aspergillosis (IA) is the most common IMD. A guideline for preventing IA has been published jointly by the Centers for Disease Control and Prevention, the Infectious Disease Society of America, and the American Society of Blood and Marrow Transplantation. Use of high-efficiency particulate air filters, adequate air exchange rates, sealing of patient rooms, and preventing exposure to moulds by nursing patients in areas away from construction sites are recommended by the guideline. However, there is limited information in relation to the actions to be undertaken by infection prevention and control teams in the event of one or more cases of nosocomial aspergillosis. In this review, we describe a systematic approach to aspergillosis by defining possible and probable nosocomial acquisition based on the number of days since hospital admission. We advocate an incremental response to the investigation of nosocomial aspergillosis in patients in protective isolation taking into account the number of cases and the likelihood of nosocomial origin. For single cases of nosocomial IA, we suggest that infection control investigations should focus on case surveillance and walk-through inspection escalating in a stepwise manner to enhanced case surveillance, verification of environmental controls, environmental monitoring, genotyping of clinical and environmental isolates, and review of antifungal prophylaxis for multiple cases and outbreaks. Where applicable, the construction site should be inspected with the aim to reduce the dispersal of conidia. Surveillance systems need to be strengthened to better understand the epidemiology of IA.
Influenza A virus NS2 protein acts on vRNA-resident polymerase to drive the transcription to replication switch
Authors: Zhang Lei , Yang Qiuxian , Shao Yuekun , Ding Shenyang , Guo Jiamei , Gao George F , Deng Tao
Published: January 2025

The heterotrimeric RNA-dependent RNA polymerase (RdRp) of influenza A virus catalyzes viral RNA transcription (vRNA→mRNA) and replication (vRNA→cRNA→vRNA) by adopting different conformations. A switch from transcription to replication occurs at a relatively late stage of infection. We recently reported that the viral NS2 protein, expressed at later stages from a spliced transcript of the NS segment messenger RNA (mRNA), inhibits transcription, promotes replication and plays a key role in the transcription-to-replication switch. In this study, we performed comprehensive functional analyses to elucidate how NS2 promotes viral genome replication. Using a cell-based single-step RNP reconstitution assay, we found that NS2 specifically promotes the first-step vRNA-to-cRNA synthesis. Further investigation revealed that this promotion is tightly associated with the intrinsic properties of the 3′-vRNA promoter. Employing a highly sensitive complementation reporter assay, we demonstrated that NS2 associates more strongly with the vRNA-resident RdRp than the cRNA-resident RdRp. These findings were further validated through in vitro replication analyses. We, therefore, propose that influenza A virus NS2 protein targets vRNA-resident RdRp to drive the transcription-to-replication switch during infection.
Discovery of reversing enzymes for RNA ADP-ribosylation reveals a possible defence module against toxic attack
Authors: Lu Yang , Schuller Marion , Bullen Nathan P , Mikolcevic Petra , Zonjic Iva , Raggiaschi Roberto , Mikoc Andreja , Whitney John C , Ahel Ivan
Published: January 2025

Nucleic acid ADP-ribosylation and its associated enzymes involved in catalysis and hydrolysis are widespread among all kingdoms of life. Yet, its roles in mammalian and bacterial physiology including inter-/intraspecies conflicts are currently underexplored. Recently, several examples of enzymatic systems for RNA ADP-ribosylation have been identified, showing that all major types of RNA species, including messenger RNA, ribosomal RNA, and transfer RNA, can be targeted by ADP-ribosyltransferases (ARTs) which attach ADP-ribose modifications either to nucleobases, the backbone ribose, or phosphate ends. Yet little is known about the reversibility of RNA ADP-ribosylation by ADP-ribosylhydrolases belonging to the macrodomain, ARH, or NADAR superfamilies. Here, we characterize the hydrolytic activity of ADP-ribosylhydrolases on RNA species ADP-ribosylated by mammalian and bacterial ARTs. We demonstrate that NADAR ADP-ribosylhydrolases are the only hydrolase family able to reverse guanosine RNA base ADP-ribosylation while they are inactive on phosphate-end RNA ADP-ribosylation. Furthermore, we reveal that macrodomain-containing PARG enzymes are the only hydrolase type with the ability for specific and efficient reversal of 2′-hydroxyl group RNA ADP-ribosylation catalysed by Pseudomonas aeruginosa effector toxin RhsP2. Moreover, using the RhsP2/bacterial PARG system as an example, we demonstrate that PARG enzymes can act as protective immunity enzymes against antibacterial RNA-targeting ART toxins.
Cancer cell target discovery: comparing laboratory evolution of expanded DNA six-nucleotide alphabets with standard four-nucleotide alphabets
Authors: Shaker Sharpkate , Li Jun , Wan Shuo , Xuan Hong , Long Jinchen , Cao Haiyan , Wei Tongxuan , Liu Qinguo , Xu Da , Benner Steven A , Zhang Liqin
Published: January 2025

Anthropogenic evolvable genetic information systems (AEGIS) are DNA-like molecules that can be copied, support laboratory in vitro evolution (LIVE), and evolve to give AegisBodies, analogs of antibodies. However, unlike DNA aptamers built from four different nucleotides, AegisBodies are currently built from six different nucleotides. Thus, six-letter AEGIS–LIVE delivers AegisBodies with greater stability in biological mixtures, more folds, and enhanced binding and catalytic power. Unlike DNA however, AEGIS has not benefited from 4 billion years of biological evolution to create AEGIS-specialized enzymes, but only a decade or so of human design. To learn whether AEGIS can nevertheless perform as well as natural DNA as a platform to create functional molecules, we compared two six-letter AegisBodies (LZH5b and LZH8) with a single standard four-letter aptamer, both evolved to bind specific cancer cells with ∼10 cycles of LIVE. Both evolved ∼50 nM affinities. Both discovered proteins on their cancer cell surfaces thought to function only inside of cells. Both can be internalized. Internalizing of LZH5b attached to an AEGIS nanotrain brings attached drugs into the cell. These data show that AEGIS–LIVE can do what four-letter LIVE can do at its limits of performance after 4 billion years of evolution of DNA-specialized enzymes, and better by a few metrics. As synthetic biologists continue to improve enzymology and analytical chemistry to support AEGIS-LIVE, this technology shoud prove increasingly useful as a tool, especially in cancer research.
An AT-hook transcription factor promotes transcription of histone, spliced-leader, and piRNA clusters
Authors: Wang Yi-Hui , Hertz Hannah L , Pastore Benjamin , Tang Wen
Published: January 2025

In all three domains of life, genes with related functions can be organized into specific genomic regions known as gene clusters. In eukaryotes, histone, piRNA (Piwi-interacting RNA), and rDNA (ribosomal DNA) clusters are among the most notable clusters which play fundamental roles in chromatin formation, genome integrity, and translation, respectively. These clusters have long been thought to be regulated by distinct transcriptional mechanisms. In this study, using Caenorhabditis elegans as a model system we identify ATTF-6, a member of the AT-hook family, as a key factor for the expression of histone, piRNA, and 5S rDNA-SL1 (spliced leader 1) clusters. ATTF-6 is essential for C. elegans viability. It forms distinct nuclear foci at both piRNA and 5S rDNA-SL1 clusters. Loss of ATTF-6 leads to a depletion of histone mRNAs, SL1 transcripts, and piRNAs. Additionally, we demonstrate that ATTF-6 is required for the recruitment of USTC (Upstream Sequence Transcription Complex) to piRNA clusters, which is necessary for piRNA production. Collectively, our findings reveal a unifying role for an AT-hook transcription factor in promoting the expression of fundamental gene clusters.
Combining CRISPR activation and interference capabilities using dCas9 and G-quadruplex structures
Authors: Kabir Mohammad Lutful , Kodikara Sineth G , Hoque Mohammed Enamul , Shiekh Sajad , Alfehaid Janan , Basu Soumitra , Balci Hamza
Published: January 2025

We demonstrate that both Clustered regularly interspaced short palindromic repeats (CRISPR) interference and CRISPR activation can be achieved at RNA and protein levels by targeting the vicinity of a putative G-quadruplex (GQ)-forming sequence (PQS) in the c-Myc promoter with nuclease-dead Cas9 (dCas9). The achieved suppression and activation in Burkitt’s Lymphoma cell line and in in vitro studies are at or beyond those reported with alternative approaches. When the template strand (contains the PQS) was targeted with CRISPR–dCas9, the GQ was destabilized and c-Myc mRNA and protein levels increased by 2.1- and 1.6-fold, respectively, compared to controls in the absence of CRISPR–dCas9. Targeting individual sites in the nontemplate strand (NTS) with CRISPR–dCas9 reduced both the c-Myc mRNA and protein levels (by 1.8- and 2.5-fold, respectively), while targeting two sites simultaneously further suppressed both the mRNA (by 3.6-fold) and protein (by 9.8-fold) levels. These were consistent with cell viability assays when single or dual sites in the NTS were targeted (1.7- and 4.7-fold reduction in viability, respectively). We also report extensive in vitro biophysical studies which are in quantitative agreement with these cellular studies and provide important mechanistic details about how the transcription is modulated via the interactions of RNA polymerase, CRISPR–dCas9, and the GQ.
376. 7 versus 14 days of Antibiotic Treatment for Patients with Bloodstream Infections
Authors: Daneman Nick , Fowler Rob
Published: January 2025

Background

Bloodstream infections are associated with substantial morbidity and mortality. Early, appropriate antibiotic therapy is important, but optimal duration of treatment is uncertain.

Methods

In a multicenter, non-inferiority trial, we randomly assigned hospitalized (ward and intensive care unit [ICU]) patients with bloodstream infection to receive 7- versus 14-day antibiotic treatment.

Antibiotic selection, dosing and route were at the discretion of the treating team. We excluded patients with severe immune-suppression, foci requiring prolonged treatment, single cultures with potential contaminants, or cultures yielding Staphylococcus aureus. The primary outcome was 90-day mortality, with a 4% absolute non-inferiority margin.

Results

Across 74 hospitals in 7 countries, 3608 patients were randomized and included in the intention-to-treat analysis (1,814 to 7-day and 1,794 to 14-day antibiotic treatment). At enrolment, 55% of patients were in the ICU and 45% on hospital wards. Infections were community-onset (75.4%), hospital-acquired (13.4%) and ICU-acquired (11.2%). Bacteremia sources were most commonly from the urinary tract (42.2%), abdomen (18.8%), lung (13.0%), vascular catheters (6.3%), and skin or soft tissue (5.2%). The primary outcome of 90-day mortality occurred in 261 (14.5%) patients receiving 7-day and in 286 (16.1%) receiving 14-day treatment (absolute difference -1.6% [95.7% confidence interval -4.0 to 0.8]), demonstrating non-inferiority of shorter duration treatment. A per-protocol analysis also demonstrated non-inferiority (-2.0% [95% confidence interval -4.5 to 0.6]). These findings were generally consistent across secondary clinical outcomes, and pre-specified patient, pathogen and syndrome subgroups.

Conclusion

Treating hospitalized patients with bloodstream infection with antibiotics for 7 days is non-inferior to treating for 14 days.

(Funded by the Canadian Institutes of Health Research, Health Research Council of New Zealand, Australian National Medical Research Council, Physicians Services Incorporated Ontario and Ontario Ministry of Health and Long-term Care Innovation Fund; ClinicalTrials.gov NCT03005145)

Disclosures

All Authors: No reported disclosures
160. RSV Pre-F IgG levels in pediatric hematopoietic stem cell transplant (HCT) and leukemia/lymphoma patients
Authors: Murray Alastair , Clark Erica , Chu Helen Y , Englund Janet A
Published: January 2025

Background

Hematopoietic stem cell transplant (HCT) patients are at increased risk of morbidity from RSV infection. Vaccines and monoclonal antibodies directed against the RSV pre-fusion surface protein are now licensed for protection of infants against RSV. Analysis of RSV-specific antibody seroprevalence in pediatric HCT and oncology patients will help identify those who may benefit from receipt of an RSV monoclonal antibody, such as nirsevimab, for protection against severe disease.Table 1.Demographic information by patient cohort

Methods

This prospective study collected deidentified serum samples from pediatric (age 0-24 years) HCT patients (n = 10), pediatric leukemia and lymphoma (LL) patients (without blood transfusion < 60 days) (n = 10) and general pediatric patients without immunocompromising conditions or respiratory illness evaluated in the emergency room (n = 10) in Seattle, WA, USA. Samples were collected at time of transplant between February-April 2024 and concurrently collected from the two other cohorts. Samples were tested for quantitative RSV pre-fusion IgG concentration using an ELISA assay. One LL patient received nirsevimab (excluded from analysis). Values were natural log-transformed before all statistical processes and comparisons were performed by ANOVA testing.Figure 1.RSV Pre-fusion IgG concentration by patient cohort

Results

Mean age was similar among HCT and general pediatrics cohorts (12.2 years versus 12.8) and slightly younger among the LL cohort (8.8) (ANOVA, p = 0.38) (Table 1). Mean log antibody concentration was similar across all three cohorts (BMT: 10.3 AU/mL, LL: 9.9, general pediatric: 10.5), (ANOVA, p = 0.62) (Figure 1). Mean log antibody concentration was also similar by age group (0-5 years: 10.1 AU/mL, 6-12 years: 10.2, 13-24 years: 10.4), (ANOVA, p = 0.33) (Figure 2).Figure 2.RSV Pre-fusion IgG concentration by patient age

Conclusion

RSV pre-fusion IgG concentration was comparable across cohorts of pediatric HCT patients, leukemia/lymphoma and general pediatric patients. Further study enrollment is ongoing to capture changes in antibody level over the course of a respiratory viral season, along with assessment of RSV neutralizing antibody, which may provide a more robust correlate of protection. This information may inform the need for further clinical trial prophylaxis studies, given the vulnerability to RSV disease in these patient populations.

Disclosures

Helen Y. Chu, MD, MPH, Abbvie: Advisor/Consultant|Merck: Advisor/Consultant|Vir: Advisor/Consultant Janet A. Englund, MD, Abbvie: Advisor/Consultant|AstraZeneca: Advisor/Consultant|AstraZeneca: Grant/Research Support|GlaxoSmithKline: Advisor/Consultant|GlaxoSmithKline: Grant/Research Support|Meissa Vaccines: Advisor/Consultant|Merck: Advisor/Consultant|Pfizer: Board Member|Pfizer: Grant/Research Support|Pfizer: Speaker at meeting|SanofiPasteur: Advisor/Consultant|Shinogi: Advisor/Consultant
210. Implementation of a Pharmacist Driven Beta-lactam Therapeutic Drug Monitoring Program with Daily Result Reporting: Initial Experiences and Challenges Faced
Authors: Pan Samantha , Weslander Erin , Fierak Sarah , Galvin Shannon , Rhodes Nathaniel J
Published: January 2025

Background

Beta-lactam (BL) antibiotics are a cornerstone of treatment for patients with serious infections. Individualized BL dosing using therapeutic drug monitoring (TDM) is an emerging approach to address variability in BL exposure that adversely impacts PK/PD; however, challenges can emerge when implementing TDM programs in the real-world. We sought to characterize the implementation of a BL TDM program by describing initial successes and challenges.

Methods

In September 2023, we implemented a front-line pharmacist driven BL TDM clinical protocol (Figure 1) with daily result reporting for the following BLs: cefepime (FEP), meropenem (MEM), and piperacillin-tazobactam (TZP). Patients with FEP, MEM, and TZP plasma TDM data analyzed between September 26th, 2023 and March 31st, 2024 were included. TDM results were interpreted using Bayesian analysis (InsightRX). For each TDM event, we characterized ordering provider specialty, whether or not TDM was performed per protocol, whether or not changes were made in response to TDM results, Bayesian model fitness, treatment indication, culture information, and PK/PD target attainment [including predicted steady state trough concentration (Ctrss) and fT> 1xMIC and fT> 4xMIC].

Results

Eighty-two BL TDM levels were obtained in 47 patients. FEP was most frequently monitored (70.7%). Model fit was good or intermediate in > 95% of cases (Table 1). The most common treatment indications were HAP/VAP (n=12, 25.5%), surgical prophylaxis (n=6, 12.8%), bone/joint (n=6, 12.8%), and CNS infection (n=6, 12.8%) (Table 2). Dose adjustments were made in 34% (n=16) of patients. In 57.4% of patients the level order or dose-adjustment deviated from recommended protocols. Targets of 100% fT> MIC and 100% fT> 4xMIC were achieved in 91.5% and 61.7% of patients, respectively (Table 3). Ctrss was above goal in 21% of patients.

Conclusion

We found that > 90% of patients undergoing BL TDM achieved 100% fT> MIC, whereas nearly 40% failed to achieve 100% fT> 4xMIC at baseline, and > 20% had a Ctrss exceeding safety goals. BL TDM resulted in dose or agent change over 60% of the time, but protocol deviations in dose adjustment were common. The frequency of interventions observed underscores the potential clinical impact of BL TDM on a broader scale when daily reporting is available.

Disclosures

Nathaniel J. Rhodes, PharmD MS, Apothecademy, LLC: Advisor/Consultant
297. Comparative In Vitro Microbiologic Activity of Two Antimicrobial Intravenous Connectors
Authors: Truong Y Lan , Rosenblatt Joel , Gerges Bahgat Z , Jiang Ying , Raad Issam I
Published: January 2025

Background

Intravenous (IV) connectors are ubiquitous access junctions in vascular access circuits. In accessing IV connectors (IVCs) for infusions, they become vulnerable to microbial contamination and colonization. Antimicrobial IVCs are treated with antimicrobial agents to resist microbial colonization. In this in vitro study, we compared the microbiologic efficacy of IVCs treated with silver and with a novel coating of Minocycline (M), Rifampin (R) and Chlorhexidine (C).

MRC vs Silver Antimicrobial IV Connectors: 7-Day Microbiologic Challenge Test

Colonization of MRSA, P. aeruginosa, and C. albicans on silver and MRC IVCs following 7 days of elution. Non-antimicrobial IVCs were used as positive controls. Data is presented as the median CFU/connector from six replicates; bars indicate the range.

Methods

M, R, and C were spray coated onto IVCs in sequential laminate layers to produce MRC IVCs. Commercially available silver IVCs were purchased (Antimicrobial Microclave Connector, ICU Medical Inc., San Clemente, CA). MRC and silver IVCs were immersed separately in tubes filled with 50% serum + 50% saline to simulate elution of the coatings. After 7 days elution (typical interval of use prior to replacement of IV connectors), eluted connectors were exposed to challenge inocula (5x105 CFU/mL) of key CLABSI clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant Pseudomonas aeruginosa (PA), and Candida albicans (CA) for 24 hours at 37C. The number of viable colonizing microbes (CFU/connector) were enumerated by sonication, serial dilution, plating, and counting. Non-coated IVCs were positive controls.

Log10 Reduction of MRC and Silver IV Connectors vs Positive Control

Log10 reduction of the median number of CFU/connector recovered from six replicates following colonization of MRSA, P. aeruginosa, and C. albicans to silver IVCs and MRC IVCs.

Results

Figure 1 presents the median number of CFU/connector with range bars indicating the highest and lowest number of viable colonies recovered from six replicates after 7 days of elution and following 24-hour microbial challenges with MRSA, PA, and CA. Table 1 shows the median log reductions between positive control and coated connectors with p-values comparing MRC and silver IVCs calculated by Wilcoxon rank sum test.

Conclusion

The absence of microbial colonization of the MRC IVCs demonstrates the efficacy and durability of the novel MRC coating. The silver IVC was unable to fully eradicate biofilms of any of the tested pathogens. MRC IVCs were superior to silver IVCs (p< 0.05) for all pathogens tested. MRC-coated IVCs merit further testing in vitro and in vivo for their potential to prevent CLABSI.

Disclosures

All Authors: No reported disclosures
300. Clinical Experience with 16S Ribosomal RNA Gene PCR and Sequencing of Normally Sterile Body Fluids and Tissues in Pediatric Patients
Authors: Li Guyu , Reis Christopher , Kruc Rebecca M , Streck Nicholas , Ristagno Elizabeth H , Zhang Ziyuan , Wolf Matthew , Gaensbauer James , Patel Robin
Published: January 2025

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
306. Patient-Derived Airway Organoids: a Pre-clinical Platform to Model RSV Infection
Authors: Merenda Alessandra , Ehsani Nilofar , Gkogkou Foteini , Pott Johanna , Bezhaeva Taya , Vries Robert G J , Boj Sylvia F
Published: January 2025

Background

HUB’s patient-derived organoids (PDOs) are novel “mini-organs in a dish” derived from adult epithelial stem cells which form 3D structures and resemble the architecture and physiology of the tissue of origin. Airway PDOs represent a valuable model for investigating the pathogenesis of respiratory infections and testing strategies to prevent or treat such diseases. Because in vivo pathogens attack the luminal surface of the epithelium, HUB has established monolayers from lung PDOs, where the luminal side is accessible for mimicking host-pathogen interactions.

Viruses such as the Respiratory Syncytial Virus (RSV) are associated with severe respiratory illnesses, especially in children and older adults. RSV uses the fusion protein, F protein, which can interact with the intercellular adhesion molecule-1 (ICAM-1) to facilitate cell entry, rendering both molecules appealing targets for inhibiting RSV infection.

Methods

This study assessed the effect of Rilematovir, an RSV antiviral agent that inhibits the viral F protein and prevents cell fusion in RSV-infected PDOs. To this end, airway PDO-derived monolayers were pre-treated with different concentrations of the inhibitor before infection with RSV. Transepithelial electrical resistance (TEER) and monolayer integrity were monitored daily, and the viral titre was quantified by real-time quantitative PCR (RT-qPCR) at different time points post-infection (PI). The production of IP-10 and CXCL2, two inflammatory cytokines released upon infection, was also measured 7 days PI.

Results

Our data revealed that when no inhibitor treatment was applied, the viral titre increased gradually, indicating that RSV could infect and propagate in airway PDO monolayers. Notably, monolayers treated with F protein inhibitors showed a significant decrease in viral titre. This viral titre decrease was accompanied by a total reduction of IP-10 and CXCL2, suggesting a potential role for F-protein inhibition in modulating RSV infection.

Conclusion

Overall, this study confirms that airway PDO-derived monolayers are innovative models to study viral infections and investigate potential targets to prevent or treat such infections. These findings could potentially lead to significant advancement in the field of respiratory infections.

Disclosures

All Authors: No reported disclosures
P-830. Comparison of Oral Antibiotic Use and Hospital Readmission Among People Who Use Drugs with Staphylococcus aureus Bacteremia and Before Medically Advised Discharge During Two Time Periods
Authors: Anam Karim Farzana , Sikka Monica K , Streifel Amber C , Strnad Luke , Sukerman Ellie
Published: January 2025

Background

Recent studies suggest the benefit to salvage oral (PO) antibiotics to support people who use drugs (PWUD) with serious bacterial infections who leave before medically advised (BMA) prior to completing antibiotics. We compared the use of PO antibiotics in PWUD with S. aureus bacteremia (SAB) discharged BMA before versus after the implementation of a multidisciplinary discharge planning conference for PWUD requiring long-term antibiotics and publication of recent literature suggesting the benefit of PO antibiotics for patients leaving BMA.

Methods

We performed a retrospective chart review of PWUD with SAB admitted to a 500-bed teaching hospital over two time periods: 1/1/16 to 12/31/17 (group A) and 7/1/21 to 7/31/23 (group B). We compared 30 and 90-day readmission, PO and IV antibiotic recommendations, prescriptions, and percent of prescriptions dispensed.

Results

There were 21 patients in group A and 20 in group B. Univariable analysis showed no significant difference in the groups (Table 1). The incidence of 30 and 90-day readmission was similar (48% vs 50%, p=0.65) and (57% vs 65%, p=0.85), respectively. Long-acting antibiotics were administered on BMA discharge in 1 patient in group A and 8 in group B. PO antibiotic/s were prescribed on BMA discharge for 33% in group A and 50% in group B. While no patients in Group A filled their prescriptions, 35% in Group B did. When incorporating PO treatment that was dispensed and long-acting antibiotics administered, only 5% (1/21) in group A received treatment on BMA discharge compared to 75% (15/20) in group B.

Conclusion

There was an improvement in providing recommendations and prescriptions for PO antibiotics as well as long-acting injectable antibiotics to provide treatment in situations of BMA discharge. These results suggest an impact of the publication of recent literature and our multidisciplinary discharge planning conference but still highlight room for improvement in recommending and prescribing PO antibiotics for PWUD with SAB who leave the hospital BMA. The lack of benefit in readmissions is likely due to the small sample size and limited duration of follow-up.

Disclosures

Monica K. Sikka, MD, F2G: Grant/Research Support
P-836. Non-Beta Lactam Agents for Definitive Treatment of Ampicillin-Susceptible Enterococcus Bacteremia: A Single Center Experience
Authors: Kang HeeEun , khan Asif , Kim Justin J , Martin Isabella W , Zuckerman Richard A
Published: January 2025

Background

Enterococcus bacteremia (EB) is a serious infection with high morbidity and mortality. While anti-enterococcal beta-lactams (BL) remain the mainstay of therapy against ampicillin-susceptible (AS) EB, non-beta-lactam (NBL) antimicrobial agents are also used to treat ASEB. Few studies evaluate NBL use for definitive therapy of ASEB.

CONSORT flow diagram of patients included in study.

Methods

A single-center retrospective study identified all ASEB episodes between 1/1/2016-12/31/2021 (Figure 1). Patient, microbiological, infection, treatment and outcomes were compared between those who received NBL versus BL for ASEB. Multivariable logistic regression analysis was used to determine factors associated with NBL use.

Baseline characteristics of patients treated with non-beta-lactam vs beta-lactam for definitive therapy for ampicillin-susceptible Enterococcus bacteremia.

Results

158 episodes of ASEB in 153 patients were included (Table 1). 43 episodes (27%) were treated with NBL for definitive therapy. Factors associated with NBL therapy were younger age (58 vs 66 years old, p=0.02), reported history of any penicillin allergy (42% vs 9%, p< 0.01) and serious penicillin allergy (14% vs 1%, p< 0.01), history of cancer (37% vs 17%, p=0.01), end-stage renal disease (ESRD; 23% vs 3%, p< 0.01), unknown source of bacteremia (24% vs 8%, p< 0.01), polymicrobial bacteremia (40% vs 16%, p< 0.01), lack of metastatic foci of infection (12% vs 31%, p=0.02), and lack of endocarditis (7 vs 23%, p=0.02). Combination therapy was used in 23% of those treated with BL therapy compared to no patients receiving NBL therapy (p< 0.01).

For NBL vs BL therapy, there was no difference between all-cause 30-day mortality, all-cause 90-day mortality, or 30-day relapse rate.

In a multivariable logistic regression model (Table 2), NBL therapy was more likely in those with: younger age (AOR 0.95, p=0.001), any penicillin allergy (AOR 5.76, p=0.001), history of cancer (AOR 5.23, p=0.001), ESRD (AOR 11.70, p=0), and polymicrobial bacteremia (AOR 4.20, p=0.001).

Factors associated with use of non-beta-lactam antibiotic for definitive therapy of ampicillin-susceptible Enterococcus bacteremia: multivariable analysis.

Conclusion

NBL was used as definitive treatment in 27% of ASEB. Penicillin allergy, access and dosing for patients on hemodialysis, younger host, and polymicrobial infection are factors associated with NBL use. This real-life experience suggests NBL can be successfully used to treat non-severe ASEB. Further studies are needed to determine the efficacy and stewardship implications of NBL use for ASEB.

Disclosures

All Authors: No reported disclosures
P-871. Outcome of Ceftriaxone resistant, Escherichia-coli and Klebsiella spp. bacteremia comparing Carbapenem and Beta-lactam/Beta-lactamase inhibitors in a public sector hospital from Pakistan
Authors: Samar Rohama , Rani Beena , Babar Zaheer Udin , Nasim Asma , Dodani Sunil
Published: January 2025

Background

Carbapenem are recommended for the treatment of Ceftriaxone (CRO) resistant Enterobacterales, however, there are concerns of cost and resistance. Our aim is to compare the outcome of CRO resistant E-coli and Klebsiella bacteremia between Carbapenem and Beta-lactam/beta-lactamase inhibitors (BL/BLI).

Methods

A prospective cohort study conducted from October 2021 to June 2022. All adult patients with E coli or Klebsiella spp. bacteremia, CRO resistant and sensitive to both BL/BLI and Carbapenem were included. The patients were divided into BL/BLI and Carbapenem groups. Demographics, clinical features, comorbidities, laboratory parameters and intensive care unit stay were compared. Outcomes were bacteriological clearance, clinical success and all-cause mortality at day 14 of bacteremia.

Results

A total of 156 patients, 93(59.6%) in BL/BLI and 63(40%) in Carbapenem group were included. There was no difference in co-morbidities, risk factors and severity of disease. The 14 day all-cause mortality was 14.1%. No statistically significant difference was found between BL/BLI and Carbapenem group regarding bacteriological clearance (p=0.27) and mortality (p=0.95). The Carbapenem group had less clinical success rate (69.8% vs 82.8%, p=0.057),however not statistically significant.

Conclusion

BL/BLIs were as effective as Carbapenem in microbiological clearance, clinical success and mortality in CRO resistant E-coli and Klebsiella bacteremia.

Disclosures

All Authors: No reported disclosures
P-873. Efficacy and Safety of Cefadroxil for Oral Transitional Therapy for Staphylococcal and Streptococcal Bloodstream Infections
Authors: Nguyen Stefanie , Minejima Emi
Published: January 2025

Background

Cefadroxil has a longer half-life and reduced clearance allowing for once or twice daily administration, making it an appealing alternative to cephalexin, which requires up to four times daily dosing. There has been increased interest in utilization of oral beta-lactams as oral transitional therapy for bloodstream infections (BSI) due to its favorable safety profile, however, there is currently limited data available evaluating cefadroxil for BSI.

Methods

A retrospective cohort study of adult patients hospitalized with MSSA or Streptococcal BSI from January 2022 to March 2024 and transitioned from IV to oral antibiotics was conducted. Patients were grouped by cefadroxil vs other highly bioavailable antibiotics (linezolid, TMP/SMX, fluoroquinolones) and compared for clinical outcomes of 30-day all-cause mortality, 30-day readmission, and 90-day recurrence.

Results

103 patients were included (cefadroxil 40 patients vs other 63 patients). Overall, 79% were male, 69% were Hispanic, 33% had uncontrolled diabetes, and median CCI was 2. Clinical presentation was similar with median Pitt bacteremia score of 0 in both groups (p=ns). 56% were MSSA BSI, and the most common Strep spp. was Strep pyogenes (15%). The most common source of infection was an intermediate-risk source of infection (78%). Median days of lead in IV antibiotic therapy did not differ between groups (cefadroxil 5 vs other 6, p=0.121). Majority of patients received cefadroxil dose of 1000 mg BID (65%). No differences were observed in 30-day all-cause mortality (cefadroxil 5% vs other 1.6%, p=0.56), 30-day readmission (30% vs 15.9%, p=0.14), or 90-day recurrence (2.5% vs 14.29%, p=0.084). Similar outcomes were seen in sub-analyses comparing cefadroxil dose, MSSA vs Strep spp., and source risk of BSI (p=ns). Adverse effects from oral therapy were reported in 35% of cefadroxil vs 15% in other group (p=0.12); resulting in 0 patients in cefadroxil and 4 patients in the other group changing to alternative therapy.

Conclusion

Cefadroxil had similar clinical outcomes to other highly bioavailable antibiotic therapy for transitional therapy for MSSA and Streptococcal BSI. As cefadroxil can be dosed less frequently compared to certain other oral beta lactams, it may be an attractive option for outpatient therapy.

Disclosures

All Authors: No reported disclosures
P-875. Bacteroides spp. drug resistance in patients with anaerobic bacteremia: a multicentric retrospective observational study
Authors: Kubo Ryotaro , Iwanaga Naoki , Nagaoka Kentaro , Yoshida Masataka , Takeda Kazuaki , Ide Shotaro , Takazono Takahiro , Kosai Kosuke , Morinaga Yoshitomo , Izumikawa Koichi , Yamamoto Yoshihiro , Yanagihara Katsunori , Kohno Shigeru , Mukae Hiroshi
Published: January 2025

Background

Bacteroides spp. are important causative anaerobes in intra-abdominal infections; however, recent reports have shown a trend toward drug resistance in non-Bacteroides fragilis. The present study aimed to evaluate bacteremia due to Bacteroides spp. by performing a multicentric retrospective observational study.

Methods

Obligate anaerobes isolated from blood culture specimens were collected from patients at Nagasaki University Hospital and five core hospitals in Toyama Prefecture from January 2012 to March 2022. Of a total of 528 patients, 102 specimens with B. fragilis and 72 with non-B. fragilis were clinically characterized using Fisher’s exact test and multiple logistic regression analysis. Drug-resistant rates over time were analyzed by the Spearman rank correlation test.

Results

In the non-B. fragilis group, compared to the B. fragilis group, the clindamycin resistance rate (non-B. fragilis group [59.7%] vs. B. fragilis group [38.2%] odds ratio [OR]=2.40 [95% confidence interval [CI]; 1.23–4.43] p=0.0058) and carbapenem resistance rate (non-B. fragilis group [27.8%] vs. B. fragilis group [10.8%] OR=3.18 [95%CI; 1.41–6.78] p=0.0049) was significantly increased. Furthermore, in the non-B. fragilis group, excluding patients who died owing to an underlying disease, a significantly increased 30-d mortality rate (non-B. fragilis group [16.7%] vs. B. fragilis group [5.9%] OR=3.20 [95%CI; 1.15–8.91] p=0.0251) was observed. Moreover, as of risk factors for 30-d mortality in non-B. fragilis bacteremia, SOFA score (adjusted OR=1.30 [95%CI; 1.11–1.57] p=0.0027) and carbapenem resistance (adjusted OR=7.05 [95%CI; 1.54–41.9] p=0.0171) were elucidated. Of note, in the non-B. fragilis group, rather than the B. fragilis group, the carbapenem resistance rate (non-B. fragilis group [r = 0.77, p=0.0141] vs. B. fragilis group [r = 0.17, p=0.6433]) and tazobactam/piperacillin resistance rate (non-B. fragilis group [r = 0.78, p=0.0120] vs. B. fragilis group [r = -0.05, p=0.8988]) have increased over time.

Conclusion

Non-B. fragilis isolated from blood cultures, compared to B. fragilis, exhibited an increasing trend in carbapenem and tazobactam/piperacillin resistance and contributed to 30-d mortality.

Disclosures

Shigeru Kohno, n/a, SHIONOGI & CO., LTD.: Board Member|SHIONOGI & CO., LTD.: Grant/Research Support Hiroshi Mukae, M.D., Ph.D., AstraZeneca: Lecture fees|Gilead Sciences: Lecture fees|GSK: Lecture fees|MSD: Advisor/Consultant|MSD: Lecture fees|Pfizer: Lecture fees|Shionogi & Co., Ltd.: Advisor/Consultant|Shionogi & Co., Ltd.: Grant/Research Support|Shionogi & Co., Ltd.: Lecture fees
P-878. The Impact of Inappropriate Empirical Antibiotic Choices on Hemodynamics in Multidrug-Resistant Bacterial Sepsis
Authors: Pakapanich Sarunya , Panichote Anupol , Meesing Atibordee
Published: January 2025

Background

Empirical antibiotics are crucial in managing sepsis, especially in multidrug-resistant (MDR) bacteria. This study aims to investigate the hemodynamic consequences of administering inappropriate empirical antibiotics to sepsis patients with MDR bacteremia.

Characteristics of the Patients

Methods

This ambispective cohort study (January 1, 2018, to December 31, 2023) focused on adults over 18 with MDR septicemia.

The inappropriate empirical antibiotic was defined as patients who did not receive the first antibiotic active in vitro against the bacteria. The primary outcome was shock control rates within 3 hours after vasopressor use.

Sepsis data and shock control

Results

Our study included 290 patients; 177 (61.0%) received inappropriate empirical antibiotic therapy. Escherichia coli and Klebsiella pneumoniae were the most common pathogens. The median time to antibiotic initiation was longer in the inappropriate group (370 minutes; IQR 139–1135) than in the appropriate group (190 minutes; IQR 82–550). Shock control within 3 hours was achieved by 73.4% in the inappropriate group and 75.2% in the appropriate group, and within 6 hours by 79.7% and 79.6%, respectively. Cox regression showed no significant difference in time to shock control or 28-day mortality due to inappropriate empirical antibiotic (HR 0.82; 95%CI 0.38–1.77 for 3 hours, HR 0.87; 95%CI 0.46–1.64 for 6 hours, and HR 1.25; 95%CI 0.82–1.91 for 28-day mortality), even after adjusting for various confounders. Achieving shock control correlated with lower 28-day mortality (HR 0.17; 95%CI 0.11–0.25 for 3 hours, HR 0.15; 95%CI 0.10–0.21 for 6 hours).

Probability of shock control at 3 hours

Conclusion

The choice of empirical antibiotics administered was not associated with shock control or mortality outcomes.

Disclosures

All Authors: No reported disclosures