Peptidoglycan-Targeted [18F]3,3,3-Trifluoro-d-alanine Tracer for Imaging Bacterial Infection

Imaging is increasingly used to detect and monitor bacterial infection. Both anatomic (X-rays, computed tomography, ultrasound, and MRI) and nuclear medicine ([111In]-WBC SPECT, [18F]FDG PET) techniques are used in clinical practice but lack specificity for the causative microorganisms themselves. To meet this challenge, many groups have developed imaging methods that target pathogen-specific metabolism, including PET tracers integrated into the bacterial cell wall. We have previously reported the d-amino acid derived PET radiotracers d-methyl-[11C]-methionine, d-[3-11C]-alanine, and d-[3-11C]-alanine-d-alanine, which showed robust bacterial accumulation in vitro and in vivo. Given the clinical importance of radionuclide half-life, in the current study, we developed [18F]3,3,3-trifluoro-d-alanine (d-[18F]-CF3-ala), a fluorine-18 labeled tracer. We tested the hypothesis that d-[18F]-CF3-ala would be incorporated into bacterial peptidoglycan given its structural similarity to d-alanine itself. NMR analysis showed that the fluorine-19 parent amino acid d-[19F]-CF3-ala was stable in human and mouse serum. d-[19F]-CF3-ala was also a poor substrate for d-amino acid oxidase, the enzyme largely responsible for mammalian d-amino acid metabolism and a likely contributor to background signals using d-amino acid derived PET tracers. In addition, d-[19F]-CF3-ala showed robust incorporation into Escherichia coli peptidoglycan, as detected by HPLC/mass spectrometry. Based on these promising results, we developed a radiosynthesis of d-[18F]-CF3-ala via displacement of a bromo-precursor with [18F]fluoride followed by chiral stationary phase HPLC. Unexpectedly, the accumulation of d-[18F]-CF3-ala by bacteria in vitro was highest for Gram-negative pathogens in particular E. coli. In a murine model of acute bacterial infection, d-[18F]-CF3-ala could distinguish live from heat-killed E. coli, with low background signals. These results indicate the viability of [18F]-modified d-amino acids for infection imaging and indicate that improved specificity for bacterial metabolism can improve tracer performance.

Presence and identity of Babesia microti in Ireland

Babesia microti is a tick-transmitted protozoan parasite of wildlife that can also cause serious disease in humans. It is now well established that B. microti represents an assemblage of different strains or species, only some of which are important zoonotic pathogens. Therefore, in order to assess the potential public health risk associated with B. microti in any given location, it is important to determine the strains that are present. This is the first study on the presence and identity of B. microti in Ireland. Overall, 314 wood mice (Apodemus sylvaticus), 243 bank voles (Myodes glareolus) and 634 questing Ixodes ricinus nymphs collected in various locations across Ireland were screened for the presence of B. microti by metabarcoding and nested PCR, respectively. Overall 8 rodent spleen samples (1.4%) were positive for B. microti, while all tick samples tested negative. Rodent isolates were identified as the 'Munich' strain which rarely causes human disease and is chiefly transmitted by the mouse tick, Ixodes trianguliceps. Together with reports from the UK these results suggest that B. microti does not represent a significant public health risk in Britain or Ireland.

Polygenic contributions to performance on the Balloon Analogue Risk Task

Risky decision-making is a common, heritable endophenotype seen across many psychiatric disorders. Its underlying genetic architecture is incompletely explored. We examined behavior in the Balloon Analogue Risk Task (BART), which tests risky decision-making, in two independent samples of European ancestry. One sample (n = 1138) comprised healthy participants and some psychiatric patients (53 schizophrenia, 42 bipolar disorder, 47 ADHD); the other (n = 911) excluded for recent treatment of various psychiatric disorders but not ADHD. Participants provided DNA and performed the BART, indexed by mean adjusted pumps. We constructed a polygenic risk score (PRS) for discovery in each dataset and tested it in the other as replication. Subsequently, a genome-wide MEGA-analysis, combining both samples, tested genetic correlation with risk-taking self-report in the UK Biobank sample and psychiatric phenotypes characterized by risk-taking (ADHD, Bipolar Disorder, Alcohol Use Disorder, prior cannabis use) in the Psychiatric Genomics Consortium. The PRS for BART performance in one dataset predicted task performance in the replication sample (r = 0.13, p = 0.000012, pFDR = 0.000052), as did the reciprocal analysis (r = 0.09, p = 0.0083, pFDR=0.04). Excluding participants with psychiatric diagnoses produced similar results. The MEGA-GWAS identified a single SNP (rs12023073; p = 3.24 × 10-8) near IGSF21, a protein involved in inhibitory brain synapses; replication samples are needed to validate this result. A PRS for self-reported cannabis use (p = 0.00047, pFDR = 0.0053), but not self-reported risk-taking or psychiatric disorder status, predicted behavior on the BART in our MEGA-GWAS sample. The findings reveal polygenic architecture of risky decision-making as measured by the BART and highlight its overlap with cannabis use.

NlpC/P60 peptidoglycan hydrolases of Trichomonas vaginalis have complementary activities that empower the protozoan to control host-protective lactobacilli

Trichomonas vaginalis is a human protozoan parasite that causes trichomoniasis, a prevalent sexually transmitted infection. Trichomoniasis is accompanied by a shift to a dysbiotic vaginal microbiome that is depleted of lactobacilli. Studies on co-cultures have shown that vaginal bacteria in eubiosis (e.g. Lactobacillus gasseri) have antagonistic effects on T. vaginalis pathogenesis, suggesting that the parasite might benefit from shaping the microbiome to dysbiosis (e.g. Gardnerella vaginalis among other anaerobes). We have recently shown that T. vaginalis has acquired NlpC/P60 genes from bacteria, expanding them to a repertoire of nine TvNlpC genes in two distinct clans, and that TvNlpCs of clan A are active against bacterial peptidoglycan. Here, we expand this characterization to TvNlpCs of clan B. In this study, we show that the clan organisation of NlpC/P60 genes is a feature of other species of Trichomonas, and that Histomonas meleagridis has sequences related to one clan. We characterized the 3D structure of TvNlpC_B3 alone and with the inhibitor E64 bound, probing the active site of these enzymes for the first time. Lastly, we demonstrated that TvNlpC_B3 and TvNlpC_B5 have complementary activities with the previously described TvNlpCs of clan A and that exogenous expression of these enzymes empower this mucosal parasite to take over populations of vaginal lactobacilli in mixed cultures. TvNlpC_B3 helps control populations of L. gasseri, but not of G. vaginalis, which action is partially inhibited by E64. This study is one of the first to show how enzymes produced by a mucosal protozoan parasite may contribute to a shift on the status of a microbiome, helping explain the link between trichomoniasis and vaginal dysbiosis. Further understanding of this process might have significant implications for treatments in the future.

Pragmatic review of interventions to prevent catheter-associated urinary tract infections (CAUTIs) in adult inpatients

BACKGROUND

Urinary tract infections (UTIs) are one of the most common hospital-acquired complications. Insertion of a urinary catheter and the duration of catheterization are the main risk factors, with catheter-associated UTIs (CAUTIs) accounting for 70-80% of hospital-acquired UTIs. Guidance is available regarding the prevention of hospital-acquired CAUTIs; however, how best to operationalize this guidance remains a challenge.

AIM

To map and summarize the peer-reviewed literature on model-of-care interventions for the prevention of CAUTIs in adult inpatients.

METHODS

PubMed, CINAHL and SCOPUS were searched for articles that reported UTI, CAUTI or urinary catheter outcomes. Articles were screened systematically, data were extracted systematically, and interventions were classified by intervention type.

FINDINGS

This review included 70 articles. Interventions were classified as single component (N=19) or multi-component (N=51). Single component interventions included: daily rounds or activities (N=4), protocols and procedure changes (N=6), reminders and order sets (N=5), audit and feedback interventions (N=3), and education with simulation (N=1). Overall, daily catheter reviews and protocol and procedure changes demonstrated the most consistent effects on catheter and CAUTI outcomes. The components of multi-component interventions were categorized to map common elements and identify novel ideas.

CONCLUSION

A range of potential intervention options with evidence of a positive effect on catheter and CAUTI outcomes was identified. This is intended to provide a 'menu' of intervention options for local decision makers, enabling them to identify interventions that are relevant and feasible in their local setting.

Abstract OT3-05-01: Adaptive Multi-Drug Treatment of Evolving Cancers (AMTEC): A Phase II, Open-Label, Study of Olaparib in Combination with either Durvalumab, Selumetinib or Capivasertib, or Ceralasertib Monotherapy in Patients with Metastatic TNBC

BACKGROUND PARP inhibitors (PARPi) afford a rational therapeutic strategy in metastatic TNBC (mTNBC) due to the high incidence of dysregulated DNA damage repair mechanisms and high-level genomic instability that resemble tumors originating in germline BRCA-mutated carriers. However, PARPi monotherapy has limited efficacy in BRCA wild-type mTNBC; in BRCA mutant disease following initial response, compensatory mechanisms inevitably restore replication fork protection. AMTEC leverages pre- and on-therapy biopsies from a 4-week PARPi monotherapy run-in period for personalized biomarker-driven patient selection to interdict adaptive resistance to the PARPi. Data from our pilot study (NCT03544125) and from Arm 1 of AMTEC (olaparib + durvalumab) identified PI3K-AKT, RAS-MEK, and ATR/CHK1/WEE1 as targetable pathways contributing to PARPi adaptive resistance in individual participants. Clinically validated assays (DNA, RNA, and protein) enable the identification of cellular mechanisms of PARPi sensitivity and resistance in individual patients and further reveal combined drug treatments that could prevent emergence of PARPi resistance. METHODS AMTEC is a non-comparative, multi-arm, open-label, phase II study to assess the efficacy of combining olaparib (ola) with durvalumab (dur), or MEKi, selumetinib (sel), or AKTi, capivasertib (cap), or monotherapy with ATRi, ceralasertib, (cer mono) in mTNBC patients. Participants with biopsy proven mTNBC (ER< 10%, PR< 10%, and HER-2 non-amplified), AR< 80% are eligible. - Participants undergo a pre-treatment biopsy, then start a 28-day induction with ola (300 mg PO BID, D1-28). On C1D14, patients undergo a repeat, on-treatment biopsy. Clinically validated assays (DNA, RNA, protein) from both biopsies inform patient assignment to a specific ola combination arm starting on C2D1: - Arm 1 tumor immune activated: ola + dur (1500 mg IV Q4W) - Arm 2 RAS-MEK-ERK pathway activation: ola + sel (BSA-based BID D1-28) - Arm 3 PI3K-AKT pathway activation: ola + cap (400 mg PO BID, 4 days on/3 days off) - Arm 4: If not eligible for Arms 1-3 (per biomarker selection criteria): Cer mono (240 mg PO BID D1-14) Endpoints: The primary endpoint is objective response rate (ORR per RECIST 1.1). Secondary endpoints include safety and toxicity, clinical benefit rate, duration of response, and survival. Statistical Methods: - Arm 1 will enroll 28 patients to detect an ORR difference of 20% (H0: π = 0.15 and Ha: π =0.35). Arm 1 will continue on to stage 2 if ORR ≥3 of the first 15 patients. The null hypothesis for Arm 1 is rejected if ≥ 7/28 patient achieve a response. - Arms 2, 3, and 4, will each enroll 22 patients to detect an ORR difference of 25% (H0: π = 0.15 and Ha: π =0.40). Arms 2, 3, and 4 will each continue on to stage 2 if ORR ≥2 of first 11 patients in each arm, respectively. The null hypothesis for Arm 2, 3, and 4 is rejected if ≥ 7/22 patients achieve a response in each arm, respectively. For arms 2 and 3, if there are ≥5/11 responses, the trial will open a biomarker negative expansion cohort for each arm (N = 19 patients/arm). ENROLLMENT The study was activated on 1/7/2019. Arm 1 met pre-specified interim analysis criteria in 12/2020, and accrual to stage 2 began in 1/2021. Arms 2, 3, and 4 start enrolling in Q4 of 2022. Up to 132 patients will be enrolled. Clinical trial information: NCT03801369 Contact information: For more information or to refer a patient, email hobbev@ohsu.edu

Citation Format: Evthokia Hobbs, Gordon Mills, Jeong Lim, Marlana Klinger, Kiara Siex, Sidney Huszti, Annie Yang, Danielle Galipeau, Christina Zheng, Lauren Murray, Becky Goodford, Nicholas Marter-Sanders, Anastasiya Olson, Jayne Stommel, Brett Johnson, Jamie Keck, Ben Kong, Allison Solanki, Shaun Goodyear, Christopher Corless, Joe Gray, Mitri Zahi. Adaptive Multi-Drug Treatment of Evolving Cancers (AMTEC): A Phase II, Open-Label, Study of Olaparib in Combination with either Durvalumab, Selumetinib or Capivasertib, or Ceralasertib Monotherapy in Patients with Metastatic TNBC [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT3-05-01.

Systematic development and feasibility testing of a multibehavioural digital prehabilitation intervention for patients approaching major surgery (iPREPWELL): A study protocol

Improving outcomes for people undergoing major surgery, specifically reducing perioperative morbidity and mortality remains a global health challenge. Prehabilitation involves the active preparation of patients prior to surgery, including support to tackle risk behaviours that mediate and undermine physical and mental health and wellbeing. The majority of prehabilitation interventions are delivered in person, however many patients express a preference for remotely-delivered interventions that provide them with tailored support and the flexibility. Digital prehabilitation interventions offer scalability and have the potential to benefit perioperative healthcare systems, however there is a lack of robustly developed and evaluated digital programmes for use in routine clinical care. We aim to systematically develop and test the feasibility of an evidence and theory-informed multibehavioural digital prehabilitation intervention 'iPREPWELL' designed to prepare patients for major surgery. The intervention will be developed with reference to the Behaviour Change Wheel, COM-B model, and the Theoretical Domains Framework. Codesign methodology will be used to develop a patient intervention and accompanying training intervention for healthcare professionals. Training will be designed to enable healthcare professionals to promote, support and facilitate delivery of the intervention as part of routine clinical care. Patients preparing for major surgery and healthcare professionals involved with their clinical care from two UK National Health Service centres will be recruited to stage 1 (systematic development) and stage 2 (feasibility testing of the intervention). Participants recruited at stage 1 will be asked to complete a COM-B questionnaire and to take part in a qualitative interview study and co-design workshops. Participants recruited at stage 2 (up to twenty healthcare professionals and forty participants) will be asked to take part in a single group intervention study where the primary outcomes will include feasibility, acceptability, and fidelity of intervention delivery, receipt, and enactment. Healthcare professionals will be trained to promote and support use of the intervention by patients, and the training intervention will be evaluated qualitatively and quantitatively. The multifaceted and systematically developed intervention will be the first of its kind and will provide a foundation for further refinement prior to formal efficacy testing.

Morphological Characteristics of Malignancy in Circulating Tumor Cells (CTCs): A New Approach to Liquid Biopsies Utilizing Affordable Standard Cytology Techniques and the FDA Cleared Parsortix® System

Introduction/Objective

The process of metastasis is responsible for most cancer deaths. Identification of tumor cells circulating in blood (CTCs) has the potential to offer important information to patients and clinicians regarding disease status, longitudinal monitoring, remission status and assessment of patient prognosis, among others. However, currently CTC tests in the market are expensive and are not covered by medical insurance, making them unaffordable for most cancer patients. Legacy CTC technologies also require the use of expensive immunofluorescence microscopes and reagents, and are not easily implemented in standard clinical laboratory settings, thus preventing their use as standard of care. Onc-ADaPT™ Clinical Laboratories have explored a method to identify CTCs using the FDA cleared Parsortix® System (ANGLE plc, Guildford, UK) followed by standard cytology processing, staining and analysis, significantly reducing the cost of operations and increasing the likelihood of affordability to patients everywhere.

Methods/Case Report

The basic features of malignancy were listed by a Senior Cytologist (CT) and reviewed by another CT. Cancer cell lines were spiked into normal donor blood collected in Streck tubes. Non-spiked healthy volunteer blood was used to establish the background. The samples were then processed through the Parsortix® system producing 200µL suspension of separated cells. The harvest was then processed using Cytospin, stained with standard Pap Stain and reviewed with bright field microscopy by qualified CTs.

Results (if a Case Study enter NA)

Spiked tumor cells were identified and correctly categorized by the Cytologists. Non-spiked normal donor samples were negative for malignancy. Cells of interest were identified in the non-spiked HNV samples and classified as non-malignant (NOS). Using the training set, CTs later analyzed the available patient sample. The positive cancer patient sample showed cells with obvious characteristics of malignancy.

Conclusion

The basic characteristics of malignancy used for analysis of standard cytology specimens are adequate to identify CTCs using the established background to eliminate the NOS cells. CTC testing can be performed using the combination of Parsortix® System, standard cytology staining and analysis by qualified Cytologists.

Discovery, isolation, heterologous expression and mode-of-action studies of the antibiotic polyketide tatiomicin from Amycolatopsis sp. DEM30355

A genomic and bioactivity informed analysis of the metabolome of the extremophile Amycolatopsis sp. DEM30355 has allowed for the discovery and isolation of the polyketide antibiotic tatiomicin. Identification of the biosynthetic gene cluster was confirmed by heterologous expression in Streptomyces coelicolor M1152. Structural elucidation, including absolute stereochemical assignment, was performed using complementary crystallographic, spectroscopic and computational methods. Tatiomicin shows antibiotic activity against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). Cytological profiling experiments suggest a putative antibiotic mode-of-action, involving membrane depolarisation and chromosomal decondensation of the target bacteria.

Metabolic labeling of the bacterial peptidoglycan by functionalized glucosamine

N-Acetylglucosamine (GlcNAc) is an essential monosaccharide required in almost all organisms. Fluorescent labeling of the peptidoglycan (PG) on N-acetylglucosamine has been poorly explored. Here, we report on the labeling of the PG with a bioorthogonal handle on the GlcNAc. We developed a facile one-step synthesis of uridine diphosphate N-azidoacetylglucosamine (UDP-GlcNAz) using the glycosyltransferase OleD, followed by in vitro incorporation of GlcNAz into the peptidoglycan precursor Lipid II and fluorescent labeling of the azido group via click chemistry. In a PG synthesis assay, fluorescent GlcNAz-labeled Lipid II was incorporated into peptidoglycan by the DD-transpeptidase activity of bifunctional class A penicillin-binding proteins. We further demonstrate the incorporation of GlcNAz into the PG layer of OleD-expressed bacteria by feeding with 2-chloro-4-nitrophenyl GlcNAz (GlcNAz-CNP). Hence, our labeling method using the heterologous expression of OleD is useful to study PG synthesis and possibly other biological processes involving GlcNAc metabolism in vivo.

•

Peptidoglycan consists of N-acetylglucosamine, N-acetylmuramic acid, and amino acids

•

We developed a one-step synthesis of azide-labeled UDP-N-acetylglucosamine

•

In vivo generated azide-labeled UDP-N-acetylglucosamine gets incorporated into peptidoglycan

•

Bacteria were fluorescently labeled on N-acetylglucosamine of peptidoglycan

Maternity services response to the COVID-19 pandemic: how Public Health England guidance was implemented in practice

Introduction

The rapidly evolving COVID-19 pandemic required systemic change in how healthcare was delivered to minimize virus transmission whilst maintaining safe service delivery. Deemed at ‘moderate-high risk’, maternity patients are an important patient group that require consideration. Public Health England (PHE) issued national guidance on how to adjust these services.

Aim

To explore how maternity units in England implemented PHE guidance.

Methods

An online survey of 22 items was distributed to individuals that had worked on an England-based maternity unit during the COVID-19 pandemic. The questionnaire was designed and tested by the multidisciplinary research team. Data was collected from November 2020 to July 2021.

Findings

Forty-four participants across 33 maternity units responded. Ninety-three percent were able to test all women requiring an overnight stay for COVID-19. Only 27% reported birth partners were tested for COVID-19. Only 73% reported they were able to isolate all COVID-19-positive patients in single rooms. Eighty-four percent stated they were aware of current PHE guidance on personal protective equipment (PPE) and 82% felt ‘confident’ in donning/doffing of PPE. Priorities for the future include rapid testing and a focus on community service provision.

Conclusions

PHE COVID-19 guidance was implemented differently in maternity units across England due to the varying resources available at each trust leading to variable ability to test and isolate patients as recommended. More specific, tailored guidance for infection control measures against COVID-19 is needed for maternity settings due to their unique position.

Resource Allocation in a National Dental Service Using Program Budgeting Marginal Analysis

INTRODUCTION

In any health system, choices must be made about the allocation of resources (budget), which are often scarce. Economics has defined frameworks to aid resource allocation, and program budgeting marginal analysis (PBMA) is one such framework. In principle, patient and public values can be incorporated into these frameworks, using techniques such as willingness to pay (WTP). However, this has not been done before, and few formal resource allocation processes have been undertaken in dentistry. This study aimed to undertake a PBMA with embedded WTP values in a national dental setting.

METHODS

The PBMA process was undertaken by a panel of participant-researchers representing commissioners, dentists, dental public health staff, and academics. The panel reviewed current allocations and generated a set of weighted criteria to evaluate services against. Services to be considered for removal and investment were determined by the panel and wider discussion and then scored against the criteria. Values from a nationally representative WTP survey of the public contributed to the scores for interventions. Final decisions on removal and investment were taken after panel discussion using individual anonymous electronic voting.

RESULTS

The PBMA process resulted in recommendations to invest in new program components to improve access to general dentists, care home dentistry, and extra support for dental public health input into local government decisions. Disinvestments were recommended in orthodontics and to remove routine scaling and polishing of teeth.

DISCUSSION

The PBMA process was successful in raising awareness of resource allocation issues. Implementation of findings will depend on the ability of decision makers to find ways of operationalizing the decisions. The process illustrates practical aspects of the process that future dental PBMAs could learn from.

KNOWLEDGE TRANSFER STATEMENT

This study illustrates a framework for resource allocation in dental health services and will aid decision makers in implementing their own resource allocation systems.

Protecting Half the Planet and Transforming Human Systems Are Complementary Goals

The unfolding crises of mass extinction and climate change call for urgent action in response. To limit biodiversity losses and avert the worst effects of climate disruption, we must greatly expand nature protection while simultaneously downsizing and transforming human systems. The conservation initiative Nature Needs Half (or Half Earth), calling for the conservation of half the Earth's land and seas, is commensurate with the enormous challenges we face. Critics have objected to this initiative as harboring hardship for people near protected areas and for failing to confront the growth economy as the main engine of global ecological destruction. In response to the first criticism, we affirm that conservation policies must be designed and implemented in collaboration with Indigenous and local communities. In response to the second criticism, we argue that protecting half the Earth needs to be complemented by downscaling and reforming economic life, humanely and gradually reducing the global population, and changing food production and consumption. By protecting nature generously, and simultaneously contracting and transforming the human enterprise, we can create the conditions for achieving justice and well-being for both people and other species. If we fail to do so, we instead accept a chaotic and impoverished world that will be dangerous for us all.

Abstract PO-014: VISTA: VIsual Semantic Tissue Analysis for pancreatic disease quantification in murine cohorts

Objective and quantifiable assessment of tissue pathology is necessary to study mechanistic disease progression; however, current quantification methods based on tissue staining have many drawbacks including cost, time, labor, batch effects, as well as uneven staining which can result in misinterpretation and investigator bias. Here we present VISTA, an automated deep learning tool for semantic segmentation and quantification of histologic features from hematoxylin and eosin (H&E) stained pancreatic tissue sections. VISTA is trained to identify four key tissue types in developing murine PDAC samples: normal acinar, acinar-to-ductal metaplasia (ADM), dysplasia, and other normal tissue. Predicted segmentations were quantitatively evaluated against pathologist annotation with Dice Coefficients, achieving scores of 0.79, 0.70, 0.79 for normal acinar, ADM, and dysplasia, respectively. Predictions were evaluated against biological ground truth using the mean structural similarity index to immunostainings amylase and pan-keratin (0.925 and 0.920, respectively). The total area of feature prediction was also correlated to the area of immunostaining in whole tissue sections using spearman correlation (0.86, 0.97, and 0.92 for DAPI, amylase, and cytokeratins, respectively). Importantly, our tool is not only able to predict staining information, but it is able to distinguish between ADM and dysplasia, which are not reliably distinguished with common immunostaining methods, showing VISTA’s potential to expand research beyond what is capable with current standards. As a use case example of VISTA, we quantified abundance of histologic features in murine cohorts with oncogenic Kras-driven disease. We observed stromal expansion, a reduction in normal acinar, and an increase in both ADM and dysplasia as the disease progresses, which matches known biology. Since VISTA is an automated algorithm, it can accelerate histological analysis and improve the consistency of quantification between laboratories and investigators. This work has been published in Nature Scientific Reports, and the code is available on github at https://github.com/GelatinFrogs/MicePan-Segmentation.

Citation Format: Luke Ternes, Ge Huang, Christian Lanciault, Guillaume Thibault, Rachelle Riggers, Joe Gray, John Muschler, Young Hwan Chang. VISTA: VIsual Semantic Tissue Analysis for pancreatic disease quantification in murine cohorts [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-014.

The art and science of priority-setting: assessing the value of Public Health England's Prioritization Framework

BACKGROUND

Findings are presented from the evaluation of Public Health England's (PHE) Prioritization Framework (PF) aimed to assist local authority commissioners with their public health investment and disinvestment decisions. The study explored the take up of the PF in three early adopter local authority settings.

METHODS

Semi-structured interviews (n = 30) across three local authorities supplemented by participant observation of workshops.

RESULTS

Participants acknowledged that the PF provided a systematic means of guiding priority-setting and one that encouraged transparency over investment and disinvestment decisions. The role performed by PHE and its regional teams in facilitating the process was especially welcomed and considered critical to the adoption process. However, uptake of the PF required a significant investment of time and commitment from public health teams at a time when resources were stretched. The impact of the political environment in the local government was a major factor determining the likely uptake of the PF. Ensuring committed leadership and engagement from senior politicians and officers was regarded as critical to success.

CONCLUSIONS

The study assessed the value and impact of PHE's PF tool in three early adopter local authorities. Further research could explore the value of the tool in aiding investment and disinvestment decisions and its impact on spending.

Localizing Peptidoglycan Synthesis in Helicobacter pylori using Clickable Metabolic Probes

The bacterial cell wall, composed of peptidoglycan (PG), provides structural integrity for the cell and is responsible for cell shape in most bacteria. Here we present tools to study the cell wall using a clickable PG-specific sugar, 2-alkyne muramic acid (MurNAc-alk), as a metabolic probe. Here we present a new reaction pathway for generating MurNAc-alk. We also include protocols for labeling PG synthesis in Helicobacter pylori, determining the identity of the labeled muropeptides using LC-MS/MS, sample preparation of cells labeled for a short fraction of the doubling time, and visualization using 3D structured illumination microscopy. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Alternative synthesis of MurNAc-alk (direct coupling) Support Protocol 1: Growing Helicobacter pylori in liquid culture Support Protocol 2: Fosfomycin rescue assay Basic Protocol 2: Mass spectrometry (MS) analysis to determine incorporation of MurNAc-alk within the peptidoglycan of H. pylori Support Protocol 3: Hayashi test to determine if SDS is present in the supernatant of peptidoglycan preparations Support Protocol 4: Creating custom cytocentrifuge units for use in a swinging-bucket tabletop centrifuge Basic Protocol 3: Labeling H. pylori with MurNAc-alk or D-Ala-alk Basic Protocol 4: Structured illumination microscopy (SIM) imaging on the DeltaVision OMX.

725 Monthly Antibiotic Use in The Sheffield Children’s Hospital ED: A Hospital-Based Clinical Audit

Aim: To evaluate guideline compliance of antibiotics prescription in Emergency Department (ED).

To improve documentation of antibiotic prescription.

To highlight the need for good antibiotic stewardship.

To optimise the use of antibiotics.

Method

A cross-sectional, retrospective patient record review was conducted regarding antibiotic prescription over 1 month in Sheffield Children’s Hospital ED. All antibiotic prescriptions over that period were collected. From the total number of prescriptions, a convenience sample of 100 prescriptions was selected to correlate their indications with local guidelines.

Results

A total of 290 prescriptions for 310 antibiotics were collected. The most frequent antibiotic prescribed was Penicillin V (26.7%), followed by Amoxicillin (21.3%), Co-amoxiclav (20.3%), and Flucloxacillin (16.5%). From the convenience sample, 12 antibiotics were prescribed inappropriately, with the most frequent being Co-amoxiclav (41.7%), followed by Penicillin V (25%), Amoxicillin and Flucloxacillin (both 16.7%). Overall, there has been good stewardship of antibiotic use with 88% of antibiotic prescribing conducted appropriately as per ED guidelines.

Conclusions

Antibiotic resistance is a growing concern, with one of the leading causes being inappropriate prescription of antibiotics. Adhering to local guidelines can help to prevent them from developing resistance. Adherence can be improved through induction and training of clinicians.

Abstract OT-16-01: A phase 1 study of abemaciclib and niraparib as neoadjuvant therapy in hormone receptor positive (HR+) HER2 negative (HER2-) breast cancer

Background: Achieving a pathologic complete response (pCR) to neoadjuvant therapy correlates with excellent outcome in early stage breast cancer, including HR+ breast cancer (HRBC). Unfortunately, less than 10% of HRBC patients achieve pCR to neoadjuvant therapy; indicating a need for novel HRBC therapies, especially in the neoadjuvant setting. This study evaluates the novel combination of the cyclin dependent kinase inhibitor (CDKi), abemaciclib, in combination with the poly-ADP ribose polymerase inhibitor (PARPi), niraparib, as a neoadjuvant therapy for HRBC.

Niraparib is an orally bioavailable PARPi indicated for the maintenance treatment of platinum-responsive, ovarian cancer, both 1st line and 2nd line. Abemaciclib is approved as a monotherapy or in combination with endocrine therapy in metastatic HRBC. In addition to targeting CDK4/6, abemaciclib also inhibits CDK1, CDK2, and Aurora A/B kinases, which are involved in DNA damage repair. Targeting kinases with abemaciclib sensitizes tumors to DNA-damaging agents, including PARPi. Preclinical data justifies the combination of abemaciclib and niraparib as a novel combination for the treatment of HRBC.

Trial Design: This is a phase I dose-finding study evaluating the combination of abemaciclib and niraparib as a neoadjuvant therapy in patients with early stage HRBC. All eligible participants with biopsy-proven HRBC will undergo a pre-treatment biopsy and start on-study treatment with the combination of abemaciclib and niraparib using a traditional 3+3 dose-escalation algorithm to determine maximum-tolerated dose (MTD). Dose levels are outlined in Table 1. Each cycle is 28 days. After 2 cycles, participants will undergo repeat imaging and biopsy: those with stable or responding disease will continue to receive an additional 2 cycles of abemaciclib and niraparib, followed by surgical resection. Participants with progressive disease will be switched to standard of care chemotherapy. Once the MTD is determined, additional participants up to a sample size maximum of 25 will be enrolled into an expansion cohort (including those from the dosing finding phase) and treated at the established MTD.

Eligibility Criteria: Key Inclusion Criteria: Age ≥ 18 years, biopsy-proven HR+ Her2 non-amplified breast cancer planned for neoadjuvant chemotherapy, ECOG PS ≤1, disease amenable to curative surgical resection. Key Exclusion Criteria: Evidence of metastatic disease, prior PARPi or CDK 4/6i exposure

Specific Aims: Primary Endpoints: Incidence of dose-limiting toxicities (DLTs), incidence of adverse events (AEs) and serious AEs (per CTCAE 5.0). Secondary Endpoints: overall objective response rate, clinical benefit rate, pCR rate, and rate of residual cancer burden 0-1

Statistical Methods: This phase I dose-escalation study for the proposed combination will follow traditional 3+3 escalation rules. The sample size maximum of 25 (including both those from the dosing finding and expansion portions) allows for a greater than 80% chance that the incidence of any AE as rare as 6.4% or greater will be observed in the cohort. For assessments of preliminary efficacy, the sample size provides a two-sided 95% confidence interval with a half width equal to 0.140 when the targeted pCR is 0.15.

Planned Activation Date: Target Accrual: n=25 participants

Contact: Zahi Mitri, MD, MS 3181 SW Sam Jackson Park Road, OC14HO, Portland, OR 97239 503-494-9160, mitri@ohsu.edu

Table 1. Study Regimen Dose LevelsDose Levels (DLAbemaciclib (PO)Niraparib (PO)DL -1100 mg BID100 mg QDDL 1 starting150 mg BID100 mg QDDL 2150 mg BID200 mg QD

Citation Format: Allen Li, Arpana Naik, Nathalie Johnson, Shaun Goodyear, Brett Johnson, Byung Park, Christopher Corless, Joe Gray, Gordon Mills, Zahi Mitri. A phase 1 study of abemaciclib and niraparib as neoadjuvant therapy in hormone receptor positive (HR+) HER2 negative (HER2-) breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr OT-16-01.

Genomic Alterations during the In Situ to Invasive Ductal Breast Carcinoma Transition Shaped by the Immune System

The drivers of ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC) transition are poorly understood. Here, we conducted an integrated genomic, transcriptomic, and whole-slide image analysis to evaluate changes in copy-number profiles, mutational profiles, expression, neoantigen load, and topology in 6 cases of matched pure DCIS and recurrent IDC. We demonstrate through combined copy-number and mutational analysis that recurrent IDC can be genetically related to its pure DCIS despite long latency periods and therapeutic interventions. Immune "hot" and "cold" tumors can arise as early as DCIS and are subtype-specific. Topologic analysis showed a similar degree of pan-leukocyte-tumor mixing in both DCIS and IDC but differ when assessing specific immune subpopulations such as CD4 T cells and CD68 macrophages. Tumor-specific copy-number aberrations in MHC-I presentation machinery and losses in 3p, 4q, and 5p are associated with differences in immune signaling in estrogen receptor (ER)-negative IDC. Common oncogenic hotspot mutations in genes including TP53 and PIK3CA are predicted to be neoantigens yet are paradoxically conserved during the DCIS-to-IDC transition, and are associated with differences in immune signaling. We highlight both tumor and immune-specific changes in the transition of pure DCIS to IDC, including genetic changes in tumor cells that may have a role in modulating immune function and assist in immune escape, driving the transition to IDC. IMPLICATIONS: We demonstrate that the in situ to IDC evolutionary bottleneck is shaped by both tumor and immune cells.

Abstract PO-059: The genomic landscape of the in situ to invasive ductal breast carcinoma transition shaped by the immune system

Background: The transition from ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC) is an evolutionary bottleneck where progression occurs only in 30% of patients. Whilst the genetic drivers of this transition remain poorly understood, we have previously shown that immune escape is a key event. In this study, we profile the evolutionary trajectory of matched pure DCIS and IDC in the context of the immune microenvironment. Methods: We have evaluated changes in copy number profiles, mutational profiles, expression and neoantigen load in 6 cases of matched pure DCIS and IDC using exome and RNA sequencing. We have integrated this information with topologic assessment of H&E images and cyclic immunofluorescence. Results: We provide evidence for an evolutionary bottleneck during DCIS to IDC in matched patient samples, showing that copy number aberrations are early events, but low overlap in mutational profiles. Variation in immune composition and spatial orientation can arise as early as in DCIS and are subtype specific. Tumor-specific copy number changes including loss of MHC-I presentation machinery or changes at cytokine rich loci specifically in ER− tumors could contribute to a more immunosuppressive environment in IDC. Oncogenic hotspot mutations can present as neoantigens yet are paradoxically conserved during the DCIS-to-IDC transition. We suggest these mutations have a secondary immune-modulatory function or may be present in normal tissue, escaping immune surveillance as early as in DCIS. Conclusions: We show both genomic and microenvironmental differences in matched pure DCIS and recurrent IDC, highlighting that progression is shaped by both tumor and immune system at this evolutionary bottleneck.

Citation Format: Anne Trinh, Carlos R. Gil Del Alcazar, Sachet A. Shukla, Koei Chin, Young Hwan Chen, Guillaume Thibault, Jennifer Eng, Bojana Jovanovic, C. Marcelo Aldaz, So Yeon Park, Joon Jong, Catherine Wu, Joe Gray, Kornelia Polyak. The genomic landscape of the in situ to invasive ductal breast carcinoma transition shaped by the immune system [abstract]. In: Proceedings of the AACR Virtual Special Conference on Tumor Heterogeneity: From Single Cells to Clinical Impact; 2020 Sep 17-18. Philadelphia (PA): AACR; Cancer Res 2020;80(21 Suppl):Abstract nr PO-059.

The need for ecocentrism in biodiversity conservation

Over the past 5 decades, scientists have been documenting negative anthropogenic environmental change, expressing increasing alarm, and urging dramatic socioecological transformation in response. A host of international meetings have been held, but the erosion of biological diversity continues to accelerate. Why, then, has no effective political action been taken? We contend that part of the answer may lie in the anthropocentric ethical premises and moral rhetoric typically deployed in the cause of conservation. We further argue that it is essential to advance moral arguments for biodiversity conservation that are not just based on perceived human interests but on ecocentric values, namely, convictions that species and ecosystems have value and interests that should be respected regardless of whether they serve human needs and aspirations. A broader array of moral rationales for biodiversity conservation, we conclude, would be more likely to lead to effective plans, adopted and enforced by governments, designed to conserve biological diversity. A good place to start in this regard would be to explicitly incorporate ecocentric values into the recommendations that will be made at the conclusion of the 15th meeting of the parties to the Convention on Biological Diversity, scheduled to be held in October 2020.

Abstract 1870: The impact of the microenvironment on heterogeneity and trametinib response in HCC1143 triple negative breast cancer cells

Triple negative breast cancer (TNBC) lacks expression of hormone receptors (ER and PR) and HER2 and is characterized by aggressive disease with poor outcomes. Recent work suggests that TNBC also has a high degree of intratumoral heterogeneity, as measured by lineage differentiation status. This heterogeneity may impact therapeutic response, as it has been shown that treatment with PI3K/mTOR (BEZ235) or MEK (trametinib) inhibitors can drive TNBC cells into more homogeneous states, but that the surviving cells are resistant to the targeted therapy. In this study, we sought to understand how the microenvironment impacts differentiation state heterogeneity and response to targeted therapeutics in HCC1143 cells using our microenvironment microarray (MEMA) platform. Under low serum growth conditions, we found that several ligands could drive the growth of HCC1143, particularly EGF family ligands like AREG and EGF. With respect to differentiation state and heterogeneity, EGF and TGFB1 drove HCC1143 cells into a more mesenchymal like state, with increased expression of VIM and decreased expression of KRT14. In contrast, BMP2 led to higher levels of KRT14 and lower levels of VIM, leading to a more basal-like state. We also grew HCC1143 on MEMA with trametinib treatment. Here we found that combinations of collagen-based substrates and NRG1, HGF, and EGF ligands all led to higher cell counts and EdU incorporation rates compared to PBS-control treated cells. However, the levels of resistance conferred by the microenvironment was less than we had previously seen in HER2 positive MEMA, as the GR50 values (dose required to inhibit growth by 50%) only increased modestly (18 nM for untreated cells, 40 nM for NRG1, 45 nM for HGF). Interestingly, in that HER2 positive MEMA study, we identified HGF and NRG1 as potent resistance factors to lapatinib, but that they functioned in a subtype specific manner. HGF was effective in basal subtype cells and NRG1 in luminal, but not vice versa. We postulated that the modest resistance we observed was due to ligands acting on subsets of cells. We thus treated cells with a combination of NRG1 plus HGF, and found that this resulted in increased resistance (GR50= 91 nM). Imaging showed that trametinib drove HCC1143 cells to a homogenous KRT14 positive state, but surprisingly, addition of ligands reverted the cells to a more heterogeneous state that was resistant to trametinib. These data demonstrate that the microenvironment can impact the differentiation state of TNBC cells and is also capable of conferring resistance within subsets of the heterogeneous cell populations.

Citation Format: Rebecca Smith, Kaylyn Devlin, Moqing Liu, Tiera Liby, David Kilburn, Elmar Bucher, Damir Sudar, Guillaume Thibault, Mark Dane, Joe Gray, Laura Heiser, James E. Korkola. The impact of the microenvironment on heterogeneity and trametinib response in HCC1143 triple negative breast cancer cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1870.

Peptidoglycan editing provides immunity to Acinetobacter baumannii during bacterial warfare

Peptidoglycan (PG) is essential in most bacteria. Thus, it is often targeted by various assaults, including interbacterial attacks via the type VI secretion system (T6SS). Here, we report that the Gram-negative bacterium Acinetobacter baumannii strain ATCC 17978 produces, secretes, and incorporates the noncanonical d-amino acid d-lysine into its PG during stationary phase. We show that PG editing increases the competitiveness of A. baumannii during bacterial warfare by providing immunity against peptidoglycan-targeting T6SS effectors from various bacterial competitors. In contrast, we found that d-Lys production is detrimental to pathogenesis due, at least in part, to the activity of the human enzyme d-amino acid oxidase (DAO), which degrades d-Lys producing H2O2 toxic to bacteria. Phylogenetic analyses indicate that the last common ancestor of A. baumannii had the ability to produce d-Lys. However, this trait was independently lost multiple times, likely reflecting the evolution of A. baumannii as a human pathogen.

COVID-19: how prepared are front-line healthcare workers in England?

National efforts are underway to prepare the UK National Health Service (NHS) for the COVID-19 pandemic; however, the efficacy of these interventions is unknown. In view of this, a cross-sectional survey of front-line healthcare workers (HCWs) at two large acute NHS hospital trusts in England was undertaken to assess their confidence and perceived level of preparedness for the virus. The survey found that there has been moderate success in readying HCWs to manage COVID-19, but that more still needs to be done, particularly in relation to educating HCWs about laboratory diagnostics.

Improving paediatric antimicrobial stewardship in hospital-based settings: why, where and how?

Background

Antimicrobial resistance (AMR) is being recognized as a priority by healthcare organizations across the world. However, many children are managed on IV antimicrobials in hospital with very little consideration of antimicrobial stewardship issues.

Objectives

A nurse-led paediatric ambulatory outpatient parenteral antimicrobial therapy (OPAT) service, managing children with common infections being ambulated on short courses of IV antimicrobials, was introduced within Southampton Children’s Hospital in January 2018. We evaluated the impact of this service in terms of the quality of antimicrobial prescribing and timing of ambulation in children presenting with common infections.

Methods

All cases managed within the service were reviewed in two separate 2 month time periods: prior to introduction of the service (September–October 2016) and then prospectively after its introduction (September–October 2018).

Results

A total of 96% of IV antibiotic management decisions at 48 h were deemed appropriate in 2018, compared with 75% in 2016. A total of 64% of patients were ambulated on IV antibiotics at some point during their treatment course in 2018, compared with 19% in 2016. However, a significant proportion of antimicrobial decisions made at the point of presentation to hospital remained suboptimal in 2018.

Conclusions

Children are commonly managed with IV antibiotics in hospital. We demonstrate marked improvements in appropriate antimicrobial use through the introduction of a nurse-led ambulatory OPAT service. In addition, such a service can promote a greater proportion of children being ambulated from hospital, freeing up valuable inpatient beds and potentially delivering cost savings that can be used to fund such services.

Distinct cytoskeletal proteins define zones of enhanced cell wall synthesis in Helicobacter pylori

Helical cell shape is necessary for efficient stomach colonization by Helicobacter pylori, but the molecular mechanisms for generating helical shape remain unclear. The helical centerline pitch and radius of wild-type H. pylori cells dictate surface curvatures of considerably higher positive and negative Gaussian curvatures than those present in straight- or curved-rod H. pylori. Quantitative 3D microscopy analysis of short pulses with either N-acetylmuramic acid or D-alanine metabolic probes showed that cell wall growth is enhanced at both sidewall curvature extremes. Immunofluorescence revealed MreB is most abundant at negative Gaussian curvature, while the bactofilin CcmA is most abundant at positive Gaussian curvature. Strains expressing CcmA variants with altered polymerization properties lose helical shape and associated positive Gaussian curvatures. We thus propose a model where CcmA and MreB promote PG synthesis at positive and negative Gaussian curvatures, respectively, and that this patterning is one mechanism necessary for maintaining helical shape.

Round spheres, straight rods, and twisting corkscrews, bacteria come in many different shapes. The shape of bacteria is dictated by their cell wall, the strong outer barrier of the cell. As bacteria grow and multiply, they must add to their cell wall while keeping the same basic shape. The cells walls are made from long chain-like molecules via processes that are guided by protein scaffolds within the cell. Many common antibiotics, including penicillin, stop bacterial infections by interrupting the growth of cell walls.

Helicobacter pylori is a common bacterium that lives in the gut and, after many years, can cause stomach ulcers and stomach cancer. H. pylori are shaped in a twisting helix, much like a corkscrew. This shape helps H. pylori to take hold and colonize the stomach.

It remains unclear how H. pylori creates and maintains its helical shape. The helix is much more curved than other bacteria, and H. pylori does not have the same helpful proteins that other curved bacteria do. If H. pylori grows asymmetrically, adding more material to the cell wall on its long outer side to create a twisting helix, what controls the process?

To find out, Taylor et al. grew H. pylori cells and watched how the cell walls took shape. First, a fluorescent dye was attached to the building blocks of the cell wall or to underlying proteins that were thought to help direct its growth. The cells were then imaged in 3D, and images from hundreds of cells were reconstructed to analyze the growth patterns of the bacteria’s cell wall.

A protein called CcmA was found most often on the long side of the twisting H. pylori. When the CcmA protein was isolated in a dish, it spontaneously formed sheets and helical bundles, confirming its role as a structural scaffold for the cell wall. When CcmA was absent from the cell of H. pylori, Taylor et al. observed that the pattern of cell growth changed substantially.

This work identifies a key component directing the growth of the cell wall of H. pylori and therefore, a new target for antibiotics. Its helical shape is essential for H. pylori to infect the gut, so blocking the action of the CcmA protein may interrupt cell wall growth and prevent stomach infections.

Shifting the Gravity of Spending: Assessing the impact of PHE’s Prioritisation Framework

Background

Findings are presented from the evaluation of Public Health England’s (PHE) new Prioritisation Framework (PF) conducted between September 2017 and December 2018 aimed to help local authority commissioners with their public health investment and disinvestment decisions. The study explored the take up of the PF in three early adopter local authority settings.

Methods

Data collection was based on semi-structured interviews (n = 30) across three local authorities supplemented by participant observation of workshops and data concerning the implementation process as well as spend and outcomes both before and, where possible, after using the PF.

Results

Participants acknowledged that the PF provided a systematic way to guide prioritisation decisions and one that encouraged transparency over investment and disinvestment decisions. The role performed by PHE and its regional teams in facilitating the process was especially welcomed and considered to be critical to the adoption process. However, uptake of the PF required a significant investment of time and commitment from public health teams at a time when resources were stretched. The impact of the political environment in local government was a major factor determining the likely uptake of the PF. Ensuring committed leadership and engagement from senior politicians and officers was regarded as critical to success.

Conclusions

The study assessed the value of the PF and the processes surrounding its implementation and use. Further research could further explore the value of the tool in aiding investment and disinvestment decisions and its impact on spending.

Key messages

The PF provides a platform for engaged and informed deliberation about priorities and does so in an open, structured and transparent manner. Organisational and political context in which prioritisation occur shape the adoption of the PF tool.