A highly multiplexed melt-curve assay for detecting the most prevalent carbapenemase, ESBL, and AmpC genes

Resistance to third-generation cephalosporins and carbapenems in Gram-negative bacteria is chiefly mediated by beta-lactamases including extended-spectrum beta-lactamase (ESBL), AmpC, and carbapenemase enzymes. Routine phenotypic detection methods do not provide timely results, and there is a lack of comprehensive molecular panels covering all important markers. An ESBL/carbapenemase high-resolution melt analysis (HRM) assay (SHV, TEM, CTX-M ESBL families, and NDM, IMP, KPC, VIM and OXA-48-like carbapenemases) and an AmpC HRM assay (16S rDNA control, FOX, MOX, ACC, EBC, CIT, and DHA) were designed and evaluated on 111 Gram-negative isolates with mixed resistance patterns. The sensitivity for carbapenemase, ESBL, and AmpC genes was 96.7% (95% confidence interval [CI]: 82.8-99.9%), 93.6% (95% CI: 85.7-97.9%), and 93.8% (95% CI: 82.8-98.7%), respectively, with a specificity of 100% (95% CI: 95.6-100%), 93.9% (95% CI: 79.8-99.3%), and 93.7% (95% CI: 84.5-98.2%). The HRM assays enable the simultaneous detection of the 14 most important ESBL, carbapenemase, and AmpC genes and could be used as a molecular surveillance tool or to hasten detection of antimicrobial resistance for treatment management.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Automated MV markerless tumor tracking for VMAT

Tumor tracking during radiotherapy treatment can improve dose accuracy, conformity and sparing of healthy tissue. Many methods have been introduced to tackle this challenge utilizing multiple imaging modalities, including a template matching based approach using the megavoltage (MV) on-board portal imager demonstrated on 3D conformal treatments. However, the complexity of treatments is evolving with the introduction of VMAT and IMRT, and successful motion management is becoming more important due to a trend towards hypofractionation. We have developed a markerless lung tumor tracking algorithm, utilizing the electronic portal imager (EPID) of the treatment machine. The algorithm has been specifically adapted to track during complex treatment deliveries with gantry and MLC motion. The core of the algorithm is an adaptive template matching method that relies on template stability metrics and local relative orientations to perform multiple feature tracking simultaneously. Only a single image is required to initialize the algorithm and features are automatically added, modified or removed in response to the input images. This algorithm was evaluated against images collected during VMAT arcs of a dynamic thorax phantom. Dynamic phantom images were collected during radiation delivery for multiple lung SBRT breathing traces and an example patient data set. The tracking error was 1.34 mm for the phantom data and 0.68 mm for the patient data. A multi-region, markerless tracking algorithm has been developed, capable of tracking multiple features simultaneously without requiring any other a priori information. This novel approach delivers robust target localization during complex treatment delivery. The reported tracking error is similar to previous reports for 3D conformal treatments.

The Canadian Cancer Research Conference 2019

The 5th Canadian Cancer Research Conference (ccrc) took place 3-5 November 2019 in Ottawa, Ontario. Nearly 1000 participants-scientists, oncologists, community members, and patients-gathered to share knowledge, foster collaboration, and fuel the future of cancer research in Canada. The scientific program included 3 plenary sessions, 26 concurrent sessions, and 2 poster sessions presenting research described in more than 600 submitted abstracts, giving participants the opportunity to share health research that collectively encompassed the 4 pillars recognized by the Canadian Institutes of Health Research. In addition to the breadth of topics addressed by Canadian and international experts, the highlights of the meeting included the integration of patients and patient advocates, new rapid-fire sessions for abstract presentation, and events that enhanced learning opportunities for trainees.

Proteasome-dependent protein quality control of the peroxisomal membrane protein Pxa1p

Peroxisomes are eukaryotic organelles that function in numerous metabolic pathways and defects in peroxisome function can cause serious developmental brain disorders such as adrenoleukodystrophy (ALD). Peroxisomal membrane proteins (PMPs) play a crucial role in regulating peroxisome function. Therefore, PMP homeostasis is vital for peroxisome function. Recently, we established that certain PMPs are degraded by the Ubiquitin Proteasome System yet little is known about how faulty/non-functional PMPs undergo quality control. Here we have investigated the degradation of Pxa1p, a fatty acid transporter in the yeast Saccharomyces cerevisiae. Pxa1p is a homologue of the human protein ALDP and mutations in ALDP result in the severe disorder ALD. By introducing two corresponding ALDP mutations into Pxa1p (Pxa1^MUT), fused to mGFP, we show that Pxa1^MUT-mGFP is rapidly degraded from peroxisomes in a proteasome-dependent manner, while wild type Pxa1-mGFP remains relatively stable. Furthermore, we identify a role for the ubiquitin ligase Ufd4p in Pxa1^MUT-mGFP degradation. Finally, we establish that inhibiting Pxa1^MUT-mGFP degradation results in a partial rescue of Pxa1p activity in cells. Together, our data demonstrate that faulty PMPs can undergo proteasome-dependent quality control. Furthermore, our observations may provide new insights into the role of ALDP degradation in ALD.

Glycerin suppositories used prophylactically in premature infants (supp): A pilot randomized controlled trial

BACKGROUND

Glycerin suppositories are often used to facilitate meconium evacuation in premature infants. The evidence for this practice is inconclusive. The purpose of this study was to assess the feasibility of a multicenter randomized controlled trial on the effectiveness of this treatment strategy.

STUDY DESIGN

We conducted an external pilot study for a multicenter randomized controlled trial of premature infants randomized to glycerin suppositories or placebo procedure. Participants were included if they were gestational age of 24 weeks 0 days to 31 weeks 6 days and/or birthweight of 500 to 1500 grams. We excluded infants with life-threatening congenital anomalies, contraindications to receiving suppositories, or signs of clinical instability. Outcomes included cost, recruitment, and treatment-related adverse events.

RESULT

A total of 109 were screened, 79 were initially eligible, and 34 consented to participate. Four of these infants were excluded prior to randomization due to thrombocytopenia, 30 were randomized, and 26 reached full enteral feeds. Three infants (10%) experienced rectal bleeding 5 to 43 days after completing study treatments. An anal fissure was noted in two of these patients. There were no cases of rectal perforation but one infant assigned to active treatment developed necrotizing enterocolitis.

CONCLUSIONS

Conducting a multicenter randomized controlled trial on the use of glycerin suppositories in premature infants is feasible. Minor modifications to the study protocol are needed to increase participant recruitment and simplify the administration of study treatments.

A nurse-led paediatric oncology fast-track clinic proves a successful ambulatory intervention for patients

AIM

To assess the impact of a pilot nurse-led paediatric oncology fast-track clinic (OFTC) for complications and side effects following chemotherapy within a paediatric tertiary hospital.

METHODS

Prospective clinical data from the first 100 patients seen in the OFTC were compared with retrospective data of oncology patient presentations to the emergency department (ED) (over a 1-year period, n = 196) who would have been eligible for review in the OFTC. Parent and patient satisfaction of clinical care were also assessed via surveys pre- and post-OFTC implementation.

RESULTS

Analysis which achieved statistical difference was a reduction in the number of blood tubes taken in OFTC (average 1.9 for those discharged from clinic, 2.9 for those admitted from clinic) in comparison to those seen in the ED (average 3.2) (p = 0.0027). The average number of interventions per patient seen in the ED were 2.1 (standard deviation 1.64) compared with 1.7 (standard deviation 1.55) interventions per patient seen in the OFTC, and who were not admitted following review. This result approached statistical significance with p = 0.0963. Other results which did not meet statistical significance included a reduction in treatment times, hospital admissions and medical oncology reviews.

CONCLUSION

Our pilot study implementing an OFTC for the triage and assessment of chemotherapy-related complications has proven successful from an operational and consumer perspective. The clinic improved care by ensuring expedited review, more streamlined interventions, and less overall hospital admissions. The improvements in efficiency were also mirrored by increased parent and patient satisfaction.

Recurrent hyperactive ESR1 fusion proteins in endocrine therapy-resistant breast cancer

Background

Estrogen receptor-positive (ER-positive) metastatic breast cancer is often intractable due to endocrine therapy resistance. Although ESR1 promoter switching events have been associated with endocrine-therapy resistance, recurrent ESR1 fusion proteins have yet to be identified in advanced breast cancer.

Patients and methods

To identify genomic structural rearrangements (REs) including gene fusions in acquired resistance, we undertook a multimodal sequencing effort in three breast cancer patient cohorts: (i) mate-pair and/or RNAseq in 6 patient-matched primary-metastatic tumors and 51 metastases, (ii) high coverage (>500×) comprehensive genomic profiling of 287-395 cancer-related genes across 9542 solid tumors (5216 from metastatic disease), and (iii) ultra-high coverage (>5000×) genomic profiling of 62 cancer-related genes in 254 ctDNA samples. In addition to traditional gene fusion detection methods (i.e. discordant reads, split reads), ESR1 REs were detected from targeted sequencing data by applying a novel algorithm (copyshift) that identifies major copy number shifts at rearrangement hotspots.

Results

We identify 88 ESR1 REs across 83 unique patients with direct confirmation of 9 ESR1 fusion proteins (including 2 via immunoblot). ESR1 REs are highly enriched in ER-positive, metastatic disease and co-occur with known ESR1 missense alterations, suggestive of polyclonal resistance. Importantly, all fusions result from a breakpoint in or near ESR1 intron 6 and therefore lack an intact ligand binding domain (LBD). In vitro characterization of three fusions reveals ligand-independence and hyperactivity dependent upon the 3' partner gene. Our lower-bound estimate of ESR1 fusions is at least 1% of metastatic solid breast cancers, the prevalence in ctDNA is at least 10× enriched. We postulate this enrichment may represent secondary resistance to more aggressive endocrine therapies applied to patients with ESR1 LBD missense alterations.

Conclusions

Collectively, these data indicate that N-terminal ESR1 fusions involving exons 6-7 are a recurrent driver of endocrine therapy resistance and are impervious to ER-targeted therapies.

Determination of Ochratoxin A in Currants, Raisins, Sultanas, Mixed Dried Fruit, and Dried Figs by Immunoaffinity Column Cleanup with Liquid Chromatography: Interlaboratory Study

An interlaboratory study was performed on behalf of the Food Standards Agency to evaluate the effectiveness of an affinity column cleanup liquid chromatographic (LC) method for the determination of ochratoxin A in a variety of dried fruit at European regulatory limits. To ensure homogeneity before analysis, laboratory samples are normally slurried with water in the ratio of 5 parts fruit to 4 parts water, and test materials in this form were used in the study. The test portion was extracted with acidified methanol. The extract was filtered, diluted with phosphate-buffered saline, and applied to an affinity column. The column was washed and ochratoxin A was eluted with methanol. Ochratoxin A was quantified by reversed-phase LC. The use of post-column pH shift to enhance the fluorescence of ochratoxin A by the addition of 1.1M ammonia solution to the column eluant is optional. Determination was by fluorescence. Currants, sultanas, raisins, figs, and mixed fruit (comprising dried pineapple, papaya, sultanas, prunes, dates, and banana chips), both naturally contaminated and blank (very low level), were sent to 24 collaborators in 7 European countries. Participants were asked to spike test portions of all test samples at a level equivalent to 5 ng/g ochra toxin A. Average recoveries ranged from 69 to 74%. Based on results for 5 naturally contaminated test samples (blind duplicates) the relative standard deviation for repeatability (RSDr) ranged from 4.9 to 8.7%, and the relative standard deviation for reproducibility (RSDR)rangedfrom14to28%. The method showed acceptable within-and be-tween-laboratory precision for all 5 matrixes, as evidenced by HORRAT values <1.3.

B-54 Insights into a Novel Integrated Screening Clinic: Parent Perceptions of Emotional Functioning in Acute Recovery Phase Following Pediatric Neurocritical Care

Objective

Children with traumatic brain injury (TBI) requiring neurocritical care are at high risk for neurocognitive, emotional, physical, and psychosocial difficulties, collectively known as Post-Intensive Care Syndrome. Our study sought to characterize parent ratings of emotional functioning in the acute recovery phase based upon mechanism of injury.

Method

Twenty children (Mdn = 12.6 years, IQR = 9-15; 65% male) were screened as part of a multidisciplinary follow-up clinic 1-month following hospital discharge. Emotional functioning was assessed using PROMIS Parent Proxy Report for Anxiety and Depression. A brief neurocognitive battery estimated presence of cognitive impairment. MANCOVA was used to compare emotional functioning across injury mechanism (high velocity injury [HVI], 65%; fall, 35%).

Results

Groups did not differ on age, gender, and presence of cognitive impairment. After controlling for severity, mechanism of injury had a significant effect on both anxiety (p = .026) and depression (p = .004). The HVI group had mildly elevated anxiety (M = 50.5, SD = 12.2) and depression (M = 54.2, SD = 10.6) scores, while the fall group had anxiety (M = 38.0, SD = 6.2) and depression (M = 39.0, SD = 7.3) scores within normal limits.

Conclusions

In the acute recovery phase following TBI, anxiety and depression symptoms are more common after HVI than falls, even when controlling for severity of injury. The HVI group includes injuries resulting from motor vehicle accidents which may have a broader impact on the family and may explain higher rates of emotional distress in this patient group compared to other mechanisms of TBI. Additional research is needed to further explore variables related to emotional functioning following TBI and how they change over the course of recovery.

Does childbirth experience affect infant behaviour? Exploring the perceptions of maternity care providers

OBJECTIVE

High levels of childbirth interventions are known to increase risk of health complications for mother and infant, alongside having a negative impact upon maternal wellbeing. However less is understood about how childbirth experience may affect infant behaviour (e.g. how calm or unsettled an infant is). This study explores maternity care provider perceptions of how and why childbirth experience may affect infant behaviour.

DESIGN

A qualitative semi-structured interview study.

SETTING

Bristol, Swansea and West Wales, UK.

PARTICIPANTS

18 maternity care providers.

MEASUREMENTS AND FINDINGS

A semi-structured interview schedule was developed to explore maternity care providers' perceptions of how maternal experience of childbirth could influence infant behaviour. Findings highlighted how maternity care providers perceived childbirth experience to sometimes impact positively or negatively on infant behaviour. A calmer birth and postnatal experience was believed to lead to a calmer infant, whilst physical and emotional stress was associated with more challenging infant behaviours such as crying and being unsettled. Pathways were perceived to be direct (pain and stress during birth might physiologically affect the infant) and indirect (birth was perceived to affect maternal wellbeing and subsequently her interactions with her baby). However, postnatal factors such as skin to skin, postnatal environment and emotional support were believed to mediate these impacts.

KEY CONCLUSIONS

Birth experience was considered to affect infant behaviour. Promoting as positive a birth experience as possible, including postnatal care, was viewed as significant in supporting positive infant behaviours. Maternity care providers believed this could help facilitate bonding, attachment, and mother-infant wellbeing in the postnatal period.

IMPLICATIONS FOR PRACTICE

The findings highlight maternity care providers' views concerning supporting normal birth and protecting emotional wellbeing during birth and postnatally. Where interventions are necessary, ensuring a calm environment, and enabling normal postnatal behaviours such as skin to skin and breastfeeding were perceived as important. Midwives, it was claimed, need time to nurture mothers alongside providing physical care.

LIMITATIONS

Participants were self-selecting and might therefore have been biased.

Piezo1 channels are mechanosensors in human fetoplacental endothelial cells

STUDY QUESTION

Does the shear stress sensing ion channel subunit Piezo1 have an important mechanotransduction role in human fetoplacental endothelium?

SUMMARY ANSWER

Piezo1 is present and functionally active in human fetoplacental endothelial cells, and disruption of Piezo1 prevents the normal response to shear stress.

WHAT IS KNOWN ALREADY

Shear stress is an important stimulus for maturation and function of placental vasculature but the molecular mechanisms by which the force is detected and transduced are unclear. Piezo1 channels are Ca²⁺-permeable non-selective cationic channels which are critical for shear stress sensing and maturation of murine embryonic vasculature.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

We investigated the relevance of Piezo1 to placental vasculature by studying human fetoplacental endothelial cells (FpECs) from healthy pregnancies. Endothelial cells were isolated from placental cotyledons and cultured, for the study of tube formation and cell alignment to shear stress. In addition, human placental arterial endothelial cells were isolated and studied immediately by patch-clamp electrophysiology.

MAIN RESULTS AND THE ROLE OF CHANCE

The synthetic Piezo1 channel agonist Yoda1 caused strong elevation of the intracellular Ca²⁺ concentration with a 50% effect occurring at about 5.4 μM. Knockdown of Piezo1 by RNA interference suppressed the Yoda1 response, consistent with it being mediated by Piezo1 channels. Alignment of cells to the direction of shear stress was also suppressed by Piezo1 knockdown without loss of cell viability. Patch-clamp recordings from freshly isolated endothelium showed shear stress-activated single channels which were characteristic of Piezo1.

LIMITATIONS, REASONS FOR CAUTION

The in vitro nature of fetoplacental endothelial cell isolation and subsequent culture may affect FpEC characteristics and PIEZO1 expression. In addition to Piezo1, alternative shear stress sensing mechanisms have been suggested in other systems and might also contribute in the placenta.

WIDER IMPLICATIONS OF THE FINDINGS

These data suggest that Piezo1 is an important molecular determinant of blood flow sensitivity in the placenta. Establishing and manipulating the molecular mechanisms regulating shear stress sensing could lead to novel therapeutic strategies to improve blood flow in the placenta.

LARGE-SCALE DATA

Not applicable.

STUDY FUNDING/COMPETING INTEREST(S)

LCM was funded by a Clinical Research Training Fellowship from the Medical Research Council and by the Royal College of Obstetricians and Gynaecologists, and has received support from a Wellcome Trust Institutional Strategic Support Fund. JS was supported by the Wellcome Trust and a BHF Intermediate Research Fellowship. HJG, CW, AJH and PJW were supported by PhD Studentships from BHF, BBSRC and the Leeds Teaching Hospitals Charitable Foundation respectively. All authors declare no conflict of interest.

Candida auris exhibits resilient biofilm characteristics in vitro: implications for environmental persistence

Surfaces within healthcare play a key role in the transmission of drug-resistant pathogens. Candida auris is an emerging multidrug-resistant yeast which can survive for prolonged periods on environmental surfaces. Here we show that the ability to form cellular aggregates increases survival after 14 days, which coincides with the upregulation of biofilm-associated genes. Additionally, the aggregating strain demonstrated tolerance to clinical concentrations of sodium hypochlorite and remained viable 14 days post treatment. The ability of C. auris to adhere to and persist on environmental surfaces emphasizes our need to better understand the biology of this fungal pathogen.

Retinal burns from laser pointers: a risk in children with behavioural problems

OBJECTIVE

To explore self-inflicted retinal burns from laser pointers in children.

METHODS

Literature review of laser pointer retinal injuries in childhood and online survey of UK Consultant Ophthalmologists. A cohort of local children with self-inflicted injury is described. The matter is topical. We review progress in recent legislation and policy change in the UK.

RESULTS

Four of 77 case reports of laser burns in childhood analysed reported psychological or behavioural issues. Three of four children in our cohort had such issues. Delay in diagnosis occurred in two of our patients. Structural retinal damage persisted for over 12 months in all four children (seven eyes). Our survey of UK ophthalmologists found 159 cases of injury (85% male), 80% under 20 years of age. The majority of the laser pointers were purchased online. Many patients (36%) suffered moderate vision loss (6/18 to 6/60 Snellen), while 17% (at least 11 patients) suffered severe vision loss (<6/60 Snellen).

CONCLUSION

We highlight the risk of macular damage and vision loss from handheld lasers specifically in children with behavioural, learning or mental health issues. The diagnosis may be difficult or delayed in such children. In children with uncertain macular changes, ophthalmologists should explore the history for possible instances of exposure to handheld lasers pointers. Regulatory authorities and manufacturers of handheld lasers need to be aware of the risk to children. Furthermore, there is a need to better inform parents, carers and teachers of the risk of ocular self-injury from such lasers pointers.