Biochemical characterisation of carious dentine zones using Raman spectroscopy

OBJECTIVE

Carious tissue discrimination in clinical operative caries management relies traditionally on the subjective hardness of carious dentine. Biochemical alterations within the lesion have the potential to discriminate the lesion zones objectively. This study aimed to determine the correlation between the biochemical proportions of amide I and phosphate moieties as these are the most prominent peaks found in dentine with the Knoop microhardness of carious dentine zones, using non-contact Raman spectroscopy. The null hypothesis investigated was that there was no correlation between Raman peak ratios, amide I: phosphateν1, and the Knoop microhardness within specific zones of a carious lesion.

METHODS

423 scan points from 20 carious dentine lesion samples examined using high-resolution Raman spectroscopy. The peak ratio of the characteristic vibration mode of amide I (1650 cm^-1) and phosphate (960 cm^-1) bands were calculated, following a straight line path through the lesion to the pulp and correlated to corresponding Knoop microhardness measurements.

RESULTS

Using logistic regression analysis, clear correlations were found between the Knoop microhardness and Raman peak ratio cut-off values between caries-infected and caries-affected dentine (81.5 % sensitivity / 92.7 % specificity), with a lower specificity (2.7 %) found between caries-affected and sound dentine.

CONCLUSION

This study concluded that non-contact Raman spectroscopy can be used in vitro to discriminate objectively between the different zones of a carious dentine lesion at high resolution, using the Raman peak ratios, amide I : phosphate ν₁.

CLINICAL SIGNIFICANCE

Specific biochemical alterations have the potential to be used in-vitro and in-vivo to identify the end-point of selective carious lesion excavation.

An automated setup to measure the linear and nonlinear magnetic ac-susceptibility down to 4 K with higher accuracy

An automated stepper motor controlled ac-susceptibility setup has been developed to measure the phase resolved linear and nonlinear magnetic ac-susceptibilities of a material in the temperature range of 4 K-300 K with a frequency range of 0.1 Hz-1.5 kHz. A maximum dc-field of ±150 Oe can be superimposed with a maximum ac-field of 100 Oe in the same coil by using a homemade ac-dc superimposing circuit. The induced voltage in the detection coil is measured by a lock-in amplifier, and temperature is controlled by a temperature controller. The very common offset voltage drifting problem is resolved by implementing a two-point measurement technique at every temperature, field, and frequency using a stepper motor. Operation of the stepper motor is controlled by a homemade computer programmable driver circuit. Sensitivity of the setup is obtained around ∼10^-7 emu, and relative accuracy of the measurement is much better than 0.1%. Higher harmonics can be measured with a maximum noise level of ±15 nV throughout the temperature, field, and frequency range.

Lifetime risk of cardiovascular-renal disease in type 2 diabetes: a population-based study in 473399 individuals

Background

Lifetime risks of cardiovascular (CV) and renal diseases are high, particularly in type 2 diabetes (T2D), but rarely studied together, and relative disease contributions are unknown. Knowledge of lifetime risk of cardiovascular-renal disease (CVRD) will better reflect disease burden in T2D.

Purpose

To investigate the lifetime risks (LTRs) of composite and individual components of major adverse reno-cardiovascular events, MARCE in T2D patients.

Method

In a population-based cohort study using national electronic health records, we studied 473399 individuals aged 45–99 years with T2D in England 2007–2018. The LTR of composite and individual components of MARCE (including CV death and CVRD: heart failure, HF; chronic kidney disease stage 3 and above, CKD; myocardial infarction, MI; stroke or peripheral artery disease, PAD) were estimated. LTRs by baseline CVRD comorbidity status were compared with individuals free from CVRD at baseline, accounting for the competing risk of death.

Results

Among T2D patients aged ≥45 years, the LTR of MARCE was 80% for individuals free from CVRD at baseline. LTR of MARCE was 97%, 93%, 98%, 89% and 91% for individuals with specific CVRD comorbidities for HF, CKD, MI, stroke and PAD, respectively at baseline. Within the CVRD-free cohort, LTR of CKD was highest at 54%, followed by CV death (41%), HF (29%), stroke (20%), MI (19%) and PAD (9%). Compared to CVRD-free, HF, MI and CKD at baseline were associated with the highest LTR of MARCE and its component diseases (Table).

Conclusion

The lifetime risk of CV disease and CKD in T2D patients is estimated to be over 60% and 50% respectively (1–3). When considered together, the LTR of MARCE is 80% in CVRD-free T2D patients, while nearly all those with T2D and HF will develop MARCE over their lifetime. Of the individual components of MARCE, LTR of CKD and HF were the highest among CVRD-free T2D patients. Preventive measures in T2D patients should be a priority in clinical practice to mitigate the burden of these complications.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): AstraZeneca

92 aetiologic factors for heart failure: prevalence, co-occurrence, prognosis and potential for prevention in 170,885 incident HF cases

Background

ESC and AHA guidelines identify 92 putative aetiological factors for heart failure, but primary prevention strategies for heart failure (HF) have had limited success. There are no previous studies systematically evaluating the potential for prevention among such a wide range of clinically manifest aetiologic factors.

Objective

To estimate for 92 (putative) aetiologic factors their prevalence, co-occurrence, preventability and impact on HF prognosis in incident HF.

Methods

We identified 170885 individuals aged ≥30 years with incident HF from 1997–2017 using linked primary and secondary care electronic health records (EHR) in the UK (CALIBER). For each of the 92 factors we developed EHR phenotypes using ICD-10 diagnosis, Read, procedure and medication codes (total = 5961 codes). We conducted a literature review of trials of primary HF prevention across 92 factors.

Results

35.6% of individuals with HF had ≥4 aetiologic factors recorded in the preceding 5 years. Of all new HF cases 71.5% had ≥1 of the 7 aetiologic factors with trial evidence of effective preventive therapy for HF; 12.9% had ≥1 aetiologic factor with effective preventive therapy for CVD and 15.6% had either no aetiological factor, or an aetiological factor with no evidence of preventive potential. 88/91 factors were represented. The commonest factors in the 5 years prior to HF diagnosis were hypertension (48.7%), smoking (46.6%), reduced physical activity (39.6%), stable angina (35.6%), obesity (29.4%), atrial arrhythmias (17.3%), unstable angina (16.9%), cancer (16.6%), myocardial infarction (15.9%), diabetes (15.2%), alcohol (14.9%) and severe anaemia (14.3%). Mortality at 1 year varied across all 91 factors (lowest: pregnancy-related hormonal disorder – 4.2%; highest: phaeochromocytoma – 73.7%).

Conclusion

We provide a systematic map of primary preventive opportunities for heart failure, demonstrate the high burden of co-occurring aetiologic factors and highlight need for trials tackling multiple aetiological factors.

Aetiologic factors of heart failure

Funding Acknowledgement

Type of funding source: Public grant(s) – EU funding. Main funding source(s): Innovative Medicines Initiative-2 Joint Undertaking

Multi-drug resistant, biofilm-producing high-risk clonal lineage of Klebsiella in companion and household animals

Antimicrobial resistance is a global emergency which needs one health approach to address. The present study was conducted to detect the prevalence of beta-lactamase and biofilm-producing Klebsiella strains in rectal swabs (n = 624) collected from healthy dogs, cats, sheep and goats reared as companion or household animals in India. The dogs and cats were frequently exposed to third- or fourth-generation cephalosporins for therapy. The sheep and goats were occasionally exposed to antibiotics and had environmental exposure. Phenotypical ESBL (n = 93) and ACBL (n = 88)-producing Klebsiella were isolated significantly more (P < 0·05) from companion animals than household animals. Majority of the Klebsiella possessed bla_CTX-M-15 . The sequences bla_CTX-M-15.2 , bla_CTX-M-197 and bla_CTX-M-225 are reported first time from the companion animals. All ACBL-producing isolates possessed bla_AmpC . The present study detected 65·8% of Klebsiella strains as biofilm producers possessing the studied biofilm associated genes. The isolates showed phenotypical resistance against chloramphenicol, tetracycline, doxycycline, co-trimoxazole, ampicillin, cefotaxime/clavulanic acid. The present study showed that companion and household animals (dogs, cats, sheep, goats) may act as a carrier of ESBL/biofilm-producing, multi-drug resistant, high-risk clonal lineage of Klebsiella.

Does Point of Care Ultrasound Improve Resuscitation Markers in Undifferentiated Hypotension? An International Randomized Controlled Trial From The Sonography in Hypotension and Cardiac Arrest in the Emergency Department (SHoC-ED) Series

Introduction

Point of Care Ultrasound (PoCUS) protocols are commonly used to guide resuscitation for patients with undifferentiated hypotension, yet there is a paucity of evidence for any outcome benefit. We undertook an international multicenter randomized controlled trial (RCT) to assess the impact of a PoCUS protocol on key clinical outcomes. Here we report on resuscitation markers. 

Methods

Adult patients presenting to six emergency departments (ED) in Canada and South Africa with undifferentiated hypotension (systolic blood pressure (SBP) <100mmHg or a Shock Index >1.0) were randomized to receive a PoCUS protocol or standard care (control). Reported physiological markers include shock index (SI), and modified early warning score (MEWS), with biochemical markers including venous bicarbonate and lactate, at baseline and four hours. 

Results

A total of 273 patients were enrolled, with data collected for 270. Baseline characteristics were similar for each group. Improvements in mean values for each marker during initial treatment were similar between groups: Shock Index; mean reduction in Control 0.39, 95% CI 0.34 to 0.44 vs. PoCUS 0.33, 0.29 to 0.38; MEWS, mean reduction in Control 2.56, 2.22 to 2.89 vs. PoCUS 2.91, 2.49 to 3.32; Bicarbonate, mean reduction in Control 2.71 mmol/L, 2.12 to 3.30 mmol/L vs. PoCUS 2.30 mmol/L, 1.75 to 2.84 mmol/L, and venous lactate, mean reduction in Control 1.39 mmol/L, 0.93 to 1.85 mmol/L vs. PoCUS 1.31 mmol/L, 0.88 to 1.74 mmol/L.

Conclusion

We found no meaningful difference in physiological and biochemical resuscitation markers with or without the use of a PoCUS protocol in the resuscitation of undifferentiated hypotensive ED patients. We are unable to exclude improvements in individual patients or in specific shock types.

Facilitators of behavior change and weight loss in an intervention for African American Breast Cancer Survivors

PURPOSE

The purpose of this study was to examine facilitators of behavior change and weight loss among African-American women who participated in the Moving Forward Efficacy trial.

METHODS

Linear mixed models were used to examine the role of self-efficacy, social support, and perceived access to healthy eating, exercise, and neighborhood safety on weight, physical activity, and diet. We also examined the mediation of self-efficacy, social support, and perceived access to healthy eating, exercise, and neighborhood safety on weight loss, physical activity, and diet using the Freedman Schatzkin statistic.

RESULTS

We found no evidence to suggest mediation, but some direct associations of self-efficacy, certain types of social support and perceived access to exercise on weight loss, and behavior change.

CONCLUSION

We determined that self-efficacy, social support, and perceived access to exercise played a role in weight loss, increased MVPA, and better diet. The role of self-efficacy and perceived access to exercise were more consistent than social support.

Nature of Magnetic Excitations in the High-Field Phase of α-RuCl_{3}

We present comprehensive electron spin resonance (ESR) studies of in-plane oriented single crystals of α-RuCl_{3}, a quasi-two-dimensional material with honeycomb structure, focusing on its high-field spin dynamics. The measurements were performed in magnetic fields up to 16 T, applied along the [110] and [100] directions. Several ESR modes were detected. Combining our findings with recent inelastic neutron- and Raman-scattering data, we identified most of the observed excitations. Most importantly, we show that the low-temperature ESR response beyond the boundary of the magnetically ordered region is dominated by single- and two-particle processes with magnons as elementary excitations. The peculiarities of the excitation spectrum in the vicinity of the critical field are discussed.

Giant electron-phonon coupling of the breathing plane oxygen phonons in the dynamic stripe phase of [Formula: see text]

Doped antiferromagnets host a vast array of physical properties and learning how to control them is one of the biggest challenges of condensed matter physics. [Formula: see text] (LSNO) is a classic example of such a material. At low temperatures holes introduced via substitution of La by Sr segregate into lines to form boundaries between magnetically ordered domains in the form of stripes. The stripes become dynamic at high temperatures, but LSNO remains insulating presumably because an interplay between magnetic correlations and electron-phonon coupling localizes charge carriers. Magnetic degrees of freedom have been extensively investigated in this system, but phonons are almost completely unexplored. We searched for electron-phonon anomalies in LSNO by inelastic neutron scattering. Giant renormalization of plane Ni-O bond-stretching modes that modulate the volume around Ni appears on entering the dynamic charge stripe phase. Other phonons are a lot less sensitive to stripe melting. Dramatic overdamping of the breathing modes indicates that dynamic stripe phase may host small polarons. We argue that this feature sets electron-phonon coupling in nickelates apart from that in cuprates where breathing phonons are not overdamped and point out remarkable similarities with the colossal magnetoresistance manganites.

[Consensus recommendations on minimally invasive removal of carious tissue from dentine]

The International Caries Consensus Collaboration (ICCC) presented recommendations on terminology, methods of carious tissue removal and managing cavitated carious lesions. It identified 'dental caries' as the disease that dentists should manage by controlling the activity of existing cavitated lesions by preserving as much hard tissue as possible, maintaining pulp sensibility and retaining functional teeth in the long-term. The ICCC recommended the level of hardness as the criterion for determining the clinical consequences of the process of demineralisation and defined new strategies for the selective removal of carious tissue. The starting point is to effectively remove the biofilm from cavitated carious lesions. Only when cavitated carious lesions are either non-cleansable or can no longer be sealed, are restorative interventions indicated, with due regard for the principles of a minimally invasive approach. Applying a restoration facilitates biofilm removal, guards the pulpodental complex and restores form, function and aesthetics.

Chemo-mechanical characterization of carious dentine using Raman microscopy and Knoop microhardness

One of the aims in the clinical operative management of dental carious lesions is to remove selectively the highly infected and structurally denatured dentine tissue, while retaining the deeper, repairable affected and intact, healthy tissues for long-term mechanical strength. The present study examined the correlation of chemical functional groups and the microhardness through the different depths of a carious lesion using Raman spectroscopy and Knoop microhardness testing. The null hypothesis investigated was that there was no correlation between Raman peak ratios (amide I : phosphate ν1 ) and equivalent Knoop microhardness measurements. Ten freshly extracted human permanent teeth with carious dentine lesions were sectioned and examined using high-resolution Raman microscopy. The ratio of absorbency at the amide I and phosphate bands were calculated from 139 scan points through the depth of the lesions and correlated with 139 juxtaposed Knoop microhardness indentations. The results indicated a high correlation (p < 0.01) between the peak ratio and the equivalent Knoop hardness within carious dentine lesions. This study concluded that Raman spectroscopy can be used as a non-invasive analytical technology for in vitro studies to discriminate the hardness of carious dentine layers using the peak ratio as an alternative to the invasive, mechanical Knoop hardness test.

Morbidity profile of communities in Bhopal city (India) vis-à-vis distance of residence from Union Carbide India Limited plant and drinking water usage pattern

Objective:

A cross-sectional study was undertaken to assess the prevalence of morbidities in communities residing at variable distances from the closed down insecticide manufacturing plant premises of Union Carbide India Limited (UCIL), Bhopal, India and to determine association of morbidities, if any, with their drinking water usage pattern and distance of localities from the UCIL plant.

Materials and Methods:

A total of 10,827 individuals belonging to 2,184 families, residing within 0-1 km (Stratum I) and 2.5-5.0 km (Stratum II) radial distances from UCIL plant were surveyed and 9,306 of them (86%) were clinically examined. Data were analyzed to examine the association between the groups of morbidities, likely due to biological and chemical water contamination, and the distance of locality from the UCIL plant. Multiple logistic regression was used to explore the risk factors for morbidities.

Results:

Nearly similar prevalence (25.3% in stratum I, 25.8% in stratum II) and the trend of all-cause morbidities were recorded in the two strata. While morbidities related to gastrointestinal tract system (P < 0.05), auditory system (P < 0.01), neoplasm/cancers (P < 0.01) and congenital anomalies (P < 0.01) were significantly higher in stratum I, the prevalence of hypertension (6.4% stratum II, 4.7% stratum I; P < 0.01) and diabetes mellitus (3.4% stratum II, 2.0% stratum I; P < 0.001) was found significantly higher in stratum II. No association (P > 0.05) was observed between the prevalence of morbidities, likely due to the consumption of biologically or chemically contaminated drinking water, and the distance of locality/stratum from the UCIL plant.

Discussion and Conclusion:

By and large similar pattern of morbidities were recorded in the two strata suggesting that the communities, irrespective of the distance of their residences from UCIL plant or sources of their drinking water, are equally vulnerable to various morbidities.

Colon capsule endoscopy

There are multiple indications for luminal imaging of the colon. From assessment of known disease, to diagnosing new pathology; intra-luminal visualisation is the mainstay of gastrointestinal diagnosis. Colonoscopy and radiological imaging are currently the most frequently deployed diagnostic methods. However, both have an associated risk profile, have significant resource pressures and are not universally tolerated. Colon capsule endoscopy (CCE) offers an adjunct to these diagnostic options. In this narrative review the utility of CCE is described. Its current uses, potential benefits and future developments are also discussed.

Possible glass-like random singlet magnetic state in 1T-TaS2

Two-dimensional layered transition-metal-dichalcogenide compound 1T-TaS₂ shows the rare coexistence of charge density wave (CDW) and electron correlation driven Mott transition. In addition, atomic-cluster spins on the triangular lattice of the CDW state of 1T-TaS₂ give rise to the possibility of the exotic spin-singlet state in which quantum fluctuations of spins are strong enough to prevent any long range magnetic ordering down to the temperature absolute zero (0 K). We present here the evidences of a glass-like random singlet magnetic state in 1T-TaS₂ at low temperatures through a study of temperature and time dependence of magnetization. Comparing the experimental results with a representative canonical spin-glass system Au(1.8%Mn), we show that this glass-like state is distinctly different from the well established canonical spin-glass state.

Integrated care for older people (ICOPE): from guidelines to demonstrating feasibility

The World Health Organization (WHO) Global strategy and action plan on ageing and health (1) provides a policy framework to align health systems to the diverse needs of older populations. It promotes person-centred care that strengthen older peoples’ intrinsic capacity (physical and mental capacity) and ability to function where they live, a shift away from specialized medical treatment for each disease or condition. With its endorsement in 2016, WHO Member States recognized a pressing need to develop integrated, community-based approaches to prevent declines in intrinsic capacity. To operationalize ‘intrinsic capacity (IC)’, domains closely associated with care dependency were proposed: mobility, cognition, psychological capacity (depressive symptoms), vitality (malnutrition), and sensory capacity (hearing and vision) (2).

Approach to dyspnoea in pregnancy in the COVID-19 era

IMPORTANCE

Dyspnoea and hypoxia in pregnant women during the COVID-19 pandemic may be due to causes other than SARS Co-V-2 infection which should not be ignored. Shared decision-making regarding early delivery is paramount.

OBJECTIVE

To highlight and discuss the differential diagnoses of dyspnoea and hypoxia in pregnant women and to discuss the risks versus benefit of delivery for maternal compromise.

DESIGN, SETTING AND PARTICIPANTS

Case series of two pregnant women who presented with dyspnoea and hypoxia during the COVID-19 pandemic.

RESULTS

Two pregnant women presented with dyspnoea and hypoxia. The first case had COVID-19 infection in the 3rd trimester. The second case had an exacerbation of asthma without concurrent COVID-19. Only the first case required intubation and delivery. Both recovered and were discharged home. Conclusion and relevance: Our two cases highlight the importance of making the correct diagnosis and timely decision-making to consider if delivery for maternal compromise is warranted. Whilst COVID-19 is a current healthcare concern other differential diagnoses must still be considered when pregnant women present with dyspnoea and hypoxia.

An oxygen-rich atmosphere or systemic fluoxetine extend the time to respiratory arrest in a rat model of obstructive apnea

Audiogenic seizure-prone mice can be protected from seizure-associated death by exposure to an oxygen atmosphere or treatment with selective serotonergic reuptake inhibitors (SSRIs). We have shown previously in a rat model that epileptic seizure activity can spread through brainstem areas to cause sufficient laryngospasm for obstructive apnea and that the period of seizure-associated obstructive apnea can last long enough for respiratory arrest to occur. We hypothesized that both the oxygen-rich atmosphere and SSRIs function by prolonging the time to respiratory arrest, thus ensuring that seizure activity stops before the point of respiratory arrest to allow recovery of respiratory function. To test this hypothesis, we evaluated each preventative treatment in a rat model of controlled airway occlusion where the times to respiratory arrest can be measured. Adult male Sprague Dawley rats (median age = 66 days) were studied in the absence of any seizure activity. By directly studying responses to controlled airway occlusion, rather than airway occlusion secondary to seizure activity, we could isolate the effects of manipulations that might prolong respiratory arrest from the effects of those manipulations on seizure intensity. All group sizes were ≥ 8 animals per group. We found that both oxygen exposure and fluoxetine significantly increased the time to respiratory arrest by up to 65% (p < .0001 for 5 min oxygen exposure; p = .031 for 25 mg/kg fluoxetine tested 60 min after injection) and, given that neither treatment has been shown to significantly alter seizure duration, these increases can account for the protection of either manipulation against death in sudden death models. Importantly, we found that 30 s of exposure to oxygen produced nearly the same protection as 5 min exposure suggesting that oxygen exposure could start after a seizure starts (p = .0012 for 30 s oxygen exposure). Experiments with 50% oxygen/50% air mixtures indicate that the oxygen concentration needs to be above about 60% to ensure that times to respiratory arrest will always be longer than a period of seizure-induced airway occlusion. Selective serotonin reuptake inhibitors, while instructive with regard to mechanism, require impractical dosing and may carry additional risk in the form of greater challenges for resuscitation. We conclude that oxygen exposure or SSRI treatment prevent seizure associated death by sufficiently prolonging the time to respiratory arrest so that respiratory function can recover after the seizure abates and eliminates the stimulus for seizure-induced apnea.

A Systematic Review and Meta-Analysis of the Role of Sugar-Free Chewing Gum in Dental Caries

OBJECTIVE

To determine the difference in level of dental caries in adults and children who chew sugar-free gum (SFG), compared with those who do not chew SFG or use alternatives such as lozenges, candies, rinses, tablets, and other nonchewing controls.

METHODS

Systematic review of published literature.

RESULTS

Twelve studies of interventions of SFG for dental caries outcomes were included. SFGs were found to significantly reduce caries increment, giving a preventative fraction (PF) of 28% (95% CI, 7% to 48%). Including the 8 trials that used xylitol gum only as the basis of the intervention, the PF was 33% (95% CI, 4% to 61%). No adverse effects were recorded. There was a high level of heterogeneity among the trials included.

CONCLUSION

The findings of this review provide tentative evidence that chewing SFG reduces caries increment in comparison to nonchewing controls. However, there is a considerable degree of variability in the effect and the trials included were generally of moderate quality. There is a need for future research to explore the acceptability and feasibility of the use of SFG as a public health intervention (PROSPERO 2018 CRD42018094676).

KNOWLEDGE TRANSFER STATEMENT

The results of this study can be used by clinicians when deciding how best to implement dental caries prevention regimes for their patients. With consideration of cost and patient preference, this information could help to develop national policy directives on caries prevention and dictate the direction of future clinical research.

Does Point-of-care Ultrasonography Change Emergency Department Care Delivered to Hypotensive Patients When Categorized by Shock Type? A Post-Hoc Analysis of an International Randomized Controlled Trial from the SHoC-ED Investigators

Introduction Our previously reported randomized-controlled-trial of point-of-care ultrasound (PoCUS) for patients with undifferentiated hypotension in the emergency department (ED) showed no survival benefit with PoCUS. Here, we examine the data to see if PoCUS led to changes in the care delivered to patients with cardiogenic and non-cardiogenic shock. Methods A post-hoc analysis was completed on a database of 273 hypotensive ED patients randomized to standard care or PoCUS in six centres in Canada and South Africa. Shock categories recorded one hour after the ED presentation were used to define subcategories of shock. We analyzed initial intravenous fluid volumes, as well as rates of inotrope use and procedures. Results  261 patients could be classified as cardiogenic or non-cardiogenic shock types. Although there were expected differences in the mean fluid volume administered between patients with non-cardiogenic and cardiogenic shock (p-value<0.001), there was no difference between the control and PoCUS groups (mean non-cardiogenic control 1881mL (95% CI 1567-2195mL) vs non-cardiogenic PoCUS 1763mL (1525-2001mL); and cardiogenic control 680mL (28.4-1332mL) vs. cardiogenic PoCUS 744mL (370-1117mL; p= 0.67). Likewise, there were no differences in rates of inotrope administration nor procedures for any of the subcategories of shock between the control group and PoCUS group patients. Conclusion Despite differences in care delivered by subcategory of shock, we did not find any difference in key elements of emergency department care delivered between patients receiving PoCUS and those who did not. This may help explain the previously reported lack of outcome differences between groups.

Characterization of beta-lactamase and biofilm producing Enterobacteriaceae isolated from organized and backyard farm ducks

This study was undertaken to detect the occurrence of beta-lactamase and biofilm producing Enterobacteriaceae in healthy ducks. A total 202 cloacal swabs were collected from ducks kept in organized (n = 92) and backyard (n = 110) farms in West Bengal (India). The ducks had no history of antibiotic intake. Among the 87 phenotypically beta-lactamase producing Escherichia coli, 19 (17·43%), 6 (5·05%) and 15 (13·76%) isolates possessed bla_TEM , bla_SHV and bla_CTX-M respectively. Whereas, 5 (38·46%) Salmonella isolates were found to harbour bla_CTX-M . In K. pneumoniae 10 (33·33%), 3 (13·33%), 4 (13·33%) isolates possessed bla_TEM , bla_SHV and bla_CTX-M respectively. The sequences of selected PCR products were found 98% cognate with bla_CTX-M-9, bla_SHV-12 and bla_TEM-1 . Beta-lactamase producing E. coli isolates belonged to 14 different serogroups such as O1, O2, O3, O5, O7, O8, O35, O83, O84, O88, O119, O128, O145 and O157. Moreover, 87 E. coli (79·82%), six Samonella (46·15%) and 13 K. pneumoniae (43·33%) isolates were detected as AmpC producers possessing bla_AmpC . Majority of E. coli (46·79%), Salmonella (46·15%) and K. pneumoniae (70%) isolates were detected as biofilm producers and possessed the associated genes (csgA, sdiA, rcsA, rpoS). Significantly higher occurrence of beta-lactamase and biofilm producing Enterobacteriaceae isolates was detected in backyard ducks than organized farms. SIGNIFICANCE AND IMPACT OF THE STUDY: Consumption of antibiotic through feed or during therapy is considered as potential reason for generation of antimicrobial resistant bacteria in birds. This study provides valuable evidence that exposure to contaminated environment may be an additional source for generation of antimicrobial resistant bacteria in backyard ducks. The backyard ducks are reared by marginal farmers in India who cannot offer antibiotics to them either through feed or during therapy due to high cost. The study also reveals a significant correlation between biofilm formation and possession of antimicrobial resistance genes in the bacterial isolates from the ducks.

P5705Machine learning for phenotyping and risk prediction in cardiovascular diseases: a systematic review

Introduction

Heart failure (HF), acute coronary syndromes (ACS) and atrial fibrillation (AF) are among the commonest cardiovascular diseases (CVD), frequently co-exist and share pathophysiology. Definitions of diagnosis and prognosis are suboptimal. Machine learning (ML) is increasingly used in subtype definition and risk prediction, but the design, methods and results of studies have not been appraised.

Purpose

To conduct a systematic review of ML for discovery of new subtypes and risk prediction in HF, ACS and AF.

Methods

PubMed, MEDLINE, and Web of Science databases were searched (January 2000-August 2018) for English language publications with agreed search terms pertaining to machine learning, clustering, CVD, subtype and risk prediction. The baseline characteristics of the study population, the method of ML, covariates and results were extracted for each study.

Results

Of 5012 identified studies, 43 met inclusion criteria. Of the 33 studies of unsupervised ML for disease clustering (mean n=2354; min 117, max 44886), there were 22 in HF, 9 in ACS and 2 in AF. 22/33 studies involved <1000 individuals and 24 were based in North America. Across diseases, 27 studies were in outpatients, and 5 used trial data. The mean number of covariates used was 26; most commonly demographic and symptom variables. The ML methods used were partitional (n=12), hierarchical (n=4), self-organising map (n=1) and hidden Markov model (n=1). Most studies used only one ML method (n=25). Only 15 studies validated or replicated findings. 20/33 studies found 2 or 3 disease clusters, Most studies found 2–3 clusters (20/33) and most clusters were based on physical or physiological characteristics (30/33).

Of the 10 studies of supervised ML for risk prediction (mean n=43003; min 228, max 378256), 4 were in HF, 5 in ACS and 1 in AF. 2/11 studies involved <1000 individuals and most were from North America (n=6). All studies had an observational design, used at least 2 ML methods and validated or replicated findings. The setting was varied: primary care (n=2), emergency department (n=2), inpatient (n=4) and mixed (n=2). The mean number of covariates was 102. The commonest ML methods were neural networks (n=5), random forest (n=4) and support vector machine (n=4). All studies showed positive finding, i.e. ML approaches improved risk prediction.

Conclusions

Studies to-date of ML in HF, ACS and AF have focused on North America (68.2%), and 50% included less than 1000 individuals. Moreover, there is heterogeneity in clinical setting, study designs for data collection and ML methods used. Comparison between methods of ML and validation are common to studies of risk prediction but not disease clustering. There is likely to be a publication bias of ML studies in HF, AF and ACS. ML may improve data-driven characterisation of CVD but consensus guidelines for reporting of research using ML are urgently needed to ensure the internal and external validity and applicability of study findings.

Acknowledgement/Funding

Innovative Medicines Initiative (European Union)