Multi-omics Analyses Reveal Synergistic Carbohydrate Metabolism in Streptococcus mutans-Candida albicans Mixed-Species Biofilms.

Candida albicans, a major opportunistic fungal pathogen, is frequently found together with Streptococcus mutans in dental biofilms associated with severe childhood caries (tooth decay), a prevalent pediatric oral disease. However, the impact of this cross-kingdom relationship on C. albicans remains largely uncharacterized. Here, we employed a novel quantitative proteomics approach in conjunction with transcriptomic profiling to unravel molecular pathways of C. albicans when cocultured with S. mutans in mixed biofilms. RNA sequencing and iTRAQ (isobaric tags for relative and absolute quantitation)-based quantitative proteomics revealed that C. albicans genes and proteins associated with carbohydrate metabolism were significantly enhanced, including sugar transport, aerobic respiration, pyruvate breakdown, and the glyoxylate cycle. Other C. albicans genes and proteins directly and indirectly related to cell morphogenesis and cell wall components such as mannan and glucan were also upregulated, indicating enhanced fungal activity in mixed-species biofilm. Further analyses revealed that S. mutans-derived exoenzyme glucosyltransferase B (GtfB), which binds to the fungal cell surface to promote coadhesion, can break down sucrose into glucose and fructose that can be readily metabolized by C. albicans, enhancing growth and acid production. Altogether, we identified key pathways used by C. albicans in the mixed biofilm, indicating an active fungal role in the sugar metabolism and environmental acidification (key virulence traits associated with caries onset) when interacting with S. mutans, and a new cross-feeding mechanism mediated by GtfB that enhances C. albicans carbohydrate utilization. In addition, we demonstrate that comprehensive transcriptomics and quantitative proteomics can be powerful tools to study microbial contributions which remain underexplored in cross-kingdom biofilms.

Dexmedetomidine-associated hyperthermia: a retrospective cohort study of intensive care unit admissions between 2009 and 2016.

Dexmedetomidine-associated hyperthermia has not been previously studied. Analysis is warranted to determine whether this potentially dangerous complication is more prevalent than previously realised. We aimed to examine the association between dexmedetomidine and temperature ≥39.5°C, including patient characteristics, temporality and potential risk factors. We conducted a retrospective cohort study of all intensive care unit (ICU) admissions between 1 July 2009 and 31 May 2016 in a tertiary ICU in Australia. Temperature data was available for 9,782 ICU admissions. Dexmedetomidine was given intravenously to 611 (6.3%) patients at a dose of 0 to 1.5 g/kg/hour. Temperatures ≥39.5°C were recorded in 341 (3.5%) patients. Overall hospital mortality was 10.8% for all admissions and 29.3% for patients with temperatures ≥39.5°C. Dexmedetomidine exposure was more frequent in patients with temperature recordings ≥39.5°C compared to those with temperatures <39.5°C, 11.94% versus 2.94% (odds ratio [OR] 4.49; 95% confidence intervals [CI] 3.37, 5.92; P <0.001). The association was stronger for patients post-open heart surgery (OHS) with temperatures ≥39.5°C (OR 12.9; 95% CI 5.01, 31.62; P <0.001). Multivariate analysis showed an independent association between dexmedetomidine and a temperature ≥39.5°C in two particular patient groups: OHS (OR 2.72; 95% CI 1.1, 6.9; P <0.001), and obesity (OR 3.44; 95% CI 1.5, 7.9; P <0.001). Dexmedetomidine exposure is associated with an increased risk of hyperthermia. Possible risk factors are open heart surgery and obesity.

Is a short arm cast appropriate for stable distal radius fractures in patients older than 55 years? A randomized prospective multicentre study.

We conducted a prospective randomized, multicentre study to compare short arm and long arm plaster casts for the treatment of stable distal radius fracture in patients older than 55 years. We randomly assigned patients over the age of 55 years who had stable distal radius fracture to either a short arm or long arm plaster cast at the first review 1 week after their injury. Radiographic and clinical follow-up was conducted at 1, 3, 5, 12 and 24 weeks following their injury. Also, degree of disability caused by each cast immobilization was evaluated at the patient's visit to remove the cast. There were no significant differences in radiological parameters between the groups except for volar tilt. Despite these differences in volar tilt, neither functional status as measured by the Disabilities of the Arm, Shoulder and Hand, nor visual analogue scale was significantly different between the groups. However, the mean score of disability caused by plaster cast immobilization and the incidence rate of shoulder pain were significantly higher in patients who had a long plaster cast. Our findings suggest that a short arm cast is as effective as a long arm cast for stable distal radius fractures in the elderly. Furthermore, it is more comfortable and introduces less restriction on daily activities. LEVEL OF EVIDENCE: II.

Proteomic Profiling of De Novo Protein Synthesis in Starvation-Induced Autophagy Using Bioorthogonal Noncanonical Amino Acid Tagging.

Autophagy is an intracellular degradation process activated by stress factors such as nutrient starvation to maintain cellular homeostasis. There is emerging evidence demonstrating that de novo protein synthesis is involved in the autophagic process. However, up-to-date characterizing of these de novo proteins is technically difficult. In this chapter, we describe a novel method to identify newly synthesized proteins during starvation-mediated autophagy by bioorthogonal noncanonical amino acid tagging (BONCAT), in conjunction with isobaric tagging for relative and absolute quantification (iTRAQ)-based quantitative proteomics. l-azidohomoalanine (AHA) is an analog of methionine, and it can be readily incorporated into the newly synthesized proteins. The AHA-containing proteins can be enriched with avidin beads after a "click" reaction between alkyne-bearing biotin and the azide moiety of AHA. The enriched proteins are then subjected to iTRAQ™ labeling for protein identification and quantification using liquid chromatography-tandem mass spectrometry (LC-MS/MS). By using this technique, we have successfully profiled more than 700 proteins that are synthesized during starvation-induced autophagy. We believe that this approach is effective in identification of newly synthesized proteins in the process of autophagy and provides useful insights to the molecular mechanisms and biological functions of autophagy.

The clinical utility of Xpert® MTB/RIF testing in induced sputum.

We performed a prospective clinical audit in hospitalised patients with suspected pulmonary tuberculosis (PTB) with the objective of evaluating the accuracy and clinical utility of Xpert® MTB/RIF in induced sputum in an intermediate-burden setting. Of 450 patients audited, 61 (13.6%) were diagnosed with PTB based on positive culture. The sensitivity, specificity and positive and negative predictive values for Xpert in smear-negative cases for induced sputum were respectively 75%, 99.5%, 94.7% and 97.0%. Xpert in induced sputum may facilitate diagnostic yield and expedite treatment in up to a quarter of PTB patients.

Risk factors for hospital and long-term mortality of critically ill elderly patients admitted to an intensive care unit.

BACKGROUND: Data on long-term outcomes of elderly (≥65 years) patients in ICU are sparse. MATERIALS AND METHODS: Adult patients (n = 1563, 45.4% elderly) admitted over 28 months were analyzed by competing risks regression model to determine independent factors related to in-hospital and long-term mortality. RESULTS: 414 (26.5%) and 337 (21.6%) patients died in-hospital and during the 52 months following discharge, respectively; the elderly group had higher mortality during both periods. After discharge, elderly patients had 2.3 times higher mortality compared to the general population of the same age-group. In-hospital mortality was independently associated with mechanical ventilation (subdistribution hazard ratio (SHR) 2.74), vasopressors (SHR 2.56), neurological disease (SHR 1.77), and Mortality Prediction Model II score (SHR 1.01) regardless of age and with malignancy (SHR, hematological 3.65, nonhematological 3.4) and prior renal replacement therapy (RRT, SHR 2.21) only in the elderly. Long-term mortality was associated with low hemoglobin concentration (SHR 0.94), airway disease (SHR 2.23), and malignancy (SHR hematological 1.11, nonhematological 2.31) regardless of age and with comorbidities especially among the nonelderly. CONCLUSIONS: Following discharge, elderly ICU patients have higher mortality compared to the nonelderly and general population. In the elderly group, prior RRT and malignancy contribute additionally to in-hospital mortality risk. In the long-term, comorbidities (age-related), anemia, airway disease, and malignancy were significantly associated with mortality.

In vivo measurement of gadolinium diffusivity by dynamic contrast-enhanced MRI: a preclinical study of human xenografts.

Compartmental tracer kinetic models currently used for analysis of dynamic contrast-enhanced MRI data yield poor fittings or parameter values that are unphysiological in necrotic regions of the tumor, as these models only describe microcirculation in perfused tissue. In this study, we explore the use of Fick's law of diffusion as an alternative method for analysis of dynamic contrast-enhanced MRI data in the necrotic regions. Xenografts of various human cancer cell lines were implanted in 14 mice that were subjected to dynamic contrast-enhanced MRI performed using a spoiled gradient recalled sequence. Tracer concentration was estimated using the variable flip angle technique. Poorly perfused and necrotic tumor regions exhibiting delayed and slow enhancement were identified using a k-means clustering algorithm. Tracer behavior in necrotic regions was shown to be consistent with Fick's diffusion equation and the in vivo gadolinium diffusivity was estimated to be 2.08 (±0.88) × 10(-4) mm(2)/s. This study proposes the use of gadolinium diffusivity as an alternative parameter for quantifying tracer transport within necrotic tumor regions.

The increased prevalence of left ventricular hypertrophy and concentric remodeling in U.K. Indian Asians compared with European whites.

Individuals of Indian Asian ethnicity living in the U.K. have at least a 50% excess of cardiovascular disease (CVD) mortality compared with European whites, yet there are no validated tools capable of identifying this excess risk. Left ventricular hypertrophy (LVH) is a powerful prognosticator for future CVD events but its prevalence in Indian Asians is unknown. We examined the prevalence of LVH and the degree of concentric remodeling amongst healthy U.K. Indian Asians compared with European whites recruited to the LOLIPOP (London Life Sciences Prospective Population) study. Transthoracic echocardiography was performed in 2127 subjects aged 35-75 years without history of clinical CVD events. The prevalence of LVH was defined and relative wall thickness was calculated to provide a measure of concentric remodeling. The prevalence of LVH was significantly higher amongst Indian Asian men as compared with European white men, with an unadjusted odds ratio (OR) of 1.8 (95% CI: 1.4-2.6). Following adjustment for clinical and hemodynamic variables, the magnitude of this effect increased (OR 2.8, 95% CI: 1.9-4.2). The degree of concentric remodeling was higher amongst Indian Asians as compared with European whites (adjusted relative wall thickness for men: 0.41 vs. 0.39, P<0.001; women: 0.40 vs. 0.38, P<0.01). An almost threefold higher prevalence of LVH amongst Indian Asian men and a greater degree of concentric remodeling amongst Indian Asian men and women was evident. Investigation of the mechanisms underlying the pathogenesis of LV remodeling and blood pressure etiology may help redress the excess CVD mortality observed in Indian Asians.

Utility of the electronic information resource UpToDate for clinical decision-making at bedside rounds.

INTRODUCTION: Clinical questions often arise at daily hospital bedside rounds. Yet, little information exists on how the search for answers may be facilitated. The aim of this prospective study was, therefore, to evaluate the overall utility, including the feasibility and usefulness of incorporating searches of UpToDate, a popular online information resource, into rounds. METHODS: Doctors searched UpToDate for any unresolved clinical questions during rounds for patients in general medicine and respiratory wards, and in the medical intensive care unit of a tertiary teaching hospital. The nature of the questions and the results of the searches were recorded. Searches were deemed feasible if they were completed during the rounds and useful if they provided a satisfactory answer. RESULTS: A total of 157 UpToDate searches were performed during the study period. Questions were raised by all ranks of clinicians from junior doctors to consultants. The searches were feasible and performed immediately during rounds 44% of the time. Each search took a median of three minutes (first quartile: two minutes, third quartile: five minutes). UpToDate provided a useful and satisfactory answer 75% of the time, a partial answer 17% of the time and no answer 9% of the time. It led to a change in investigations, diagnosis or management 37% of the time, confirmed what was originally known or planned 38% of the time and had no effect 25% of the time. CONCLUSION: Incorporating UpToDate searches into daily bedside rounds was feasible and useful in clinical decision-making.

Short-term mortality among older persons hospitalized for pneumonia: influence of baseline patient characteristics beyond severity of illness.

BACKGROUND: Although severity of illness indices such as pneumonia severity index (PSI) are good predictors of short-term mortality for community-acquired pneumonia (CAP) and healthcare-associated pneumonia (HCAP), other patient factors may have added prognostic value. OBJECTIVE: To identify patient factors beyond the PSI which explain 30-day mortality among older persons hospitalized with CAP and HCAP. DESIGN: Retrospective cohort study. SETTING: Three acute care hospitals in Singapore in 2007. PATIENTS: Hospitalized adults aged 65 years or older who have primary International Classification of Diseases, 9th revision, Clinical Modification (ICD-9-CM) codes 480 to 486 with clinical and radiological features of pneumonia. INTERVENTIONS: None. MEASUREMENTS: Thirty-day mortality, PSI class, demographic and clinical features, comorbid conditions, functional status, selected laboratory tests, and chest radiographic findings. RESULTS: Among 1607 patients included, 890 (55.4%) had CAP and 717 (44.6%) had HCAP. After adjustment for PSI class in logistic regression analyses, pre-morbid ambulation impairment (odds ratio [OR] 2.61, 95% confidence interval [CI] 1.98 to 3.45), hospitalization in the prior 30 days (OR 1.93, 95% CI 1.38 to 2.71), and absence of cough and purulent sputum (OR 1.47, 95% CI 1.14 to 1.90) were all significantly associated with 30-day mortality. These associations remained constant when CAP and HCAP were analyzed separately. CONCLUSIONS: Recent hospitalization, pre-morbid ambulation impairment, and atypical presentation were independently associated with higher 30-day mortality among older persons hospitalized for pneumonia, after adjusting for severity of illness. These factors could be considered in addition to PSI when performing risk stratification and adjustment in this setting.

Diagnostic characteristics of clinical prediction models for obstructive sleep apnea in different clinic populations.

PURPOSE: As predictive factors and their diagnostic values are affected by the characteristics of the population studied, clinical prediction model for obstructive sleep apnea (OSA) may exhibit different diagnostic characteristics in different populations. We aimed to compare the diagnostic characteristics of clinical prediction models developed in two different populations. METHODS: One hundred seventeen consecutive clinic patients (group 1) were evaluated to develop a clinical prediction model for OSA (local model). The diagnostic characteristics of this local model were compared with those of a foreign model by applying both models to another group of 52 patients who were referred to the same clinic (group 2). All patients underwent overnight polysomnography. RESULTS: The local model had an area under receiver operator characteristics curve of 79%. A cutoff of 0.6 was associated with sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 77.9%, 72.5%, 84.5%, and 63.0%, respectively. The overall diagnostic accuracy, sensitivity, specificity, PPV, and NPV of the local model using data from patients in group 2 were 69.0%, 78.1%, 45.0%, 69.4%, and 56.3%, respectively. The foreign model had an overall diagnostic accuracy of 64.0% when applied to data from patients in group 2. At the optimal cutoff of 17, the foreign model was associated with sensitivity of 38.2%, specificity of 83.3%, NPV of 41.7% and PPV of 81.3%. CONCLUSIONS: Clinical prediction model for OSA derived from a foreign population exhibits markedly different diagnostic characteristics from one that is developed locally, even though the overall accuracy is similar. Our findings challenge the predictive usefulness and the external validity of clinical prediction models.

The impact of a delay in intensive care unit admission for community-acquired pneumonia.

The primary objective of the present study was to evaluate the effect on hospital mortality of a delay in intensive care unit (ICU) admission for severe community-acquired pneumonia (CAP). The secondary objectives were to assess if such delays were associated with treatment variations by the emergency department (ED) and deterioration in the general wards, and to evaluate the prognostic ability of the Infectious Disease Society of America (IDSA)/American Thoracic Society (ATS) minor criteria. We retrospectively compared patients who were admitted straight from the ED to the ICU (direct group, n = 54) and those who were first admitted from the ED to the general wards before ICU transfer (delayed group, n = 49), over 2.5 yrs. Even after excluding patients who required mechanical ventilation and/or vasopressors at the ED, delayed ICU admission was an independent predictor of hospital mortality (OR 9.61). The delayed group received fewer fluid boluses in the ED and rapidly deteriorated in the general wards. The presence of ≥3 IDSA/ATS minor criteria was associated with increased mortality in the delayed group. In conclusion, prompt recognition of severe CAP using the IDSA/ATS minor criteria, followed by aggressive management at the ED and direct ICU admission, are all crucial toward improving outcomes.

Metered-dose inhaler with spacer instead of nebulizer during the outbreak of severe acute respiratory syndrome in Singapore.

BACKGROUND: The use of metered-dose inhaler (MDI) with spacer instead of nebulizer may be important during an outbreak of an airborne infection. However, there is a paucity of data on patients' and nurses' abilities and perspectives on MDI with spacer for the treatment of acute airway obstruction during such an outbreak. METHODS: We evaluated 50 consecutive MDI-with-spacer treatments administered in the respiratory wards of the National University Hospital of Singapore, and interviewed the patients after each treatment during the outbreak of severe acute respiratory syndrome (SARS). We also conducted interviews with 50 nurses who had experience in administering bronchodilators via both nebulizer and MDI with spacer. RESULTS: Forty-six patients (92%) were able to use MDI with spacer effectively. Sixteen percent of the patients preferred nebulizer over MDI with spacer. Fifty-eight percent of the patients thought MDI with spacer was easier to use than nebulizer, and 34% thought MDI was as easy to use as nebulizer. Sixteen percent of the patients thought that nebulizer was more effective than MDI with spacer in relieving their symptoms. Ninety-six percent of the nurses preferred nebulizer over MDI with spacer. Forty-two nurses (84%) thought that nebulizer was more effective for treating acute airflow obstruction in the hospital. CONCLUSIONS: In the in-patient setting during an outbreak of an airborne infection, for treatment of acute airflow obstruction, MDI with spacer was acceptable and preferred by a high percentage of patients. However, a high percentage of nurses had misconceptions regarding the efficacy of and patients' ability to use MDI with spacer.

Independent value of left atrial volume index for the prediction of mortality in patients with suspected heart failure referred from the community.

BACKGROUND: The left atrial volume index (LAVI) reflects left ventricular (LV) filling pressure and has been shown to predict outcome in various cardiovascular diseases. However, its value for the prediction of mortality in patients referred for suspected heart failure (HF) is unknown. OBJECTIVE: To assess the value of LAVI for the prediction of mortality independently of clinical, electrocardiographic (ECG) and echocardiographic prognostic parameters in patients with suspected HF referred from the community. METHODS: 356 (mean (SD) age 72 (13) years) patients with suspected HF referred from the community were followed up for mortality after undergoing clinical assessment, ECG and echocardiography, including Doppler, to assess LV filling. RESULTS: Data were obtained for 335/356 (94%) patients (162 male, 173 female) over a mean (SD) follow-up period of 30 (10) months, during which 38 (11.3%) died. The univariate predictors for all-cause mortality were age, symptom of leg swelling, clinical signs of HF, abnormal ECG, LV ejection fraction, LAVI, LV end-systolic (LVESD) and diastolic dimension, septal wall thickness and the presence of other significant cardiac abnormalities. The only independent predictors of mortality were age (hazard ratio (HR) = 2.15, 95% CI 1.42 to 3.25, p<0.001), symptom of leg swelling (HR = 2.83, 95% CI 1.43 to 5.59, p = 0.005), LAVI (HR = 1.25, 95% CI 1.01 to 1.54, p = 0.04) and LVESD (HR = 1.32, 95% CI 1.02 to 1.70, p = 0.04). CONCLUSION: LAVI provided independent information over clinical and other echocardiographic variables for predicting mortality in patients with suspected HF referred from the community.

Validation and clinical implications of the IDSA/ATS minor criteria for severe community-acquired pneumonia.

BACKGROUND: The 2007 Infectious Disease Society of America (IDSA)/American Thoracic Society (ATS) guidelines defined severe community-acquired pneumonia (CAP) and recommended intensive care unit (ICU) admission when patients fulfilled three out of nine minor criteria. These criteria have not been validated. METHODS: All patients admitted to our hospital from 2004 to 2007 for CAP were reviewed retrospectively. Patients who fulfilled any IDSA/ATS major criteria for severe CAP at the emergency department (ie, the need for mechanical ventilation or vasopressors) were excluded. The predictive characteristics of the IDSA/ATS minor criteria were compared with those of the Pneumonia Severity Index (PSI) and the CURB-65 score for hospital mortality and ICU admission. RESULTS: 1242 patients were studied (mean age 65.7 years, hospital mortality 14.7%). The areas under the receiver operating characteristic curves for the IDSA/ATS minor criteria were 0.88 (95% CI 0.86 to 0.91) and 0.85 (95% CI 0.81 to 0.88) for predicting hospital mortality and ICU admission, respectively. These were greater than the corresponding areas for the PSI and the CURB-65 score (p < 0.05). The sensitivity, specificity, positive and negative predictive values of the minor criteria were 81.4%, 82.9%, 45.2% and 96.3%, respectively, for hospital mortality and 58.3%, 90.6%, 52.9% and 92.3%, respectively, for ICU admission. The minor criteria were more specific than the PSI and more sensitive than the CURB-65 score for both outcomes. CONCLUSION: These findings support the use of the IDSA/ATS minor criteria to predict hospital mortality and guide ICU admission in inpatients with CAP who do not require emergency mechanical ventilation or vasopressors.