Time-to-positivity, type of culture media and oxidase test performed on positive blood culture vials to predict Pseudomonas aeruginosa in patients with Gram-negative bacilli bacteraemia

OBJECTIVE

The aim of this study was to determine the usefulness of oxidase test and time-to-positivity (TTP) in aerobic and anaerobic blood culture vials to detect the presence of Pseudomonas aeruginosa in patients with Gram-negative bacilli (GNB) bacteraemia.

METHODS

TTP was recorded for each aerobic and anaerobic blood culture vial of monomicrobial bacteraemia due to GNB. Oxidase test was performed in a pellet of the centrifuged content of the positive blood culture. An algorithm was developed in order to perform the oxidase test efficiently taking into account TTP and type of vial.

RESULTS

A total of 341 episodes of GNB bacteraemia were analysed. Sensitivity, specificity, positive predictive value and negative predictive value of the oxidase test performed on positive vials with GNB to predict P. aeruginosa were 95%, 99%, 91%, and 99%, respectively. When growth was first or exclusively detected in anaerobic vials, P. aeruginosa was never identified hence the performance of the oxidase test could be avoided. When growth was only or first detected in aerobic vials, a TTP≥8h predicted P. aeruginosa in 37% or cases (63 of 169), therefore oxidase test is highly recommended.

CONCLUSIONS

Oxidase test performed onto positive blood culture vials previously selected by TTP and type of vials is an easy and inexpensive way to predict P. aeruginosa. In most cases, this can lead to optimization of treatment in less than 24 hours.

Differential uPA Expression by TGF-β1 in Gingival Fibroblasts

Transforming Growth Factor-β1 (TGF-β1) plays a key role in connective tissue remodeling and inflammation. Under pathological conditions, like periodontal disease, fibroblasts may display an altered response to this growth factor. To investigate this question, we have studied whether TGF-β1 may differentially regulate the expression of urokinase at the protein level in primary cultures of fibroblasts derived from healthy gingiva, granulation tissue from gingival wounds, and chronic periodontal disease. We observed that TGF-β1 may repress urokinase expression in healthy gingival fibroblasts and promote its production in granulation-tissue fibroblasts. A significant correlation was found between expression of the myofibroblast marker α-smooth-muscle actin and stimulation of urokinase production by TGF-β1. Immunostaining of gingival wounds showed that myofibroblasts were involved in urokinase production. TGF-β1-stimulated urokinase expression was blocked after inhibition of the c-jun-NH2 terminal kinase signaling pathway. We propose that stimulation of urokinase production by TGF-β1 is involved in the responses of activated fibroblasts to tissue injury.

Risk of incident ischemic stroke according to the metabolic health and obesity states in the Vascular-Metabolic CUN cohort

Background

Whether obesity is a major risk factor for cardiovascular disease in the absence of metabolic comorbidities remains under debate. Indeed, some obese individuals may be at low risk of metabolic-related complications, while normal-weight individuals may not be “healthy.”

Aims

To assess the incidence of ischemic stroke according to the metabolic health and obesity states of 5171 participants from the Vascular-Metabolic CUN cohort.

Methods

A Cox proportional-hazard analysis was conducted to estimate the hazard ratio and their 95% confidence interval of stroke according to the metabolic health and obesity states based on TyG index and Adult Treatment Panel-III criteria, during 9.1 years of follow-up.

Results

After 50,056.2 person-years of follow-up, 162 subjects developed an ischemic stroke (incidence rate 3.23 per 1000 person-years). Metabolically healthy obese subjects did not show greater risk of stroke, while metabolically unhealthy participants, obese and non-obese, had an increased risk of stroke, compared with healthy non-obese. The hazard ratios for the multivariable adjusted model were 1.55 (95% CI: 1.36–1.77) and 1.86 (95% CI: 1.57–2.21), respectively.

Conclusions

Metabolically unhealthy individuals exhibited a greater risk of ischemic stroke than metabolically healthy obese individuals.

Changes in Volatile Compounds during Ripening in Grapes of Airén, Macabeo and Chardonnay White Varieties Grown in La Mancha Region (Spain)

Changes in volatile compounds in musts and skins of grapes of Airén, Macabeo and Chardonnay white varieties were determined during ripening. The musts of the Airén variety contained higher concentrations of c-3-hexenol; musts of the Macabeo variety were the richest in t-3-hexenol and 2,4-hexadienal, while the Chardonnay musts stood out for having higher concentrations of benzaldehyde, phenylacetaldehyde and benzyl alcohol. The skins of the three varieties were both qualitatively and quantitatively richer in volatiles than were the musts. The skins of the Airén grapes had the highest levels of nerol. Airén grapes were the only variety in which citronellol was present in the skins. Low concentrations of eugenol were detected in the skins of the Chardonnay grape variety but were not present in the other two varieties. Changes in the concentration of the volatile compounds during ripening were not uniform; this made difficult the determination of the optimum level of ripening for each variety on the basis of the volatile compound content. Nevertheless, results indicated that C6 compounds and terpene concentrations reached a maximum at 6-8 ° Baumé in the Airén grapes and at around 11 ° Baumé in the Chardonnay and Macabeo grapes.

[Approach to directed therapy after knowledge of the isolate: carbapenemase-producing Enterobacteriaceae, multidrug-resistant Pseudomonas aeruginosa and carbapenem-resistant Acinetobacter baumannii]

Directed treatment of infections due to multidrug-resistant Gram-negative bacilli is a difficult task, since it requires the use of a limited number of antibiotics that are often more toxic and possibly less efficacious than β-lactams and fluoroquinolones. Furthermore, there are very few controlled trials informing on the relative efficacy of different therapeutic strategies. As a general rule, it is recommended to use at least two active drugs or a combination with proven synergistic activity in vitro, because several observational studies have associated this practice with better outcomes and as a measure to potentially curb the emergence of further resistance. It is already available a new cephalosporin active against most strains of Pseudomonas aeruginosa resistant to ceftazidime due to derepression of ampC and in the near future an effective inhibitor of class A, class C and OXA-48 will be available which combined with ceftazidime is expected to mean a significant addition to the armamentarium against Gram-negative bacilli with these resistance determinants.

Eicosapentaenoic acid promotes mitochondrial biogenesis and beige-like features in subcutaneous adipocytes from overweight subjects

Eicosapentaenoic acid (EPA), a n-3 long-chain polyunsaturated fatty acid, has been reported to have beneficial effects in obesity-associated metabolic disorders. The objective of the present study was to determine the effects of EPA on the regulation of genes involved in lipid metabolism, and the ability of EPA to induce mitochondrial biogenesis and beiging in subcutaneous adipocytes from overweight subjects. Fully differentiated human subcutaneous adipocytes from overweight females (BMI: 28.1-29.8kg/m²) were treated with EPA (100-200 μM) for 24 h. Changes in mRNA expression levels of genes involved in lipogenesis, fatty acid oxidation and mitochondrial biogenesis were determined by qRT-PCR. Mitochondrial content was evaluated using MitoTracker® Green stain. The effects on peroxisome proliferator-activated receptor gamma, co-activator 1 alpha (PGC-1α) and AMP-activated protein kinase (AMPK) were also characterized. EPA down-regulated lipogenic genes expression while up-regulated genes involved in fatty acid oxidation. Moreover, EPA-treated adipocytes showed increased mitochondrial content, accompanied by an up-regulation of nuclear respiratory factor-1, mitochondrial transcription factor A and cytochrome c oxidase IV mRNA expression. EPA also promoted the activation of master regulators of mitochondrial biogenesis such as sirtuin 1, PGC1-α and AMPK. In parallel, EPA induced the expression of genes that typify beige adipocytes such as fat determination factor PR domain containing 16, uncoupling protein 1 and cell death-inducing DFFA-like effector A, T-Box protein 1 and CD137. Our results suggest that EPA induces a remodeling of adipocyte metabolism preventing fat storage and promoting fatty acid oxidation, mitochondrial biogenesis and beige-like markers in human subcutaneous adipocytes from overweight subjects.

Yogurt consumption and abdominal obesity reversion in the PREDIMED study

BACKGROUND AND AIMS

Evidence on the association yogurt consumption and obesity is not conclusive. The aim of this study was to prospectively evaluate the association between yogurt consumption, reversion of abdominal obesity status and waist circumference change in elderly.

METHODS AND RESULTS

4545 individuals at high cardiovascular risk were prospectively followed. Total, whole-fat and low-fat yogurt consumption were assessed using food frequency questionnaires. Generalized estimating equations were used to analyze the association between yogurt consumption and waist circumference change (measured at baseline and yearly during the follow-up). Logistic regression models were used to evaluate the odds ratios (ORs) and 95% CIs of the reversion rate of abdominal obesity for each quintile of yogurt consumption compared with the lowest quintile. After multivariable adjustment, the average yearly waist circumference change in the quintiles of whole-fat yogurt consumption was: Q1: 0.00, Q2: 0.00 (-0.23 to 0.23), Q3: -0.15 (-0.42 to 0.13), Q4: 0.10 (-0.21 to 0.42), and Q5: -0.23 (-0.46 to -0.00) cm; p for trend = 0.05. The ORs for the reversion of abdominal obesity for whole-fat yogurt consumption were Q1: 1.00, Q2: 1.40 (1.04-1.90), Q3: 1.33 (0.94-1.89), Q4: 1.21 (0.83-1.77), and Q5: 1.43 (1.06-1.93); p for trend = 0.26.

CONCLUSION

Total yogurt consumption was not significantly associated with reversion of abdominal obesity status and a lower waist circumference. However, consumption of whole-fat yogurt was associated with changes in waist circumference and higher probability for reversion of abdominal obesity. Therefore, it seems that whole-fat yogurt has more beneficial effects in management of abdominal obesity in elderly population at high cardiovascular risk.

Risk factors associated with high linezolid trough plasma concentrations

AIM

The major concern of linezolid is the adverse events. High linezolid trough serum concentration (Cmin) has been associated with toxicity. The aim of this study was to analyze factors associated with high Cmin.

METHODS

Main clinical characteristics of 104 patients treated with 600 mg/12 hours of linezolid were retrospectively reviewed. Samples were obtained just before the next dose after at least three doses and within the first 8 days of treatment. High Cmin was considered when it was >8 mg/L. Univariate and multivariate analysis were performed.

RESULTS

34.6% patients had a Cmin >8 mg/L, and they were older and had more frequently an estimated glomerular filtration by MDRD <40 mL/min. There were more patients co-treated with rifampin in the group with low Cmin. The only factor independently associated with Cmin >8 was the renal function. Patients with an eGF < 40 mL/min had significantly higher Cmin than those with eGF > 80 mL/min (OR: 4.273) and there was a trend towards a high Cmin in patients with eGF between 40-80 mL/min (OR: 2.109).

CONCLUSIONS

High Cmin were frequent, especially in patients with MDRD <40 mL/min. Therapeutic drug monitoring could be useful to avoid toxicity in patients with renal dysfunction.

Coronavirus Infection in Ferrets: Antigen Distribution and Inflammatory Response

Multisystemic granulomatous lesions are the most common finding in ferrets infected by ferret systemic coronavirus (FRSCV). To characterize the inflammatory response developed against this virus, lesions from 4 naturally infected ferrets were examined. Lesions were classified into the 4 known types of granulomas (granulomas without necrosis [G], granulomas with necrosis [G-N], granulomas with neutrophils [G-NL], and diffuse granulomatous inflammation [DG]). The cellular composition of the lesions was characterized on the basis of cellular morphology and immunohistochemistry using markers for T and B-lymphocytes, plasma cells, macrophages, and neutrophils. The extent and distribution of viral antigen expression was also assessed. In G lesions, macrophages were mainly located in the center of the granuloma, with a moderate number of T-lymphocytes scattered among the macrophages, plasma cells, and B-lymphocytes. G-N lesions exhibited a necrotic center surrounded by abundant macrophages, some T-lymphocytes, plasma cells, and a few B-lymphocytes. In G-NL lesions, there was a central area dominated by neutrophils with low numbers of macrophages, plasma cells, and lymphocytes. DG presented similar cell proportions, but distributed evenly throughout the lesions. FRSCV was expressed in G, G-NL, G-N, and DG, with decreasing numbers of immunoreactive cells. This study reveals the important role of macrophages in the inflammatory response of ferrets against the virus and the variable proportions of leukocytes among different types of lesions, indicating their variable age. The results also confirm the similarities of the disease in ferrets to feline infectious peritonitis.

Serum 25-hydroxyvitamin D, parathyroid hormone, calcium intake, and bone mineral density in Spanish adults

Vitamin D insufficiency is very common among Spanish community-dwelling adult subjects. A threshold of serum 25(OH)D around 30 ng/ml would be necessary for the prevention of secondary hyperparathyroidism and hip bone loss in our population, regardless of the dairy calcium ingestion.

INTRODUCTION

This study aims to assess 25-hydroxyvitamin D-25(OH)D-status in Spanish adult subjects and to analyze its relationships with serum PTH levels, calcium intake, and bone mineral density (BMD).

METHODS

A total of 1811 individuals (1154 postmenopausal women and 657 men) aged 44-93 years participated in the study. Serum 25(OH)D, intact parathyroid hormone (PTH), aminoterminal propeptide of type I collagen (P1NP), and C-terminal telopeptide of type I collagen (β-CTX) levels were measured by electrochemiluminescence. BMD was determined by dual x-ray absorptiometry (DXA) at lumbar spine, femoral neck, and total hip.

RESULTS

Serum 25(OH)D levels were below 10, 20, and 30 ng/ml in 5, 40, and 83 % of participants, respectively. There was a significant seasonal difference in mean serum 25(OH)D, with higher levels in summer-autumn. In multivariate analysis, 25(OH)D levels were negatively correlated with age, serum PTH and creatinine, body mass index, smoking, alcohol intake, and a number of chronic diseases, but positively with dairy calcium intake. The magnitude of the difference in serum PTH according to 25(OH)D quartiles was not influenced by calcium intake. A threshold of serum 25(OH)D around 30 ng/ml was observed for serum PTH and hip BMD.

CONCLUSIONS

Vitamin D insufficiency is very common among Spanish community-dwelling adult subjects. A threshold of serum 25(OH)D around 30 ng/ml would be necessary for the prevention of secondary hyperparathyroidism and hip bone loss in our population, regardless of the dairy calcium ingestion. Programs to improve vitamin D status may be required in our country.

Trans-resveratrol induces a potential anti-lipogenic effect in lipopolysaccharide-stimulated enterocytes

A DNA microarray analysis was conducted in Caco-2 cells to analyse the protective effects of trans-resveratrol on enterocyte physiology and metabolism in pro-inflammatory conditions. Cells were pre-treated with 50 μΜ of trans-resveratrol and, subsequently, lipopolysaccharide (LPS) was added for 48 h. The microarray analysis revealed 121 genes differentially expressed between resveratrol-treated and non-treated cells (B> 0, is the odd thatthe gene is differentially expressed). Inhibitor of DNA binding 1 (ID1), histidine-rich glycoprotein (HRG), NADPH oxidase (NOX1) and sprouty homolog 1 (SPRY), were upregulated by LPS treatment, but significantly blocked by trans-resveratrol pre-treatment (padj< 0.05, after adjusting for Benjamini-Hocheberg procedure). Moreover, genes implicated in synthesis of lipids (z-score= -1.195) and concentration of cholesterol (z-score= -0.109), were markedly downregulated by trans-resveratrol. Other genes involved in fat turnover, but also in cell death and survival function, such as transcription factors Krüppel-like factor 5 (KLF5) and amphiregulin (AREG), were also significantly inhibited by trans-resveratrol pre-treatment. RT-qPCR-data confirmed the microarray results. Special mention deserves acyl-CoA synthetase long-chain family member 3 (ACSL3) and endothelial lipase (LIPG), which were downregulated by this stilbene and have been previously associated with fatty acid synthesis and obesity in other tissues. This study envisages that trans-resveratrol might exert an important anti-lipogenic effect at intestinal level under pro-inflammatory conditions, which has not been previously described.