Inflammation markers in point-of-care testing (POCT)

Point-of-care C-reactive protein-based tuberculosis screening for people living with HIV: a diagnostic accuracy study

Background

Symptom-based screening for tuberculosis (TB) is recommended for all people living with HIV (PLHIV) resulting in unnecessary Xpert MTB/RIF testing for the vast majority of individuals living in TB endemic areas and thus, poor implementation of intensified case finding (ICF) and TB preventive therapy. Novel approaches to TB screening are therefore critical in achieving global targets for TB elimination.

Methods

In a prospective study of PLHIV with CD4+ T-cell count ≤350 cells/uL initiating antiretroviral therapy (ART) from two HIV/AIDS clinics in Uganda, we evaluated the performance of C-reactive protein (CRP) measured using a rapid and inexpensive point-of-care (POC) assay as a screening tool for active pulmonary TB.

Findings

Of 1177 HIV-infected adults (median CD4+ T-cell count 168 cells/µL) enrolled, 163 (14%) had culture-confirmed TB. POC CRP had 89% (145/163) sensitivity and 72% (731/1014) specificity for culture-confirmed TB. Compared to the WHO symptom screen, POC CRP had lower sensitivity (difference −7% [95% CI: −12 to −2], p=0.002) but substantially higher specificity (difference +58% [95% CI: +61 to +55], p<0.0001). When Xpert MTB/RIF results were used as the reference standard, sensitivity of POC CRP and the WHO symptom screen were similar (94% [79/84] vs. 99% [83/84]; difference −5% [95% CI: −12 to +2], p=0.10).

Interpretation

The performance characteristics of CRP support its use as a TB screening test for PLHIV with CD4+ T-cell count ≤350 cells/µL initiating ART. HIV/AIDS programs should consider POC CRP-based TB screening to improve the efficiency of ICF and increase uptake of TB preventive therapy.

FUNDING

National Institutes of Health; Presidential Emergency Plan for AIDS Relief; University of California, San Francisco, Nina Ireland Program for Lung Health

Detection of aflatoxin B1 in food samples based on target-responsive aptamer-cross-linked hydrogel using a handheld pH meter as readout

Aflatoxin B₁ (AFB₁) can cause great threat to human health, so the development of convenient and portable device for sensitive detection of AFB₁ is highly desired. The portable pH meter has the characters of facile operation, low cost, and easy availability. Therefore, in this study, we investigate the applicability of utilizing a pH meter as the readout to develop a portable sensor for AFB₁. The specific detection of AFB₁ is realized via the combination of AFB₁-responsive aptamer-cross-linked hydrogel. Upon the addition of AFB₁, AFB₁ binds to its aptamer with high affinity in lieu of aptamer/DNA complex, causing the collapse of hydrogel network and results in the releasing of urease into the solution. The released urease can catalyse the hydrolysis of urea and result in the rise of pH value. The change of pH value has a direct relationship to the concentration of AFB₁ in the range of 0.2-20µM with a detection limit of 0.1µM (S/N = 3). The proposed portable device is successfully applied to assay AFB₁ in the food samples with satisfied results.

C-Reactive Protein Mediating Immunopathological Lesions: A Potential Treatment Option for Severe Influenza A Diseases

Severe influenza diseases with high mortality have been frequently reported, especially in those patients infected with avian influenza A (H5N1, H7N9 or H10N8) or during a pandemic. Respiratory distress, which is attributed to alveolar damage associated with immunopathological lesions, is the most common cause of death. There is a wealth of information on pathogenesis or treatment options. In this study, we showed that high levels of C-reactive protein (CRP) were induced and correlated with complement activation in patients infected with severe influenza A (H5N1, H7N9 or H10N8), and higher levels were induced in fatal patients than in survivors. CRP treatment enhanced the phagocytosis of monocytes THP-1 to H5N1 virus as well as the expression of proinflammatory cytokines or apoptosis-associated genes in THP-1 cells or pneumocytes A-549 respectively. CRP may link to proinflammatory mediators contributing to activation of complement and boosting inflammatory response in severe influenza infections. Compound 1,6-bis(phosphocholine)-hexane improved the severity and mortality of mice infected with lethal influenza virus significantly. These observations showed that CRP is involved in deterioration of severe influenza diseases, and indicated a substantial candidate molecule for immunotherapy of severe influenza diseases.

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CRP induces exacerbated immunoresponse toward overt pulmonary inflammation in severe influenza infections.

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CRP may link to proinflammatory mediators contributing to activation of complement and boosting inflammatory response.

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CRP stabilizer can alleviate the immunopathological lesions and mortality in mice infected with lethal influenza virus.

Severe influenza diseases with high mortality have been frequently reported, especially in those patients infected with avian influenza A (H5N1, H7N9, or H10N8) or during a pandemic. Respiratory distress associated with immunopathological lesions is the most common cause of death in patients infected by these viruses. In this study, we found that CRP may be linked to exacerbated immunoresponse toward overt pulmonary inflammation, which led to alveolar damage and respiratory failure in severe influenza infection. Our data identified that CRP stabilizer can be used to alleviate the immunopathological lesions and mortality in mice infected with lethal influenza virus.

C-reactive protein is differentially modulated by co-existing infections, vitamin deficiencies and maternal factors in pregnant and lactating indigenous Panamanian women

Background

The usefulness of C-reactive protein (CRP) as a non-specific marker of inflammation during pregnancy and lactation is unclear in impoverished populations where co-existing infections and vitamin deficiencies are common.

Methods

This cross-sectional study in Panama recruited 120 pregnant and 99 lactating Ngäbe-Buglé women from 14 communities in rural Panama. Obstetric history, indoor wood smoke exposure, fieldwork, BMI, vitamins A, B₁₂, D, and folic acid, and inflammation markers (CRP, neutrophil/lymphocyte ratio (NLR), plateletcrit and cytokines) were measured. Multiple regressions explored both associations of CRP with other inflammatory markers and associations of CRP and elevated CRP based on trimester-specific cut-offs with maternal factors, infections and vitamin deficiencies.

Results

CRP was higher in pregnancy (51.4 ± 4.7 nmol/L) than lactation (27.8 ± 3.5 nmol/L) and was elevated above trimester specific cut-offs in 21% of pregnant and 30% of lactating women. Vitamin deficiencies were common (vitamin A 29.6%; vitamin D 68.5%; vitamin B₁₂ 68%; folic acid 25.5%) and over 50% of women had two or more concurrent deficiencies as well as multiple infections. Multiple regression models highlighted differences in variables associated with CRP between pregnancy and lactation. In pregnancy, CRP was positively associated with greater indoor wood smoke exposure, caries and hookworm and negatively associated with Ascaris and vaginal Lactobacillus and Bacteroides/Gardnerella scores. Consistent with this, greater wood smoke exposure, caries as well as higher diplococcal infection score increased the odds of trimester-elevated CRP concentrations whereas longer gestational age lowered the likelihood of a trimester-elevated CRP. During lactation, folic acid deficiency was associated with higher CRP whereas parity, number of eosinophils and Mobiluncus score were associated with lower CRP. Also, a higher BMI and Trichomonas vaginalis score increased the likelihood of an elevated CRP whereas higher parity and number of eosinophils were associated with lower likelihood of an elevated CRP.

Conclusions

Infections both raise and lower CRP concentrations in pregnant and lactating mothers. Only folic acid deficiency during lactation was associated with higher CRP concentrations. Caution is required when interpreting CRP concentrations in pregnant and lactating women who have co-existing nutrient deficiencies and multiple infections.

Electronic supplementary material

The online version of this article (doi:10.1186/s40249-017-0307-1) contains supplementary material, which is available to authorized users.

Non-professional marathon running: RAGE axis and ST2 family changes in relation to open-window effect, inflammation and renal function

Conflicting data exist on the relevance of marathon (M) and half marathon (HM) running for health. The number of non-professional athletes finishing M and HM events is steadily growing. In order to investigate molecular changes occurring in amateur athletes, we enrolled 70 non-professional runners finishing a single M (34) or HM (36) event at baseline, the finish line and during recovery, and 30 controls. The measurement of the Receptor for Advanced Glycation Endproducts, Interleukin 1 receptor antagonist, ST2 and cytokeratin 18 was combined with molecules measured during clinical routine. Results were analyzed in the light of blood cell analysis, lactate measurements, correction for changes in plasma volume and body composition assessments. There were intrinsic differences in body mass index, abdominal body fat percentage and training time between M and HM runners. C-reactive protein changes in M and HM runners. While soluble RAGE, AGEs and ST2 increased immediately after the race in HM runners, HMGB1 increased in HM and M after the race and declined to baseline after a recovery period. We give insights into the regulation of various molecules involved in physical stress reactions and their possible implications for the cardiovascular system or renal function.

Serum Procalcitonin as a Useful Serologic Marker for Differential Diagnosis between Acute Gouty Attack and Bacterial Infection

PURPOSE

Patients with gout are similar to those with bacterial infection in terms of the nature of inflammation. Herein we compared the differences in procalcitonin (PCT) levels between these two inflammatory conditions and evaluated the ability of serum PCT to function as a clinical marker for differential diagnosis between acute gouty attack and bacterial infection.

MATERIALS AND METHODS

Serum samples were obtained from 67 patients with acute gouty arthritis and 90 age-matched patients with bacterial infection. Serum PCT levels were measured with an enzyme-linked fluorescent assay.

RESULTS

Serum PCT levels in patients with acute gouty arthritis were significantly lower than those in patients with bacterial infection (0.096±0.105 ng/mL vs. 4.94±13.763 ng/mL, p=0.001). However, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels showed no significant differences between the two groups. To assess the ability of PCT to discriminate between acute gouty arthritis and bacterial infection, the areas under the curves (AUCs) of serum PCT, uric acid, and CRP were 0.857 [95% confidence interval (CI), 0.798-0.917, p<0.001], 0.808 (95% CI, 0.738-0.878, p<0.001), and 0.638 (95% CI, 0.544-0.731, p=0.005), respectively. There were no significant differences in ESR and white blood cell counts between these two conditions. With a cut-off value of 0.095 ng/mL, the sums of sensitivity and specificity of PCT were the highest (81.0% and 80.6%, respectively).

CONCLUSION

Serum PCT levels were significantly lower in patients with acute gouty attack than in patients with bacterial infection. Thus, serum PCT can be used as a useful serologic marker to differentiate between acute gouty arthritis and bacterial infections.

Usefulness of serum procalcitonin as a diagnostic biomarker of infection in children with chronic kidney disease

INTRODUCTION

Serum procalcitonin (PCT) levels are known to be low in healthy individuals in healthy subjects but are increased in patients with a severe bacterial infection. It has not been extensively studied in children with chronic kidney disease (CKD), treated either with hemodialysis (HD) or with renal transplantation.

MATERIAL AND METHODS

During a 6-month period, blood samples were taken from 102 (55 HD children and 47 renal transplant recipients) children with a strong clinical suspicion of infection. Procalcitonin levels were measured by ELISA.

RESULTS

Thirty-four/102 cases had proven infections as defined previously. Children with proven infections had a significantly higher PCT (0.920 ±0.24 ng/ml) than those without (0.456 ±0.53 ng/ml), p = 0.04. The ideal cutoff value derived for serum PCT was 0.5 ng/ml. This threshold value established a sensitivity of 94.1% and a specificity of 87.9%.

CONCLUSIONS

This study indicates that significantly increased PCT concentration is a promising predictor of systemic bacterial infection in children with CKD, with good sensitivity and specificity. This study proposes that serum PCT is a convenient index of infection in CKD children at a cutoff value of 0.5 ng/ml.

Association between increased blood interleukin-6 levels on emergency department arrival and prolonged length of intensive care unit stay for blunt trauma

Background

Systemic immune response to injury plays a key role in the pathophysiological mechanism of blunt trauma. We tested the hypothesis that increased blood interleukin-6 (IL-6) levels of blunt trauma patients on emergency department (ED) arrival are associated with poor clinical outcomes, and investigated the utility of rapid measurement of the blood IL-6 level.

Methods

We enrolled 208 consecutive trauma patients who were transferred from the scene of an accident to a level I trauma centre in Japan and admitted to the intensive care unit (ICU). Blood IL-6 levels on ED arrival were measured by using a rapid measurement assay. The primary outcome variable was prolonged ICU stay (length of ICU stay > 7 days). The secondary outcomes were 28-day mortality, probability of survival and Abbreviated Injury Scale (AIS) scores.

Results

Patients with prolonged ICU stay had significantly higher blood IL-6 levels on ED arrival than the patients without prolonged ICU stay (P < 0.0001). The receiver-operating characteristic curves produced an area under the curve of 0.75 (95 % confidence interval [CI], 0.66–0.84; P < 0.0001) for prolonged ICU stay. The patients who had increased blood IL-6 levels on ED arrival had increased 28-day mortality (P = 0.021) and decreased probability of survival (P < 0.0001). The AIS scores for the thorax, abdomen, extremity, and external body regions independently correlated with blood IL-6 levels (unstandardized coefficients [95 % CI] for the thorax: 23.8 [12.6–35.1]; P < 0.0001; abdomen: 42.7 [23.8–61.7]; P < 0.0001; extremity: 19.0 [5.5–32.4]; P = 0.0060; external body regions: 62.9 [13.2–112.7]; P = 0.030); the standardized coefficients for the thorax (0.27) and abdomen (0.28) were larger than those for the extremity (0.18) and external body regions (0.15).

Conclusions

Increased blood IL-6 level on ED arrival was significantly associated with prolonged length of ICU stay. Blood IL-6 level on ED arrival independently correlated with the AIS scores for the abdomen and thorax, and, to a lesser extent, those for the extremity and external body regions. The rapid measurement of blood IL-6 level on ED arrival can be utilized as a fast screening tool to improve assessment of injury severity and prediction of clinical outcomes in the initial phase of trauma care.

The Neutrophil to Lymphocyte Ratio on Admission and Short-Term Outcomes in Orthogeriatric Patients

AIM

To investigate the association of the neutrophil to lymphocyte ratio (NLR) at admission with presence of fracture, comorbid conditions, and its prognostic value for short-term outcomes in orthogeriatric patients.

METHODS

On 415 consecutive patients (mean age 78.8 ±8.7[SD] years, 281 women, 255 with a non-vertebral bone fracture, including 167 with a hip fracture, HF) admitted to the Department of Orthopaedic Surgery at the Canberra hospital (2010 - 2011) data on clinical and laboratory characteristics were collected prospectively. The validation dataset included 294 consecutive patients (mean age 82.1 ± 8.0 years, 72.1% women) with HF.

RESULTS

Multivariate regression revealed four variables, presence of HF, hypoalbuminaemia (<33g/L), anaemia (<120g/L) and hyperparathyroidism (PTH>6.8 pmol/L), as independent determinants of admission NLR≥5.1. There was a dose-graded relationship between presence of fracture, especially HF, postoperative complications and levels of NLR categorized as tertiles. Compared to patients with NLR<5.1(first tertile), patients with NLR 5.1-8.5 (second tertile) had a 1.8-, 3.1-, 2.6-, and 2.5-fold higher risk for presence of any fracture, HF, developing postoperative myocardial injury (troponin I rise) and a high inflammatory response/infection (CRP>100mg/L after the 3rd postoperative day), respectively, while in subjects with NLR>8.5 (third tertile) these risks were 2.6-, 4.9-, 5.9- and 4.5-times higher, respectively; subjects with NLR>8.5 had a 9.7 times higher chance of dying in the hospital compared to patients with NLR 5.1-8.5; the NLR retained its significance on multivariate analyses. The NLR ≥5.1 predicted postoperative myocardial injury with an area under the curve (AUC) of 0.626, CRP>100mg/L with AUC of 0.631 and the NLR >8.5 predicted in-hospital mortality with an AUC of 0.793, showing moderately high sensitivity (86.7%, 80% and 90%, respectively) and negative predictive value (92.9%, 71.2%, 99.6%, respectively), but low specificity. Admission NLR was superior to other, except hypoalbuminaemia, prognostic markers; combined use of both NLR≥5.1 and albumin<33g/L only moderately increased the accuracy of prediction. The validation study confirmed the prognostic value of the admission NLR.

CONCLUSIONS

In orthogeriatric patients, high NLR on admission is an independent indicator of fracture presence, a significant risk factor and moderate predictor of postoperative myocardial injury, high inflammatory response/infection and in-hospital death.

Influence of in-line microfilters on systemic inflammation in adult critically ill patients: a prospective, randomized, controlled open-label trial

Background

In critically ill children, in-line microfilters may reduce the incidence of the systemic inflammatory response syndrome (SIRS), the overall complication and organ dysfunction rate. No data on the use of in-line microfilters exist in critically ill adults.

Methods

In this prospective, randomized, controlled open-label study, we evaluated the influence of in-line microfilters on systemic immune activation in 504 critically ill adults with a central venous catheter in place and an expected length of stay in the intensive care unit >24 h. Patients were randomized to have in-line microfilters placed into all intravenous lines (intervention group) or usual care (control group). The primary endpoint was the number of intensive care unit days with SIRS. Secondary endpoints were the incidence of SIRS, SIRS criteria per day, duration of invasive mechanical ventilation, intensive care unit length of stay, the incidence of acute lung injury, maximum C-reactive protein, maximum white blood cell count, incidence of new candida and/or central-line-associated bloodstream infections, incidence of new thromboembolic complications, cumulative insulin requirements and presence of hyper- or hypoglycemia.

Results

The study groups did not differ in any baseline variable. There was no difference in the number of days in the intensive care unit with SIRS between microfilter and control patients [2 (0.8–4.7) vs. 1.8 (0.7–4.4), p = 0.62]. Except for a higher incidence of SIRS in microfilter patients (99.6 vs. 96.8 %, p = 0.04), no difference between the groups was observed in any secondary outcome parameter. Results did not change when only patients with an intensive care unit length of stay of greater than 7 days were included in the analysis. The rate of adverse events was comparable between microfilter and control patients. In two patients allocated to the microfilter group, the study intervention was discontinued for technical reasons. Use of in-line microfilters was associated with additional costs.

Conclusions

The use of in-line microfilters failed to modulate systemic inflammation and clinical outcome parameters in critically ill adults.

Trial registration: Clinical Trials NCT01534390

A point of care test for the determination of amniotic fluid interleukin-6 and the chemokine CXCL-10/IP-10

OBJECTIVE

Intra-amniotic inflammation is a mechanism of disease implicated in preterm labor, preterm prelabor rupture of membrane, cervical insufficiency, a short cervix, and idiopathic vaginal bleeding. Determination of interleukin (IL)-6 with immunoassays has been proven for more than two decades to be an excellent method for the detection of intra-amniotic inflammation. However, assessment of IL-6 for this indication has been based on immunoassays which are not clinically available, and this has been an obstacle for the implementation of this test in clinical practice. It is now possible to obtain results within 20 min with a point of care (POC) test which requires minimal laboratory support. This test is based on lateral flow-based immunoassay. The objective of this study was to compare amniotic fluid (AF) IL-6 and interferon-γ - inducible protein 10 (IP-10 or CXCL-10) concentrations determined using lateral flow-based immunoassay or POC test and standard enzyme-linked immunosorbent assay (ELISA) techniques.

MATERIAL AND METHODS

AF samples were collected from patients with singleton gestations and symptoms of preterm labor (n = 20). AF IL-6 and IP-10 concentrations were determined by lateral flow-based immunoassay and ELISA. Intra-amniotic inflammation was defined as AF IL-6 ≥ 2.6 ng/ml. AF IL-6 and IP-10 concentrations between two assays were compared.

RESULTS

(1) Lateral flow-based immunoassay POC AF IL-6 and IP-10 test results were strongly correlated with concentrations of this cytokine/chemokine determined by ELISA (Spearman's ρ = 0.92 and 0.83, respectively, both p < 0.0001); (2) AF IL-6 concentrations determined by the lateral flow-based immunoassay test were, on average, 30% lower than those determined by ELISA, and the median difference was statistically significant (p < 0.0001); and (3) in contrast, AF IP-10 concentrations determined by the lateral flow-based immunoassay test were, on average, only 7% lower than those determined by ELISA, and the median difference was not statistically significant (p = 0.81).

CONCLUSION

AF IL-6 and IP-10 concentrations determined using a lateral flow-based immunoassay POC are strongly correlated with concentrations determined by conventional ELISA. This justifies further studies about the diagnostic indices and predictive values of this POC test.

Human Neutrophil Lipocalin as a Superior Diagnostic Means To Distinguish between Acute Bacterial and Viral Infections

The distinction between causes of acute infections is a major clinical challenge. Current biomarkers, however, are not sufficiently accurate. Human neutrophil lipocalin (HNL) concentrations in serum or whole blood activated by formyl-methionine-leucine-phenylalanine (fMLP) were shown to distinguish acute infections of bacterial or viral cause with high accuracy. The aim was therefore to compare the clinical performance of HNL with currently used biomarkers. Seven hundred twenty-five subjects (144 healthy controls and 581 patients with signs and symptoms of acute infections) were included in the study. C-reactive protein (CRP), the expression of CD64 on neutrophils, procalcitonin (PCT), and blood neutrophil counts were measured by established techniques, and HNL concentrations were measured in whole-blood samples after activation with fMLP. All tested biomarkers were elevated in bacterial as opposed to viral infections (P < 0.001). CRP, PCT, and CD64 expression in neutrophils was elevated in viral infections compared to healthy controls (P < 0.001). In the distinction between healthy controls and patients with bacterial infections, the areas under the receiver operating characteristic (ROC) curves were >0.85 for all biomarkers, whereas for the distinction between bacterial and viral infections, only HNL concentration in fMLP-activated whole blood showed an area under the ROC curve (AUROC) of >0.90 and superior clinical performance. The clinical performance of HNL in fMLP-activated whole blood was superior to current biomarkers and similar to previous results of HNL in serum. The procedure can be adopted for point-of-care testing with response times of <15 min.

Aptamer-based Sandwich Assay and its Clinical Outlooks for Detecting Lipocalin-2 in Hepatocellular Carcinoma (HCC)

We validated a single-stranded, DNA aptamer-based, diagnostic method capable of detecting Lipocalin-2 (LCN2), a biomarker from clinically relevant hepatocellular carcinoma (HCC) patient serum, in the sandwich assay format. Nine aptamers (LCN2_apta1 to LCN2_apta9) for LCN2 were screened with SELEX processes, and a sandwich pair (LCN2_apta2 and LCN2_apta4) was finally chosen using surface plasmon resonance (SPR) and dot blotting analysis. The result of the proposed aptamer sandwich construction shows that LCN2 was sensitively detected in the concentration range of 2.5–500 ng mL⁻¹ with a limit of detection of 0.6 ng mL⁻¹. Quantitative measurement tests in HCC patients were run on straight serum and were compared with the performance of the conventional antibody-based ELISA kit. The aptamer sandwich assay demonstrated an excellent dynamic range for LCN2 at clinically relevant serum levels, covering sub-nanogram per mL concentrations. The new approach offers a simple and robust method for detecting serum biomarkers that have low and moderate abundance. It consists of functionalization, hybridization and signal read-out, and no dilution is required. The results of the study demonstrate the capability of the aptamer sandwich assay platform for diagnosing HCC and its potential applicability to the point-of-care testing (POCT) system.

Accuracy and feasibility of point-of-care white blood cell count and C-reactive protein measurements at the pediatric emergency department

Background

Several point-of-care (POC) tests are available for evaluation of febrile patients, but the data about their performance in acute care setting is sparse. We investigated the analytical accuracy and feasibility of POC tests for white blood cell (WBC) count and C-reactive protein (CRP) at the pediatric emergency department (ED).

Methods

In the first part of the study, HemoCue WBC and Afinion AS100 CRP POC analyzers were compared with laboratory’s routine WBC (Sysmex XE-2100) and CRP (Modular P) analyzers in the hospital central laboratory in 77 and 48 clinical blood samples, respectively. The POC tests were then adopted in use at the pediatric ED. In the second part of the study, we compared WBC and CRP levels measured by POC and routine methods during 171 ED patient visits by 168 febrile children and adolescents. Attending physicians performed POC tests in capillary fingerprick samples.

Results

In parallel measurements in the laboratory both WBC and CRP POC analyzers showed good agreement with the reference methods. In febrile children at the emergency department (median age 2.4 years), physician performed POC determinations in capillary blood gave comparable results with those in venous blood analyzed in the laboratory. The mean difference between POC and reference test result was 1.1 E9/L (95% limits of agreement from -6.5 to 8.8 E9/L) for WBC and -1.2 mg/L (95% limits of agreement from -29.6 to 27.2 mg/L) for CRP.

Conclusions

POC tests are feasible and relatively accurate methods to assess CRP level and WBC count among febrile children at the ED.

Human neutrophil lipocalin in fMLP-activated whole blood as a diagnostic means to distinguish between acute bacterial and viral infections

The distinction between causes of acute infections is a major clinical challenge. Current biomarkers, however, are not sufficiently accurate. Human neutrophil lipocalin (HNL) in serum distinguishes acute infections with high accuracy, but in the emergency setting the assay time should be <15-20min, which excludes the use of serum samples. The aim was therefore to develop a novel rapid assay principle and test its clinical performance.

METHODS

Serum and neutrophils obtained from 84 infected and 20 healthy subjects were used in the experimental study. 725 subjects (144 healthy controls and 581 patients with signs and symptoms of acute infections) were included in the clinical study. HNL was measured in EDTA-plasma by ELISA or in heparinized whole blood after fMLP activation by a prototype point-of-care assay.

RESULTS

Increased release of HNL from neutrophils after activation with fMLP was seen already after 5 min incubation. The release of HNL from purified neutrophils after 15 min incubation with fMLP was significantly correlated to the HNL concentrations in serum obtained from the same patient (r = 0.74, p < 0.001). In the distinction between healthy controls and patients with bacterial infections, the areas under the ROC-curves were 0.95 (95% CI 0.91-0.97) and 0.88 (95% CI 0.84-0.91) for HNL in fMLP-activated whole blood and EDTA-plasma, respectively, (p < 0.001) and in the distinction between bacterial and viral infections 0.91 (95% CI 0.86-0.95) and 0.76 (95% CI 0.70-0.81), respectively (p < 0.001).

CONCLUSION

The clinical performance of HNL in fMLP-activated whole blood was superior to HNL in EDTA-plasma and similar to HNL in serum. The procedure can be adopted for point-of-care testing with response times of <15 min.

Interleukin-6 as an early diagnostic marker for bacterial sepsis in patients with liver cirrhosis

OBJECTIVE

Liver cirrhosis is associated with frequent bacterial infections that increase the mortality rate. However, the early diagnosis and treatment of these infections are often difficult. In this retrospective-prospective observational study, the serum levels of interleukin-6 (IL-6) and procalcitonin (PCT) were measured in 233 cirrhotic patients to evaluate the early diagnostic and prognostic values of IL-6 and PCT for cirrhotic patients.

METHODS

Cirrhotic patients admitted to the Liver Research Center of the First Affiliated Hospital of Fujian Medical University between 1 October 2012 and 30 June 2014 were enrolled. They showed no evidence of infection on admission, and all had first onset of fever and met the systemic inflammatory response syndrome criteria 72 hours after admission. The serum IL-6 and PCT levels were determined on admission, at the onset of fever (0 hour) and 24 and 48 hours after fever onset.

RESULTS

A total of 233 cirrhotic patients, including 183 men and 50 women, with a median age of 56 (46-65) years were enrolled. A training group of 159 patients was retrospectively enrolled from 1 October 2012 to 31 December 2013, and a validation group of 74 patients was prospectively enrolled from 1 January 2014 to 30 June 2014. Among these patients, 134 were diagnosed with bacterial sepsis, 96 of whom were in the training group and 38 of whom were in the validation group; infections were ultimately ruled out in 99 patients: 63 training patients and 36 validation patients. At 0 hour, the IL-6 and PCT levels as well as the proportion of neutrophils were much higher in septic patients than in nonseptic ones. The IL-6 level and proportion of neutrophils peaked upon the onset of fever, 24 hours before the PCT levels and white blood cell count, and then sharply declined. The area under the receiver operating characteristic curve of IL-6 for diagnosing sepsis was largest at the onset of fever (area under the receiver operating characteristic curve, 0.983; 95% confidence interval, 0.967-0.999). The threshold of IL-6 for diagnosis was 135 pg/mL, with a sensitivity of 94.8% and a specificity of 93.7%. These diagnostic values were also confirmed in the validation group, with a sensitivity of 97.4% and specificity of 80.6%. Eleven (11.5%) patients died, and 85 (88.5%) patients recovered in the sepsis group of training patients after a 4-week follow-up. The IL-6 level was significantly higher in the nonsurvival group than that in the survival group (1813.00 vs 472.10 pg/mL, P = .004) at the onset of sepsis. The cutoff value for predicting prognosis was 1105 pg/mL, with a sensitivity of 81.8% and a specificity of 76.5%.

CONCLUSIONS

The serum IL-6 levels increased earlier than the PCT in septic cirrhotic patients. The direct measurement of the serum IL-6 level can help to rapidly detect bacterial infection, thus allowing for early therapeutic decisions and prognostic predictions.

Cutoff value of serum procalcitonin as a diagnostic biomarker of infection in end-stage renal disease patients

BACKGROUND/AIMS

Serum procalcitonin (PCT) levels are low in healthy individuals but are elevated in patients with a serious bacterial infection or sepsis. In this study, we examined the ability of serum PCT concentration to diagnose infections in end-stage renal disease (ESRD) patients, and sought to determine an appropriate threshold level.

METHODS

Serum PCT levels were measured in ESRD patients on antibiotic therapy for a suspected bacterial infection (ESRD infection [iESRD] group, n = 21), and compared with those of ESRD patients on hemodialysis with no sign of infection (ESRD control [cESRD] group, n = 20).

RESULTS

The mean serum PCT concentration of the iESRD group was significantly higher than in the cESRD group (2.95 ± 3.67 ng/mL vs. 0.50 ± 0.49 ng/mL, p = 0.006), but serum PCT concentrations did not correlate with severity of infection. The optimized threshold level derived for serum PCT was 0.75 ng/mL, rather than the currently used 0.5 ng/mL; this threshold demonstrated a sensitivity and specificity of 76.2% and 80.0% for infection and 100% and 60.6% for systemic inflammatory response syndrome, respectively, compared with the cutoff of 0.5 ng/mL.

CONCLUSIONS

This study suggests that serum PCT at a cutoff value of 0.75 ng/mL is an appropriate indicator of infection in ESRD patients.

Correlation of ischemia-modified albumin with SOFA and APACHE II scores in preoperative patients with colorectal cancer

Purpose. Critical illnesses are assessed according to the sequential organ failure assessment (SOFA) and acute physiology and chronic health evaluation (APACHE) II. Circulating ischemia-modified albumin (IMA) is a biomarker generated under ischemic and oxidative conditions and may reflect disease severity in preoperative patients. This study investigated the correlations of IMA with SOFA and APACHE II scores in inpatients admitted for colorectal surgery. Methods. We examined 27 patients with advanced colorectal cancers (mean age 69 years, men/women = 15/12). Correlations between SOFA and APACHE II scores in addition to preoperative serum IMA and C-reactive protein (CRP) levels were analyzed. Results. The mean IMA level was 0.5 AU, and the median CRP level was 0.6 mg/dL. Median scores for SOFA and APACHE II were 2 and 12 points, respectively. Significant positive correlations between IMA and SOFA (r = 0.45, P < 0.05) and IMA and APACHE II (r = 0.45, P < 0.05) were identified which remained significant in confounder-adjusted analyses. In contrast, weak correlations were observed between CRP and the SOFA and APACHE II scores. Conclusions. The positive correlations between IMA and both SOFA and APACHE II scores suggest that serum IMA measurements reflect the severity of systemic failure in patients admitted for colorectal surgery in the preoperative phase.

Coincident helminth infection modulates systemic inflammation and immune activation in active pulmonary tuberculosis

BACKGROUND

Helminth infections are known to modulate innate and adaptive immune responses in active and latent tuberculosis (TB). However, the role of helminth infections in modulating responses associated with inflammation and immune activation (reflecting disease activity and/or severity) in TB is not known.

METHODOLOGY

We measured markers of inflammation and immune activation in active pulmonary TB individuals (ATB) with co-incidental Strongyloides stercoralis (Ss) infection. These included systemic levels of acute phase proteins, matrix metalloproteinases and their endogenous inhibitors and immune activation markers. As a control, we measured the systemic levels of the same molecules in TB-uninfected individuals (NTB) with or without Ss infection.

PRINCIPAL FINDINGS

Our data confirm that ATB is associated with elevated levels of the various measured molecules when compared to those seen in NTB. Our data also reveal that co-incident Ss infection in ATB individuals is associated with significantly decreased circulating levels of acute phase proteins, matrix metalloproteinases, tissue inhibitors of matrix metalloproteinases as well as the systemic immune activation markers, sCD14 and sCD163. These changes are specific to ATB since they are absent in NTB individuals with Ss infection.

CONCLUSIONS

Our data therefore reveal a profound effect of Ss infection on the markers associated with TB disease activity and severity and indicate that co-incidental helminth infections might dampen the severity of TB disease.

Procalcitonin versus C-reactive protein: Usefulness as biomarker of sepsis in ICU patient

Background:

Early diagnosis and appropriate therapy of sepsis is a daily challenge in intensive care units (ICUs) despite the advances in critical care medicine. Procalcitonin (PCT); an innovative laboratory marker, has been recently proven valuable worldwide in this regard.

Objectives:

This study was undertaken to evaluate the utility of PCT in a resource constrained country like ours when compared to the traditional inflammatory markers like C - reactive protein (CRP) to introduce PCT as a routine biochemical tool in regional hospitals.

Materials and Methods:

PCT and CRP were simultaneously measured and compared in 73 medico-surgical ICU patients according to the American College of Chest Physicians (ACCP) criteria based study groups.

Results:

The clinical presentation of 75% cases revealed a range of systemic inflammatory responses (SIRS). The diagnostic accuracy of PCT was higher (75%) with greater specificity (72%), sensitivity (76%), positive and negative predictive values (89% and 50%), positive likelihood ratio (2.75) as well as the smaller negative likelihood ratio (0.33). Both serum PCT and CRP values in cases with sepsis, severe sepsis and septic shock were significantly higher from that of the cases with SIRS and no SIRS (P < 0.01).

Conclusion:

PCT is found to be superior to CRP in terms of accuracy in identification and to assess the severity of sepsis even though both markers cannot be used in differentiating infectious from noninfectious clinical syndrome.

Basic evaluation of Pentra MS CRP, a new automated hematology analyzer for rapid 5-part WBC differential and CRP using a small volume of whole blood

INTRODUCTION

Pentra MS CRP is a new automated hematology analyzer that can rapidly and reliably provide 5-part differential of leukocytes (5-Diff) and C-reactive protein (CRP) within approximately 3.5 min using a small volume of whole blood (35 μL).

METHODS

We evaluated the basic performance of Pentra MS CRP and correlations with Sysmex XN-3000, manual microscopic count, and Hitachi LABOSPECT.

RESULTS

Pentra MS CRP demonstrated good repeatability and linearity without any significant carryover for all parameters examined (WBC, RBC, HGB, Hct, PLT, 5-Diff, and CRP). Complete blood cell count (CBC) data examined by Pentra MS CRP correlated well with those evaluated by Sysmex XN-3000 (R ≥ 0.9880). Absolute number of NEU, LYM, and EOS also showed the good correlation (R ≥ 0.9866) between the two analyzers. The correlation with the manual microscopic count was within acceptable criteria. Furthermore, when CRP was examined in hemolyzed whole blood by Pentra MS CRP and converted to plasma concentrations according to Hct, it correlated well (R = 0.9964) with serum CRP examined by Hitachi LABOSPECT.

CONCLUSION

Pentra MS CRP is a convenient and reliable analyzer especially in the emergency unit of hospitals in which the prompt and simultaneous measurement of CBC including 5-Diff and CRP is often necessary.

A three-line lateral flow assay strip for the measurement of C-reactive protein covering a broad physiological concentration range in human sera

The lateral flow assay (LFA) strip sensor possesses many advantages as a diagnostic device, including the capabilities of rapid, one-step assay performance, and high throughput production. A major limitation of the sensor, however, is its difficulty in measuring a broad concentration range of target proteins, including C-reactive protein (CRP), due to the "hook effect." In this study, we report the use of a three-line LFA strip sensor, adding an antigen line to the conventional two-line LFA sensor, for detecting CRP within a broad concentration range in human sera. We introduced an antigen line between test and control lines in the LFA sensor. The antigen line was formed by dispensing a CRP antibody solution followed by a CRP solution in nitrocellulose membrane. All other conditions were identical to those applied to the conventional LFA strip sensor. The CRP level in test samples was generated by data processing from the intensities of three lines. The strip sensor measured a linear detection range of CRP concentration from 1 ng/mL to 500 μg/mL within 10 min, with a calculated detection range of 0.69 ng/mL-1.02 mg/mL. Using the developed three-line LFA sensor, 50 clinical samples were measured at a detection range of 0.4-84.7 μg/mL. This novel and easy-to-use CRP sensor can be a useful tool for rapid, sensitive, and cost-effective detection of a broad physiological concentration range of CRP capabilities that are vital for various diagnostic applications.

Extreme Procalcitonin Elevation without Proven Bacterial Infection Related to Amphetamine Abuse

Systemic inflammatory response with rhabdomyolysis and consequent multiorgan failure is a known sequela of psychotropic drug abuse. However, in cases with uncertain past medical history the initial diagnosis can be challenging. Here we report the case of a 21-year-old male who was admitted to the intensive care unit with severe neurological impairment caused by amphetamine intoxication. First laboratory investigations revealed extremely high serum procalcitonin (PCT) levels reaching a maximum concentration of 1640 ng/mL on the second day of observation. Although PCT has high sensitivity and specificity in differentiating bacterial sepsis from nonbacterial inflammation, our case report shows for the first time that it can be extremely elevated following serious amphetamine intoxication without bacterial infection.

Increased serum interleukin-6 levels in early stages of psychosis: associations with at-risk mental states and the severity of psychotic symptoms

Schizophrenia patients experience activated inflammatory responses, but little is known about the presence of such inflammatory processes at or prior to disease onset. We measured interleukin-6 (IL-6) and C-reactive protein (CRP) serum levels and plasma fibrinogen in 17 at-risk mental state (ARMS) subjects, 77 patients with psychotic disorder (PD) and 25 healthy control subjects (HC). ARMS subjects were followed-up, and transition to psychosis was registered. IL6 rs1800795 SNP was genotyped, as IL-6 levels may be influenced by this genetic variant. We did not observe significant differences in the IL6 rs1800795 SNP genotype frequencies between the groups. ARMS subjects exhibited significantly higher IL-6 levels than did controls (p=0.019). In subjects not taking cannabis, we found that patients diagnosed with ARMS or PD exhibited increased IL-6 levels when compared with HC (p=0.004). In both ARMS and PD subjects, IL-6 levels were positively associated with negative symptoms. However, with respect to positive psychotic symptoms, a different relationship was observed in the ARMS and PD groups (positive relationship in ARMS; negative relationship in PD). These findings could not be attributed to confounding variables, including gender, body mass index (BMI), tobacco consumption or the rs1800795 genotype. Six of 17 ARMS subjects (35%) exhibited a transition to psychosis during the follow-up period of 26 months. ARMS subjects who developed psychosis exhibited increased median IL-6 levels compared with those who did not transition (0.61 vs. 0.35pg/mL). However, this difference was not statistically significant, which could be explained by a lack of statistical power due to the small sample size. Our results suggest that IL-6 may be a biomarker for early psychotic symptoms; however, further studies in larger samples are needed to confirm this result.

Point-of-care platforms

Point-of-care applications are gaining increasing interest in clinical diagnostics and emergency applications. Biosensors are used to monitor the biomolecular interaction process between a disease biomarker and a recognition element such as a reagent. Essential are the quality and selectivity of the recognition elements and assay types used to improve sensitivity and to avoid nonspecific interactions. In addition, quality measures are influenced by the detection principle and the evaluation strategies. For these reasons, this review provides a survey and validation of recognition elements, assays, and various types of detection methods for point-of-care testing (POCT) platforms. Common applications of clinical parameters are discussed and considered. In this ever-changing field, a snapshot of current applications is needed. We provide such a snapshot by way of a table including literature citations and also discuss these applications in more detail throughout.

Interpretation of C-reactive protein concentrations in critically ill patients

Infection is often difficult to recognize in critically ill patients because of the marked coexisting inflammatory process. Lack of early recognition prevents timely resuscitation and effective antimicrobial therapy, resulting in increased morbidity and mortality. Measurement of a biomarker, such as C-reactive protein (CRP) concentration, in addition to history and physical signs, could facilitate diagnosis. Although frequently measured in clinical practice, few studies have reported on the pathophysiological role of this biomarker and its predictive value in critically ill patients. In this review, we discuss the pathophysiological role of CRP and its potential interpretation in the inflammatory processes observed in critically ill patients.

Five days of head-down-tilt bed rest induces noninflammatory shedding of L-selectin

Head-down-tilt bed rest (HDTBR) is a popular model, simulating alterations of gravitation during space missions. The aim of this study was to obtain a better insight into the complexly orchestrated regulations of HDTBR-induced immunological responses, hypothesizing that artificial gravity can mitigate these HDTBR-related physiological effects. This crossover-designed 5 days of HDTBR study included three protocols with no, or daily 30 min of centrifugation or 6 × 5 min of centrifugation. Twelve healthy, male participants donated blood pre-HDTBR, post-HDTBR, and twice during HDTBR. Cellular immune changes were assessed either by enumerative and immune cell phenotyping assays or by functional testing of responses to either recall antigens or receptor-dependent activation by chemotactic agents N-formyl-methionyl-leucyl-phenylalanine (fMLP) and with TNF-α. The expression of the adhesion molecule L-selectin (CD62L) on the surface of granulocytes and its shedding into plasma samples were measured. In parallel, other humoral factor, such as interleukin-6 and interleukin-8, parameters of endothelial damage (glycocalyx) were determined. Hematocrit and hemoglobin were significantly increased during HDTBR. Although immune functional tests did not indicate a change in the immune performance, the expression of CD62L on resting granulocytes was significantly shed by 50% during HDTBR. Although the latter is normally associated to an activation of inflammatory innate immune responses and during interaction of granulocytes with the endothelium, CD62L shedding was, however, not related either to a systemic inflammatory alteration or to shedding of the endothelial glycocalyx during bed rest. This suggests a noninflammatory or “mechanical” shedding related to fluid shifts during head-down intervention and not to an acute inflammatory process.

Procalcitonin as a biomarker of infectious diseases

Traditional biomarkers, including C-reactive protein, leukocytes, erythrocyte sedimentation rate, and clinical signs and symptoms, are not sufficiently sensitive or specific enough to guide treatment decisions in infectious febrile diseases. Procalcitonin (PCT) is synthesized by a large number of tissues and organs in response to invasion by pathogenic bacteria, fungi, and some parasites. A growing body of evidence supports the use of PCT as a marker to improve the diagnosis of bacterial infections and to guide antibiotic therapy. Clinically, PCT levels may help guide the need for empirical antibiotic therapy, source control for infections, and duration of antibiotic therapy. The aim of this review is to summarize the current evidence for PCT in different infections and clinical settings, and to discuss the reliability of this marker in order to provide physicians with an overview of the potential for PCT to guide antibiotic therapy.

Circulating biomarkers of pulmonary and extrapulmonary tuberculosis in children

Tuberculosis (TB) in children is not only more likely to cause more severe disease than that seen in adults, it is also more likely to be extrapulmonary. Moreover, pediatric TB is very difficult to diagnose and suffers from a lack of understanding of host biomarkers for monitoring the progression of disease. Hence, we sought to identify the expression patterns of a variety of biomarkers in the plasma of children with pulmonary TB (PTB) and extrapulmonary TB (ETB), as well as in healthy control (HC) children. Thus, we examined a variety of circulating markers reflecting tissue inflammation, oxidative stress, innate immune activation, fibrosis, and the cytokine response. Children with active TB, compared to HC children, showed markedly elevated plasma levels of matrix metalloproteinases and their endogenous inhibitors. In addition, children with active TB had significantly elevated levels of C-reactive protein, α-2 macroglobulin, and haptoglobin, as well as hemoxygenase 1. Markers of innate immune activation (lipopolysaccharide [LPS] and lipopolysaccharide-binding protein [LBP]) were significantly lower in ETB than in PTB children. Although there were no significant differences between the two groups in their levels of cytokines (type 1 [gamma interferon (IFN-γ), tumor necrosis factor α (TNF-α), interleukin 2 (IL-2), and IL-12], type 2 [IL-4, IL-5, IL-13, and IL-33], and most type 17 [IL-17A, IL-22, IL-1β, and IL-6] and type 1 interferons [IFN-α and IFN-β]) or most of the cytokines associated with immune modulation (IL-10 and IL-20), pediatric TB was associated with elevated plasma transforming growth factor β (TGF-β), IL-21, and IL-23 levels. Thus, pediatric TB is characterized by elevated levels of a variety of biomarkers at homeostasis, suggesting that these responses may play a crucial role in disease pathogenesis.

Vertical flow immunoassay (VFA) biosensor for a rapid one-step immunoassay

A highly rapid, one-step immunoassay of high sensitivity C-reactive protein (hsCRP) using a biosensor with a vertical flow immunoassay (VFA) was developed. The VFA biosensor was primarily composed of a sample pad, conjugate pad, FTH film and nitrocellulose (NC) membrane, which were all vertically stacked upon one another. Anti-hsCRP and secondary antibodies were consecutively immobilized on the NC membrane at the position below the holes. Gold nanoparticles (AuNPs) conjugated with another anti-hsCRP antibody were encapsulated in the conjugation pad. Various assay conditions, including the size of the hole and the sample volume, were optimized. Under optimized conditions, hsCRP concentrations from 0.01 to 10 μg mL(-1) were detected within 2 min. In comparison with a lateral flow assay (LFA) system, the VFA sensor showed a gradual increase of signal in a concentration-dependent manner without a hook effect in the tested range.

Miniaturized technology for protein and nucleic acid point-of-care testing

The field of point-of-care (POC) testing technology is developing quickly and producing instruments that are increasingly reliable, while their size is being gradually reduced. Proteins are a common target for POC analyses and the detection of protein markers typically involves immunoassays aimed at detecting different groups of proteins such as tumor markers, inflammation proteins, and cardiac markers; but other techniques can also be used to analyze plasma proteins. In the case of nucleic acids, hybridization and amplification strategies can be used to record electromagnetic or electric signals. These techniques allow for the identification of specific viral or bacterial infections as well as specific cancers. In this review, we consider some of the latest advances in the analysis of specific nucleic acid and protein biomarkers, taking into account their trend toward miniaturization and paying special attention to the technology that can be implemented in future applications, such as lab-on-a-chip instruments.

Management of bacterial infections in cirrhosis

Bacterial infections are very frequent in advanced cirrhosis and become the first cause of death of these patients. Despite numerous experimental data and significant advances in the understanding of the pathogenesis of sepsis in cirrhosis, the outcome remains poor. Classical diagnostic parameters such as C-reactive protein and SIRS criteria have less diagnostic capacity in the cirrhotic population, often delaying the diagnosis and the management of bacterial infection. Prompt and appropriate empirical antibiotic treatment of infection and early resuscitation of patients with severe sepsis or septic shock are essential in determining patient's outcome. A strategy of careful restriction of prophylactic antibiotics to the high-risk populations could reduce the spread of multidrug resistant bacteria. This review is focused on the currently recommended diagnostic, therapeutic and prophylactic strategies for bacterial infections in the cirrhotic population.

Use of laboratory tests in out-of-hours services in Norway

OBJECTIVE

To investigate the use of laboratory tests and which factors influence the use in Norwegian out-of-hours (OOH) services.

DESIGN

Cross-sectional observational study.

SETTING

Out-of-hours services in Norway.

SUBJECTS

All electronic reimbursement claims from doctors at OOH services in Norway in 2007.

MAIN OUTCOME MEASURES

Number of contacts and laboratory tests in relation to patients' and doctors' characteristics.

RESULTS

1 323 281 consultations and home visits were reported. Laboratory tests were used in 31% of the contacts. C-reactive protein (CRP) was the most common test (27% of all contacts), especially in respiratory illness (55%) and infants (44%). Electrocardiogram and rapid strep A test were used in 4% of the contacts. Young doctors, female doctors, and doctors in central areas used laboratory tests more often.

CONCLUSION

CRP is extensively used in OOH services, especially by young and inexperienced doctors, and in central areas. Further investigations are required to see if this extensive use of CRP is of importance for correct diagnosis and treatment.

Molecular and cellular characterization of a Salmonella enterica serovar Paratyphi a outbreak strain and the human immune response to infection

Enteric fever is an invasive life-threatening systemic disease caused by the Salmonella enterica human-adapted serovars Typhi and Paratyphi. Increasing incidence of infections with Salmonella enterica serovar Paratyphi A and the spreading of its antibiotic-resistant derivates pose a significant health concern in some areas of the world. Herein, we describe a molecular and phenotypic characterization of an S. Paratyphi A strain accounted for a recent paratyphoid outbreak in Nepal that affected at least 37 travelers. Pulsed-field gel electrophoresis analysis of the outbreak isolates revealed one genetic clone (pulsotype), confirming a single infecting source. Genetic profiling of the outbreak strain demonstrated the contribution of specific bacteriophages as a prime source of genetic diversity among clinical isolates of S. Paratyphi A. Phenotypic characterization in comparison with the S. Paratyphi A ATCC 9150 reference sequenced strain showed differences in flagellar morphology and increased abilities of the outbreak strain with respect to its motility, invasion into nonphagocytic cells, intracellular multiplication, survival within macrophages, and higher induction of interleukin-8 (IL-8) secreted by host cells. Collectively, these differences suggest an enhanced virulence potential of this strain and demonstrate an interesting phenotypic variation among S. Paratyphi A isolates. In vivo profiling of 16 inflammatory cytokines in patients infected with the outbreak strain revealed a common profile of a remarkable gamma interferon (IFN-γ) induction together with elevated concentrations of tumor necrosis factor alpha (TNF-α), IL-6, IL-8, IL-10, and IL-15, but not IL-12, which was previously demonstrated as elevated in nontyphoidal Salmonella infections. This apparent profile implies a distinct immune response to paratyphoid infections.

Wash-free, electrochemical platform for the quantitative, multiplexed detection of specific antibodies

The diagnosis, prevention, and treatment of many illnesses, including infectious and autoimmune diseases, would benefit from the ability to measure specific antibodies directly at the point of care. Thus motivated, we designed a wash-free, electrochemical method for the rapid, quantitative detection of specific antibodies directly in undiluted, unprocessed blood serum. Our approach employs short, contiguous polypeptide epitopes coupled to the distal end of an electrode-bound nucleic acid "scaffold" modified with a reporting methylene blue. The binding of the relevant antibody to the epitope reduces the efficiency with which the redox reporter approaches, and thus exchanges electrons with, the underlying sensor electrode, producing readily measurable change in current. To demonstrate the versatility of the approach, we fabricated a set of six such sensors, each aimed at the detection of a different monoclonal antibody. All six sensors are sensitive (subnanomolar detection limits), rapid (equilibration time constants ∼8 min), and specific (no appreciable cross reactivity with the targets of the other five). When deployed in a millimeter-scale, an 18-pixel array with each of the six sensors in triplicate support the simultaneous measurement of the concentrations of multiple antibodies in a single, submilliliter sample volume. The described sensor platform thus appears be a relatively general approach to the rapid and specific quantification of antibodies in clinical materials.

Strategies for reduction in duration of antibiotic use in hospitalized patients

There is a global crisis of antibiotic resistance in part because of the collateral damage of antibiotic use. Reduction in antibiotic consumption is clearly important to minimize this problem. Limiting treatment duration may be the most clinically palatable means of reducing antibiotic consumption. Antimicrobial stewardship programs play an important role in this process. Their effectiveness may be increased by drawing on evidence from randomized controlled trials regarding optimal antibiotic duration. However, in most clinical scenarios, the recommended duration of therapy in published guidelines is based on expert opinion. Biological markers, such as procalcitonin, have been shown to reduce antimicrobial consumption with no adverse outcome in 11 randomized controlled trials. Although procalcitonin may not be the perfect biomarker, the concept of procalcitonin-guided antibiotic discontinuation after clinical stabilization, in conjunction with antimicrobial stewardship programs, appears to be ready for introduction into clinical practice.

Molecular analysis of blood with micro-/nanoscale field-effect-transistor biosensors

Rapid and accurate molecular blood analysis is essential for disease diagnosis and management. Field-effect transistor (FET) biosensors are a type of device that promise to advance blood point-of-care testing by offering desirable characteristics such as portability, high sensitivity, brief detection time, low manufacturing cost, multiplexing, and label-free detection. By controlling device parameters, desired FET biosensor performance is obtained. This review focuses on the effects of sensing environment, micro-/nanoscale device structure, operation mode, and surface functionalization on device performance and long-term stability.

Influence of high dose tumescent local anaesthesia with prilocaine on systemic interleukin (IL)-6, IL-8 and tumour necrosis factor-α

BACKGROUND AND OBJECTIVE

Tumescent local anaesthesia (TLA) with high prilocaine doses leads to formation of methemoglobin (MHb) which is known to be a potent activator of pro-inflammatory endothelial cell response in vitro. As TLA is widely used for large dermatological resections, the aim of this study was to investigate the effects of high prilocaine doses on the systemic inflammatory response in vivo and its clinical relevance.

METHODS

This prospective study examines the influence of MHb on serum interleukin (IL)-6, IL-8 and tumour necrosis tumour necrosis (TNF)-α levels up to 72 h after application of TLA with prilocaine in doses higher than 600 mg.

RESULTS

A total of 30 patients received prilocaine in a median dose of 1500 mg (range: 880-4160 mg) for large resections. Peak prilocaine serum concentration was reached 4 h (0.72 ± 0.07 μg/mL), the maximum concentration of MHb (7.43 ± 0.87%) and IL-6 (28.4 ± 4.1 U/L) 12 h after TLA application. TNF-α and IL-8 release were not found significantly increased. Three patients developed MHb concentrations >15%.

CONCLUSIONS

This clinical study shows for the first time that a high prilocaine serum concentration leads in vivo to elevated systemic levels of IL-6 but not of IL-8 and TNF-α because of initial high MHb levels. Because of possible and unpredictable high MHb concentrations, TLA should only be performed with prilocaine in doses of 2.5 mg/kg. In general, new solutions of TLA are necessary to achieve adequate anaesthesia for large dermatological resections to decrease the risk of methemoglobinaemia.

Elevated procalcitonin predicts Gram-negative sepsis in haematological patients with febrile neutropenia

OBJECTIVE

To compare semi-quantitative procalcitonin with C-reactive protein in predicting bacteraemia in haematological patients with neutropenic fever.

METHODS

A total of 77 patients treated with intensive chemotherapy for haematological malignancy at Kuopio University Hospital were candidates for study entry. Eleven of these patients did not fulfil the criteria for neutropenic fever, and 66 patients were finally included. Nineteen patients had acute myeloid leukaemia and 47 had received high-dose chemotherapy supported by autologous stem cell transplant. Ninety neutropenic fever episodes in these 66 patients fulfilled the study entry criteria, with microbiological cultures, procalcitonin and C-reactive protein measurements available. Serum procalcitonin and C-reactive protein were analyzed at the onset of each neutropenic fever episode on day 0, and then daily from days 1 to 4.

RESULTS

Bacteraemia was observed in 21 episodes (23%) and the criteria for severe sepsis were fulfilled in 13 episodes (14%). Half of the bacteraemic episodes were caused by Gram-negative bacteria. The kinetics of procalcitonin and C-reactive protein were similar, with increasing levels for 2 to 4 days after the onset of fever. The procalcitonin level on days 1, 2, 3 and 4 was associated with bacteraemia and Gram-negative bacteraemia, but not with the development of severe sepsis. On day 1, a procalcitonin level above 0.5 ng/ml had a sensitivity of 57% and 70% and specificity of 81% and 77% to predict bacteraemia and Gram-negative bacteraemia, respectively.

CONCLUSIONS

An elevated level of procalcitonin within 24 h after the onset of neutropenic fever predicts bacteraemia and Gram-negative bacteraemia in haematological patients.