Evaluation of tumor necrosis factor-alpha, interleukin-6 and C-reactive protein plasma levels as predictors of bacteremia in patients presenting signs of sepsis without shock

Flexible, Electrochemical Skin-Like Platform for Inflammatory Biomarker Monitoring

Addressing global challenges in wound management has greatly encouraged the emergence of home diagnosis and monitoring devices. This technological shift has accelerated the development of new skin patch sensors for continuous health monitoring. A key requirement is the creation of flexible platforms capable of mimicking human skin features. Here, for the first time, an innovative, highly adaptable electrochemical biosensor with molecularly imprinted polymers (MIPs) is customized for the detection of the inflammatory biomarker interleukin-6 (IL-6). The 3-electrode gold pattern is geometrically standardized onto a 6 µm thick polyimide flexible membrane, an optically transparent, and biocompatible polymeric substrate. Subsequently, a biomimetic sensing layer specifically designed for the detection of IL-6 target is produced on these transducers. The obtained MIP biosensor shows a good linear response within the concentration range 50 pg mL-1-50 ng mL-1, with a low limit of detection (8 pg mL-1). X-ray photoelectron spectroscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy characterizations confirm the modifications of the flexible gold transducer. After optimization, the biosensing device shows remarkable potential in terms of sensitivity, selectivity, and reproducibility. Overall, the integration of a low-cost electrochemical sensor on biocompatible flexible polymers opens the way for a new generation of monitoring tools with higher accuracy, less invasiveness, and greater patient comfort.

Clinical prediction rule for bacterial arthritis: Chi-squared automatic interaction detector decision tree analysis model

Objectives:

Differences in demographic factors, symptoms, and laboratory data between bacterial and non-bacterial arthritis have not been defined. We aimed to identify predictors of bacterial arthritis, excluding synovial testing.

Methods:

This retrospective cross-sectional survey was performed at a university hospital. All patients included received arthrocentesis from January 1, 2010, to December 31, 2020. Clinical information was gathered from medical charts from the time of synovial fluid sample collection. Factors potentially predictive of bacterial arthritis were analyzed using the Student’s t-test or chi-squared test, and the chi-squared automatic interaction detector decision tree analysis. The resulting subgroups were divided into three groups according to the risk of bacterial arthritis: low-risk, intermediate-risk, or high-risk groups.

Results:

A total of 460 patients (male/female = 229/231; mean ± standard deviation age, 70.26 ± 17.66 years) were included, of whom 68 patients (14.8%) had bacterial arthritis. The chi-squared automatic interaction detector decision tree analysis revealed that patients with C-reactive protein > 21.09 mg/dL (incidence of septic arthritis: 48.7%) and C-reactive protein ⩽ 21.09 mg/dL plus 27.70 < platelet count ⩽ 30.70 × 10⁴/μL (incidence: 36.1%) were high-risk groups.

Conclusions:

Our results emphasize that patients categorized as high risk of bacterial arthritis, and appropriate treatment could be initiated as soon as possible.

Clinical prediction rule for bacteremia with pyelonephritis and hospitalization judgment: chi-square automatic interaction detector (CHAID) decision tree analysis model

Objective

This study was performed to identify predictive factors for bacteremia among patients with pyelonephritis using a chi-square automatic interaction detector (CHAID) decision tree analysis model.

Methods

This retrospective cross-sectional survey was performed at Juntendo University Nerima Hospital, Tokyo, Japan and included all patients with pyelonephritis from whom blood cultures were taken. At the time of blood culture sample collection, clinical information was extracted from the patients’ medical charts, including vital signs, symptoms, laboratory data, and culture results. Factors potentially predictive of bacteremia among patients with pyelonephritis were analyzed using Student’s t-test or the chi-square test and the CHAID decision tree analysis model.

Results

In total, 198 patients (60 (30.3%) men, 138 (69.7%) women; mean age, 74.69 ± 15.27 years) were included in this study, of whom 92 (46.4%) had positive blood culture results. The CHAID decision tree analysis revealed that patients with a white blood cell count of >21,000/μL had a very high risk (89.5%) of developing bacteremia. Patients with a white blood cell count of ≤21,000/μL plus chills plus an aspartate aminotransferase concentration of >19 IU/L constituted the high-risk group (69.0%).

Conclusion

The present results are extremely useful for predicting the results of bacteremia among patients with pyelonephritis.

Peak C-reactive protein levels do not predict 30-day mortality for bacteremia: A retrospective cohort study

INTRODUCTION

Although peak C-reactive protein (CRP) levels are correlated with the prognosis of some diseases, there have been no reports regarding the association between peak CRP levels and mortality in patients with bacteremia. The present study aimed to determine the association between peak CRP levels and prognosis in patients with bacteremia.

METHODS

This retrospective cohort study was conducted in a single tertiary hospital and included patients with bacteremia admitted to the emergency department from November 2012 to March 2017. Cox regression analysis was performed to examine the association between peak CRP levels and 30-day mortality. We also performed propensity score adjustment using potential confounding factors.

RESULTS

One hundred fifty-nine patients were included in the study. Peak CRP levels were significantly higher in the β-hemolytic streptococci (P = 0.001) and Streptococcus pneumoniae (P = 0.003) groups. The C-statistic of the multivariate logistic regression model for the propensity score was 0.88. For 30-day mortality, peak CRP levels >20 mg/dL did not show significance in the Cox regression analysis (hazard ratio, 0.866; 95% confidence interval, 0.489-1.537; P = 0.62). Even after propensity score adjustment, no significance was noted (hazard ratio, 0.865; 95% confidence interval, 0.399-1.876; P = 0.71).

CONCLUSIONS

Peak CRP levels were not an independent predictor of mortality in patients with bacteremia in the emergency department. Clinicians should consider that patients with extremely high peak CRP levels do not necessarily have high mortality and vice versa.

Plasma interleukin-6 concentration for the diagnosis of sepsis in critically ill adults

BACKGROUND

The definition of sepsis has evolved over time, along with the clinical and scientific knowledge behind it. For years, sepsis was defined as a systemic inflammatory response syndrome (SIRS) in the presence of a documented or suspected infection. At present, sepsis is defined as a life-threatening organ dysfunction resulting from a dysregulated host response to infection. Even though sepsis is one of the leading causes of mortality in critically ill patients, and the World Health Organization (WHO) recognizes it as a healthcare priority, it still lacks an accurate diagnostic test. Determining the accuracy of interleukin-6 (IL-6) concentrations in plasma, which is proposed as a new biomarker for the diagnosis of sepsis, might be helpful to provide adequate and timely management of critically ill patients, and thus reduce the morbidity and mortality associated with this condition.

OBJECTIVES

To determine the diagnostic accuracy of plasma interleukin-6 (IL-6) concentration for the diagnosis of bacterial sepsis in critically ill adults.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS, and Web of Science on 25 January 2019. We screened references in the included studies to identify additional studies. We did not apply any language restriction to the electronic searches.

SELECTION CRITERIA

We included diagnostic accuracy studies enrolling critically ill adults aged 18 years or older under suspicion of sepsis during their hospitalization, where IL-6 concentrations were evaluated by serological measurement.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the references to identify relevant studies and extracted data. We assessed the methodological quality of studies using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. We estimated a summary receiver operating characteristic (SROC) curve by fitting a hierarchical summary ROC (HSROC) non-linear mixed model. We explored sources of heterogeneity using the HSROC model parameters. We conducted all analyses in the SAS statistical software package and R software.

MAIN RESULTS

We included 23 studies (n = 4192) assessing the accuracy of IL-6 for the diagnosis of sepsis in critically ill adults. Twenty studies that were available as conference proceedings only are awaiting classification. The included participants were heterogeneous in terms of their distribution of age, gender, main diagnosis, setting, country, positivity threshold, sepsis criteria, year of publication, and origin of infection, among other factors. Prevalence of sepsis greatly varied across studies, ranging from 12% to 78%. We considered all studies to be at high risk of bias due to issues related to the index test domain in QUADAS-2. The SROC curve showed a great dispersion in individual studies accuracy estimates (21 studies, 3650 adult patients), therefore the considerable heterogeneity in the collected data prevented us from calculating formal accuracy estimates. Using a fixed prevalence of sepsis of 50% and a fixed specificity of 74%, we found a sensitivity of 66% (95% confidence interval 60 to 72). If we test a cohort 1000 adult patients under suspicion of sepsis with IL-6, we will find that 330 patients would receive appropriate and timely antibiotic therapy, while 130 patients would be wrongly considered to have sepsis. In addition, 370 out of 1000 patients would avoid unnecessary antibiotic therapy, and 170 patients would have been undiagnosed of sepsis. This numerical approach should be interpreted with caution due to the limitations described above.

AUTHORS' CONCLUSIONS

Our evidence assessment of plasma interleukin-6 concentrations for the diagnosis of sepsis in critically ill adults reveals several limitations. High heterogeneity of collected evidence regarding the main diagnosis, setting, country, positivity threshold, sepsis criteria, year of publication, and the origin of infection, among other factors, along with the potential number of misclassifications, remain significant constraints for its implementation. The 20 conference proceedings assessed as studies awaiting classification may alter the conclusions of the review once they are fully published and evaluated. Further studies about the accuracy of interleukin-6 for the diagnosis of sepsis in adults that apply rigorous methodology for conducting diagnostic test accuracy studies are needed. The conclusions of the review will likely change once the 20 studies pending publication are fully published and included.

Bacteraemia predictive factors among general medical inpatients: a retrospective cross-sectional survey in a Japanese university hospital

OBJECTIVES

The precise criteria for obtaining blood cultures have not been established; they depend on the physician's judgement. We examined clinical parameters to determine predictive factors of bacteraemia and the need for blood cultures among general medical inpatients.

DESIGN

A retrospective cross-sectional survey.

SETTING

A Japanese university hospital.

PARTICIPANTS

All general inpatients who had blood cultures taken from 1 January 2011 to 31 December 2012.

MAIN MEASURES

Clinical information at or just before blood culture sampling was extracted from medical charts. Factors potentially predictive of bacteraemia were analysed using Fisher's exact test, followed by multivariable logistic regression model analysis.

MAIN RESULTS

A total of 200 patients (male: female=119:81, 64.3±19.1 years old) comprised this study; 57 (28.5%) had positive blood culture results. Multivariable logistic regression analysis revealed that age >60 years (OR=2.75, 95% CI 1.23 to 6.48, p=0.015), female sex (OR=2.21, 95% CI 1.07 to 4.67, p=0.038), pulse rate >90 bpm (OR=5.18, 95% CI 2.25 to 12.48, p<0.001) and neutrophil percentage >80% (OR=3.61, 95% CI 1.71 to 8.00, p=0.001) were independent risk factors for positive blood culture results. The area under the receiver operating characteristic curve analysis of this model was 0.796.

CONCLUSIONS

Our results emphasise the importance of taking blood cultures if the pulse rate is >90 bpm, in elderly patients and in women, and for ordering a differential white cell count.

Characteristics of patients with community-acquired bacteremia who have low levels of C-reactive protein (≤20 mg/L)

OBJECTIVES

To characterize patients presenting with community-acquired bacteremia and a low C-reactive protein (CRP) plasma level at date of bacteremia.

METHODS

Population-based cohort study. Patient characteristics were compared for three CRP groups (≤20 mg/L, 21-100 mg/L and >100 mg/L) using chi-square test and oneway anova. The 30-day mortality rates were compared using logistic regression analyses.

RESULTS

Of the 2017 patients included, 193 (9.6%) had a CRP ≤20 mg/L. These patients were younger, more likely to be male, overrepresented in the intensive care unit and had more comorbidities. In blood cultures from the low CRP group hemolytic streptococci and coagulase-negative staphylococci were found relatively more common, whereas Streptococcus pneumoniae or Staphylococcus aureus were found relatively less common compared to the other CRP groups. The majority of patients with an initial low CRP mounted a CRP response the following days. The 30-day mortality rate was lower in the low CRP group (13.5%) than in the group with CRP >100 mg/L (20.6%).

CONCLUSIONS

A considerable proportion of patients with community-acquired bacteremia has a normal or low initial CRP level. The plasma CRP level should not be used to rule out serious infection or withhold antibiotic therapy.

Risk factors for negative blood cultures in adult medical inpatients--a retrospective analysis

BACKGROUND

The identification of clinical factors associated with negative blood cultures could help to avoid unnecessary blood cultures. C-reactive protein (CRP) is a well-established inflammation marker commonly used in the management of medical inpatients.

METHODS

We studied the association of clinical factors, CRP levels and changes of CRP documented prior to blood culture draws with the absence of bacteremia for hospitalized medical patients.

RESULTS

In the retrospective analysis of 710 blood cultures obtained from 310 medical inpatients of non-intensive-care wards during one year (admission blood cultures obtained in the emergency room were excluded), the following retrospectively available factors were the only independent predictors of blood cultures negative for obligate pathogens: a good clinical condition represented by the lowest of three general nursing categories (OR 4.2, 95% CI 1.8 - 9.5), a CRP rise > 50 mg/L documented before the blood culture draw (OR 2.0 95% CI 1.8-9.5) and any antibiotic treatment in the previous seven days (OR 2.0, 95% CI 1.1-3.5).

CONCLUSION

Including the general clinical condition, antibiotic pre-treatment and a substantial rise of CRP into the decision, whether or not to obtain blood cultures from medical inpatients with a suspected infection, could improve the diagnostic yield.

High-sensitivity C-reactive protein levels in cerebrospinal fluid and serum in severe head injury: Relationship to tumor necrosis factor-α and interleukin-6

Recent studies have demonstrated the role of high-sensitivity C-reactive protein (hsCRP) in inflammatory diseases; however, it is unclear whether this molecule has a role after severe head injury (SHI). Our aim was to evaluate the levels of hsCRP in both cerebrospinal fluid (CSF) and serum from patients after SHI. The study focused on 11 patients with SHI, and evaluated CSF and serum levels of hsCRP, tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in a 10-day period following the head trauma. The values were compared with those from nine control patients, who had normal pressure hydrocephalus. In the CSF and serum of the patients after SHI, HsCRP was found to be significantly higher, at all times, than in the controls; TNF-alpha and IL-6 levels were also higher in these patients. However, hsCRP levels did not correlate with either TNF-alpha or IL-6. TNF-alpha and IL-6 increased during the period immediately following the SHI, and intrathecal levels were always higher than those of the serum. This study demonstrates for the first time that hsCRP reaches high levels in both CSF and serum in patients with SHI, and it may therefore be used as an inflammatory index. This finding suggests a need for further studies in this area, which are larger in scope than the present study.

Dynamics of C-reactive protein and white blood cell count in critically ill patients with nosocomial Gram positive vs. Gram negative bacteremia: a historical cohort study

Background

Nosocomial bacteremia is associated with a poor prognosis. Early adequate therapy has been shown to improve outcome. Consequently, rapid detection of a beginning sepsis is therefore of the utmost importance. This historical cohort study was designed to evaluate if different patterns can be observed in either C-reactive protein (CRP) and white blood cell count (WCC) between Gram positive bacteremia (GPB) vs. Gram negative bacteremia (GNB), and to assess the potential benefit of serial measurements of both biomarkers in terms of early antimicrobial therapy initiation.

Methods

A historical study (2003–2004) was conducted, including all adult intensive care unit patients with a nosocomial bacteremia. CRP and WCC count measurements were recorded daily from two days prior (d_-2) until one day after onset of bacteremia (d₊₁). Delta (Δ) CRP and Δ WCC levels from the level at d_-2 onward were calculated.

Results

CRP levels and WCC counts were substantially higher in patients with GNB. Logistic regression analysis demonstrated that GNB and Acute Physiology and Chronic Health Evaluation (APACHE) II score were independently associated with a CRP increase of 5 mg/dL from d_-2 to d₊₁, and both were also independently associated with an increase of WCC levels from d_-2 to d₊₁ of 5,000 × 10³ cells/mm³.

Conclusion

Increased levels of CRP and WCC are suggestive for GNB, while almost unchanged CRP and WCC levels are observed in patients with GPB. However, despite the different patterns observed, antimicrobial treatment as such cannot be guided based on both biomarkers.

Detection of caspase-3, neuron specific enolase, and high-sensitivity C-reactive protein levels in both cerebrospinal fluid and serum of patients after aneurysmal subarachnoid hemorrhage

OBJECTIVE

The purpose of this study is to explore whether or not the levels of caspase-3 (Casp3), neuron-specific enolase (NSE), and high-sensitivity C-reactive protein (hsCRP) were elevated in cerebrospinal fluid (CSF) and serum of patients after aneurysmal subarachnoid hemorrhage (SAH).

METHODS

This prospective clinical study consisted of 20 patients who experienced recent aneurysmal SAH and 15 control patients who experienced hydrocephalus without any other central nervous system disease. CSF and serum samples obtained within the first 3 days, and on the fifth and seventh days of SAH were assayed for Casp3, NSE, and hsCRP by using enzyme-linked immunosorbent assay.

RESULTS

Levels of Casp3, NSE, and hsCRP in the CSF (P = 0.00001, P = 0.00001, and P <0.003, respectively) and in the serum (P = 0.00001, P <0.01, and P = 0.00001, respectively) of SAH patients were found to be elevated when compared with controls with normal pressure hydrocephalus.

CONCLUSION

The authors have demonstrated the synchronized elevation of Casp3, NSE, and hsCRP in both CSF and serum of patients with aneurysmal SAH. Further studies with a large number of patients are recommended to more accurately determine the roles of these molecules in aneurysmal SAH.

Sedimentation characteristics of leucocytes can predict bacteraemia in critical care patients

BACKGROUND

Early detection of blood stream infection can be lifesaving, but the results of blood cultures are not usually available before 24 hours after blood sampling. An earlier indication would lead to the initiation of immediate and adequate antibiotic treatment with obvious advantages for the patient.

OBJECTIVE

To evaluate the ability of leucocyte count, serum procalcitonin (PCT) concentration, erythrocyte sedimentation rate (ESR), and leucocyte antisedimentation rate (LAR) in predicting the blood culture results in critical care patients.

METHODS

39 consecutive patients with their first febrile episode were investigated prospectively. LAR was determined as the percentage of leucocytes crossing the midline of a blood column upward during one hour of gravity sedimentation. The relevance of the different variables was estimated by likelihood ratio tests and area under receiver operating characteristic curves (AUC).

RESULTS

23 patients had positive blood culture results and 16 negative. LAR was significantly higher in bacteraemic patients than in non-bacteraemic patients (p = 0.001), but leucocyte count, ESR and PCT level failed to show significant differences. Leucocyte count, PCT, and ESR yielded low discriminative values with the AUCs of 0.66, 0.64, and 0.52, respectively. LAR provided a likelihood ratio of 3.6 and an AUC of 0.80 (95% confidence interval, 0.64 to 0.95) (p = 0.002).

CONCLUSIONS

The simple LAR test can predict blood culture results and support urgent treatment decisions in critical care patients in their first febrile episode.

A simple prediction algorithm for bacteraemia in patients with acute febrile illness

BACKGROUND

Existing prediction models for the risk of bacteraemia are complex and difficult to use. Physicians are likely to use a model only if it is simple and sensitive.

AIM

To develop a simple classification algorithm predicting the risk of bacteraemia.

DESIGN

Hospital-based study.

METHODS

We enrolled 526 adult consecutive patients with acute febrile illness (40 with bacteraemia) presenting to the emergency department at a community hospital in Okinawa, Japan. Recursive partitioning analysis was used to build the classification algorithm with V-fold cross-validation. We used two clinical scenarios: in the first, laboratory tests were not available; in the second, they were.

RESULTS

The two prediction algorithms generated three different risk groups for bacteraemia. In the first scenario, the important variables were chills, pulse, and physician diagnosis of a low-risk site. The low-risk group from this first algorithm included 68% of the total patients; sensitivity was 87.5% and the misclassification rate was 1.4% (5/358). In the second scenario, the important variables were chills, C-reactive protein, and physician diagnosis of a low-risk site. The low-risk group for the second algorithm included 62% of the total patients; sensitivity was 92.5% and misclassification rate 0.9% (3/328). The algorithms had negative predictive values of 98.6% (first scenario) and 99.1% (second).

DISCUSSION

This simple and sensitive prediction algorithm may be useful for identifying patients at low risk of bacteraemia. Prospective validation is needed in other settings.

Bacteraemia prediction in emergency medical admissions: role of C reactive protein

AIM

To define the contribution made by C reactive protein (CRP) measurement to bacteraemia prediction in adults with medical emergencies in the UK.

METHODS

This two year cohort study involved 6234 patients admitted as emergency cases to the acute medical or infectious diseases services of the Oxford Radcliffe Hospitals, in whom blood cultures were taken on arrival. The main outcome measures were bacteraemia risk associated with admission CRP concentrations, lymphocyte counts, and neutrophil counts.

RESULTS

The quantitative associations between CRP concentration, admission lymphocyte count, and neutrophil count were defined. Risk of bacteraemia rose continuously as the CRP increased: no "cutoff" value was evident. Models examining combinations of CRP, neutrophil count, and lymphocyte count were developed and validated using a split sample technique. CRP contributed to a model including lymphocyte and neutrophil counts, but its effect was small. CRP alone performed no better than either a model combining lymphopenia and neutrophilia, or than lymphopenia alone.

CONCLUSIONS

In patients with acute medical emergencies who are suspected of bacteraemia clinically, CRP concentrations, although associated with bacteraemia, have a limited role in bacteraemia prediction.

C-reactive protein used as an early indicator of infection in patients with systemic inflammatory response syndrome

OBJECTIVE

To assess the diagnostic value of a single determination of serum C-reactive protein as a marker of sepsis in critically ill patients.

DESIGN

Prospective, observational study.

SETTING

Intensive care unit of a university hospital.

PATIENTS AND PARTICIPANTS

One hundred twenty-five adult patients with systemic inflammatory response syndrome (SIRS) (55 patients without evidence of infection and 70 patients with the diagnosis of sepsis confirmed by documented infection). Twenty-five patients with non-complicated acute myocardial infarctions (AMI) and 50 healthy volunteers were used as controls.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Serum C-reactive protein concentration was measured within the first 24 h of SIRS onset. Healthy subjects, AMI and non-infectious SIRS patients showed lower C-reactive protein median values ([(0.21 [95% confidence intervals (95% CI), 0.21-0.4] mg/dl, 2.2 [95% CI, 2.1-4.9] mg/dl and 1.7 [95% CI, 2.4-5.5] mg/dl, respectively) than patients with sepsis (18.9 [95% CI, 17.1-21.8]), p<0.001. The presence of severe sepsis ( r(s)=0.27; p=0.03), SOFA score ( r(s)=0.25; p=0.03) and arterial lactate ( r(s)=0.24; p=0.04) correlated significantly with C-reactive protein concentrations in sepsis cases. The best threshold value for C-reactive protein for predicting sepsis was 8 mg/dl (sensitivity 94.3%, specificity 87.3%). The area under the receiver-operating characteristic curve for C-reactive protein was 0.94 (95% CI, 0.89-0.98).

CONCLUSIONS

Determination of serum C-reactive protein can be used as an early indicator of infection in patients with SIRS.