Procalcitonin as a marker for the detection of bacteremia and sepsis in the emergency department

No causal association between COVID-19 and sepsis: a bidirectional two-sample Mendelian randomization study

Background

Sepsis and COVID-19 have a well-established observable relationship. Whether COVID-19 increases the likelihood of developing sepsis and whether patients with sepsis are at increased risk for COVID-19 infection is unknown. Using a bidirectional 2-sample Mendelian randomization (TSMR) analysis techniques in sizable cohorts, we sought to answer this question.

Methods

The current study performed Mendelian randomization (MR) on publicly accessible genome-wide association study (GWAS) summary data in order to investigate the causal linkages between COVID-19 and sepsis. A Two-Sample MR(TSMR) analyses was performed. As instrumental variables, a COVID-19 dataset of single nucleotide polymorphisms (SNPs) with significance value smaller than 5*10-8 was employed and Sepsis dataset of SNPs with significance value smaller than 5*10-7was employed.

Results

The results suggested that Very severe respiratory confirmed COVID-19(VSRC), hospitalized COVID-19(HC) and Infected COVID-19(IC) had no causal influence on sepsis risk using the inverse variance weighted (IVW) technique (VSRC OR = 1.000, 95% CI, 0.956-1.046, P = 0.996, HC OR = 0.976, 95% CI, 0.920-1.036, P = 0.430, IC OR = 0.923, 95% CI, 0.796-1.071, P = 0.291) and there was no causal effect of sepsis on the risk of VSRC, HC and IC (VSRC OR = 0.955, 95% CI, 0.844-1.173, P = 0.953, HC OR = 0.993, 95% CI, 0.859-1.147, P = 0.921, IC OR = 1.001, 95% CI, 0.959-1.045, P = 0.961).

Conclusions

Our findings do not support a causal relationship between COVID-19 and sepsis risk, nor do they suggest a causal link between sepsis and COVID-19. The bidirectional relationship between COVID-19 and sepsis warrants further investigation in large cohorts.

Misleading Procalcitonin in Patients With Staphylococcus aureus Bacteremia: A Report of Two Cases

Procalcitonin (PCT) is an important biomarker for bacterial infection with a high negative predictive value. It is almost always positive in patients who are bacteremic with pathogenic bacteria. Here, we report two cases of Staphylococcus aureus bacteremia, where PCT levels were unexpectedly negative. This uncommon occurrence challenges the assumption of PCT's infallibility as a diagnostic marker in patients with true bacteremia. The first case is a 55-year-old woman with no past medical issues who presented with one week of generalized weakness and two days of fever and chills. Though her white blood cell (WBC) count and c-reactive protein (CRP) were elevated, PCT was normal, with no apparent source of infection, and hence antibiotic differed. However, her blood cultures returned positive for methicillin-resistant Staphylococcus aureus (MRSA). The patient was started on vancomycin and discharged on daptomycin, she responded appropriately and improved. The second case is an intravenous (IV) drug user, a 40-year-old woman, who presented with septic arthritis and osteomyelitis involving the right hip. She had blood cultures positive for methicillin-susceptible Staphylococcus aureus (MSSA); however, a PCT check on the day of positive blood cultures and various occasions subsequently was normal. These two cases remind us that we cannot over-rely on one test to rule out bacterial infection and should consider the whole clinical picture. They highlight the need for vigilance among clinicians that PCT can rarely be negative in cases of true bacteremia in spite of its high negative predictive value. Physicians and antibiotic stewardship programs should be cautious and aware of this potential pitfall when utilizing PCT as a diagnostic tool.

Costs and Consequences of a Novel Emergency Department Sepsis Diagnostic Test: The IntelliSep Index

Sepsis causes 270,000 deaths and costs $38 billion annually in the United States. Most cases of sepsis present in the emergency department (ED), where rapid diagnosis remains challenging. The IntelliSep Index (ISI) is a novel diagnostic test that analyzes characteristics of WBC structure and provides a reliable early signal for sepsis. This study performs a cost-consequence analysis of the ISI relative to procalcitonin for early sepsis diagnosis in the ED.

PERSPECTIVE

U.S. healthcare system.

SETTING

Community hospital ED.

METHODS

A decision tree analysis was performed comparing ISI with procalcitonin. Model parameters included prevalence of sepsis, sensitivity and specificity of diagnostic tests (both ISI and procalcitonin), costs of hospitalization, and mortality rate stratified by diagnostic test result. Mortality and prevalence of sepsis were estimated from best available literature. Costs were estimated based on an analysis of a large, national discharge dataset, and adjusted to 2018 U.S. dollars. Outcomes included expected costs and survival.

RESULTS

Assuming a confirmed sepsis prevalence of 16.9% (adjudicated to Sepsis-3), the ISI strategy had an expected cost per patient of $3,849 and expected survival rate of 95.08%, whereas the procalcitonin strategy had an expected cost of $4,656 per patient and an expected survival of 94.98%. ISI was both less costly and more effective than procalcitonin, primarily because of fewer false-negative results. These results were robust in sensitivity analyses.

CONCLUSIONS

ISI was both less costly and more effective in preventing mortality than procalcitonin, primarily because of fewer false-negative results. The ISI may provide health systems with a higher-value diagnostic test in ED sepsis evaluation. Additional work is needed to validate these results in clinical practice.

Specificity of Presepsin as a Biomarker of Bacterial Infection in Mouse Sepsis Models

INTRODUCTION

Since its discovery in 2002, presepsin (P-SEP) has been reported to be useful in the early diagnosis of sepsis and has been evaluated in many clinical studies. However, as antibodies that bind to mouse P-SEP were previously unavailable, serum P-SEP levels in mice are limited. This study used a P-SEP enzyme-linked immunosorbent assay kit to evaluate the changes in serum P-SEP levels in mouse sepsis models compared with changes in other inflammatory markers and determine whether P-SEP can function as a biomarker specific to bacterial infections.

METHODS

Sepsis was induced in mice via cecal ligation and puncture (CLP), induction with lipopolysaccharide (LPS), and cecal ligation (CL) model was created as a control for the CLP model, following which clinical biomarkers (P-SEP, C-reactive protein, and procalcitonin) were evaluated.

RESULTS

The 48-h survival rates in the CLP, CL, and LPS-induced sepsis models were 67%, 89%, and 57%, respectively. Serum C-reactive protein levels did not increase in the CLP and CL models within 24 h but significantly increased in the LPS-induced sepsis model. Serum procalcitonin levels increased in the CLP and CL models and especially increased in the LPS-induced sepsis model. In contrast, an increase in serum P-SEP level was found in the CLP model at 6 h compared with those at baseline, the CL, and LPS-induced sepsis models.

CONCLUSIONS

Mouse P-SEP is elevated early in infection and more specific to bacterial infection compared with other biomarkers.

Detection of COVID-19-related biomarkers by electrochemical biosensors and potential for diagnosis, prognosis, and prediction of the course of the disease in the context of personalized medicine

As a more efficient and effective way to address disease diagnosis and intervention, cutting-edge technologies, devices, therapeutic approaches, and practices have emerged within the personalized medicine concept depending on the particular patient's biology and the molecular basis of the disease. Personalized medicine is expected to play a pivotal role in assessing disease risk or predicting response to treatment, understanding a person's health status, and, therefore, health care decision-making. This work discusses electrochemical biosensors for monitoring multiparametric biomarkers at different molecular levels and their potential to elucidate the health status of an individual in a personalized manner. In particular, and as an illustration, we discuss several aspects of the infection produced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as a current health care concern worldwide. This includes SARS-CoV-2 structure, mechanism of infection, biomarkers, and electrochemical biosensors most commonly explored for diagnostics, prognostics, and potentially assessing the risk of complications in patients in the context of personalized medicine. Finally, some concluding remarks and perspectives hint at the use of electrochemical biosensors in the frame of other cutting-edge converging/emerging technologies toward the inauguration of a new paradigm of personalized medicine.

Current Status of Antibiotic Stewardship and the Role of Biomarkers in Antibiotic Stewardship Programs

The importance of antibiotic stewardship is increasingly emphasized in accordance with the increasing incidences of multidrug-resistant organisms and accompanying increases in disease burden. This review describes the obstacles in operating an antibiotic stewardship program (ASP), and whether the use of biomarkers within currently available resources can help. Surveys conducted around the world have shown that major obstacles to ASPs are shortages of time and personnel, lack of appropriate compensation for ASP operation, and lack of guidelines or appropriate manuals. Sufficient investment, such as the provision of full-time equivalent ASP practitioners, and adoption of computerized clinical decision systems are useful measures to improve ASP within an institution. However, these methods are not easy in terms of both time commitments and cost. Some biomarkers, such as C-reactive protein, procalcitonin, and presepsin are promising tools in ASP due to their utility in diagnosis and forecasting the prognosis of sepsis. Recent studies have demonstrated the usefulness of algorithmic approaches based on procalcitonin level to determine the initiation or discontinuation of antibiotics, which would be helpful in decreasing antibiotics use, resulting in more appropriate antibiotics use.

Electrochemiluminescence Systems for the Detection of Biomarkers: Strategical and Technological Advances

Electrochemiluminescence (ECL)-based sensing systems rely on light emissions from luminophores, which are generated by high-energy electron transfer reactions between electrogenerated species on an electrode. ECL systems have been widely used in the detection and monitoring of diverse, disease-related biomarkers due to their high selectivity and fast response times, as well as their spatial and temporal control of luminance, high controllability, and a wide detection range. This review focuses on the recent strategic and technological advances in ECL-based biomarker detection systems. We introduce several sensing systems for medical applications that are classified according to the reactions that drive ECL signal emissions. We also provide recent examples of sensing strategies and technologies based on factors that enhance sensitivity and multiplexing abilities as well as simplify sensing procedures. This review also discusses the potential strategies and technologies for the development of ECL systems with an enhanced detection ability.

Performance of presepsin and procalcitonin predicting culture-proven bacterial infection and 28-day mortality: A cross sectional study

Presepsin is a highly specific biomarker for diagnosing bacterial infections, but its clinical usefulness is not well validated. A retrospective cross-sectional study was conducted. Among the patients suspected bacterial infection or fulfilled the criteria of systemic inflammatory response syndrome (SIRS) and patients who underwent blood culture, presepsin, procalcitonin (PCT), and C-reactive protein (CRP) at the same time were included. Receiver operating characteristic (ROC) curve analysis and logistic regression were used to compare performance of three biomarkers. A total of 757 patients were enrolled, including 256 patients (33.8%) with culture-proven bacterial infection and 109 patients (14.4%) with bacteremia. The 28-day mortality rate was 8.6%. ROC curve analysis revealed that the area under the curve (AUC) of PCT was higher than that of presepsin for both culture-proven bacterial infection (0.665 and 0.596, respectively; p = 0.003) and bacteremia (0.791 and 0.685; p < 0.001). In contrast, AUC of PCT for 28-day mortality was slower than presepsin (0.593 and 0.720; p = 0.002). In multivariable logistic regression analysis, PCT showed the highest ORs for culture-proven bacterial infection (OR 2.23, 95% CI 1.55–3.19; p < 0.001) and for bacteremia (OR 5.18, 95% CI 3.13–8.56; p < 0.001), while presepsin showed the highest OR for 28-day mortality (OR 3.31, 95% CI 1.67–6.54; p < 0.001). CRP did not show better performance than PCT or presepsin in any of the analyses. PCT showed the best performance predicting culture-proven bacterial infection and bacteremia, while presepsin would rather be useful as a prognostic marker.

Optimal use of procalcitonin to rule out bacteremia in patients with possible viral infections

Objective

During the winter, many patients present with suspected infection that could be a viral or a bacterial (co)infection. The aim of this study is to investigate whether the optimal use of procalcitonin (PCT) is different in patients with and without proven viral infections for the purpose of excluding bacteremia. We hypothesize that when a viral infection is confirmed, this lowers the probability of bacteremia and, therefore, influences the appropriate cutoff of procalcitonin.

Methods

This study was conducted in the emergency department of an academic medical center in The Netherlands in the winter seasons of 2019 and 2020. Adults (>18 years) with suspected infection, in whom a blood culture and a rapid polymerase chain reaction test for influenza was performed were included.

Results

A total of 546 patients were included of whom 47 (8.6%) had a positive blood culture. PCT had an area under the curve of 0.85, 95% confidence interval (95% CI) 0.80-0.91, for prediction of bacteremia. In patients with a proven viral infection (N = 212) PCT < 0.5 μg/L had a sensitivity of 100% (95% CI 63.1-100) and specificity of 81.2% (95% CI 75.1-86.3) to exclude bacteremia. In patients without a viral infection, the procalcitonin cutoff point of < 0.25 μg/L showed a sensitivity of 87.2% (95% CI 72.6-95.7) and specificity of 64.1 % (95% CI 58.3-69.6).

Conclusion

In patients with a viral infection, our findings suggest that a PCT concentration of <0.50 μg/L makes bacteremia unlikely. However, this finding needs to be confirmed in a larger population of patients with viral infections, especially because the rate of coinfection in our cohort was low.

New testing guidelines for community-acquired pneumonia

PURPOSE OF REVIEW

The purpose of this article is to review diagnostic testing recommendations outlined in the current American Thoracic Society (ATS)/Infectious Diseases Society of America (IDSA) community-acquired pneumonia (CAP) guideline and the 2021 ATS guideline for noninfluenza respiratory viruses.

RECENT FINDINGS

Diagnostic testing in CAP with gram stain, lower respiratory and blood cultures, Streptococcal and Legionella urinary antigens are not routinely recommended unless identified as severe CAP or with risk factors for Methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa infection. Influenza virus testing remains a strong recommendation during periods of community viral spread.An additional 2021 ATS clinical practice guideline reviewed the use of molecular testing for noninfluenza viral pathogens in adults with suspected CAP and recommended testing in those hospitalized with severe CAP and/or various immunocompromising conditions.

SUMMARY

Diagnostic testing remains an important component of confirming and treating CAP. The CAP guideline includes recommendations surrounding diagnostic testing with lower respiratory gram stain and culture, blood cultures, Legionella and Pneumococcal urinary antigen, influenza viral testing and serum procalcitonin.There is a strong recommendation to obtain influenza virus testing during periods of community spread. However, the use of other diagnostics such as gram stain, lower respiratory and blood culture, and urinary antigen testing are dependent on severity of illness and whether a patient has been identified as having strong risk factors for MRSA or P. aeruginosa infection. The 2021 ATS clinical practice document did not routinely recommend testing noninfluenza respiratory viruses unless identified as having severe CAP and/or various immunocompromising conditions.

Bacteremia detection from complete blood count and differential leukocyte count with machine learning: complementary and competitive with C-reactive protein and procalcitonin tests

Background

Biomarkers, such as leukocyte count, C-reactive protein (CRP), and procalcitonin (PCT), have been commonly used to predict the occurrence of life-threatening bacteremia and provide prognostic information, given the need for prompt intervention. However, such diagnosis methods require much time and money. Therefore, we propose a method with a high prediction capability using machine learning (ML) models based on complete blood count (CBC) and differential leukocyte count (DC) and compare its performance with traditional CRP or PCT biomarker methods and those of models incorporating CRP or PCT biomarkers.

Methods

We collected 366,586 daily blood culture (BC) results, of which 350,775 (93.2%), 308,803 (82.1%), and 23,912 (6.4%) cases were issued CBC/DC (CBC/DC group), CRP with CBC/DC (CRP&CBC/DC group), and PCT with CBC/DC (PCT&CBC/DC group), respectively. For the ML methods, conventional logistic regression and random forest models were selected, trained, applied, and validated for each group. Fivefold validation and prediction capability were also evaluated and reported.

Results

Overall, the ML methods, such as the random forest model, demonstrated promising performances. When trained with CBC/DC data, it achieved an area under the ROC curve (AUC) of 0.802, which is superior to the prediction conventionally made with CRP/PCT levels (0.699/0.731). Upon evaluating the performance enhanced by incorporating CRP or PCT biomarkers, it reported no substantial AUC increase with the addition of either CRP or PCT to CBC/DC data, which suggests the predicting power and applicability of using only CBC/DC data. Moreover, it showed competitive prognostic capability compared to the PCT test with similar all-cause in-hospital mortality (45.10% vs. 47.40%) and overall median survival time (27 vs. 25 days).

Conclusions

The ML models using only CBC/DC data yielded more accurate bacteremia predictions compared to those by methods using CRP and PCT data and reached similar prognostic performance as by PCT data. Thus, such models are potentially complementary and competitive with traditional CRP and PCT biomarkers for conducting and guiding antibiotic usage.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07223-7.

Identification of Hub Genes With Differential Correlations in Sepsis

As a multifaceted syndrome, sepsis leads to high risk of death worldwide. It is difficult to be intervened due to insufficient biomarkers and potential targets. The reason is that regulatory mechanisms during sepsis are poorly understood. In this study, expression profiles of sepsis from GSE134347 were integrated to construct gene interaction network through weighted gene co-expression network analysis (WGCNA). R package DiffCorr was utilized to evaluate differential correlations and identify significant differences between sepsis and healthy tissues. As a result, twenty-six modules were detected in the network, among which blue and darkred modules exhibited the most significant associations with sepsis. Finally, we identified some novel genes with opposite correlations including ZNF366, ZMYND11, SVIP and UBE2H. Further biological analysis revealed their promising roles in sepsis management. Hence, differential correlations-based algorithm was firstly established for the discovery of appealing regulators in sepsis.

Changes of pituitary adenylate cyclase activating polypeptide (PACAP) level in polytrauma patients in the early post-traumatic period

In polytrauma patients who survive the primary insult, the imbalance between the pro- and anti-inflammatory processes seems to be responsible for life-threatening complications such as sepsis or multiple organ dysfunction syndrome. Measurement of C-reactive protein (CRP) and procalcitonin (PCT) is a standard way for differentiating between infectious (bacterial) and non-infectious inflammation. Monitoring of immune cell functions, like leukocyte anti-sedimentation rate (LAR) can also be useful to diagnose infectious complications. Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide with well-known immunomodulatory and anti-inflammatory effects. The aim of our study was to determine the changes of PACAP38 levels in polytrauma patients in the early post-traumatic period in intensive care unit and analyse possible correlation of its level with conventional (CRP, PCT) and unconventional (LAR) laboratory parameters. Twenty polytrauma patients were enrolled. Blood samples were taken daily for five days. We observed significant correlation between PACAP38 and CRP levels on day 4 and 5 as well as between PACAP38 and LAR levels all of the days. This could be due to the anti-inflammatory and cytoprotective functions of PACAP38 as part of an endogenous response to the trauma induced systemic inflammatory response syndrome. These significant correlations could have clinical importance in monitoring the dynamic balance of pro- and anti-inflammatory processes in case of polytraumatic patients.

Monocyte distribution width (MDW) as a new tool for the prediction of sepsis in critically ill patients: a preliminary investigation in an intensive care unit

Background

Monocyte Distribution Width (MDW), a simple proxy marker of innate monocyte activation, can be used for the early recognition of sepsis along with Procalcitonin. This study explored the added value of MDW as an early predictor of ensuing sepsis in patients hospitalised in an Intensive Care Unit.

Methods

We performed an observational prospective monocentric study to estimate the analytical performance of MDW in detecting ensuing sepsis in a sample of consecutive patients assisted in an Intensive Care Unit for > 48 h for any reason. Demographic and clinical characteristics, past medical history and other laboratory measurements were included as potential predictors of confirmed sepsis in multivariate logistic regression.

Results

A total of 211 patients were observed, 129 of whom were included in the final sample due to the suspect of ensuing sepsis; of these, 74 (57%) had a confirmed diagnosis of sepsis, which was best predicted with the combination of MDW > 23.0 and PCT > 0.5 ng/mL (Positive Predictive Value, PPV: 92.6, 95% CI: 82.1–97.9). The best MDW cut-off to rule out sepsis was ≤20.0 (Negative Predictive Value, NPV: 86.4, 95% CI: 65.1–97.1). Multivariate analyses using both MDW and PCT found a significant association for MDW > 23 only (OR:17.64, 95% CI: 5.53–67.91).

Conclusion

We found that values of MDW > 23 were associated with a high PPV for sepsis, whereas values of MDW ≤ 20 were associated with a high NPV. Our findings suggest that MDW may help clinicians to monitor ICU patients at risk of sepsis, with minimal additional efforts over standard of care.

Clinical and microbiological characteristics of patients with bacteremia and normal procalcitonin

Procalcitonin is a biomarker of bacterial infection used to guide antimicrobial therapy. However, emerging studies have highlighted bacteremic patients with low procalcitonin, potentially limiting its clinical utility. Here, we conducted an observational, retrospective study analyzing clinical and microbiological parameters of adult patients with bacteremia and procalcitonin <2 ng/mL. High proportions of patients required intensive care (31.2%) with vasopressor (14.9%) or ventilatory (17.7%) support, developed renal injury (30.7%), or had in-hospital mortality (14.4%). When divided into subgroups by procalcitonin level, patients with procalcitonin 0.5 to 2.0 ng/mL had significantly higher rates of in-hospital mortality, vasopressor requirement, and renal injury than those with procalcitonin <0.5 ng/mL. Altogether, bacteremic patients had significant morbidity and mortality despite low procalcitonin. While subgroup analysis suggested that higher procalcitonin may correlate with illness severity, a more sensitive procalcitonin cutoff did not eliminate patients with significant disease. Procalcitonin-based algorithms may not be clinically appropriate for management of bacteremia.

Relationship of serum procalcitonin levels and c-reactive protein levels in newborns with sepsis in different types of respiratory support in intensive care unit

Sepsis in newborns with RDSy and asphyxia is essential; it is a life-threatening condition and still represents an important cause of mortality and morbidity. The aim of this study was to evaluate the predictive values of procalcitonin (PCT) as an early diagnostic and prognostic biochemical marker for sepsis in newborns with RDS and asphyxia. Material and methods: The study was designed as prospective and we examined 110 newborns with proven sepsis admitted in the Intensive  Care Unit at the University Clinic of Pediatrics – Skopje in the period between December 2018 and Јanuary 2021. Procalcitonin levels were measured by using the immunoassay system Vidas based on the ELFA principles. The newborns with proven sepsis were divided into two groups. The first group comprised 55 newborns with RDS and proven sepsis and the second group included 55 newborns with asphyxia and proven sepsis. The statistical analysis confirmed significantly different values ​​of PCT in the analyzed time period in first group of newborns with RDS and proven sepsis, p<0.001. The highest average values (40.37±53.79) ​​were measured on admission with a high level of peak compared to the second group of newborns with asphyxia and proven sepsis. The statistical analysis confirmed significantly different values ​​of PCT in the analyzed time period in the first group of newborns with RDS and proven sepsis with mechanical ventilation (MV) and bubble continuous positive airway pressure (BCPAP) compared to the second group of newborns with asphyxia  and proven sepsis,  p<0.001. PCT is a promising sepsis marker in newborns with RDSy, capable of complementing clinical signs and routine laboratory parameters suggestive of severe infection at the time of ICU admission.  

Detection of canine and equine procalcitonin for sepsis diagnosis in veterinary clinic by the development of novel MIP-based SPR biosensors

Procalcitonin (PCT) has emerged as a promising biomarker for the rapid identification of sepsis both in human and veterinary medicine. Nevertheless, the only analytical method currently available for the detection of PCT in veterinary species, is represented by immunoassays, useful only for research purposes. In this work, we report the development of two biosensors which utilize molecularly imprinted polymers (MIPs) for the detection of canine and equine PCT. Dopamine (DA) and norepinephrine (NE) were used as monomers for the synthesis of the MIP films on surface plasmon resonance (SPR) gold chips and the imprinting efficiency of canine and equine PCT in terms of binding affinity toward the analyte, selectivity, and sensitivity were compared. After optimization in buffer conditions, PCTs calibration was successfully achieved also in animal plasma, with good specificity and reproducibility. More effective protein binding and imprinting was obtained with polynorepinephrine (PNE) for both PCTs, and the SPR biosensors were able to detect the biomarkers in plasma with a LOD of 15 ng mL^-1 and 30 ng mL^-1 respectively for equine and canine PCT.

Neglected Variables in the Interpretation of Serum Procalcitonin Levels in Patients With Septic Shock

The interpretation of serum procalcitonin (PCT) levels in septic patients is facilitated by reviewing the known stimuli that activate the PCT family of genes. Herein we describe 7 pathways that, alone or in combination, can increase serum PCT levels. As a marker of activation of innate immunity, high PCT levels affect clinical diagnosis, can be trended as a measure of "source" control, and can guide duration of antibacterial therapy in septic patients. Low PCT levels reflect little to no activation of an innate immune response, influence the differential diagnosis, and support the discontinuation of empiric antibiotic therapy. Understanding the pathways that result in elevated serum PCT levels is necessary for interpretation and subsequent clinical management.

Diagnostic performance of biomarkers in maternal sepsis: A prospective observational study

OBJECTIVES

Maternal sepsis is a life-threatening condition. Biomarkers have been found to be useful in early detection of sepsis in the critical care setting. We aimed to determine the diagnostic performance of different biomarkers such as procalcitonin, C-reactive protein (CRP), absolute eosinophil count, and activated partial thromboplastin time (aPTT) in maternal sepsis.

METHODS

A total of 35 patients were enrolled in this prospective observational study. Patients with suspected sepsis were evaluated for multi-organ dysfunction. The blood samples for testing of these biomarker levels were obtained at the time of enrollment in the study (day 1), and on day 3 and day 7. Trends of each marker were followed and correlated with the clinical picture.

RESULTS

Of 35 enrolled patients, 30 completed the study. Among these, 18 had sepsis and 12 were designated as without sepsis. Sensitivities of procalcitonin, CRP, aPTT, and absolute eosinophil count were 83.33%, 77.78%, 55.56%, and 58.82% whereas their specificities were 66.67%, 75.0%, 100%, and 75%, respectively. Area under the curve was highest for procalcitonin (0.813) followed in decreasing order by CRP (0.778), aPTT (0.731), and eosinophil count (0.642), respectively.

CONCLUSION

Procalcitonin and CRP may be used as a valuable adjunct in the clinical stepwise approach for the prompt diagnosis of maternal sepsis.

The relationships between LncRNA NNT-AS1, CRP, PCT and their interactions and the refractory mycoplasma pneumoniae pneumonia in children

To investigate the relationships between LncRNA NNT-AS1, CRP, PCT and their interactions and the refractory mycoplasma pneumoniae pneumonia (RMPP) in children. Serum levels of LncRNA NNT-AS1 of RMPP and non-RMPP (NRMPP) patients were detected by real-time PCR, and were analyzed together with serum c-reactive protein (CRP) and procalcitonin (PCT). Correlations between LncRNA NNT-AS1 and CRP and PCT were analyzed by Pearson correlation test. The ROC curve was used to analyze the potential of LncRNA NNT-AS1, CRP and PCT as biomarkers for predicting RMPP. Logistic regression crossover model and the Excel compiled by Andersson et al. were used to analyze the interactions among the biomarkers. We found that LncRNA NNT-AS1, CRP and PCT were all highly expressed in patients with RMPP. LncRNA NNT-AS1 could positively correlate with the expressions of CRP and PCT, and jointly promote the occurrence of RMPP. The combined diagnosis of LncRNA NNT-AS1, CRP and PCT could predict the occurrence of RMPP.

Procalcitonin utilization in the real world: An observational study of antibiotic prescribing practices

OBJECTIVES

This study aims to better understand and describe antibiotic prescribing practices and adherence to a procalcitonin (PCT)-guided algorithm in patients undergoing serum PCT testing in adult hospitalized patients.

METHODS

We performed an observational, retrospective study of 201 randomly selected patients who are aged ≥18 years, admitted to the general medicine floors or step-down unit between 1 January 2017 and 31 December 2017, and had serum PCT testing. Physician adherence to a PCT-guided algorithm was assessed through chart review.

RESULTS

We found an overall adherence of 64.7%. Adherence was highest for PCT values above 0.25 ng/mL (82.8% for 0.25-0.50 ng/mL and 83.6% for >0.50 ng/mL). Adherence was lower for PCT values less than 0.25 ng/mL (59% for <0.1 ng/mL and 38% for 0.1-0.24 ng/mL). Serial testing was performed in 10% of patients.

CONCLUSIONS

Hospital-based providers are more likely to overrule the algorithm and either initiate or continue antibiotics when guidelines encourage discontinuing antibiotics. These findings have important implications for antimicrobial stewardship and patient care and suggest that hospital-based providers may benefit from targeted didactics regarding the interpretation of the serum PCT assay.

Predicting Bacterial Versus Viral Infection, or None of the Above: Current and Future Prospects of Biomarkers

Sepsis and pneumonia cause significant morbidity and mortality worldwide. Despite improvements in diagnostic methodologies for organism identification, the early recognition and further risk stratification of these infections can be challenging. Although traditional clinical scoring systems are beneficial for the management of sepsis and pneumonia, biomarkers supporting the diagnosis and management of these infectious diseases are needed. Many biomarkers have been identified and there is no lack of studies and meta-analyses assessing the utility of biomarkers. Focusing primarily on sepsis and pneumonia, this article discusses the most commonly used biomarkers for which clinical laboratory testing methods are available.

Effect of Pentoxifylline on Organ Dysfunction and Mortality in Severe Sepsis

Background:

Sepsis and infection are among the leading causes of death world-wide. The annual burden of sepsis in high-income countries is rising with a mortality rate of 40% and 90% of the worldwide deaths from pneumonia, meningitis or other infections occur in less developed countries. This study was performed to evaluate the therapeutic efficacy of pentoxifylline as an adjuvant therapy in septic patients and its effect on multiple organ dysfunction and mortality in septic patients.

Methods:

This randomized, double-blinded prospective study was conducted from October 2017 to November 2018, which included a total sample size of 52 cases of septic patients. Organ dysfunction was used as a primary outcome with proposed large effect size ((0.8) and alfa =0.05 and power=0.80, so, 26 cases were needed in each group). Secondary outcomes were inflammatory markers C-Reactive Protein (CRP) and pro-calcitonin, duration of hospital stay, need for hemodialysis, need for vasopressor & inotropes, need for mechanical ventilation and 28 days survival.

Results:

Fifty-two patients with sepsis were divided in 1: 1 ratio to receive pentoxifylline or not. The average age of the included patients was almost 53 years, chest disorders were the main cause of sepsis in both groups. There were no statistically significant differences between both groups in terms of Sequential Organ Failure Assessment (SOFA) score, lactate level, CRP level and pro-calcitonin level. As regards secondary outcomes, there were no statistically significant differences between study’s groups in terms of length of hospital stay (p =0.707), need for hemodialysis (p =0.541), need for vasopressor & inotropes (p =0.249), need for mechanical ventilation (p =0.703), and 28 days survival (p =0.5).

Conclusion:

We concluded that pentoxifylline as an adjuvant therapy in septic patients had no significant influence on multiple organ dysfunction and mortality.

Clinical evaluation of FAPlus/FNPlus bottles compared with the combination of SA/SN and FA/FN bottles in the BacT/Alert blood culture system

Background : The comparison of the performance of FAPlus/FNPlus bottles and combination of SA/SN and FA/FN bottles is not yet reported. Methods : We used human blood samples to investigate microorganism detection rates and the time to positivity (TTP) in a before-vs.-after study (a combination of SA/SN and FA/FN bottles from September 2012 to August 2013 vs. FAPlus/FNPlus bottles from September 2013 to August 2014). Results : The microorganism detection rate was significantly higher in the later period than in the earlier period (11.2% vs. 9.6%, P < 0.001), particularly for Enterococcus and Streptococcus species, nonfermentative Gram-negative bacilli, and Helicobacter cinaedi. TTP for pathogens was longer when FAPlus/FNPlus bottles were used than when a combination of SA/SN and FA/FN bottles was used (14.9 vs. 13.3 h, P = 0.014), particularly, in the case of Gram-negative bacilli including Escherichia coli. Conclusion : The microorganism detection rate was improved with the use of FAPlus/FNPlus bottles compared with the combination of SA/SN and FA/FN bottles ; however, FAPlus/FNPlus bottles seemed to be inferior to SA/SN and FA/FN bottles in terms of TTP. J. Med. Invest. 67 : 90-94, February, 2020.

Low Sensitivity of Procalcitonin for Bacteremia at an Academic Medical Center: A Cautionary Tale for Antimicrobial Stewardship

Background

Procalcitonin testing has been adopted by antimicrobial stewardship programs as a means of reducing inappropriate antibiotic use, including within intensive care units (ICUs). However, concerns regarding procalcitonin's sensitivity exist. The purpose of this study is to calculate the sensitivity of procalcitonin for bacteremia among hospitalized patients.

Methods

This was a retrospective cohort study of adult patients admitted to an academic medical center between July 1, 2018, and June 30, 2019, with ≥1 positive blood culture within 24 hours of admission and procalcitonin testing within 48 hours. Low procalcitonin was defined as <0.5 µg/L.

Results

A total of 332 patients were included. The sensitivity of procalcitonin for bacteremia was 62% at the sepsis threshold of 0.5 µg/L, 76% at a threshold of 0.25 µg/L, and 92% at a threshold of 0.1 µg/L. Of the 125 patients with low procalcitonin, 14% were initially admitted to the ICU and 9% required the use of vasopressors. In that same group, the top 3 organisms isolated were Staphylococcus aureus (39%), Escherichia coli (17%), and Klebsiella spp. (7%). Compared with those patients with elevated procalcitonin, patients with low procalcitonin were significantly more likely to have >24-hour delayed receipt of antibiotic therapy (3% vs 8%; P = .04), including among patients admitted to the ICU (1% vs 18%; P = .02).

Conclusions

The sensitivity of procalcitonin for bacteremia is unacceptably low for a rule-out test. Antimicrobial stewardship programs should use caution before promoting the withholding of antibiotic therapy for patients with low initial procalcitonin values.

The Dynamical Assessment of Inflammatory Biomarkers in Predicting the Outcome of Septic Patients and the Response to Antimicrobial Therapy

Aims

To evaluate the kinetics of inflammatory biomarkers in septic patients in order to identify the most reliable predictor of unfavorable outcome.

Methods

A prospective analysis of septic patients was performed. Median levels of neutrophil/lymphocyte count ratio, fibrinogen, C-reactive protein and procalcitonin were dynamically assessed and comparatively analyzed.

Results

Seventy-seven patients were included. Descendent kinetic patterns were registered for all biomarkers, except C-reactive protein. At 24 hours, neutrophil/lymphocyte count ratio significantly decreased in 42.85% of cases, procalcitonin in 37.33%, C-reactive protein in 16.12% and fibrinogen in 1.58% of cases. At 72 hours, procalcitonin decreased to one-half in 70% of cases and neutrophil/lymphocyte count ratio in 67.53% of cases.

Conclusions

Neutrophil/lymphocyte count ratio and procalcitonin significantly decreased in the first 72 hours, while C-reactive protein increased in the first 24 hours. The proportions of patients with major decrease of baseline values were higher for neutrophil/lymphocyte count ratio and procalcitonin.

Procalcitonin: A promising tool or just another overhyped test?

Sepsis is the leading cause of death worldwide. Timely administration of antibiotics is recognized as the cornerstone in the management of sepsis. However, inappropriate use of antibiotics may lead to adverse effects and the selection of drug-resistant pathogens. Microbiological cultures remain the gold standard to diagnose infection despite their low sensitivity and the intrinsic delay to obtain the results. Certain biomarkers have the benefit of rapid turnover, potentially providing an advantage in timely diagnosis leading to accurate treatment. Over the last few decades, there is an ongoing quest for the ideal biomarker in sepsis. Procalcitonin (PCT), when used alone or alongside additional clinical information, has shown to be a promising tool to aid in the diagnosis and management of patients with sepsis. In February 2017, the Food and Drug Administration (FDA) approved the use of PCT to guide antibiotic treatment in lower respiratory tract infections and sepsis. Despite a good negative predictive value for bacterial infection, the utility of PCT-guided antibiotic initiation is conflicting at best. On the other hand, the use of PCT-guided antibiotic discontinuation has shown to reduce the duration of antibiotic use, the associated adverse effects, and to decrease the overall mortality. The current review discusses the history and pathophysiology of procalcitonin, synthesizes its utility in the diagnosis and management of sepsis, highlights its limitations and compares it with other biomarkers in sepsis.

Procalcitonin as a biomarker for critically ill patients with sepsis: Effects of vitamin D supplementation

Early diagnosis of sepsis is often difficult in clinical practice, whilst it can be vital for positive patient outcomes in sepsis management. Any delay in diagnosis and treatment may lead to significant organ failure and can be associated with elevated mortality rates. Early diagnosis and effective management of sepsis can allow for prompt antibiotic therapy and a potential reduction in mortality; it can also minimize the unnecessary use of antibiotics. Furthermore, vitamin D supplementation, which is commonly used in the intensive care units to reduce mortality, may interfere with the ability to use procalcitonin (PCT) as a means of assessing clinical progression. This paper aims to explore the diagnostic and prognostic value of serum levels of PCT as an early marker of sepsis and to assess whether it can be used as a guide for using antibiotic therapy. Several serum-based biomarkers such as C-reactive protein, lactate, presepsin, and cytokines, such as interleukin-1 (IL-1), and IL-6 have been evaluated as early indicators of sepsis but none have been proven sensitive and/or specific enough to make a definitive diagnosis. Finally the potential benefits and disadvantages of using serum levels of PCT to diagnose and monitor patients with sepsis and septic shock will be briefly discussed.

Albumin/Procalcitonin Ratio Is a Sensitive Early Marker of Nosocomial Blood Stream Infection in Patients with Intra-Cerebral Hemorrhage

Background: This study was performed to investigate the combination of admission serum procalcitonin (PCT) and albumin (alb) concentrations as a diagnostic predictor for discriminating patients with nosocomial blood stream infection (BSI) among those with spontaneous intra-cerebral hemorrhage (ICH). Methods: We conducted a retrospective study on patients with ICH and hospital-acquired BSI. Clinical and microbiological data were compared in patients who experienced nosocomial BSI during a hospital stay and those who did not. Multivariable logistic regression analyses were used to identify independent risk factors for nosocomial BSI. A receiver operating characteristic (ROC) curve analysis was performed to compare the predictive accuracy of the albumin:PCT ratio. Results: Patients with nosocomial BSI had lower albumin:PCT ratios than those without BSI (11.739 [3.192-38.452] versus 200.000 [40.634-417.500]; p < 0.001). Multivariable logistic regression analysis revealed that the albumin:PCT ratio (odds ratio [OR] 1.006; 95% confidence interval [CI] 1.002-1.011; p = 0.001], white blood cell count (OR 1.129; 95% CI 1.044-1.220; p = 0.002), and shock (OR 4.504; 95% CI 1.774-11.435; p = 0.002) were independent predictors of nosocomial BSI, allowing distinction of patients with the infection from those without. The area under the ROC curve for the albumin:PCT ratio was 0.830 (95% CI 0.768-0.892; p < 0.001). The cut-off value of the albumin:PCT ratio was <1.087 with a sensitivity of 90.6% and a specificity of 98.8%. In the subgroup of 85 patients with nosocomial BSI, the albumin:PCT ratio in patients with shock was lower than that in those without shock (7.154 [2.975-26.267] vs 28.000 [3.818-57.812]; p = 0.027). Conclusion: The albumin:PCT ratio can be used as an early diagnostic predictor for nosocomial BSI in patients with ICH. Additionally, BSI patients with lower albumin:PCT ratios are more likely to experience shock. The albumin:PCT ratio is expected to be a rapid and low-cost tool for clinical practice.

Prognostic value of procalcitonin and lipopolysaccharide binding protein in cancer patients with chemotherapy-associated febrile neutropenia presenting to an emergency department

INTRODUCTION

Cancer patients with chemotherapy-induced febrile neutropenia are a heterogeneous group with a significant risk of serious medical complications. In these patients, the Multinational Association for Supportive Care in Cancer (MASCC) score is the most widely used tool for risk-stratification. The aim of this prospective study was to analyse the value of procalcitonin (PCT) and lipopolysaccharide binding protein (LBP) to predict serious complications and bacteraemia in cancer patients with febrile neutropenia, compared with MASCC score.

MATERIALS AND METHODS

Data were collected from 111 episodes of febrile neutropenia admitted consecutively to the emergency department. In all of them, MASCC score was calculated and serum samples were collected for measurement of PCT and LBP by well-established methods. The main and secondary outcomes were the development of serious complications and bacteraemia, respectively.

RESULTS

A serious complication occurred in 20 (18%) episodes and in 16 (14%) bacteraemia was detected. Areas under the receiver operating characteristic curve (ROC AUC) of MASCC score, PCT and LBP to select low-risk patients were 0.83 (95% confidence interval (CI): 0.74 - 0.89), 0.85 (95% CI: 0.77 - 0.91) and 0.70 (95% CI: 0.61 - 0.78), respectively. For bacteraemia, MASCC score, PCT and LBP showed ROC AUCs of 0.74 (95% CI: 0.64 - 0.82), 0.86 (95% CI: 0.78 - 0.92) and 0.76 (95% CI: 0.67 - 0.83), respectively.

CONCLUSION

A single measurement of PCT performs similarly as MASCC score to predict serious medical complications in cancer patients with febrile neutropenia and can be a useful tool for risk stratification. Besides, low PCT concentrations can be used to rule-out the presence of bacteraemia.

Performance enhancement of procalcitonin by high-sensitivity C-reactive protein at the optimal cutoff in predicting bacteremia in emergency department adult patients

Pathogenic bacteremia portends a high mortality risk in adult patients admitted to an Emergency Department (ED). This study aims to investigate the effect of adding high-sensitivity C-reactive protein (hs-CRP) to procalcitonin (PCT) and lactate in predicting bacteremia, Gram-negative (GNB) and Gram-positive bacteremia (GPB), using the optimal cutoff derived from the receiver operating characteristics analysis. We evaluated the diagnostic measures, including the positive-test likelihood (LR+), the negative-test likelihood (LR-), and the diagnostic odds ratio (DOR) using a single-center retrospective analysis design. This Standards for Reporting Diagnostic-compliant study comprised 886 consecutive adults who were admitted to the ED in 2010; to this cohort, a 22.2% prevalence of true bacteremia was subsequently confirmed. At the cutoff of 3.9 μg/L, PCT had a DOR of 5.3 (95% confidence interval [CI]: 3.76-7.61) and LR + of 2.8 (95% CI: 2.3-3.4) in predicting overall bacteremia. Elevated PCT and lactate (cutoff at 2 mmol/L), increased the DOR and LR + to 6.3 (95% CI: 4.27-9.29) and 4.0 (95% CI: 3.1-5.2). The DOR and LR + were further improved to 7.1 (95% CI: 4.2-11.95) and 5.6 (95% CI: 3.7-8.6), respectively, when hs-CRP at the cutoff of 1238 nmol/L was added to PCT plus lactate. High-sensitivity CRP at the cutoff of 1,255 nmol/L can enhance the discriminative power raising DOR and LR + values for GPB. The elevation of hs-CRP at the optimal cutoff might improve the diagnostic performance to predict unspecified bacteremia and GPB, but not GNB.

Clinical characteristics, organ failure, inflammatory markers and prediction of mortality in patients with community acquired bloodstream infection

BACKGROUND

Community acquired bloodstream infection (CABSI) in low- and middle income countries is associated with a high mortality. This study describes the clinical manifestations, laboratory findings and correlation of SOFA and qSOFA with mortality in patients with CABSI in northern Vietnam.

METHODS

This was a retrospective study of 393 patients with at least one positive blood culture with not more than one bacterium taken within 48 h of hospitalisation. Clinical characteristic and laboratory results from the first 24 h in hospital were collected. SOFA and qSOFA scores were calculated and their validity in this setting was evaluated.

RESULTS

Among 393 patients with bacterial CABSI, approximately 80% (307/393) of patients had dysfunction of one or more organ on admission to the study hospital with the most common being that of coagulation (57.1% or 226/393). SOFA performed well in prediction of mortality in those patients initially admitted to the critical care unit (AUC 0.858, 95%CI 0.793-0.922) but poor in those admitted to medical wards (AUC 0.667, 95%CI 0.577-0.758). In contrast qSOFA had poor predictive validity in both settings (AUC 0.692, 95%CI 0.605-0.780 and AUC 0.527, 95%CI 0.424-0.630, respectively). The overall case fatality rate was 28%. HIV infection (HR = 3.145, p = 0.001), neutropenia (HR = 2.442, p = 0.002), SOFA score 1-point increment (HR = 1.19, p < 0.001) and infection with Enterobacteriaceae (HR = 1.722, p = 0.037) were independent risk factors for in-hospital mortality.

CONCLUSIONS

Organ dysfunction was common among Vietnamese patients with CABSI and associated with high case fatality. SOFA and qSOFA both need to be further validated in this setting.

Expression and Significance of Th17 and Treg Cells in Pulmonary Infections with Gram-Negative Bacteria

The aim of this study was to investigate the expression and significance of T helper type 17 (Th17) and regulatory T (Treg) cells in severe pulmonary infection with gram-negative bacteria (GNB). The peripheral venous blood (PVB) and bronchoalveolar lavage fluid (BALF) were collected from patients receiving mechanical ventilation in the intensive care unit (ICU) owing to: (1) pulmonary GNB infection (group I) and (2) nonpulmonary infection (group NI). Patients from the two groups were matched based on their Acute Physiology and Chronic Health Evaluation II (APACHE II) scores and were recruited in the same period. The levels of Th17 and Treg cells in the PVB and BALF were measured by flow cytometry. (1) The levels of Th17 and Treg cells in the PVB and BALF of the infection group (I) were significantly higher than those of the noninfection group (NI) (p < 0.01), and the levels decreased significantly after treatment (p < 0.01). (2) The Treg/Th17 cell ratio in the PVB and BALF of group I was significantly lower than those of group NI and after treatment (p < 0.01). (3) The levels of Th17 and Treg cells in the PVB and BALF could not predict the 28-day mortality (p > 0.05). The expression of Th17 and Treg cells was abnormal in patients with severe pulmonary GNB infection. Our data suggest an overactive immune response in the early stages of inflammation, but the levels of Treg and Th17 cells failed to predict the 28-day mortality.

Role of Procalcitonin in the Management of Infected Patients in the Intensive Care Unit

The combination of molecular pathogen diagnostics and the biomarker procalcitonin (PCT) are changing the use of antimicrobials in patients admitted to critical care units with severe community-acquired pneumonia, possible septic shock, or other clinical syndromes. An elevated serum PCT level is good supportive evidence of a bacterial pneumonia, whereas a low serum PCT level virtually eliminates an etiologic role for bacteria even if the culture for a potential bacterial pathogen is positive. Serum PCT levels can be increased in any shocklike state; a low PCT level eliminates invasive bacterial infection as an etiology in more than 90% of patients.

Procalcitonin as Biomarker of Infection: Implications for Evaluation and Treatment

Procalcitonin (PCT) is a quickly measurable marker, assumed to have high sensitivity and specificity for sepsis and infection. A literature search was conducted to evaluate PCT ability as a diagnostic and prognostic tool in infectious processes and its ability to monitor the antibiotic therapy. PCT level is increased in bacterial and fungal infections, but not in viral infections, with a significantly higher level in patients with bacteremia compared with uninfected patients (2.5 vs. 0.3 ng/mL; P < 0.0001). A PCT value of ≤0.1 ng/mL discards bacteremia and microbiological tests (negative predictive value of 96.3%), >0.1 ng/mL needs microbiological tests, and >1.0 ng/mL is indicative of bacteremia. Antibiotic treatment algorithms guided by PCT decreased the need for antibiotic treatment in approximately 50%. PCT is a promising test in clinical practice to decide the introduction of antibiotic therapy in addition to the existing tools, without neglecting the clinical assessment, with a significant decrease in costs.

Clinical value of procalcitonin for suspected nosocomial bloodstream infection

BACKGROUND/AIMS

Procalcitonin (PCT) may prove to be a useful marker to exclude or predict bloodstream infection (BSI). However, the ability of PCT levels to differentiate BSI from non-BSI episodes has not been evaluated in nosocomial BSI.

METHODS

We retrospectively reviewed the medical records of patients ≥ 18 years of age with suspected BSI that developed more than 48 hours after admission.

RESULTS

Of the 785 included patients, 105 (13.4%) had BSI episodes and 680 (86.6%) had non-BSI episodes. The median serum PCT level was elevated in patients with BSI as compared with those without BSI (0.65 ng/mL vs. 0.22 ng/mL, p = 0.001). The optimal PCT cut-off value of BSI was 0.27 ng/mL, with a corresponding sensitivity of 74.6% (95% confidence interval [CI], 66.4% to 81.7%) and a specificity of 56.5% (95% CI, 52.7% to 60.2%). The area under curve of PCT (0.692) was significantly larger than that of C-reactive protein (CRP; 0.526) or white blood cell (WBC) count (0.518). However, at the optimal cut-off value, PCT failed to predict BSI in 28 of 105 cases (26.7%). The PCT level was significantly higher in patients with an eGFR < 60 mL/min/1.73 m² than in those with an eGFR ≥ 60 mL/min/1.73 m² (0.68 vs. 0.17, p = 0.01).

CONCLUSIONS

PCT was more useful for predicting nosocomial BSI than CRP or WBC count. However, the diagnostic accuracy of predicting BSI remains inadequate. Thus, PCT is not recommended as a single diagnostic tool to avoid taking blood cultures in the nosocomial setting.

Diagnostic and prognostic performances of serum procalcitonin in patients with bloodstream infections: A parallel, case-control study comprising adults and elderly

Objective:

To examine the diagnostic and prognostic performances of serum procalcitonin (PCT) in adult and elderly patients with bloodstream infections (BSIs).

Method:

A total of 176 patients with culture-proven BSIs and 200 healthy counterparts were studied prospectively. Participants were studied in two adult (age≤65 years, n=92) and elderly (age>65 years, n=84) groups. Admission serum PCT level was measured using a standard enzyme-linked immunosorbent assay (ELISA) technique.

Results:

The mean serum PCT level (in ng/mL) was significantly higher in cases than in controls (0.18 vs. 0.07, p=0.01 in adults; 0.20 vs. 0.07, p=0.002 in elderly). At cut-off values of 0.09 ng/mL in adults and 0.08 ng/mL in the elderly, the corresponding sensitivity and specificity were 82.6 and 82.0% in adults, and 69.1 and 70.0% in elderly, respectively. At a cut-off value of 0.2 ng/mL, the sensitivity and specificity of serum PCT in predicting 28-day mortality were 81 and 81.7% in adults, and 75 and 80.4% in elderly, respectively.

Conclusion:

Although admission serum PCT is a sensitive and specific biomarker for the diagnosis of BSIs in patients younger than 65 years old, its short-term prognostic value is comparable between adults and the elderly.

Sepsis: A Review of Advances in Management

Infections represent a common health problem in people of all ages. Usually, the response given to them is appropriate and so little treatment is needed. Sometimes, however, the response to the infection is inadequate and may lead to organ dysfunction; this is the condition known as sepsis. Sepsis can be caused by bacteria, fungi or viruses and at present there is no specific treatment; its management basically focuses on containing the infection through source control and antibiotics plus organ function support. This article reviews key elements of sepsis management, focusing on diagnosis, biomarkers and therapy. The main recent advance in therapy is the strategy of personalized medicine, based on a precise approach using biomarkers to identify specific individuals who are likely to benefit from more personalized attention.

Design and rationale of the Procalcitonin Antibiotic Consensus Trial (ProACT), a multicenter randomized trial of procalcitonin antibiotic guidance in lower respiratory tract infection

BACKGROUND

Overuse of antibiotics is a major public health problem, contributing to growing antibiotic resistance. Procalcitonin has been reported to be commonly elevated in bacterial, but not viral infection. Multiple European trials found procalcitonin-guided care reduced antibiotic use in lower respiratory tract infection, with no apparent harm. However, applicability to US practice is limited due to trial design features impractical in the US, between-country differences, and residual safety concerns.

METHODS

The Procalcitonin Antibiotic Consensus Trial (ProACT) is a multicenter randomized trial to determine the impact of a procalcitonin antibiotic prescribing guideline, implemented with basic reproducible strategies, in US patients with lower respiratory tract infection.

DISCUSSION

We describe the trial methods using the Consolidated Standards of Reporting Trials (CONSORT) framework, and the rationale for key design decisions, including choice of eligibility criteria, choice of control arm, and approach to guideline implementation.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02130986 . Registered May 1, 2014.

Comparative diagnostic test evaluation of serum procalcitonin and C-reactive protein in suspected bloodstream infections in children with cancer

PURPOSE

To compute diagnostic test properties of C-reactive protein (CRP) and serum procalcitonin (PCT) levels in bloodstream infections in children with cancer and suspected sepsis, in comparison with blood culture as the gold standard.

METHODOLOGY

Consecutive paediatric cancer patients, aged ≤14 years, with clinically suspected bloodstream infections were evaluated with blood culture and assay of PCT and CRP levels. Blood culture was taken as the gold standard for comparison. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratio (LR) and receiver operating characteristic (ROC) with area under ROC curve (AUC) were calculated to assess the diagnostic test performance for PCT and CRP.Results/Key findings. The ROC curve for PCT was better than that for CRP, with an AUC of 0.751 for PCT at a cut-off of 2.25 ng ml-1. The AUC for CRP was 0.638 at a cut-off of 8.0 mg dl-1. Among the three cut-off values of PCT selected from the ROC curve applicable to the patients under study, the cut-off value of ≥0.49 ng ml-1 had the maximum sensitivity of 81.4 % and an NPV of 94.67 %; ≥2.25 ng ml-1 had a sensitivity and specificity of 65.12 and 71.6 %, respectively, and ≥6.47 ng ml-1 had a maximum specificity of 82.10 %. For CRP, the cut-off value of ≥5.3 mg dl-1 had the maximum sensitivity of 72.09 %; ≥8.0 mg dl-1 had a sensitivity and specificity of 58.14 and 68.09 %, respectively, and ≥8.4 mg dl-1 had the maximum specificity of 70.04 %.

CONCLUSION

PCT is a better serological marker for excluding bloodstream infections than CRP. The cut-off value of 0.49 ng ml-1 with a negative predictive value of 94.67 % will be ideal in a clinical setting of immune-compromised children with suspected sepsis.

Rapid and Sensitive Lateral Flow Immunoassay Method for Procalcitonin (PCT) Based on Time-Resolved Immunochromatography

Procalcitonin (PCT) is a current, frequently-used marker for severe bacterial infection. The aim of this study was to develop a cost-effective detection kit for rapid quantitative and on-site detection of PCT. To develop the new PCT quantitative detecting kit, a double-antibody sandwich immunofluorescent assay was employed based on time-resolved immunofluorescent assay (TRFIA) combined with lateral flow immunoassay (LFIA). The performance of the new developed kit was evaluated in the aspects of linearity, precision, accuracy, and specificity. Two-hundred thirty-four serum samples were enrolled to carry out the comparison test. The new PCT quantitative detecting kit exhibited a higher sensitivity (0.08 ng/mL). The inter-assay coefficient of variation (CV) and the intra-assay CV were 5.4%–7.7% and 5.7%–13.4%, respectively. The recovery rates ranged from 93% to 105%. Furthermore, a high correlation (n = 234, r = 0.977, p < 0.0001) and consistency (Kappa = 0.875) were obtained when compared with the PCT kit from Roche Elecsys BRAHMS. Thus, the new quantitative method for detecting PCT has been successfully established. The results indicated that the newly-developed system based on TRFIA combined with LFIA was suitable for rapid and on-site detection for PCT, which might be a useful platform for other biomarkers in point-of-care tests.

Comparative Study of Plasma Endotoxin with Procalcitonin Levels in Diagnosis of Bacteremia in Intensive Care Unit Patients

BACKGROUND

Both procalcitonin (PCT) and plasma endotoxin levels cannot be solely used for a definite diagnosis of bacteremia or sepsis, and there has been few study comparing the values of the two biomarkers for the diagnosis of bacteremia. The aim of this study was to identify bacteria causing bacteremia and evaluate the role of the two biomarkers in the diagnosis of bacteremia in Intensive Care Unit (ICU).

METHODS

The medical records of 420 patients in ICU were retrospectively reviewed. Patients (n = 241) who met the inclusion criteria were subjected to blood culture (BC) for the analysis of the endotoxin or PCT levels. The exclusion criteria included the presence of infection with human immunodeficiency virus and/or AIDS, neutropenia without sepsis, pregnancy, treatment with immunosuppressive therapies, or blood diseases such as hematological tumors. Patients' BC episodes were divided into BC negative, Gram-negative (GN) bacteria, Gram-positive bacteria, and fungi groups. The PCT and plasma endotoxin levels were compared in the different groups.

RESULTS

A total of 241 patients with 505 episodes of BC were analyzed. The GN bacteria group showed higher levels of PCT and endotoxin than the BC negative, Gram-positive bacteria, and fungi groups. GN bacteremia was more prevalent than Gram-positive bacteremia. The GN bacteremia caused by non-Enterobacteriaceae infection presented higher endotoxin level than that by Enterobacteriaceae, but no significant difference in PCT levels was observed between the two groups. The plasma endotoxin significantly differed among different groups and was bacterial species dependent.

CONCLUSIONS

Plasma endotoxin was more related to GN than to Gram-positive bacteremia, and that endotoxin level was species dependent, but PCT level remained relatively more stable within the GN bacteria caused bacteremia. Both GN and positive bacteria caused bacteremia in the ICU patients in different regions of China. And PCT is a more valuable biomarker than endotoxin in the diagnosis of bacteremia.

Diagnostic value of serum procalcitonin, lactate, and high-sensitivity C-reactive protein for predicting bacteremia in adult patients in the emergency department

BACKGROUND

Few studies compared the diagnostic value of procalcitonin with a combination of other tests including lactate and high-sensitivity C-reactive protein in the prediction of pathogenic bacteremia in emergency department adult patients.

METHODS

We performed a retrospective study assessing the differences in performances of procalcitonin at a cutoff of 0.5 ng/mL, lactate at a cutoff of 19.8 mg/dL, high-sensitivity C-reactive protein at a cutoff of 0.8 mg/dL and their combinations for predicting bacteremia in emergency department adult patients. Sensitivity, specificity, overall accuracy, positive-test and negative-test likelihood, and diagnostic odds ratio with 95% confidence interval for each test combination were calculated for comparison. The receiver operating characteristic curve for every single test were compared using DeLong's method. We also performed a sensitivity analysis in two expanded patient cohorts to assess the discriminative ability of procalcitonin or test combination.

RESULTS

A total of 886 patients formed the initial patient cohort. The area under the receiver operating characteristic curve for discriminating positive blood culture was: procalcitonin = 0.72 (95% CI [0.69-0.75]) with a derived optimal cutoff at 3.9 ng/mL; lactate 0.69 (0.66-0.72) with an optimal cutoff at 17.9 mg/dL; high-sensitivity C-reactive protein 0.56 (0.53-0.59) with an optimal cutoff of 13 mg/dL; with pairwise comparisons showing statistically significant better performance of either procalcitonin or lactate outperforming high-sensitivity C-reactive protein. To predict positive blood cultures, the diagnostic odds ratio for procalcitonin was 3.64 (95% CI [2.46-5.51]), lactate 2.93 (2.09-4.14), and high-sensitivity C-reactive protein 0.91 (0.55-1.55; P = 0.79). About combined tests, the diagnostic odds ratio for procalcitonin and lactate increases were 3.98 (95% CI [2.81-5.63]) for positive blood culture prediction. Elevated procalcitonin level rendered a six-fold increased risk of positive gram-negative bacteremia with a diagnostic odds ratio of 6.44 (95% CI [3.65-12.15]), which showed no further improvement in any test combinations. In the sensitivity analysis, as a single test to predict unspecified, gram-negative and gram-positive bacteremia, procalcitonin performed even better in an expanded cohort of 2,234 adult patients in terms of the diagnostic odds ratio.

DISCUSSIONS

For adult emergency patients, procalcitonin has an acceptable discriminative ability for bacterial blood culture and a better discriminative ability for gram-negative bacteremia when compared with lactate and high-sensitivity C-reactive protein. High-sensitivity C-reactive protein at a cutoff of 0.8 mg/dL performed poorly for the prediction of positive bacterial culture.

The Use of Procalcitonin (PCT) for Diagnosis of Sepsis in Burn Patients: A Meta-Analysis

The continuous development of resuscitation techniques and intensive care reduced the mortality rate induced by the initial shock in burn patients and, currently, infections (especially sepsis) are the main causes of mortality of these patients. The misuse of antimicrobial agents is strongly related to antimicrobial and adverse patient outcomes, development of microbial resistance and increased healthcare-related costs. To overcome these risks, antimicrobial stewardship is mandatory and biomarkers are useful to avoid unnecessary medical prescription, to monitor antimicrobial therapy and to support the decision of its stop. Among a large array of laboratory tests, procalcitonin (PCT) emerged as the leading biomarker to accurately and time-effectively indicate the presence of systemic infection. In the presence of systemic infection, PCT blood levels undergo a sudden and dramatic increase, following the course of the infection, and quickly subside after the control of the septic process. This work is a meta-analysis on PCT performance as a biomarker for sepsis. This meta–analysis showed that overall pooled area under the curve (AUC) is 0.83 (95% CI = 0.76 to 0.90); the estimated cut-off is 1.47 ng/mL. The overall sepsis effect in PCT levels is significant and strong (Cohen's d is 2.1 and 95% CI = 1.1 to 3.2). This meta–analysis showed PCT may be considered as a biomarker with a strong diagnostic ability to discriminate between the septic from the non-septic burn patients. Thus, this work encourages the determination of PCT levels in clinical practice for the management of these patients, in order to timely identify the susceptibility to sepsis and to initiate the antimicrobial therapy, improving the patients’ outcomes.

Are prognostic scores and biomarkers such as procalcitonin the appropriate prognostic precursors for elderly patients with sepsis in the emergency department?

BACKGROUND

The mortality of patients with severe sepsis and septic shock is still high, and the prognosis of elderly patients tends to be particularly poor. Therefore, this study sought to conduct a comparative analysis of the abbreviated mortality in emergency department sepsis (abbMEDS) score, sequential organ failure assessment (SOFA) score, infection probability score (IPS), initial procalcitonin (PCT), and cytokine levels to investigate the effectiveness of each index in predicting the prognosis of elderly patients with sepsis in the emergency department (ED).

METHODS

This was a single-center prospective study, and classified 55 patients (≥65 years of age) with systemic inflammatory response syndrome (SIRS) from January 2013 to December 2013 in the ED. A total of 36 elderly patients were diagnosed with sepsis. The prediction of prognosis using the prognostic scores (abbMEDS, SOFA, IPS) was analyzed. An early blood examination (WBC count, C-reactive protein, PCT, and cytokines) was conducted within the first 2 h of the patient's arrival at the ED.

RESULTS

The median (IQR) age of subjects was 76.5 (70.5-81.5). After 28 days, 27 subjects (75 %) had survived, and 9 (25 %) had died. Fifteen (41.7 %) were sent to intensive care units (ICUs). The SOFA score and abbMEDS showed higher median (IQR) values of 9.5 (7.0-11.0) and 13.5 (12.0-15.0), respectively, in the ICU group than in the general ward group (p < 0.001). Analysis of the levels of PCT, IL-10, IL-6, and IL-5 had a significantly better ability to predict ICU admission (p = 0.001, p = 0.023, p = 0.030, p = 0.001). The prediction of mortality in the first 28 days via SOFA and the abbMEDS resulted in scores of 11.0 (8.0-11.0) and 14.0 (12.5-15.5) (p = 0.004, p = 0.003), respectively. However, levels of IPS, PCT, and cytokines did not show significant differences.

CONCLUSIONS

In predicting ICU admission and the death of elderly sepsis patients in ED, SOFA and abbMEDS scores were effective. Of the various biomarkers, PCT, IL-10, IL-6, and IL-5 were effective in predicting ICU admission, but were not effective in predicting the death of elderly sepsis patients.

Procalcitonin levels predict to identify bacterial strains in blood cultures of septic patients

BACKGROUND

We examined whether the values obtained from principal component analysis (PCA) on laboratory tests can be used to predict bacterial infections and identify bacterial strains in blood culture (BC).

METHOD

This study is a single-center retrospective analysis of 315 patients suspected of having sepsis. We applied PCA on procalcitonin (PCT) and laboratory test biomarkers, namely, platelet (PLT), white blood cell, and C-reactive protein (CRP) as well as BC.

RESULTS

Principal component analysis showed that PCT, CRP, and PLT contributions to component 1 were associated with bacterial infection. The number of patients who had BC-negative results, gram-positive cocci (GPC), and gram-negative rods (GNRs) were 124, 28, and 19, respectively. The mean value of component 1 in GNR-positive patients was 1.58±1.41 and was significantly higher than that in GPC-positive patients (0.28±0.87; P<.0001). Furthermore, the mean values of component 1 in both GNR- and GPC-positive patients were significantly higher than that in BC-negative patients (-0.31±0.65; P<.0001 and P<.002, respectively). One certain range showing higher value more than 2.00 for component 1 and -1.00 for component 2 only included GNR-positive patients. There were no BC-positive patients who showed less than -1.00 for component 1.

CONCLUSION

The present results obtained by PCA on laboratory tests involving PCT, PLT, white blood cell, and CRP suggest the potential of PCA-obtained values to not only predict bloodstream infection but also identify bacterial strains. This provides some clinical significance in the management of sepsis in acute care.