Procalcitonin-guided antibiotic therapy in patients with fever in a general emergency department population: a multicentre non-inferiority randomized clinical trial (HiTEMP study)

European Society of Clinical Microbiology and Infectious Diseases (ESCMID) guidelines for Antimicrobial Stewardship in Emergency Departments (endorsed by European Association of Hospital Pharmacists)

SCOPE

This ESCMID guideline provides evidence-based recommendations to support a selection of appropriate antibiotic use practices for patients seen in the emergency department (ED) and guidance for their implementation. The topics addressed in this guideline are: 1) Do biomarkers or rapid pathogen tests improve antibiotic prescribing and/or clinical outcomes? 2) Does taking blood cultures in common infectious syndromes improve antibiotic prescribing and/or clinical outcomes? 3) Does watchful waiting without antibacterial therapy or with delayed antibiotic prescribing reduce antibiotic prescribing without worsening clinical outcomes in patients with specific infectious syndromes? 4) Do structured culture follow-up programs in patients discharged from the ED with cultures pending improve antibiotic prescribing?

METHODS

An expert panel was convened by ESCMID and the guideline chair. The panel selected in consensus the four most relevant AMS topics according to pre-defined relevance criteria. For each main question for the four topics, a systematic review was performed, including randomized controlled trials and observational studies. Both clinical outcomes as well as stewardship process outcomes related to antibiotic use were deemed relevant. The literature searches were conducted between May 2021 and March 2022. In April 2022, the panel members were formally asked to suggest additional studies that were not identified in the initial searches. Data were summarized in a meta-analysis if possible or otherwise summarized narratively. The certainty of the evidence was classified according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria. The guideline panel reviewed the evidence per topic critically appraising the evidence and formulated recommendations through a consensus-based process. The strength of the recommendations was classified as strong or weak. To substantiate the implementation process, implementation trials or observational studies describing facilitators/barriers for implementation were identified from the same searches and were summarized narratively.

RECOMMENDATIONS

The recommendations on the use of biomarkers and rapid pathogen diagnostic tests focus on the initiation of antibiotics in patients admitted through the ED. Their effect on the discontinuation or de-escalation of antibiotics during hospital stay was not reported, neither was their effect on hospital infection prevention and control practices. The recommendations on watchful waiting (i.e., withholding antibiotics with some form of follow-up) focus on specific infectious syndromes for which the primary care literature was also included. The recommendations on blood cultures focus on the indication in three common infectious syndromes in the ED explicitly excluding patients with sepsis or septic shock. Most recommendations are based on very-low- and low-certainty of evidence, leading to weak recommendations or, when no evidence was available, to best practice statements. Implementation of these recommendations needs to be adapted to the specific settings and circumstances of the ED. The scarcity of high-quality studies in the area of antimicrobial stewardship in the ED highlights the need for future research in this field.

Distinct patterns of vital sign and inflammatory marker responses in adults with suspected bloodstream infection

OBJECTIVES

To identify patterns in inflammatory marker and vital sign responses in adult with suspected bloodstream infection (BSI) and define expected trends in normal recovery.

METHODS

We included patients ≥16 y from Oxford University Hospitals with a blood culture taken between 1-January-2016 and 28-June-2021. We used linear and latent class mixed models to estimate trajectories in C-reactive protein (CRP), white blood count, heart rate, respiratory rate and temperature and identify CRP response subgroups. Centile charts for expected CRP responses were constructed via the lambda-mu-sigma method.

RESULTS

In 88,348 suspected BSI episodes; 6908 (7.8%) were culture-positive with a probable pathogen, 4309 (4.9%) contained potential contaminants, and 77,131(87.3%) were culture-negative. CRP levels generally peaked 1-2 days after blood culture collection, with varying responses for different pathogens and infection sources (p < 0.0001). We identified five CRP trajectory subgroups: peak on day 1 (36,091; 46.3%) or 2 (4529; 5.8%), slow recovery (10,666; 13.7%), peak on day 6 (743; 1.0%), and low response (25,928; 33.3%). Centile reference charts tracking normal responses were constructed from those peaking on day 1/2.

CONCLUSIONS

CRP and other infection response markers rise and recover differently depending on clinical syndrome and pathogen involved. However, centile reference charts, that account for these differences, can be used to track if patients are recovering line as expected and to help personalise infection.

Diagnostic value of procalcitonin in patients with periprosthetic joint infection: a diagnostic meta-analysis

Background

The success rate of periprosthetic joint infection (PJI) treatment is still low. Early diagnosis is the key to successful treatment. Therefore, it is necessary to find a biomarker with high sensitivity and specificity. The diagnostic value of serum procalcitonin (PCT) for PJI was systematically evaluated to provide the theoretical basis for clinical diagnosis and treatment in this study.

Methods

We searched the Web of Science, Embase, Cochrane Library, and PubMed for studies that evaluated the diagnostic value of serum PCT for PJI (from the inception of each database until September 2020). Two authors independently screened the literature according to the inclusion and exclusion criteria. The quality of each selected literature was evaluated by using the Quality Assessment of Diagnostic Accuracy Studies tool (QUADAS-2) tool. RevMan 5.3 software was used for the quality evaluation. The sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were merged by using Meta-DiSc 1.4 software. The area under the curve (AUC) and Q index were calculated after the summary receiver operating characteristic (SROC) was generated. We also performed subgroup analysis.

Results

A total of 621 patients were enrolled in the nine studies. The pooled sensitivity of serum PCT for PJI diagnosis was 0.441 [95% confidence interval (CI), 0.384-0.500], the pooled specificity was 0.852 (95% CI, 0.811-0.888), the pooled PLR was 2.271 (95% CI, 1.808-2.853), the pooled NLR was 0.713 (95% CI, 0.646-0.786), and the pooled DOR was 5.756 (95% CI, 3.673-9.026). The area under SROC (the pooled AUC) was 0.76 (0.72-0.79). Q index was 0.6948.

Conclusion

This study showed that PCT detection of PJI had poor diagnostic accuracy. Hence, the serum PCT is not suitable as a serum marker for PJI diagnosis.

A clinical decision rule to rule out bloodstream infection in the emergency department: retrospective multicentric observational cohort study

BACKGROUND

We aimed to identify patients at low risk of bloodstream infection (BSI) in the ED.

METHODS

We derived and validated a prediction model to rule out BSI in the ED without the need for laboratory testing by determining variables associated with a positive blood culture (BC) and assigned points according to regression coefficients. This retrospective study included adult patients suspected of having BSI (defined by at least one BC collection) from two European ED between 1 January 2017 and 31 December 2019. The primary end point was the BSI rate in the validation cohort for patients with a negative Bacteremia Rule Out Criteria (BAROC) score. The effect of adding laboratory variables to the model was evaluated as a second step in a two-step diagnostic strategy.

RESULTS

We analysed 2580 patients with a mean age of 64 years±21, of whom 46.1% were women. The derived BAROC score comprises 12 categorical clinical variables. In the validation cohort, it safely ruled out BSI without BCs in 9% (58/648) of patients with a sensitivity of 100% (95% CI 95% to 100%), a specificity of 10% (95% CI 8% to 13%) and a negative predictive value of 100% (95% CI 94% to 100%). Adding laboratory variables (creatinine ≥177 µmol/L (2.0 mg/dL), platelet count ≤150 000/mm3 and neutrophil count ≥12 000/mm3) to the model, ruled out BSI in 10.2% (58/570) of remaining patients who had been positive on the BAROC score. The BAROC score with laboratory results had a sensitivity of 100% (95% CI 94% to 100%), specificity of 11% (95% CI 9% to 14%) and negative predictive value of 100% (95% CI 94 to 100%). In the validation cohort, there was no evidence of a difference in discrimination between the area under the receiver operating characteristic for BAROC score with versus without laboratory testing (p=0.6).

CONCLUSION

The BAROC score safely identified patients at low risk of BSI and may reduce BC collection in the ED without the need for laboratory testing.

Serum procalcitonin has no significance in the diagnosis of periprosthesis joint infection before total hip and knee replacement

Background

Currently, there is no "gold standard" for early diagnosing PJI. The diagnosis of periprosthetic joint infection (PJI) is a challenging problem in the clinic. As we know, many serum markers have been used in the early diagnosis of PJI. The aim of this study was to validate the value of PCT in the diagnosis of PJI.

Methods

A retrospective review of 77 patients with revision arthroplasties from January 2013 to July 2020 was conducted. PJI was defined using the modified Musculoskeletal Infection Society (MSIS) criteria combined with follow-up results. Besides medical history, clinical and laboratory data was gathered. Preoperative blood was taken for serum PCT and other biomarkers measurement. Receiver operating characteristic (ROC) curves were generated to evaluate the biomarkers' diagnostic performance and optimal cut-off value.

Results

Forty-one patients were identified as the PJI group (27 hips and 14 knees), while thirty-six patients were identified as the aseptic loosening (AL) group (33 hips and 3 knees). The AUCs for C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), Platelets (PLT), Fibrinogen (FIB), and Procalcitonin (PCT) were 0.845 (95% CI 0.755-0.936, p < 0.001), 0.817 (95% CI 0.718-0.916, p < 0.001), 0.728 (95% CI 0.613-0.843, p < 0.001), 0.810 (95% CI 0.710-0.910, p < 0.001) and 0.504 (95% CI 0.373-0.635, p = 0.950), respectively. Higher Area under the Curve (AUC) values were obtained for the combinations of PCT and CRP (AUC = 0.870) (95% CI, 0.774-0.936), PCT and ESR (AUC = 0.817) (95% CI, 0.712-0.896), PCT and PLT (AUC = 0.731) (95% CI, 0.617-0.825), PCT and FIB (AUC = 0.815) (95% CI, 0.710-0.894). The serum PCT indicated a sensitivity of 19.51% and a specificity of 83.33% for diagnosing PJI. When the optimal cut-off value for PCT was set as 0.05 ng/ml, its positive and negative likelihood ratios were 57.1% and 47.6%, respectively.

Conclusion

In conclusion, serum PCT appeared to be no reliable biomarker in differentiating PJI from aseptic loosening before revision arthroplasties. However, PCT combined with other biomarkers further increases the diagnostic accuracy.

Procalcitonin-guided antibiotic therapy may shorten length of treatment and may improve survival-a systematic review and meta-analysis

BACKGROUND

Appropriate antibiotic (AB) therapy remains a challenge in the intensive care unit (ICU). Procalcitonin (PCT)-guided AB stewardship could help optimize AB treatment and decrease AB-related adverse effects, but firm evidence is still lacking. Our aim was to compare the effects of PCT-guided AB therapy with standard of care (SOC) in critically ill patients.

METHODS

We searched databases CENTRAL, Embase and Medline. We included randomized controlled trials (RCTs) comparing PCT-guided AB therapy (PCT group) with SOC reporting on length of AB therapy, mortality, recurrent and secondary infection, ICU length of stay (LOS), hospital LOS or healthcare costs. Due to recent changes in sepsis definitions, subgroup analyses were performed in studies applying the Sepsis-3 definition. In the statistical analysis, a random-effects model was used to pool effect sizes.

RESULTS

We included 26 RCTs (n = 9048 patients) in the quantitative analysis. In comparison with SOC, length of AB therapy was significantly shorter in the PCT group (MD - 1.79 days, 95% CI: -2.65, - 0.92) and was associated with a significantly lower 28-day mortality (OR 0.84, 95% CI: 0.74, 0.95). In Sepsis-3 patients, mortality benefit was more pronounced (OR 0.46 95% CI: 0.27, 0.79). Odds of recurrent infection were significantly higher in the PCT group (OR 1.36, 95% CI: 1.10, 1.68), but there was no significant difference in the odds of secondary infection (OR 0.81, 95% CI: 0.54, 1.21), ICU and hospital length of stay (MD - 0.67 days 95% CI: - 1.76, 0.41 and MD - 1.23 days, 95% CI: - 3.13, 0.67, respectively).

CONCLUSIONS

PCT-guided AB therapy may be associated with reduced AB use, lower 28-day mortality but higher infection recurrence, with similar ICU and hospital length of stay. Our results render the need for better designed studies investigating the role of PCT-guided AB stewardship in critically ill patients.

Use of Biomarkers to Improve 28-Day Mortality Stratification in Patients with Sepsis and SOFA ≤ 6

Early diagnosis and appropriate treatments are crucial to reducing mortality risk in septic patients. Low SOFA scores and current biomarkers may not adequately discern patients that could develop severe organ dysfunction or have an elevated mortality risk. The aim of this prospective observational study was to evaluate the predictive value of the biomarkers mid-regional pro-adrenomedullin (MR-proADM), procalcitonin (PCT), C-reactive protein (CRP), and lactate for 28-day mortality in patients with sepsis, and patients with a SOFA score ≤6. 284 were included, with a 28-day all-cause mortality of 8.45% (n = 24). Non-survivors were older (p = 0.003), required mechanical ventilation (p = 0.04), were ventilated for longer (p = 0.02), and had higher APACHE II (p = 0.015) and SOFA (p = 0.027) scores. Lactate showed the highest predictive ability for all-cause 28-day mortality, with an area under the receiver-operating characteristic curve (AUROC) of 0.67 (0.55-0.79). The AUROC for all-cause 28-day mortality in patients with community-acquired infection was 0.69 (0.57-0.84) for SOFA and 0.70 (0.58-0.82) for MR-proADM. A 2.1 nmol/L cut-off point for this biomarker in this subgroup of patients discerned, with 100% sensibility, survivors from non-survivors at 28 days. In patients with community-acquired sepsis and initial SOFA score ≤ 6, MR-proADM could help identify patients at risk of 28-day mortality.

One biomarker does not fit all: tailoring anti-infective therapy through utilization of procalcitonin and other specific biomarkers

INTRODUCTION

Considering the ongoing increase in antibiotic resistance, the importance of judicious use of antibiotics through reduction of exposure is crucial. Adding procalcitonin (PCT) and other biomarkers to pathogen-specific tests may help to further improve antibiotic therapy algorithms and advance antibiotic stewardship programs to achieve these goals.

AREAS COVERED

In recent years, several trials have investigated the inclusion of biomarkers such as PCT into clinical decision-making algorithms. For adult patients, findings demonstrated improvements in the individualization of antibiotic treatment, particularly for patients with respiratory tract infections and sepsis. While most trials were performed in hospitals with central laboratories, point-of-care testing might further advance the field by providing a cost-effective and rapid diagnostic tool in upcoming years. Furthermore, novel biomarkers including CD-64, presepsin, Pancreatic stone and sTREM-1, have all shown promising results for increased accuracy of sepsis diagnosis. Availability of these markers however is currently still limited and there is insufficient evidence for their routine use in clinical care.

EXPERT OPINION

In addition to new host-response markers, combining such biomarkers with pathogen-directed diagnostics present a promising strategy to increase algorithm accuracy in differentiating between bacterial and viral infections. Recent advances in microbiologic testing using PCR or nucleic amplification tests may further improve the diagnostic yield and promote more targeted pathogen-specific antibiotic therapy.

Antibacterial Activity and Mechanisms of TroHepc2-22, a Derived Peptide of Hepcidin2 from Golden Pompano (Trachinotus ovatus)

Hepcidin, a cysteine-rich antimicrobial peptide, has a highly conserved gene structure in teleosts, and it plays an essential role in host immune response against various pathogenic bacteria. Nonetheless, few studies on the antibacterial mechanism of hepcidin in golden pompano (Trachinotus ovatus) have been reported. In this study, we synthesized a derived peptide, TroHepc2-22, from the mature peptide of T. ovatus hepcidin2. Our results showed that TroHepc2-22 has superior antibacterial abilities against both Gram-negative (Vibrio harveyi and Edwardsiella piscicida) and Gram-positive (Staphylococcus aureus and Streptococcus agalactiae) bacteria. Based on the results of a bacterial membrane depolarization assay and propidium iodide (PI) staining assay in vitro, TroHepc2-22 displayed antimicrobial activity by inducing the bacterial membrane depolarization and changing the bacterial membrane permeability. Scanning electron microscopy (SEM) visualization illustrated that TroHepc2-22 brought about membrane rupturing and the leakage of the cytoplasm for the bacteria. In addition, TroHepc2-22 was verified to have hydrolytic activity on bacterial genomic DNA in view of the results of the gel retardation assay. In terms of the in vivo assay, the bacterial loads of V. harveyi in the tested immune tissues (liver, spleen, and head kidney) were significantly reduced in T. ovatus, revealing that TroHepc2-22 significantly enhanced the resistance against V. harveyi infection. Furthermore, the expressions of immune-related genes, including tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin 1-β (IL-1β), IL-6, Toll-like receptor 1 (TLR1), and myeloid differentiation factor 88 (MyD88) were significantly increased, indicating that TroHepc2-22 might regulate inflammatory cytokines and activate immune-related signaling pathways. To summarize, TroHepc2-22 possesses appreciable antimicrobial activity and plays a vital role in resisting bacterial infection. The observation of our present study unveils the excellent application prospect of hepcidin as a substitute for antibiotics to resist pathogenic microorganisms in teleosts.

Bioengineered extracellular vesicles: future of precision medicine for sepsis

Sepsis is a syndromic response to infection and is frequently a final common pathway to death from many infectious diseases worldwide. The complexity and high heterogeneity of sepsis hinder the possibility to treat all patients with the same protocol, requiring personalized management. The versatility of extracellular vesicles (EVs) and their contribution to sepsis progression bring along promises for one-to-one tailoring sepsis treatment and diagnosis. In this article, we critically review the endogenous role of EVs in sepsis progression and how current advancements have improved EVs-based therapies toward their translational future clinical application, with innovative strategies to enhance EVs effect. More complex approaches, including hybrid and fully synthetic nanocarriers that mimic EVs, are also discussed. Several pre-clinical and clinical studies are examined through the review to offer a general outlook of the current and future perspectives of EV-based sepsis diagnosis and treatment.

Procalcitonin for the early discrimination of fever etiology in patients with systemic autoimmune diseases attending the emergency department

In febrile patients with known systemic autoimmune disease, early discrimination between infection and disease flare often represents a clinical challenge. This study aimed at evaluating the efficacy of procalcitonin (PCT) and other common inflammatory biomarkers in discriminating disease flare from bacterial infections in the Emergency Department (ED). In a cross-sectional observational retrospective study, we identified consecutive febrile patients with a known diagnosis of systemic autoimmune disease, admitted to the ED, and subsequently hospitalized. Flare vs infective disease was defined on clinical records at hospital discharge. Dosage of common inflammatory markers was performed at ED admission. Out of 177 patients, those with infection were most commonly elderly, frail, and with reduced peripheral oxygen saturation at admission. When compared to C-reactive protein (CRP) and white blood count (WBC), PCT showed the best performance in discriminating infections vs flare. However, only at a very high threshold value of 2 ng/ml, the PCT had a satisfactory negative predictive value of 88.9%, although with a very low specificity of 13.6% and a positive predictive value of 35.8%. Our data suggest that in the ED setting, the early PCT determination has low accuracy in the differentiation of disease flare from infection in patients with known rheumatologic disease. However, the PCT could be useful in elderly and comorbid subjects, in supporting clinical assessment and in recognizing those febrile patients needing prompt antibiotic treatment.

Implementation of Procalcitonin in Antibiotic Stewardship: Derivation of a Consensus Algorithm for Procalcitonin Use in Clinical Practice

Reducing antibiotics overuse is essential to minimize antibiotics related side effects and to prevent the emergence of multidrug-resistant bacteria. Procalcitonin (PCT) guided antibiotics therapy has been reported to be safe in patients with acute respiratory infections and sepsis, improving clinical outcomes as well as reducing the duration of antibiotics use. However, there is still no universal agreement on clinical guidelines in Korea for optimal PCT applications. Through this expert consensus meeting, clinical research findings in the PCT-guided antibiotics treatment interventions and real-world clinical applications were discussed. From the perspective of antibiotic stewardship, PCT application target groups, cut-offs, and testing cycles were discussed to reach a consensus on the PCT-guided antibiotics treatment algorithm for application in Korea. Combining clinical assessment for patients with an appropriate PCT-guided antibiotics treatment algorithm could improve the diagnosis and treatment of acute respiratory infections and sepsis. In addition, continuous education and regular feedback would improve the effectiveness of antibiotic stewardship.

Procalcitonin-guided antibiotic therapy for pediatrics with infective disease: A updated meta-analyses and trial sequential analysis

Objective

We aimed to evaluate the effect of procalcitonin (PCT) guided therapy on antibiotic exposure in pediatric patients with infectious disease.

Methods

We performed an updated systematic review and meta-analysis of randomized controlled trials (RCTs) identified in systematic searches of MEDLINE, Embase, the Cochrane Database, Google Scholar, and SinoMed (through July 2021). The primary outcome was the length of the antibiotic therapy. Required information size (RIS) was calculated using trial sequential analysis (TSA).

Results

Four RCTs with 1,313 patients with infectious disease were included. Overall, after a mean 22-day follow-up, PCT-guided antibiotic therapy was associated with a significantly shorter length of antibiotic therapy compared with the control group (WMD, −2.22 days; 95% CI, −3.41 to −1.03; P <0.001) and a decreased rate of antibiotic adverse events (RR, 0.25; 95% CI, 0.11–0.58; P <0.001). However, the length of hospital stay (WMD, −0.39 days; 95% CI, −0.84 to 0.07; P = 0.094), rates of antibiotic prescription (RR, 1.10; 95% CI, 0.97–1.25; P = 0.122), hospital readmission (RR, 1.03; 95% CI, 0.92–1.16; P = 0.613) and mortality (RR, 0.73; 95% CI, 0.17–3.19; P = 0.674) were comparable between the PCT-guided antibiotic and control groups. TSA showed that the RIS was 2,340, indicating a statistically significantly shorter length of antibiotic therapy between PCT-guided antibiotic and control groups (P <0.05).

Conclusions

PCT-guided management seems to be able to decrease antibiotic exposure in patients with infectious disease. However, much larger prospective clinical studies are warranted to confirm these findings.

ACCURACY OF C-REACTIVE PROTEIN AND PROCALCITONIN FOR DIAGNOSING BACTERIAL INFECTIONS AMONG SUBJECTS WITH PERSISTENT FEVER IN THE TROPICS

Background

In low-resource settings, inflammatory biomarkers can help identify patients with acute febrile illness who do not require antibiotics. Their use has not been studied in persistent fever (defined as fever lasting for ≥7 days at presentation).

Methods

C-reactive protein (CRP) and procalcitonin (PCT) levels were measured in stored serum samples of patients with persistent fever prospectively enrolled in Cambodia, the Democratic Republic of Congo, Nepal, and Sudan. Diagnostic accuracy was assessed for identifying all bacterial infections and the subcategory of severe infections judged to require immediate antibiotics.

Results

Among 1838 participants, CRP and PCT levels were determined in 1777 (96.7%) and 1711 (93.1%) samples, respectively, while white blood cell (WBC) count was available for 1762 (95.9%). Areas under the receiver operating characteristic curve for bacterial infections were higher for CRP (0.669) and WBC count (0.651) as compared with PCT (0.600; P <.001). Sensitivity for overall and severe bacterial infections was 76.3% (469/615) and 88.2% (194/220) for CRP >10 mg/L, 62.4% (380/609) and 76.8% (169/220) for PCT >0.1 µg/L, and 30.5% (184/604) and 43.7% (94/215) for WBC >11 000/µL, respectively. Initial CRP level was <10 mg/L in 45% of the participants who received antibiotics at first presentation.

Conclusions

In patients with persistent fever, CRP and PCT showed higher sensitivity for bacterial infections than WBC count, applying commonly used cutoffs for normal values. A normal CRP value excluded the vast majority of severe infections and could therefore assist in deciding whether to withhold empiric antibiotics after cautious clinical assessment.

A retrospective cohort study of the effect of rapid versus delayed-result procalcitonin testing on antibiotic use at a community hospital

BACKGROUND

Procalcitonin is a serum biomarker used to distinguish bacterial infection from viral or noninfectious syndromes. Primary literature shows mixed data on use of procalcitonin for de-escalation of antimicrobials. Delays in test results of send-out procalcitonin assays may result in prolonged antimicrobial durations. It is unknown whether availability of rapid-result assays may shorten time to antibiotic de-escalation.

AIM

This retrospective, cohort study compared antibiotic durations of treatment between groups with rapid-result versus delayed send-out, procalcitonin test modality. This study was exempt from Ethics Committee Approval, as determined by the Institutional Review Board at the study site.

METHOD

Adult hospitalized patients were included if they had at least one procalcitonin test performed during the study period. The primary outcome compared mean duration of antimicrobial therapy between groups receiving a rapid-result procalcitonin test and a send-out test. Secondary outcomes included incidence of Clostridiodes difficile infection, mention of procalcitonin testing in the electronic medical record in reference to antimicrobial therapy decision making, and presence of comorbidities which affect procalcitonin levels independent of infection.

RESULTS

A total of 350 lab results were analyzed. The duration of antimicrobial treatment between groups was not statistically different with the median duration of treatment in the send-out group being 2.95 days compared to 3.35 in the rapid result group, p = 0.856. Patient comorbidities with potential to lead to a noninfectious elevation or falsely high level of procalcitonin were common.

CONCLUSION

Use of a rapid-result procalcitonin assay does not reduce hospital antimicrobial therapy duration as compared with send-out testing.

Prevalence of Discordant Procalcitonin Use at an Academic Medical Center

OBJECTIVES

Despite multiple trials demonstrating that procalcitonin (PCT) is an effective tool for antibiotic stewardship, inconsistent application in real-world settings continues to fuel controversy regarding its clinical utility. We sought to determine rates of concordance between PCT results and antibiotic prescribing in hospitalized patients.

METHODS

We performed a retrospective review of all inpatient encounters at an academic tertiary care health system with a PCT result between February 2017 and October 2019. Concordant prescribing was defined as starting or continuing antibiotics following an elevated PCT (>0.5 ng/mL) finding and withholding or stopping antibiotics following a low PCT (< 0.1 ng/mL) finding.

RESULTS

Antibiotic prescribing decisions were discordant from the PCT level in 32.5% of our sample. Among patients not receiving antibiotics at the time of testing, 25.9% (430 of 1,662) were prescribed antibiotics despite a low PCT result. Among patients already receiving antibiotics, treatment was continued despite a low PCT level in 80.4% (728 of 906) of cases. Enhanced decision support tools introduced during the study period had no impact on PCT use for antibiotic decisions.

CONCLUSIONS

Overall concordance between PCT results and antibiotic use is relatively low in a real-world setting. The potential value of PCT for antibiotic stewardship may not be fully realized.

Antimicrobial Stewardship Using Biomarkers: Accumulating Evidence for the Critically Ill

This review aims to summarize current progress in the management of critically ill, using biomarkers as guidance for antimicrobial treatment with a focus on antimicrobial stewardship. Accumulated evidence from randomized clinical trials (RCTs) and observational studies in adults for the biomarker-guided antimicrobial treatment of critically ill (mainly sepsis and COVID-19 patients) has been extensively searched and is provided. Procalcitonin (PCT) is the best studied biomarker; in the majority of randomized clinical trials an algorithm of discontinuation of antibiotics with decreasing PCT over serial measurements has been proven safe and effective to reduce length of antimicrobial treatment, antibiotic-associated adverse events and long-term infectious complications like infections by multidrug-resistant organisms and Clostridioides difficile. Other biomarkers, such as C-reactive protein and presepsin, are already being tested as guidance for shorter antimicrobial treatment, but more research is needed. Current evidence suggests that biomarkers, mainly procalcitonin, should be implemented in antimicrobial stewardship programs even in the COVID-19 era, when, although bacterial coinfection rate is low, antimicrobial overconsumption remains high.

High procalcitonin levels associated with increased intensive care unit admission and mortality in patients with a COVID-19 infection in the emergency department

Background

Patients with a severe COVID-19 infection often require admission at an intensive care unit (ICU) when they develop acute respiratory distress syndrome (ARDS). Hyperinflammation plays an important role in the development of ARDS in COVID-19. Procalcitonin (PCT) is a biomarker which may be a predictor of hyperinflammation. When patients with COVID-19 are in the emergency department (ED), elevated PCT levels could be associated with severe COVID-19 infections. The goal of this study is to investigate the association between PCT levels and severe COVID-19 infections in the ED.

Methods

This was a retrospective cohort study including patients with a confirmed COVID-19 infection who visited the ED of Erasmus Medical Center in Rotterdam, the Netherlands, between March and December 2020. The primary outcome was a severe COVID-19 infection, which was defined as patients who required ICU admission, all cause in-hospital mortality and mortality within 30 days after hospital discharge. PCT levels were measured during the ED visit. We used logistic regression to calculate the odds ratio (OR) with 95% confidence interval (95% CI) and corresponding area under the curve (AUC) of PCT on a severe COVID-19 infection, adjusting for bacterial coinfections, age, sex, comorbidities, C-reactive protein (CRP) and D-dimer.

Results

A total of 332 patients were included in the final analysis of this study, of which 105 patients reached the composite outcome of a severe COVID-19 infection. PCT showed an unadjusted OR of 4.19 (95%CI: 2.52–7.69) on a severe COVID-19 infection with an AUC of 0.82 (95% CI: 0.76–0.87). Corrected for bacterial coinfection, the OR of PCT was 4.05 (95% CI: 2.45–7.41). Adjusted for sex, bacterial coinfection, age any comorbidity, CRP and D-dimer, elevated PCT levels were still significantly associated with a severe COVID-19 infection with an adjusted OR of 2.11 (95% CI: 1.36–3.61). The AUC of this multivariable model was 0.85 (95%CI: 0.81–0.90).

Conclusion

High PCT levels are associated with high rates of severe COVID-19 infections in patients with a COVID-19 infection in the ED. The routine measurement of PCT in patients with a COVID-19 infection in the ED may assist physicians in the clinical decision making process regarding ICU disposition.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07144-5.

Procalcitonin for individualizing antibiotic treatment: an update with a focus on COVID-19

Procalcitonin (PCT) is useful for differentiating between viral and bacterial infections and for reducing the unnecessary use of antibiotics. As the rise of antimicrobial resistance reaches “alarming” levels according to the World Health Organization, the importance of using biomarkers, such as PCT to limit unnecessary antibiotic exposure has further increased. Randomized trials in patients with respiratory tract infections have shown that PCT has prognostic implications and its use, embedded in stewardship protocols, leads to reductions in the use of antibiotics in different clinical settings without compromising clinical outcomes. However, available data are heterogeneous and recent trials found no significant benefit. Still, from these trials, we have learned several key considerations for the optimal use of PCT, which depend on the clinical setting, severity of presentation, and pretest probability for bacterial infection. For patients with respiratory infections and sepsis, PCT can be used to determine whether to initiate antimicrobial therapy in low-risk settings and, together with clinical data, whether to discontinue antimicrobial therapy in certain high-risk settings. There is also increasing evidence regarding PCT-guided therapy in patients with coronavirus disease 2019 (COVID-19). This review provides an up-to-date overview of the use of PCT in different clinical settings and diseases, including a discussion about its potential to improve the care of patients with COVID-19.

Prognostic Role of Serum Procalcitonin Measurement in Adult Patients Admitted to the Emergency Department with Fever

Background and Objectives. Fever is one of the most common presenting complaints in the Emergency Department (ED). This study aimed at evaluating the prognostic role of serum Procalcitonin (PCT) measurement among adult patients admitted to the ED with fever. Materials and Methods. This is a retrospective cross-sectional study including all consecutive patients admitted to ED with fever and subsequently hospitalized in a period of six-year (January 2014 to December 2019). Inclusion criteria were age > 18 years, fever (T ≥ 38 °C) or chills within 24 h from presentation to the ED as the main symptom, and availability of a PCT determination obtained <24 h since ED access. The primary endpoint was overall in-hospital mortality. Results. Overall, 6595 patients were included in the study cohort (3734 males, 55.6%), with a median age of 71 [58-81] years. Among these, based on clinical findings and quick sequential organ failure assessment (qSOFA), 422 were considered septic (36.2% deceased), and 6173 patients non-septic (16.2% deceased). After correction for baseline covariates, a PCT > 0.5 ng/mL was an independent risk factor for all-cause in-hospital death in both groups (HR 1.77 [1.27-2.48], and 1.80 [1.59-2.59], respectively). Conclusions. Among adult patients admitted with fever, the PCT assessment in ED could have reduced prognostic power for patients with a high suspicion of sepsis. On the other hand, it could be useful for sepsis rule-out for patients at low risk. In these latter patients, the prognostic role of PCT is higher for those with a final diagnosis of bloodstream infection.

Predicting mortality in adult patients with sepsis in the emergency department by using combinations of biomarkers and clinical scoring systems: a systematic review

Background

Sepsis can be detected in an early stage in the emergency department (ED) by biomarkers and clinical scoring systems. A combination of multiple biomarkers or biomarker with clinical scoring system might result in a higher predictive value on mortality. The goal of this systematic review is to evaluate the available literature on combinations of biomarkers and clinical scoring systems on 1-month mortality in patients with sepsis in the ED.

Methods

We performed a systematic search using MEDLINE, EMBASE and Google Scholar. Articles were included if they evaluated at least one biomarker combined with another biomarker or clinical scoring system and reported the prognostic accuracy on 28 or 30 day mortality by area under the curve (AUC) in patients with sepsis. We did not define biomarker cut-off values in advance.

Results

We included 18 articles in which a total of 35 combinations of biomarkers and clinical scoring systems were studied, of which 33 unique combinations. In total, seven different clinical scoring systems and 21 different biomarkers were investigated. The combination of procalcitonin (PCT), lactate, interleukin-6 (IL-6) and Simplified Acute Physiology Score-2 (SAPS-2) resulted in the highest AUC on 1-month mortality.

Conclusion

The studies we found in this systematic review were too heterogeneous to conclude that a certain combination it should be used in the ED to predict 1-month mortality in patients with sepsis. Future studies should focus on clinical scoring systems which require a limited amount of clinical parameters, such as the qSOFA score in combination with a biomarker that is already routinely available in the ED.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-021-00461-z.

Type I Interferon in Children with Viral or Bacterial Infections

BACKGROUND

Fever is one of the leading causes of consultation in the pediatric emergency department for patients under the age of 3 years. Distinguishing between bacterial and viral infections etiologies in febrile patients remains challenging. We hypothesized that specific host biomarkers for viral infections, such as type I-interferon (IFN), could help clinicians' decisions and limit antibiotic overuse.

METHODS

Paxgene tubes and serum were collected from febrile children (n = 101), age from 7 days to 36 months, with proven viral or bacterial infections, being treated at pediatric emergency departments in France. We assessed the performance of an IFN signature, which was based on quantification of expression of IFN-stimulated genes using the Nanostring® technology and plasma IFN-α quantified by digital ELISA technology.

RESULTS

Serum concentrations of IFN-α were below the quantification threshold (30 fg/mL) for 2% (1/46) of children with proven viral infections and for 71% (39/55) of children with bacterial infections (P < 0.001). IFN-α concentrations and IFN score were significantly higher in viral compared to bacterial infection (P < 0.001). There was a strong correlation between serum IFN-α concentrations and IFN score (p-pearson = 0.83). Both serum IFN-α concentration and IFN score robustly discriminated (Area Under the Curve >0.91 for both) between viral and bacterial infection in febrile children, compared to C-reactive protein (0.83).

CONCLUSIONS

IFN-α is increased in blood of febrile infants with viral infections. The discriminative performance of IFN-α femtomolar concentrations as well as blood transcriptional signatures could show a diagnostic benefit and potentially limit antibiotic overuse.

CLINICAL TRIALS REGISTRATION

clinicaltrials.gov (NCT03163628).

The Role of Early Procalcitonin Determination in the Emergency Departiment in Adults Hospitalized with Fever

Background and Objectives: Fever is one of the most common presenting complaints in the Emergency Department (ED). The role of serum procalcitonin (PCT) determination in the ED evaluation of adults presenting with fever is still debated. The aim of this study was to evaluate if, in adults presenting to the ED with fever and then hospitalized, the early PCT determination could improve prognosis. Materials and Methods. This is a retrospective, mono-centric study, conducted over a 10-year period (2009-2018). We analyzed consecutive patients ≥18 years admitted to ED with fever and then hospitalized. According to quick sequential organ failure assessment (qSOFA) at admission, we compared patients that had a PCT determination vs. controls. Primary endpoint was overall in-hospital mortality; secondary endpoints were in-hospital length of stay, and mortality in patients with bloodstream infection and acute respiratory infections. Results. The sample included 12,062 patients, median age was 71 years and 55.1% were men. In patients with qSOFA ≥ 2 overall mortality was significantly lower if they had a PCT-guided management in ED, (20.5% vs. 26.5%; p = 0.046). In the qSOFA < 2 group the mortality was not significantly different in PCT patients, except for those with a final diagnosis of bloodstream infection. Conclusions. Among adults hospitalized with fever, the PCT evaluation at ED admission was not associated with better outcomes, with the possible exception of patients affected by bloodstream infections. However, in febrile patients presenting to the ED with qSOFA ≥ 2, the early PCT evaluation could improve the overall in-hospital survival.

Early Procalcitonin Assessment in the Emergency Department in Patients with Intra-Abdominal Infection: An Excess or a Need?

Background: Intra-abdominal infection (IAI) is a wide range of intra-abdominal disease. Management involves empirical therapy and source control. Procalcitonin (PCT) has been suggested to assist in defining individual infection status and delivering individualized therapy. The aim of this study was to investigate the effects on patient outcomes of an early procalcitonin (PCT) assessment (in the emergency department [ED]) in patients with IAI. Methods: This was a retrospective, mono-centric study evaluating consecutive patients admitted to the ED from 2015 to 2019 with diagnosis of IAI. According to whether there had been PCT determination in the ED, patients were divided into no ePCT determination (no-ePCT) and early PCT determination in the ED (ePCT). The primary endpoint was the intra-hospital mortality rate. Secondary endpoints were occurrence of major complications and length of hospital stay (LOS). The propensity score match (PSM) was generated using a logistic regression model on the baseline covariates considered to be potentially influencing the decision to determine PCT in the ED and confounding factors identified as significant at a preliminary statistical analysis with respect to in-hospital death. Results: A series of 3,429 patients were included. The ePCT group consisted to 768 (22.4%), whereas the no-ePCT group contained 2,661 patients (77.6%). When the PSM was matched to the two groups, no significant difference was observed. Considering patients with uncomplicated infections, the PCT determination was associated with a higher mortality rate. We found no significant differences regarding outcomes with the exception of LOS, which was slightly longer in the ePCT group. However, we observed a tendency toward a minor difference in the number of complications in the ePCT group, in particular a reduced rate of progression to sepsis. Conclusion: Early PCT determination could be irrelevant in IAIs. The PCT value may be cost-effective and possibly improve the prognosis in cIAIs. Further research is needed to understand the optimal use of PCT, including in combination with other emerging diagnostic tests.

Strategies for implementation of a multidisciplinary approach to the treatment of nosocomial infections in critically ill patients

INTRODUCTION

Intensive Care Units (ICU) are among the hospital wards exhibiting the highest prevalence of antimicrobial resistance (AMR), and resulting impact on patient outcomes. Antimicrobial resistance surveillance and antimicrobial stewardship (AMS) programs play a pivotal role in promoting interventions tailored to optimize infection diagnosis and treatment in the final attempt to limit unnecessary antimicrobial use and development of resistance.

AREAS COVERED

A narrative review of the literature was carried out to summarize the available evidence and develop a set of actions that should be considered for integration into the ICU stewardship framework. Four questions were addressed: how AMR surveillance can inform antibiotic policy in ICU; whether pharmacokinetic and pharmacodynamic (PK/PD) principles and the use of procalcitonin should be incorporated as a standard practice in ICU AMS programs to optimize antibiotic treatment and to drive antibiotic discontinuation; which criteria should drive treatment duration of ICU-associated infections.

EXPERT OPINION

In this review we aim to highlight that the ICU must be considered in its own right. Each ICU has its own characteristics depending on the country, on the local antibiotic resistance profile, on the patients feature and the severity of infection.

Early procalcitonin determination in the emergency department and clinical outcome of community-acquired pneumonia in old and oldest old patients

We evaluated patients admitted through our ED for community-acquired pneumonia (CAP) to assess the relevance of an early procalcitonin (PCT) determination on patient's outcomes.

METHODS

We reviewed all patients admitted for CAP in a 10 years period (2008-2017). Patients were stratified according to age groups: (18-65 years; 65-84 years; and ≥85 years), CURB-65 score, need for ventilation, Sepsis-3 criteria at admission, enrollment period, blood culture in ED. In-hospital mortality rate and length of hospital stay (LOS) were compared between patients that had an early PCT determination in ED vs. patients admitted without.

RESULTS

Our study cohort consisted of 4056 CAP patients, age 76 [IQ range 64-84] years. We enrolled 1039 patients <65 years old, 2015 aged 65-84 years, and 1002 aged ≥85 years. Overall, the early PCT determination in ED was not associated to a reduced LOS (p=0.630), nor to a reduced mortality rate (p=0.134). However, in patients ≥ 85 years, the PCT determination in ED was associated with lower mortality in those with CURB-65 ≥ 2, and Charlson's score ≥ 2 (p=0.033 and p=0.002, respectively).

CONCLUSIONS

Although an early PCT assessment in ED was not associated with better outcomes in term of LOS and mortality in patients with CAP, our findings suggest that it might be associated with reduced mortality in patients ≥ 85 years with severe CAP or high comorbidity.

Procalcitonin (PCT)-guided antibiotic stewardship: an international experts consensus on optimized clinical use

Background Procalcitonin (PCT)-guided antibiotic stewardship (ABS) has been shown to reduce antibiotics (ABxs), with lower side-effects and an improvement in clinical outcomes. The aim of this experts workshop was to derive a PCT algorithm ABS for easier implementation into clinical routine across different clinical settings. Methods Clinical evidence and practical experience with PCT-guided ABS was analyzed and discussed, with a focus on optimal PCT use in the clinical context and increased adherence to PCT protocols. Using a Delphi process, the experts group reached consensus on different PCT algorithms based on clinical severity of the patient and probability of bacterial infection. Results The group agreed that there is strong evidence that PCT-guided ABS supports individual decisions on initiation and duration of ABx treatment in patients with acute respiratory infections and sepsis from any source, thereby reducing overall ABx exposure and associated side effects, and improving clinical outcomes. To simplify practical application, the expert group refined the established PCT algorithms by incorporating severity of illness and probability of bacterial infection and reducing the fixed cut-offs to only one for mild to moderate and one for severe disease (0.25 μg/L and 0.5 μg/L, respectively). Further, guidance on interpretation of PCT results to initiate, withhold or discontinue ABx treatment was included. Conclusions A combination of clinical patient assessment with PCT levels in well-defined ABS algorithms, in context with continuous education and regular feedback to all ABS stakeholders, has the potential to improve the diagnostic and therapeutic management of patients suspected of bacterial infection, thereby improving ABS effectiveness.

Blood transcriptomic discrimination of bacterial and viral infections in the emergency department: a multi-cohort observational validation study

BACKGROUND

There is an urgent need to develop biomarkers that stratify risk of bacterial infection in order to support antimicrobial stewardship in emergency hospital admissions.

METHODS

We used computational machine learning to derive a rule-out blood transcriptomic signature of bacterial infection (SeptiCyte™ TRIAGE) from eight published case-control studies. We then validated this signature by itself in independent case-control data from more than 1500 samples in total, and in combination with our previously published signature for viral infections (SeptiCyte™ VIRUS) using pooled data from a further 1088 samples. Finally, we tested the performance of these signatures in a prospective observational cohort of emergency department (ED) patients with fever, and we used the combined SeptiCyte™ signature in a mixture modelling approach to estimate the prevalence of bacterial and viral infections in febrile ED patients without microbiological diagnoses.

RESULTS

The combination of SeptiCyte™ TRIAGE with our published signature for viral infections (SeptiCyte™ VIRUS) discriminated bacterial and viral infections in febrile ED patients, with a receiver operating characteristic area under the curve of 0.95 (95% confidence interval 0.90-1), compared to 0.79 (0.68-0.91) for WCC and 0.73 (0.61-0.86) for CRP. At pre-test probabilities 0.35 and 0.72, the combined SeptiCyte™ score achieved a negative predictive value for bacterial infection of 0.97 (0.90-0.99) and 0.86 (0.64-0.96), compared to 0.90 (0.80-0.94) and 0.66 (0.48-0.79) for WCC and 0.88 (0.69-0.95) and 0.60 (0.31-0.72) for CRP. In a mixture modelling approach, the combined SeptiCyte™ score estimated that 24% of febrile ED cases receiving antibacterials without a microbiological diagnosis were due to viral infections. Our analysis also suggested that a proportion of patients with bacterial infection recovered without antibacterials.

CONCLUSIONS

Blood transcriptional biomarkers offer exciting opportunities to support precision antibacterial prescribing in ED and improve diagnostic classification of patients without microbiologically confirmed infections.

Antibiotic treatment in patients with sepsis: a narrative review

Sepsis is a medical emergency and life-threatening condition due to a dysregulated host response to infection, with unacceptably high morbidity and mortality. Similar to acute myocardial infarction or cerebral vascular accident, sepsis is a severe and continuous time-dependent condition. Thus, in the case of sepsis, early and adequate administration of antimicrobials must be a priority, ideally within the first hour of diagnosis, simultaneously with organ support.As a consequence of the emergence of multidrug-resistant pathogens, the choice of antimicrobials should be performed according to the local pathogen patterns of resistance. Individual antimicrobial optimization is essential to achieve adequate concentrations of antimicrobials, to reduce adverse effects, and to ensure successful outcomes, as well as preventing the emergence of multidrug-resistant pathogens. The loading dose is the administration of an initial higher dose of antimicrobials, regardless of the presence of organ dysfunction. Further doses should be implemented according to pharmacokinetics/pharmacodynamics of antimicrobials and should be adjusted according to the presence of renal or liver dysfunction. Extended or continuous infusion of beta-lactams and therapeutic drug monitoring can help to achieve therapeutic levels of antimicrobials. Duration and adequacy of treatment must be reviewed at regular intervals to allow effective de-escalation and administration of short courses of antimicrobials for most patients. Antimicrobial stewardship frameworks, leadership, focus on the optimal duration of treatments, de-escalation, and novel diagnostic stewardship approaches will help us to improve patients the process of care and overall quality of care.

Clinical characteristics and laboratory results of pregnant women with COVID-19 in Wuhan, China

Objective

To evaluate the clinical characteristics and laboratory test results in pregnant women with coronavirus disease 2019 (COVID‐19).

Methods

A retrospective study to review and compare clinical data including electronic medical records and laboratory tests from pregnant and nonpregnant patients admitted the Central Hospital of Wuhan, China from December 8, 2019 to April 1, 2020.

Results

A total of 72 women (30 pregnant and 42 nonpregnant) with COVID‐19 were included. No patients developed severe pneumonia during the study. Compared with the nonpregnant group, pregnant patients were admitted to hospital earlier (0.25 vs 11.00 days; P<0.001), presented milder symptoms, had a higher rate of asymptomatic infection (26.7% vs 0%), and shorter length of hospital stay (14.5 vs 17.0 days; P<0.01). Laboratory test results showed that levels of inflammation markers such as white blood cell count, neutrophil count and percentage, C‐reactive protein, procalcitonin, and D‐dimer were significantly higher in pregnant women, whereas mean lymphocyte percentage was significantly lower compared with nonpregnant women.

Conclusion

In some respects, the clinical characteristics and laboratory test results of COVID‐19 in pregnant patients seems to be distinctive from their nonpregnant counterparts. Appropriate advice and positive treatment might be critical to the prognosis when dealing with these pregnant patients. Pregnant patients with COVID‐19 had their own positive clinical characteristics and special laboratory test results. Responsive medical advice and active treatment for those patients are critical to recovery.

The clinical characteristics and laboratory test results of COVID‐19 in pregnancy seemed to be distinctive from those in non‐pregnancy in some respects. Immediate medical advice and active treatment for pregnant patients with COVID‐19 are critical to recovery.

The value of biomarker-guided antibiotic therapy

INTRODUCTION

There is an increasing interest to individualize patient management and decisions regarding antibiotic treatment. Biomarkers may provide relevant information for this purpose.

AREAS COVERED

Despite a growing number of clinical trials investigating several biomarkers, there remain open questions regarding the best type of biomarker, timing or frequency of testing, and optimal cutoffs among others. The most promising results in regard to diagnosis of bacterial infection and therapy monitoring are found for procalcitonin (PCT), although some recent trials were not able to validate the promising earlier findings. Furthermore, less specific markers like C-reactive protein (CRP) and new prognostic biomarkers such as proadrenomedullin (MR-proADM) may improve the prognostic assessment of patients and proteomics may help shorten time to microbiological results. The aim of this review is to summarize the current concept of biomarker-guided management and provide an outlook of promising ongoing investigations.

EXPERT OPINION

'Antibiotic stewardship' is complex and needs more than just the measurement of one single biomarker. However, when integrated into the context of a thorough clinical examination, standard blood parameters and a well done risk stratification by clinical scores such as the SOFA-score, biomarkers have great potential to improve the diagnostic and prognostic assessment of patients.

Biomarkers of sepsis: time for a reappraisal

INTRODUCTION

Sepsis biomarkers can have important diagnostic, therapeutic, and prognostic functions. In a previous review, we identified 3370 references reporting on 178 different biomarkers related to sepsis. In the present review, we evaluate the progress in the research of sepsis biomarkers.

METHODS

Using the same methodology as in our previous review, we searched the PubMed database from 2009 until September 2019 using the terms "Biomarker" AND "Sepsis." There were no restrictions by age or language, and all studies, clinical and experimental, were included.

RESULTS

We retrieved a total of 5367 new references since our previous review. We identified 258 biomarkers, 80 of which were new compared to our previous list. The majority of biomarkers have been evaluated in fewer than 5 studies, with 81 (31%) being assessed in just a single study. Apart from studies of C-reactive protein (CRP) or procalcitonin (PCT), only 26 biomarkers have been assessed in clinical studies with more than 300 participants. Forty biomarkers have been compared to PCT and/or CRP for their diagnostic value; 9 were shown to have a better diagnostic value for sepsis than either or both of these biomarkers. Forty-four biomarkers have been evaluated for a role in answering a specific clinical question rather than for their general diagnostic or prognostic properties in sepsis.

CONCLUSIONS

The number of biomarkers being identified is still increasing although at a slower rate than in the past. Most of the biomarkers have not been well-studied; in particular, the clinical role of these biomarkers needs to be better evaluated.

Procalcitonin to guide antibiotic decision making

PURPOSE OF REVIEW

There is convincing evidence linking antibiotic-stewardship efforts which include the infection marker procalcitonin (PCT) to more rational use of antibiotics with improvements in side-effects and clinical outcomes. This is particularly true in the setting of respiratory infection and sepsis. Yet, some recent trials have shown no benefit of PCT-guided care. Our aim was to discuss the benefits and limitations of using PCT for early infection recognition, severity assessment and therapeutic decisions in individual patients based on most the recent study data.

RECENT FINDINGS

Current evidence from randomized trials, and meta-analyses of these trials, indicates that PCT-guided antibiotic stewardship results in a reduction in antibiotic use and antibiotic side-effects, which translates into improved survival of patients with respiratory infections and sepsis. Notably, initial PCT levels have been found to be helpful in defining the risk for bacterial infection in the context of a low pretest probability for bacterial infections (i.e., patients with bronchitis or chronic bastructive pulmonary disease exacerbation). Monitoring of repeated PCT measurements over time has also been found helpful for estimating recovery from bacterial infection and prognosis in higher risk situations (i.e., pneumonia or sepsis) and results in early and safe discontinuation of antibiotic therapy. Some trials, however, did not find a strong effect of PCT guidance which may be explained by low protocol adherence, assessment using only a single rather than repeat PCT levels and lower antibiotic exposure in control group patients. Using PCT in the right patient population, with high-sensitivity assays and with adequate training of physicians is important to increase protocol adherence and reduce antibiotic exposure.

SUMMARY

Inclusion of PCT into antibiotic stewardship algorithms has the potential to improve the diagnostic and therapeutic management of patients presenting with respiratory illnesses and sepsis, and holds great promise to mitigate the global bacterial resistance crisis and move from a default position of standardized care to more personalized treatment decisions.

A 2020 review on the role of procalcitonin in different clinical settings: an update conducted with the tools of the Evidence Based Laboratory Medicine

Biomarkers to guide antibiotic treatment decisions have been proposed as an effective way to enhancing a more appropriate use of antibiotics. As a biomarker, procalcitonin (PCT) has been found to have good specificity to distinguish bacterial from non-bacterial inflammations. Decisions regarding antibiotic use in an individual patient are complex and should be based on the pre-test probability for bacterial infection, the severity of presentation and the results of PCT serum concentration. In the context of a high pre-test probability for bacterial infections and/or a high-risk patient with sepsis, monitoring of PCT over time helps to track the resolution of infection and decisions regarding early stop of antibiotic treatment. As outlined by the Evidence Based Laboratory Medicine (EBLM), not only the pre-test probability but also the positive likelihood ratio influence the performance of a test do be really diagnostic. This aspect should be taken into account in the interpretation of the results of clinical trials evaluating the performance of PCT in guiding antibiotic therapy.

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.

Biomarkers and clinical scores to aid the identification of disease severity and intensive care requirement following activation of an in-hospital sepsis code

BACKGROUND

Few validated biomarker or clinical score combinations exist which can discriminate between cases of infection and other non-infectious conditions following activation of an in-hospital sepsis code, as well as provide an accurate severity assessment of the corresponding host response. This study aimed to identify suitable blood biomarker (MR-proADM, PCT, CRP and lactate) or clinical score (SOFA and APACHE II) combinations to address this unmet clinical need.

METHODS

A prospective, observational study of patients activating the Vall d'Hebron University Hospital sepsis code (ISC) within the emergency department (ED), hospital wards and intensive care unit (ICU). Area under the receiver operating characteristic (AUROC) curves, logistic and Cox regression analysis were used to assess performance.

RESULTS

148 patients fulfilled the Vall d'Hebron ISC criteria, of which 130 (87.8%) were retrospectively found to have a confirmed diagnosis of infection. Both PCT and MR-proADM had a moderate-to-high performance in discriminating between infected and non-infected patients following ISC activation, although the optimal PCT cut-off varied significantly across departments. Similarly, MR-proADM and SOFA performed well in predicting 28- and 90-day mortality within the total infected patient population, as well as within patients presenting with a community-acquired infection or following a medical emergency or prior surgical procedure. Importantly, MR-proADM also showed a high association with the requirement for ICU admission after ED presentation [OR (95% CI) 8.18 (1.75-28.33)] or during treatment on the ward [OR (95% CI) 3.64 (1.43-9.29)], although the predictive performance of all biomarkers and clinical scores diminished between both settings.

CONCLUSIONS

Results suggest that the individual use of PCT and MR-proADM might help to accurately identify patients with infection and assess the overall severity of the host response, respectively. In addition, the use of MR-proADM could accurately identify patients requiring admission onto the ICU, irrespective of whether patients presented to the ED or were undergoing treatment on the ward. Initial measurement of both biomarkers might therefore facilitate early treatment strategies following activation of an in-hospital sepsis code.

Reduced utility of early procalcitonin and blood culture determination in patients with febrile urinary tract infections in the emergency department

To investigate the prognostic role of procalcitonin (PCT) assessment and blood culture (BC) acquisition in the emergency department (ED) in patients with urinary tract infection (UTI) or urosepsis. We enrolled patients admitted for UTI to our ED over a 10-year period. Mortality and in hospital length of stay (LOS) were compared between patients with UTI or urosepsis who had sampling for PCT levels and BC taken in the ED (ePCT group-eBC group) and those who had not (no-ePCT group-no-eBC group). 1029 patients were analyzed, 52.7% of which were female. Median age was 77 [65-83]; 139 patients (13.5%) had complicated UTI. Median LOS was 10 [7-17] days. In the ePCT group, LOS was 10 [7-16] days, vs. 10 [7-17] (p = 0.428) in the no-ePCT group. In the eBC group, LOS was 10 [6-16] days vs. 10 [7-17] days (p = 0.369) in the no-eBC group. The overall mortality rate was 6.6%. The mortality rate was not affected by early PCT determination (6% in the ePCT group vs. 6.9% in the no-ePCT group, p = 0.584). Similarly, the mortality rate was not different in the eBC group as compared to the no-eBC group (5.4% vs. 6.9%, p = 0.415). Performance of ePCT or eBC testing made no significant difference in terms of improvement of mortality rates in septic patients (11.4% vs. 7.2%; p = 0.397 and 8.8% vs. 9.8%; p = 0.845, respectively). The prognostic relevance of early evaluation of PCT and BC in the ED of patients with febrile UTI appears limited. In complicated UTI patients, PCT and BC testing may be more appropriate in the context of improving antibiotic stewardship, or as an integral component of PCT-guided standardized protocols.

The use of procalcitonin for the management of sepsis in Internal Medicine wards: current evidence

Procalcitonin (PCT) is a circulating polypeptide produced in response to bacterial infections. Studies conducted in the Intensive Care Unit (ICU) setting have demonstrated its utility as a biomarker of bacterial infection and sepsis. Thus, PCT is widely used to distinguish between sepsis and SIRS, and to guide antibiotic therapy. At present sepsis represents a frequent diagnosis among patients admitted to internal medicine (IM) departments. Basing on the knowledge derived from ICU studies, the use of PCT has become routine in non-intensive wards, contributing to improve the management of sepsis. However, some differences between the two populations of patients - the IM being older, affected by multiple chronic comorbidities and lacking of invasive monitoring - could limit the generalizability of ICU results. Most of the studies on PCT conducted in the IM setting have focused on chronic obstructive pulmonary disease, pneumonia and sepsis. Although PCT represents one of the best biomarker available in routine clinical practice, there are uncertainties on the optimal cut-offs to be used for starting or discontinuing antibiotic treatment in patients with suspected bacterial infection or sepsis, for predicting outcome and on the role of PCT variations during antibiotic treatment. Moreover, several diseases can produce an elevation of PCT levels, thus producing false positive results. This represents a narrative review summarizing current evidences on PCT for the management of sepsis in an Internal Medicine wards, highlighting differences with ICU, with a special focus on the role of PCT variations as predictor of outcomes in non-ICU wards.

Biomarkers and clinical scores to identify patient populations at risk of delayed antibiotic administration or intensive care admission

BACKGROUND

The performance of blood biomarkers (mid-regional proadrenomedullin (MR-proADM), procalcitonin (PCT), C-reactive protein (CRP), and lactate) and clinical scores (Sequential Organ Failure Assessment (SOFA), National Early Warning Score (NEWS), and quick SOFA) was compared to identify patient populations at risk of delayed treatment initiation and disease progression after presenting to the emergency department (ED) with a suspected infection.

METHODS

A prospective observational study across three EDs. Biomarker and clinical score values were calculated upon presentation and 72 h, and logistic and Cox regression used to assess the strength of association. Primary outcomes comprised of 28-day mortality prediction and delayed antibiotic administration or intensive care (ICU) admission, whilst secondary outcomes identified subsequent disease progression.

RESULTS

Six hundred eighty-four patients were enrolled with hospitalisation, ICU admission, and infection-related 28-day mortality rates of 72.8%, 3.4%, and 4.4%, respectively. MR-proADM and NEWS had the strongest association with hospitalisation and the requirement for antibiotic administration, whereas MR-proADM alone had the strongest association with ICU admission (OR [95% CI]: 5.8 [3.1 - 10.8]) and mortality (HR [95% CI]: 3.8 [2.2 - 6.5]). Patient subgroups with high MR-proADM concentrations (≥ 1.77 nmol/L) and low NEWS (< 5 points) values had significantly higher rates of ICU admission (8.1% vs 1.6%; p < 0.001), hospital readmission (18.9% vs. 5.9%; p < 0.001), infection-related mortality (13.5% vs. 0.2%; p < 0.001), and disease progression (29.7% vs. 4.9%; p < 0.001) than corresponding patients with low MR-proADM concentrations. ICU admission was delayed by 1.5 [0.25 - 5.0] days in patients with high MR-proADM and low NEWS values compared to corresponding patients with high NEWS values, despite similar 28-day mortality rates (13.5% vs. 16.5%). Antibiotics were withheld in 17.4% of patients with high MR-proADM and low NEWS values, with higher subsequent rates of ICU admission (27.3% vs. 4.8%) and infection-related hospital readmission (54.5% vs. 14.3%) compared to those administered antibiotics during ED treatment.

CONCLUSIONS

Patients with low severity signs of infection but high MR-proADM concentrations had an increased likelihood of subsequent disease progression, delayed antibiotic administration or ICU admission. Appropriate triage decisions and the rapid use of antibiotics in patients with high MR-proADM concentrations may constitute initial steps in escalating or intensifying early treatment strategies.

Evidence-Informed Practice: Diagnostic Questions in Urinary Tract Infections in the Elderly

Introduction

Routine interventions in the practice of medicine often lack definitive evidence or are based on evidence that is either not high quality or of only modest-to-marginal effect sizes. An abnormal urinalysis in an elderly patient presenting to the emergency department (ED) with non-specific symptoms represents one condition that requires an evidence-informed approach to diagnosis and management of either asymptomatic bacteriuria or urinary tract infection (UTI). The emergency provider often will not have access to urine cultures, and the risks associated with antibiotic use in the elderly are not without potentially significant side effects.

Methods

We performed a historical and clinical review of the growing body of literature suggesting measurable differences in the systemic immune response manifest among patients with asymptomatic pyuria and UTI, including increases in the pro-inflammatory cytokine interleukin-6 and the acute phase reactant procalcitonin.

Results

Serum procalcitonin, a peptide that undergoes proteolysis into calcitonin, has been demonstrated to quickly and reliably rise in patients with severe bacterial infections, and may serve as a potentially sensitive and specific marker for identification of bacterial illness.

Conclusion

In the absence of validated risk scores for diagnosing UTI in elderly patients presenting to the ED, there may be a role for the use of procalcitonin in this patient population.

The early identification of disease progression in patients with suspected infection presenting to the emergency department: a multi-centre derivation and validation study

Background

There is a lack of validated tools to assess potential disease progression and hospitalisation decisions in patients presenting to the emergency department (ED) with a suspected infection. This study aimed to identify suitable blood biomarkers (MR-proADM, PCT, lactate and CRP) or clinical scores (SIRS, SOFA, qSOFA, NEWS and CRB-65) to fulfil this unmet clinical need.

Methods

An observational derivation patient cohort validated by an independent secondary analysis across nine EDs. Logistic and Cox regression, area under the receiver operating characteristic (AUROC) and Kaplan-Meier curves were used to assess performance. Disease progression was identified using a composite endpoint of 28-day mortality, ICU admission and hospitalisation > 10 days.

Results

One thousand one hundred seventy-five derivation and 896 validation patients were analysed with respective 28-day mortality rates of 7.1% and 5.0%, and hospitalisation rates of 77.9% and 76.2%. MR-proADM showed greatest accuracy in predicting 28-day mortality and hospitalisation requirement across both cohorts. Patient subgroups with high MR-proADM concentrations (≥ 1.54 nmol/L) and low biomarker (PCT < 0.25 ng/mL, lactate < 2.0 mmol/L or CRP < 67 mg/L) or clinical score (SOFA < 2 points, qSOFA < 2 points, NEWS < 4 points or CRB-65 < 2 points) values were characterised by a significantly longer length of hospitalisation (p < 0.001), rate of ICU admission (p < 0.001), elevated mortality risk (e.g. SOFA, qSOFA and NEWS HR [95%CI], 45.5 [10.0–207.6], 23.4 [11.1–49.3] and 32.6 [9.4–113.6], respectively) and a greater number of disease progression events (p < 0.001), compared to similar subgroups with low MR-proADM concentrations (< 1.54 nmol/L). Increased out-patient treatment across both cohorts could be facilitated using a derivation-derived MR-proADM cut-off of < 0.87 nmol/L (15.0% and 16.6%), with decreased readmission rates and no mortalities.

Conclusions

In patients presenting to the ED with a suspected infection, the blood biomarker MR-proADM could most accurately identify the likelihood of further disease progression. Incorporation into an early sepsis management protocol may therefore aid rapid decision-making in order to either initiate, escalate or intensify early treatment strategies, or identify patients suitable for safe out-patient treatment.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2329-5) contains supplementary material, which is available to authorized users.

Identifying patients with bacterial infections using a combination of C-reactive protein, procalcitonin, TRAIL, and IP-10 in the emergency department: a prospective observational cohort study

OBJECTIVES

The aim was to effectively reduce the unnecessary use of broad spectrum antibiotics in the emergency department (ED), patients with bacterial infections need to be identified accurately. We investigated the diagnostic value of a combination of biomarkers for bacterial infections, C-reactive protein (CRP), and procalcitonin (PCT), together with biomarkers for viral infections, tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), and interferon-gamma-induced protein-10 (IP-10), in identifying suspected and confirmed bacterial infections in a general ED population with fever.

METHODS

This is a sub-study in the HiTEMP cohort. Patients with fever were included during ED triage, and blood samples were obtained. Using both diagnostics and expert panel analysis, all patients were classified as having either suspected or confirmed bacterial infections, or non-bacterial disease. Using multivariable logistic regression analysis, three biomarker models were analysed: model 1, CRP, TRAIL, IP-10; model 2, PCT, TRAIL, IP-10; and model 3, CRP, PCT, TRAIL, IP-10.

RESULTS

A total of 315 patients were included, of whom 228 patients had a suspected or confirmed bacterial infection. The areas under the curve for the combined models were the following: model 1, 0.730 (95% CI 0.665-0.795); model 2, 0.748 (95% CI 0.685-0.811); and model 3, 0.767(95% CI 0.704-0.829).

CONCLUSIONS

These findings show that a combination of CRP, PCT, TRAIL and IP-10 can identify bacterial infections with higher accuracy than single biomarkers and combinations of a single bacterial biomarkers combined with TRAIL and IP-10.

Procalcitonin-guided antibiotic therapy algorithms for different types of acute respiratory infections based on previous trials

INTRODUCTION

Although evidence indicates that use of procalcitonin to guide antibiotic decisions for the treatment of acute respiratory infections (ARI) decreases antibiotic consumption and improves clinical outcomes, algorithms used within studies had differences in PCT cut-off points and frequency of testing. We therefore analyzed studies evaluating procalcitonin-guided antibiotic therapy and propose consensus algorithms for different respiratory infection types. Areas covered: We systematically searched randomized-controlled trials (search strategy updated on February 2018) on procalcitonin-guided antibiotic therapy of ARI in adults using a pre-specified Cochrane protocol and analyzed algorithms from 32 trials that included 10,285 patients treated in primary care settings, emergency departments (ED), and intensive care units (ICU). We derived consensus algorithms for use of procalcitonin by the type of ARI including community-acquired pneumonia, bronchitis, chronic obstructive pulmonary disease or asthma exacerbation, sepsis, and post-operative sepsis due to respiratory infection. Consensus algorithm recommendations differ with regard to timing of treatment (i.e. timing of initiation in low-risk patients or discontinuation in high-risk patients) and procalcitonin cut-off points for the recommendation/strong recommendation to discontinue antibiotics (≤ 0.25/≤ 0.1 µg/L in ED and inpatients, ≤ 0.5/≤ 0.25 µg/L in ICU patients, and reduction by ≥ 80% from peak levels in sepsis patients). Expert commentary: Our proposed algorithms may facilitate safe and efficient implementation of procalcitonin-guided antibiotic protocols in diverse healthcare settings. Still, the decision about initiation and cessation of antibiotic treatment remains a clinical decision based on the patient assessment and the severity of illness and use of procalcitonin should not delay empirical treatment in high risk situations.