Meta-analysis and systematic review of procalcitonin-guided therapy in respiratory tract infections

The potential clinical value of pairing procalcitonin and lung ultrasonography to guide antibiotic therapy in patients with community-acquired pneumonia: a narrative review

INTRODUCTION

Lower respiratory tract infections (LRTIs) are among the most frequent infections and are prone to inappropriate antibiotic treatments. This results from a limited accuracy of diagnostic tools in identifying bacterial pneumonia. Lung ultrasound (LUS) has excellent sensitivity and specificity in diagnosing pneumonia. Additionally, elevated procalcitonin (PCT) levels correlate with an increased likelihood of bacterial infection. LUS and PCT appear to be complementary in identifying patients with bacterial pneumonia who are likely to benefit from antibiotics.

AREAS COVERED

This narrative review aims to summarize the current evidence for LUS to diagnose pneumonia, for PCT to guide antibiotic therapy and the clinical value of pairing both tools.

EXPERT OPINION

LUS has excellent diagnostic accuracy for pneumonia in different settings, regardless of the examiner's experience. PCT guidance safely reduces antibiotic prescription in LRTIs. The combination of both tools has demonstrated an enhanced accuracy in the diagnosis of pneumonia, including CAP in the ED and VAP in the ICU, but randomized controlled studies need to validate the clinical impact of a combined approach.

The Procalcitonin-guided Antibiotics in Respiratory Infections (PARI) project in general practice – a study protocol

Background

Antibiotic resistance is a global health challenge and the close correlation between antibiotic use and the development of resistance makes it essential to maintain a rational use of antibiotics. Most antibiotics are prescribed in general practice against acute respiratory tract infections (ARTI), even though most of these infections are of viral etiology. Thus, a safe method to substantially reduce unnecessary use of antibiotics in general practice is needed. Procalcitonin (PCT) is a precursor protein with very low circulating levels in the blood under physiological conditions. However, in response serious bacterial infection the level of PCT in the blood may increase significantly. Until recently, quantitative analyses of PCT was performed in hospital laboratories, impeding the implementation of PCT in primary care. Our aim is to determine whether it is possible to lower the use of antibiotics in patients presenting with symptoms of ARTI, without significantly prolonging the period of illness, by using a newly released PCT point-of-care test in general practice.

Methods

The Procalcitonin-Guided Antibiotics in Respiratory Infections (PARI) study is a randomized, single-blinded, non-inferiority, multi-practice intervention study comparing a PCT-group to a control group. Patients (N = 508) will be randomly assigned 1:1 to standard care or to the PCT group. The primary outcomes the duration of illness and symptoms from ARTI measured with the Acute Respiratory Tract Infection Questionnaire. Secondary outcomes include (1) Number of participants in each trial arm exposed to antibiotic treatment at index consultation (day 1) and within 30 days, (2) Number of participants in each trial arm with side effects from antibiotic treatment within 14 days, (3) Number of participants in each trial arm with re-consultations within 30 days, (4) Number of participants in each trial arm admitted to hospital (including diagnosis and mortality) within 30 days, (5) Characterization of biomarker (CRP and PCT) level at index consultation. Tertiary outcomes include patient and general practitioner satisfaction with the use of the PCT point-of-care test, and long-term follow-up.

Discussion

To our knowledge, this is the first study to examine a PCT point-of-care test in general practice with the aim of reducing the use of antibiotics in patients with symptoms of ARTI. Results of this study may prove important in targeting antibiotic treatment only to those patients who need it, thus contributing to limiting the spread of antibiotic resistance.

Trial registration

ClinicalTrials.gov Identifier: NCT04216277, date of registration: 2. of January 2020.

Procalcitonin as a Candidate Biomarker for Malarial Infection and Severe Malaria: A Meta-Analysis

Procalcitonin (PCT), as a marker of malaria severity, remains to be investigated. The present study collated and compared the levels of PCT between patients with severe malaria, uncomplicated malaria, and control participants to assess their role in predicting malaria infection and disease severity. The systematic review was registered at PROSPERO with registration number CRD42021297243. The search for relevant studies that reported PCT in patients with malaria was performed in PubMed, Scopus, and Web of Science. The following meta-analyses were conducted; (1) the pooled mean PCT levels in patients with severe and uncomplicated malaria, and (2) the pooled mean difference in PCT levels between patients with severe and uncomplicated malaria. Fifteen studies were included for qualitative and quantitative syntheses. The meta-analysis results show that the pooled mean PCT levels in patients with uncomplicated malaria were 3.92 ng/mL (95% CI: 2.26-5.58 ng/mL, I²: 96.5, five studies), whereas the pooled mean PCT levels in patients with severe malaria were 14.13 ng/mL (95% CI: 8.75-19.5 ng/mL, I²: 92.6, six studies). The meta-analysis showed that patients with severe malaria had an equal mean of PCT compared to those with uncomplicated malaria when the random-effects model was used (p: 0.055, weighted mean difference: 6.93, 95% CI: -0.16-14.02, I²: 84.6%, four studies). There were probable correlations between the level of parasitemia, immunity level, and possibly bacterial or other parasitic co-infection that could affect the PCT level among different clinical severities of malaria. Therefore, the PCT level alone does not seem to be a suitable biomarker to discriminate the severe/uncomplicated or infected/uninfected cases. Further studies should investigate the increased PCT levels in combination with other markers in association with malaria infection and severity.

The clinical characters and prognosis of COVID-19 patients with multiple organ dysfunction

To depict the clinical characters and prognosis of coronavirus disease 2019 patients who developed multiple organ dysfunction syndrome (MODS).A cohort consisted of 526 patients, which including 109 patients complicated MODS, was retrospectively analyzed to examine the clinical characteristics and risk factors of MODS.Among the 526 novel coronavirus-infected pneumonia patients, 109 patients developed multiple organ failure, the incidence rate was 20.7%. Among all 109 patients with MODS, 81.7% were over 60 years old, and 63.3% were male. The most common symptoms were fever (79.8%), dyspnea (73.4%), and fatigue (55.0%). Compared with patients non-MODS patients, there were 70 cases of MODS patients with one or more underlying diseases (64.2% vs 41.0%, P < .001). Respiratory failure (92.7%), circulatory failure (52.0%), and liver function injury (30.9%) were the most common symptoms within the spectrum of MODS. Invasive ventilator, noninvasive ventilator, and high-flow respiratory support treatment for patients in MODS patients were higher than those in the non-MODS group (P < .001). The antiviral therapy and 2 or more antibacterial drug treatments in MODS patients were higher than those in the non-MODS group (P < .001). The median hospital stay of all patients was 16 days (interquartile range [IQR], 9-26), of which 20 days (IQR, 11.5-30.5) in the MODS patients, which was approximately 4 days longer than that of non-MODS patients. In addition, our data suggested that lymphocyte counts <1.0 ∗ 109/L, Troponin T > 0.014 ng/mL and lower oxygenation index were risk factors for MODS. In the early stage of hospital admission, higher inflammatory indexes and lactic acid concentration were associated with increased risk of death.MODS often leads to poor prognosis in coronavirus disease 2019. Our data suggested the importance of early identification of MODS. We recommend close monitoring and timely supportive therapy for patients with high risks, stopping the disease progression before it was too late.

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.

Viral respiratory infections: a cause of community-acquired pneumonia or a predisposing factor?

PURPOSE OF REVIEW

A cause for community-acquired pneumonia (CAP) is only identified in ∼50% of cases. Nasopharyngeal PCR panels contain more viruses than previously. The problem then becomes determining the relevance of the organisms identified rather than figuring out which virus is present. This review addresses how to distinguish between viral CAP and bacterial CAP, how viral CAP predisposes to bacterial CAP and some novel antiviral treatment being conducted.

RECENT FINDINGS

The pneumonia severity index has been studied in patients with viral CAP. There are new studies using biomarkers to help determine when antimicrobial treatment is needed in CAP patients, and there is still no consensus. Newer devices are being invented in an effort to separate upper from lower respiratory organisms to make test results more relevant. Several outcome studies in patients with viral CAP are reviewed.

SUMMARY

In addition to clinical correlation, using biomarkers can be useful to distinguish viral from bacterial CAP. Outcomes in patients with a co-infection are generally worse as a viral infection may predispose someone to a bacterial pneumonia. Influenza CAP treatment may be initially accompanied with antimicrobials until a patient's diagnosis is clear (∼48-72 h). Future research is being conducted for antiviral treatment more than for influenza.

International Survey on Determinants of Antibiotic Duration and Discontinuation in Pediatric Critically Ill Patients

OBJECTIVES

We hypothesized that antibiotic use in PICUs is based on criteria not always supported by evidence. We aimed to describe determinants of empiric antibiotic use in PICUs in eight different countries.

DESIGN

Cross-sectional survey.

SETTING

PICUs in Canada, the United States, France, Italy, Saudi Arabia, Japan, Thailand, and Brazil.

SUBJECTS

Pediatric intensivists.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We used literature review and focus groups to develop the survey and its clinical scenarios (pneumonia, septic shock, meningitis, and intra-abdominal infections) in which cultures were unreliable due to antibiotic pretreatment. Data analyses included descriptive statistics and linear regression with bootstrapped SEs. Overall response rate was 39% (482/1,251), with individual country response rates ranging from 25% to 76%. Respondents in all countries prolonged antibiotic duration based on patient characteristics, disease severity, pathogens, and radiologic findings (from a median increase of 1.8 d [95% CI, 0.5-4.0 d] to 9.5 d [95% CI, 8.5-10.5 d]). Younger age, severe disease, and ventilator-associated pneumonia prolonged antibiotic treatment duration despite a lack of evidence for such practices. No variables were reported to shorten treatment duration for all countries. Importantly, more than 39% of respondents would use greater than or equal to 7 days of antibiotics for patients with a positive viral polymerase chain reaction test in all scenarios, except in France for pneumonia (29%), septic shock (13%), and meningitis (6%). The use of elevated levels of inflammatory markers to prolong antibiotic treatment duration varied among different countries.

CONCLUSIONS

Antibiotic-related decisions are complex and may be influenced by cultural and contextual factors. Evidence-based criteria are necessary to guide antibiotic duration and ensure the rational use of antibiotics in PICUs.

Molecular Diagnostics in Pulmonary Infections

Infection of the lung parenchyma, or pneumonia, accounts for over four million deaths per year worldwide (Ferkol and Schraufnagel, Ann Am Thorac Soc 11:404–406, 2014). The condition is common, but also over-diagnosed, in part due to relatively poor laboratory and radiographic diagnostics. Indeed, we continue to rely on antiquated tools such as sputum culture and chest X-ray – the former of which lacks speed and sensitivity, and the latter specificity (Albaum et al. Chest 110:343–50, 1996). The resulting presumptive diagnoses of pneumonia lead to excessive use of empiric broad spectrum antibiotics; indeed, by some estimates, 30–70% of antibiotic prescriptions for lower respiratory tract infection are inappropriate (Kraus, PLoS One 12(3): e0174584, 2017). This approach begets microbial resistance, exposes patients to medication side effects, and puts patients at risk of potentially life-threatening complications including Clostridium difficile colitis.

To improve diagnostic certainty in patients with suspected pneumonia, we must begin to consider and implement emerging technologies for efficient and accurate characterization of host responses to infection and identification of pathogens. In this chapter, we will discuss precision diagnostics already in common practice and those poised to be, and how these tools may ultimately enable personalization in the diagnosis of pneumonia.

Opportunities Revealed for Antimicrobial Stewardship and Clinical Practice with Implementation of a Rapid Respiratory Multiplex Assay

Few studies assess the utility of rapid multiplex molecular respiratory panels in adult patients. Previous multiplex PCR assays took hours to days from order time to result. We analyze the clinical impact of switching to a molecular assay with a 3-h test-turnaround-time (TAT). We performed a retrospective review of adult patients who presented to our emergency departments with respiratory symptoms and had a respiratory viral panel (xTAG RVP; RVP) or respiratory pathogen panel (ePlex RP; RPP) within 48 h of presentation. The average TATs for the RVP and RPP were 27.9 and 3.0 h, respectively (P < 0.0001). In RVP-positive and RPP-positive patients, 68.9 and 44.5% of those with normal chest imaging received antibiotics (P = 0.013), while 95.4 and 89.6% of those with abnormal imaging received antibiotics, respectively (P = 0.187). There was no difference in antibiotic duration in RVP-positive and RPP-positive patients with abnormal chest imaging (6.2 and 6.0 days, respectively; P = 0.923) and normal chest imaging (4.5 and 4.3 days, respectively; P = 0.922). Fewer patients were admitted in the RPP-positive compared to the RVP-positive group (76.9 and 88.6%, respectively; P = 0.013), while the proportion of admissions were similar among RPP-negative and RVP-negative patients (85.3 and 87.1%, P = 0.726). Switching to a multiplex respiratory panel with a clinically actionable TAT is associated with reduced hospital admissions and, in admitted adults without focal radiographic findings, reduced antibiotic initiation. Opportunities to further mitigate inappropriate antibiotic use may be realized by combining rapid multiplex PCR with provider education, clinical decision-care algorithms, and active antibiotic stewardship.

Procalcitonin guidance in patients with lower respiratory tract infections: a systematic review and meta-analysis

Although effective for bacterial lower respiratory tract infections (LRTIs), antibiotic treatment is often incorrectly prescribed for non-bacterial LRTIs. Procalcitonin has emerged as a promising biomarker to diagnose bacterial infections and guide antibiotic treatment decisions. As part of a regulatory submission to the U.S. Food and Drug Administration, this systematic review and meta-analysis summarizes the effects of procalcitonin-guided antibiotic stewardship on antibiotic use and clinical outcomes in adult LRTI patients. PubMed and the Cochrane Database of Systematic Reviews were searched for English-language randomized controlled trials published between January 2004 and May 2016. Random and fixed effects meta-analyses were performed to study efficacy (initiation of antibiotics, antibiotic use) and safety (mortality, length of hospital stay). Eleven trials were retained, comprising 4090 patients. Procalcitonin-guided patients had lower odds of antibiotic initiation (odds ratio: 0.26; 95% confidence interval [CI]: 0.13-0.52) and shorter mean antibiotic use (weighted mean difference: -2.15 days; 95% CI: -3.30 to -0.99) compared to patients treated with standard care. Procalcitonin use had no adverse impact on mortality (relative risk: 0.94; 95% CI: 0.69-1.28) and length of hospital stay (weighted mean difference: -0.15 days; 95% CI: -0.60 to 0.30). Procalcitonin guidance reduces antibiotic initiation and use among adults with LRTIs with no apparent adverse impact on length of hospital stay or mortality.

Uso de procalcitonina como diagnóstico de sepsis o shock séptico: revisión sistemática y metaanálisis

Introducción: La procalcitonina (PCT) es una prohormona de la calcitonina, producida por las células C de la glándula tiroides y convertida intracelularmente por enzimas proteolíticas en la hormona activa. La producción de PCT durante procesos inflamatorios, está ligada a endotoxinas bacterianas y a citoquinas inflamatorias. La mortalidad por sepsis, depende en gran medida de la detección precoz y del inicio de una terapia adecuada, incluyendo la administración de antibióticos apropiados, sin embargo, no está claro si el rendimiento diagnóstico de la PCT en el contexto de la nueva definición de sepsis en el tercer consenso es igual que con la definición previa.Métodos: Se incluyeron estudios que describieran el uso de PCT dentro de las primeras 24 horas de admisión, como prueba diagnóstica de sepsis. Se realizó la búsqueda en las bases de datos de Medline (Pubmed) y Embase. La calidad metodológica se evaluó según la Colaboración Cochrane en el desarrollo de Revisiones Sistemáticas sobre Test de Análisis para la herramienta QUADAS-II. El sesgo de publicación fue estudiado con el Test de Asimetría de Deeks. Se usó el módulo de MIDAS de STATA 14 para el análisis univariado y la construcción de la Curva de ROC.Resultados: Se obtuvieron 2076 registros (783 de Medline y 1293 de Embase). De los 12 estudios seleccionados, se incluyeron un total de 1353 pacientes, con una prevalencia en los estudios revisados entre el 9% y 88%, con un promedio del 47%. La Sensibilidad agrupada fue 0,83% (IC95% (0,74-0,89)) y la Especificidad fue 0,84% (IC95%(0,76-0,89)). El área bajo la Curva fue 0,90 (IC95%(0,87-0,92)). La heterogeneidad entre los estudios es importante I2 88% (IC95%(77-100)). Existe un sesgo de publicación según el test de Deek, con resultado P=0,04. En el análisis sobre la Probabilidad Post test según el nomograma de Fagan, es del 56%, teniendo en cuenta una probabilidad pretest del 20% según el LR positivo 5.Conclusión: La PCT es una prueba diagnóstica con buen rendimiento para sepsis o shock séptico, en pacientes adultos, no gestantes. Aunque hay sesgo de publicación y una gran heterogeneidad en los resultados, la prueba se considera adecuada para el escenario de sepsis según las nuevas definiciones.

Implementation of the Procalcitonin Assay in a Rural Hospital

Objective: Most positive studies in procalcitonin (PCT) utilization were done in large, tertiary medical centers. Furthermore, there is a paucity of data describing the implementation process. This article is the first to describe in detail the implementation process and initial outcomes after 6 months of PCT testing in a rural, 65-bed, primary hospital. Methods: Education before and during PCT implementation as well as facility rollout are described. Initial outcomes were assessed using a before and after quasi-experimental study design comparing 2 identical 6-month time periods: May to October 2016 and May to October 2017. Antibiotic consumption is described with days of therapy (DOT) per 1000 patient days (PD). Antimicrobial purchasing costs, admission rates, and length of stay (LOS) are also compared. Results: Antimicrobial consumption was variable with the greatest reduction at 6 months: 856 DOT/1000 PD before versus 576 DOT/1000 PD after (P < .0001). Admission rates and LOS were unaffected. There was no associated savings in antibiotic purchasing costs: $114 189.79 before and $139 829.26 after (difference +$25 639.47). Conclusion: Although implementation of PCT testing is feasible in a rural health care facility, after 6 months, it was associated with a marginal decrease in antibiotic consumption with no decrease in admission rates, LOS, or antibiotic cost savings.

A meta-analysis to assess usefulness of procalcitonin-guided antibiotic usage for decision making

Background & objectives:

Development of antibacterial resistance and its association with antibiotic overuse makes it necessary to identify a specific and sensitive biomarker for the diagnosis of bacterial infection and guiding antibiotic therapy. Procalcitonin (PCT), as a sepsis biomarker, may play a role in guiding antibiotics treatment in hospital settings. The aim of the current meta-analysis was to analyze the utility of PCT on various outcomes of interest in inpatients.

Methods:

Different databases were searched for randomized controlled trials comparing PCT-guided therapy with standard therapy in admitted patients with bacterial infections. Twenty six articles were found suitable for full text search and of these, 16 studies were considered finally for data extraction.

Results:

There were no significant differences found in total mortality [pooled odds ratio (OR) 1.04, 95% confidence interval (CI) 0.89-1.22, P=0.63], 28-day mortality (pooled OR 0.97, 95% CI 0.80-1.19, P=0.79), need of Intensive Care Unit admission (OR=0.80, 95% CI 0.59-1.09, P=0.16) and duration of stay in hospital (pooled mean difference −0.01, 95% CI −0.50-0.49, P=0.98) between treatment and control groups. PCT-guided treatment significantly decreased the duration of antibiotic treatment (pooled mean difference −2.79, 95% CI −3.52-−2.06, P<0.00001).

Interpretation & conclusions:

PCT-guided therapy significantly decreased antibiotics exposure and thus treatment cost. However, the hard endpoints did not demonstrate any significant benefits, possibly due to low power to detect differences and/or the presence of comorbidities.

The utility of procalcitonin in the prediction of serious bacterial infection in a tertiary paediatric intensive care unit

To determine utility of procalcitonin (PCT) for the prediction of bacterial infection in critically ill children, we analysed the relationship between serum PCT, cultures and other laboratory markers of bacterial sepsis or viral infection in a tertiary paediatric intensive care unit (PICU). The outcome measures were levels of PCT in proven bacteraemia, pneumonia and viral respiratory infection; and comparison of PCT to immature to total neutrophil ratio (ITR) in prediction of bacteraemia. In 420 children with suspected sepsis, 1,226 serum PCT levels were analysed. Children with bacteraemia had a higher median PCT (2.03 ng/ml, interquartile range [IQR] 0.67-42.4) than those who did not have bacteraemia (0.82 ng/ml, IQR 0.295-2.87) (P=0.033). PCT was a significant but only moderate predictor of bacteraemia (AUC 0.65). In 866 episodes of suspected sepsis where paired PCT and ITR were performed, the median ITR in children with bacteraemia was 0.19 ng/ml (IQR 0.04-0.35), and the median PCT was 6.5 ng/ml (IQR 0.71-61.8). PCT was a marginally better predictor of bacteraemia (AUC 0.69) than the ITR (AUC 0.66). In children with viral respiratory tract infection only, the median PCT was 1.26 ng/ml (0.35-5.5), and in those with likely bacterial pneumonia the median PCT was 0.80 ng/ml (IQR 0.28-1.70). In a heterogeneous population of children in a tertiary PICU, PCT measured at a single timepoint was a moderate predictor of proven bacteraemia. In our population PCT did not reliably identify localised bacterial infection or distinguish bacterial from viral respiratory infection.

Procalcitonin and CRP as Biomarkers in Discrimination of Community-acquired Pneumonia and Exacerbation of COPD

Background

Serum procalcitonin (PCT) and C-reactive protein (CRP) are markers of systemic inflammation and bacterial infection. We aimed to compare the usefulness of procalcitonin and CRP in patients with community-acquired pneumonia and exacerbations of chronic obstructive pulmonary disease (COPD).

Methods

A total of 116 consecutive patients were included in the study: 76 with chronic obstructive pulmonary disease in group 1, and 40 with pneumonia in group 2.

Results

Median serum CRP level was 44 mg/L in the COPD group and 132 mg/L in the pneumonia group. Median value of serum PCT was found to be 0.07 in the COPD group and 0.14 ng/mL in the pneumonia group. Serum PCT and CRP levels were significantly higher in the pneumonia group compared to the COPD group (p<0.001). The area under the ROC curve was 0.788 (CI: 0.704–0.872) for CRP and 0.699 (CI: 0.599–0.800) for procalcitonin to identify pneumonia.

Conclusions

Procalcitonin and CRP levels were significantly higher in patients with community-acquired pneumonia presenting to the emergency department with indications for hospitalization than in patients with exacerbations of chronic obstructive pulmonary disease. Serum CRP and procalcitonin concentrations were strongly correlated. CRP might be a more valuable marker in these patients with lower respiratory tract infections.

De-escalating Antibiotic Use in the Inpatient Setting: Strategies, Controversies, and Challenges

PURPOSE OF REVIEW

Antibiotic de-escalation (ADE) is widely accepted as an integral strategy to curtail the global antibiotic resistance crisis. However, there is significant uncertainty regarding the ideal ADE strategy and its true impact on antibiotic resistance. Rapid diagnostic testing has the potential to enhance ADE strategies. Herein, we aim to discuss the current strategies, controversies, and challenges of ADE in the inpatient setting.

RECENT FINDINGS

A consensus definition of ADE remains elusive at this time. Preliminary studies utilizing rapid diagnostic tests including matrix-assisted laser desorption/ionization time of flight (MALDI-TOF), procalcitonin, and other molecular techniques have demonstrated the potential to support ADE strategies. In the absence of evidence-based, highly specific ADE protocols, the likelihood that individual providers will make consistent, often challenging, decisions to de-escalate antibiotic therapy is low. Antimicrobial stewardship programs should support local physicians with ADE and develop innovative ways to integrate ADE into the broader construct of antimicrobial stewardship programs. The evolving field of rapid diagnostics has significant potential to improve ADE strategies, but more research is needed to fully realize this goal.

Postviral Complications: Bacterial Pneumonia

Secondary bacterial pneumonia after viral respiratory infection remains a significant source of morbidity and mortality. Susceptibility is mediated by a variety of viral and bacterial factors, and complex interactions with the host immune system. Prevention and treatment strategies are limited to influenza vaccination and antibiotics/antivirals respectively. Novel approaches to identifying the individuals with influenza who are at increased risk for secondary bacterial pneumonias are urgently needed. Given the threat of further pandemics and the heightened prevalence of these viruses, more research into the immunologic mechanisms of this disease is warranted with the hope of discovering new potential therapies.

Procalcitonin testing to guide antibiotic therapy for the treatment of sepsis in intensive care settings and for suspected bacterial infection in emergency department settings: a systematic review and cost-effectiveness analysis

BACKGROUND

Determination of the presence or absence of bacterial infection is important to guide appropriate therapy and reduce antibiotic exposure. Procalcitonin (PCT) is an inflammatory marker that has been suggested as a marker for bacterial infection.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of adding PCT testing to the information used to guide antibiotic therapy in adults and children (1) with confirmed or highly suspected sepsis in intensive care and (2) presenting to the emergency department (ED) with suspected bacterial infection.

METHODS

Twelve databases were searched to June 2014. Randomised controlled trials were assessed for quality using the Cochrane Risk of Bias tool. Summary relative risks (RRs) and weighted mean differences (WMDs) were estimated using random-effects models. Heterogeneity was assessed visually using forest plots and statistically using the I (2) and Q statistics and investigated through subgroup analysis. The cost-effectiveness of PCT testing in addition to current clinical practice was compared with current clinical practice using a decision tree with a 6 months' time horizon.

RESULTS

Eighteen studies (36 reports) were included in the systematic review. PCT algorithms were associated with reduced antibiotic duration [WMD -3.19 days, 95% confidence interval (CI) -5.44 to -0.95 days, I (2) = 95.2%; four studies], hospital stay (WMD -3.85 days, 95% CI -6.78 to -0.92 days, I (2) = 75.2%; four studies) and a trend towards reduced intensive care unit (ICU) stay (WMD -2.03 days, 95% CI -4.19 to 0.13 days, I (2) = 81.0%; four studies). There were no differences for adverse clinical outcomes. PCT algorithms were associated with a reduction in the proportion of adults (RR 0.77, 95% CI 0.68 to 0.87; seven studies) and children (RR 0.86, 95% CI 0.80 to 0.93) receiving antibiotics, reduced antibiotic duration (two studies). There were no differences for adverse clinical outcomes. All but one of the studies in the ED were conducted in people presenting with respiratory symptoms. Cost-effectiveness: the base-case analyses indicated that PCT testing was cost-saving for (1) adults with confirmed or highly suspected sepsis in an ICU setting; (2) adults with suspected bacterial infection presenting to the ED; and (3) children with suspected bacterial infection presenting to the ED. Cost-savings ranged from £368 to £3268. Moreover, PCT-guided treatment resulted in a small quality-adjusted life-year (QALY) gain (ranging between < 0.001 and 0.005). Cost-effectiveness acceptability curves showed that PCT-guided treatment has a probability of ≥ 84% of being cost-effective for all settings and populations considered (at willingness-to-pay thresholds of £20,000 and £30,000 per QALY).

CONCLUSIONS

The limited available data suggest that PCT testing may be effective and cost-effective when used to guide discontinuation of antibiotics in adults being treated for suspected or confirmed sepsis in ICU settings and initiation of antibiotics in adults presenting to the ED with respiratory symptoms and suspected bacterial infection. However, it is not clear that observed costs and effects are directly attributable to PCT testing, are generalisable outside people presenting with respiratory symptoms (for the ED setting) and would be reproducible in the UK NHS. Further studies are needed to assess the effectiveness of adding PCT algorithms to the information used to guide antibiotic treatment in children with suspected or confirmed sepsis in ICU settings. Additional research is needed to examine whether the outcomes presented in this report are fully generalisable to the UK.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014010822.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Procalcitonin as a biomarker for infection-related mortality in cancer patients

PURPOSE OF REVIEW

Infectious diseases are the second leading cause of death following direct cancer-related complications in the field of oncology. Clinical studies using the classic inflammatory biomarkers, C-reactive protein, erythrocyte sedimentation rate, leukocytosis, and thrombocytosis fail to show a significant correlation between these biomarkers and infection-related mortality. It is therefore crucial to define new biomarkers that are not affected by the primary cancer and precisely show the severity of the infection to help in the decision-making process.

RECENT FINDINGS

A significant increase in the number of cancer patients in the past decades has created an exponential increase in the number of immunocompromised patients. Preemptive and typically unnecessary usage of broad-spectrum antibiotics is common during the treatment of these patients and may result in an increase in multidrug-resistant microbial strains. Recent clinical studies suggest that a significant reduction in antibiotic consumption may be achieved by procalcitonin-guided algorithms without sacrificing the outcome of patients with severe infection.

SUMMARY

In this article, we focus on procalcitonin and its potential role in differentiating cancer and infection-induced inflammation. Using this strategy may significantly reduce the usage of empirical broad-spectrum antibiotics and result in earlier discharge of patients.

New Insights into Sepsis Therapy Using Sepia Officinalis

BACKGROUND

Sepsis remains a major problem for both scientists and clinicians. Cecal ligation and puncture (CLP) is considered the gold standard for animal models of sepsis. The undesirable side effects of certain antibiotics have forced scientists to discover new, natural, and safe antimicrobial agents, such as cephalopods, which are known to display significant antimicrobial activity.

OBJECTIVES

The present investigation aims to evaluate the in vitro and in vivo antibacterial and antiseptic efficacy of Sepia officinalis body tissue (SOBT) extract and S. officinalis polysaccharide (SOP) from its cuttlebone.

MATERIALS AND METHODS

Forty-eight rats were divided into 4 groups, and starting 2 hours after CLP, treatments were given for 2 days as follows: sham control rats treated orally with distilled water, septic rats treated orally distilled water, septic rats treated orally methanolic extract of SOBT (500 mg/kg b.wt) suspended in distilled water, and septic rats treated orally SOP extract (200 mg /kg b.wt) dissolved in distilled water. On the third day, half of the rats in each group were euthanized for blood collection. The other half were kept alive and used for the survival study.

RESULTS

The present study revealed that the SOBT and SOP extracts showed in vitro bactericidal activity against gram-positive and gram-negative bacteria. Furthermore, administration of SOBT and SOP increased the rats' survival rates by 66.7% and 83.33%, respectively, as compared to the untreated CLP-septic rats. Treatment of the CLP-septic rats with SOBT and SOP significantly alleviated alterations in procalcitonin levels and in some hematological parameters induced by CLP.

CONCLUSIONS

SOBT and SOP had profound antiseptic efficacy.

Performance of C-reactive protein and procalcitonin to distinguish viral from bacterial and malarial causes of fever in Southeast Asia

BACKGROUND

Poor targeting of antimicrobial drugs contributes to the millions of deaths each year from malaria, pneumonia, and other tropical infectious diseases. While malaria rapid diagnostic tests have improved use of antimalarial drugs, there are no similar tests to guide the use of antibiotics in undifferentiated fevers. In this study we estimate the diagnostic accuracy of two well established biomarkers of bacterial infection, procalcitonin and C-reactive protein (CRP) in discriminating between common viral and bacterial infections in malaria endemic settings of Southeast Asia.

METHODS

Serum procalcitonin and CRP levels were measured in stored serum samples from febrile patients enrolled in three prospective studies conducted in Cambodia, Laos and, Thailand. Of the 1372 patients with a microbiologically confirmed diagnosis, 1105 had a single viral, bacterial or malarial infection. Procalcitonin and CRP levels were compared amongst these aetiological groups and their sensitivity and specificity in distinguishing bacterial infections and bacteraemias from viral infections were estimated using standard thresholds.

RESULTS

Serum concentrations of both biomarkers were significantly higher in bacterial infections and malaria than in viral infections. The AUROC for CRP in discriminating between bacterial and viral infections was 0.83 (0.81-0.86) compared with 0.74 (0.71-0.77) for procalcitonin (p < 0.0001). This relative advantage was evident in all sites and when stratifying patients by age and admission status. For CRP at a threshold of 10 mg/L, the sensitivity of detecting bacterial infections was 95% with a specificity of 49%. At a threshold of 20 mg/L sensitivity was 86% with a specificity of 67%. For procalcitonin at a low threshold of 0.1 ng/mL the sensitivity was 90% with a specificity of 39%. At a higher threshold of 0.5 ng/ul sensitivity was 60% with a specificity of 76%.

CONCLUSION

In samples from febrile patients with mono-infections from rural settings in Southeast Asia, CRP was a highly sensitive and moderately specific biomarker for discriminating between viral and bacterial infections. Use of a CRP rapid test in peripheral health settings could potentially be a simple and affordable measure to better identify patients in need of antibacterial treatment and part of a global strategy to combat the emergence of antibiotic resistance.

Procalcitonin: potential role in diagnosis and management of sepsis

Sepsis is an important cause of worldwide morbidity and mortality. Early recognition and diagnosis are keys to achieving improved outcomes. Procalcitonin has been widely investigated as a potential biomarker for sepsis. Furthermore, management of sepsis and other infectious disease is becoming increasingly complicated by the emergence of antibiotic resistant strains of pathogens. Good antibiotic governance is important in reducing the risk of the development of further antibiotic resistance. We reviewed the current literature on the use of procalcitonin in sepsis to determine whether it should be recommended for use in either of these roles. Procalcitonin should not be used as a stand-alone diagnostic test to rule-in or rule-out sepsis or bacterial infection, or for prognostication, in the absence of clinical judgment. Used as part of a clinical algorithm, however, it has been shown to reduce antibiotic prescribing in critical care environments and for respiratory tract infections.

Can Procalcitonin Add to the Prognostic Power of the Severity Scoring System in Adults with Pneumonia?

BACKGROUND

The first decision confronting clinicians in the management of patients with community acquired pneumonia (CAP) is whether the patient is to be hospitalized or not. We sought to validate the pneumonia scoring system and assess the power of procalcitonin (PCT) level to predict in-hospital mortality (IHM) and intensive vasopressor and respiratory support (IVRS) requirements in patients with CAP.

MATERIALS AND METHODS

A total of 120 patients with CAP were evaluated for severity of illness based on the defined scoring systems including pneumonia severity index (PSI), confusion, urea, respiratory rate, blood pressure, age>65 (CURB-65), confusion, respiratory rate, blood pressure, age>65 (CRB-65), infectious diseases society of America/American thoracic society 2007 criteria (IDSA/ATS 2007) and systolic blood pressure, multilobar infiltrate, albumin, respiratory rate, tachycardia, confusion, low oxygen, low pH (SMART-COP). Demographic, clinical, laboratory and radiographic data were collected prospectively. The accuracy of each scoring system in predicting IVRS requirement and IHM was assessed from the area under the receiver operating characteristic (ROC) curve (AUC). Level of PCT was determined by semi-quantitative PCT-Q method (BRAHMS). The accuracy of the defined scoring systems, PCT levels and each scoring system plus PCT levels in prediction of IHM and IVRS requirement was analyzed.

RESULTS

The accuracy of PCT levels in predicting IHM and IVRS requirement based on AUC was 0.542 and 0.658, respectively and the best threshold was ≥ 2ng/mL for both of them. Adding the level of procalcitonin to different scoring systems (based on the defined scoring systems) improved the accuracy of all systems.

CONCLUSION

We do not suggest using the PCT level alone as a predictor for mortality and IVRS requirement. Instead, we suggest PSI plus PCT and IDSA/ATS 2007 plus PCT as accurate predictors for IHM and SMART-COP plus PCT for IVRS requirement in patients who presented with CAP.

Evaluation of procalcitonin as a marker to predict antibiotic response in adult patients with acute appendicitis: a prospective observational study

BACKGROUND

The aim of the study was to investigate the value of serum procalcitonin (PCT) as a predictor of early antibiotic treatment response in patients with acute appendicitis. Procalcitonin is a biochemical marker that increases rapidly in cases of bacterial infection and sepsis; however, the benefit of PCT as a diagnostic tool in acute appendicitis has not been confirmed.

METHODS

Observations of PCT dynamics were conducted as part of a prospective clinical trial at Sahlgrenska University Hospital between May 2009 and February 2010 on adult patients with acute appendicitis treated with antibiotics as first-line therapy. Procalcitonin, C-reactive protein (CRP), and white blood cell count (WBC) were measured before administration of antibiotics and subsequently between 4-24 h following treatment.

RESULTS

Three hundred sixteen patients were included in the study. Almost 80% recovered on antibiotics without the need of surgery. Serum PCT concentrations before initiation of antibiotic therapy and during treatment did not differ significantly between antibiotic responders and non-responders (p<0.94). However, differences were observed for CRP (p<0.04) and WBC (p<0.001), with a trend for body temperature (p<0.06).

CONCLUSION

Procalcitonin has limited additional value, compared with standard laboratory tests as CRP, WBC, and body temperature to predict antibiotic treatment response in adult patients with acute appendicitis.

Biomarkers for sepsis

Bloodstream infections are a major concern because of high levels of antibiotic consumption and of the increasing prevalence of antimicrobial resistance. Bacteraemia is identified in a small percentage of patients with signs and symptoms of sepsis. Biomarkers are widely used in clinical practice and they are useful for monitoring the infectious process. Procalcitonin (PCT) and C-reactive protein (CRP) have been most widely used, but even these have limited abilities to distinguish sepsis from other inflammatory conditions or to predict outcome. PCT has been used to guide empirical antibacterial therapy in patients with respiratory infections and help to determine if antibacterial therapy can be stopped. New biomarkers such as those in this review will discuss the major types of biomarkers of bloodstream infections/sepsis, including soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), soluble urokinase-type plasminogen receptor (suPAR), proadrenomedullin (ProADM), and presepsin.

Thirty and ninety days mortality predictive value of admission and in-hospital procalcitonin and mid-regional pro-adrenomedullin testing in patients with dyspnea. Results from the VERyfing DYspnea trial

INTRODUCTION

Mid-regional pro-atrial natriuretic peptide (MR-proANP), procalcitonin (PCT), and mid-regional pro-adrenomedullin (MR-proADM) demonstrated usefulness for management of emergency department patients with dyspnea.

METHODS

To evaluate in patients with dyspnea, the prognostic value for 30 and 90 days mortality and readmission of PCT, MR-proADM, and MR-proANP, a multicenter prospective study was performed evaluating biomarkers at admission, 24 and 72 hours after admission. Based on final diagnosis, patients were divided into acute heart failure (AHF), primary lung diseases, or both (AHF + NO AHF).

RESULTS

Five hundred one patients were enrolled. Procalcitonin and MR-proADM values at admission and at 72 hours were significantly (P < .001) predictive for 30-day mortality: baseline PCT with an area under the curve (AUC) of 0.70 and PCT at 72 hours with an AUC of 0.61; baseline MR-proADM with an AUC of 0.62 and MR-proADM at 72 hours with an AUC of 0.68. As for 90-day mortality, both PCT and MR-proADM baseline and 72 hours values showed a significant (P < .0001) predictive ability: baseline PCT with an AUC of 0.73 and 72 hours PCT with an AUC of 0.64; baseline MR-proADM with an AUC of 0.66 and 72 hours MR-proADM with an AUC of 0.71. In AHF, group biomarkers predicted rehospitalization and mortality at 90 days, whereas in AHF + NO AHF group, they predict mortality at 30 and 90 days.

CONCLUSIONS

In patients admitted for dyspnea, assessment of PCT plus MR-proADM improves risk stratification and management. Combined use of biomarkers is able to predict in the total cohort both rehospitalization and death at 30 and 90 days.

Role of biomarkers in the management of antibiotic therapy: an expert panel review II: clinical use of biomarkers for initiation or discontinuation of antibiotic therapy

Biomarker-guided initiation of antibiotic therapy has been studied in four conditions: acute pancreatitis, lower respiratory tract infection (LRTI), meningitis, and sepsis in the ICU. In pancreatitis with suspected infected necrosis, initiating antibiotics best relies on fine-needle aspiration and demonstration of infected material. We suggest that PCT be measured to help predict infection; however, available data are insufficient to decide on initiating antibiotics based on PCT levels. In adult patients suspected of community-acquired LRTI, we suggest withholding antibiotic therapy when the serum PCT level is low (<0.25 ng/mL); in patients having nosocomial LRTI, data are insufficient to recommend initiating therapy based on a single PCT level or even repeated measurements. For children with suspected bacterial meningitis, we recommend using a decision rule as an aid to therapeutic decisions, such as the Bacterial Meningitis Score or the Meningitest®; a single PCT level ≥0.5 ng/mL also may be used, but false-negatives may occur. In adults with suspected bacterial meningitis, we suggest integrating serum PCT measurements in a clinical decision rule to help distinguish between viral and bacterial meningitis, using a 0.5 ng/mL threshold. For ICU patients suspected of community-acquired infection, we do not recommend using a threshold serum PCT value to help the decision to initiate antibiotic therapy; data are insufficient to recommend using PCT serum kinetics for the decision to initiate antibiotic therapy in patients suspected of ICU-acquired infection. In children, CRP can probably be used to help discontinue therapy, although the evidence is limited. In adults, antibiotic discontinuation can be based on an algorithm using repeated PCT measurements. In non-immunocompromised out- or in- patients treated for RTI, antibiotics can be discontinued if the PCT level at day 3 is < 0.25 ng/mL or has decreased by >80-90%, whether or not microbiological documentation has been obtained. For ICU patients who have nonbacteremic sepsis from a known site of infection, antibiotics can be stopped if the PCT level at day 3 is < 0.5 ng/mL or has decreased by >80% relative to the highest level recorded, irrespective of the severity of the infectious episode; in bacteremic patients, a minimal duration of therapy of 5 days is recommended.

Procalcitonin as a biomarker of infectious diseases

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

New approaches to sepsis: molecular diagnostics and biomarkers

Sepsis is among the most common causes of death in hospitals. It arises from the host response to infection. Currently, diagnosis relies on nonspecific physiological criteria and culture-based pathogen detection. This results in diagnostic uncertainty, therapeutic delays, the mis- and overuse of antibiotics, and the failure to identify patients who might benefit from immunomodulatory therapies. There is a need for new sepsis biomarkers that can aid in therapeutic decision making and add information about screening, diagnosis, risk stratification, and monitoring of the response to therapy. The host response involves hundreds of mediators and single molecules, many of which have been proposed as biomarkers. It is, however, unlikely that one single biomarker is able to satisfy all the needs and expectations for sepsis research and management. Among biomarkers that are measurable by assays approved for clinical use, procalcitonin (PCT) has shown some usefulness as an infection marker and for antibiotic stewardship. Other possible new approaches consist of molecular strategies to improve pathogen detection and molecular diagnostics and prognostics based on transcriptomic, proteomic, or metabolic profiling. Novel approaches to sepsis promise to transform sepsis from a physiologic syndrome into a group of distinct biochemical disorders and help in the development of better diagnostic tools and effective adjunctive sepsis therapies.

Soluble receptor for urokinase plasminogen activator in community-acquired pneumonia in children

Community-acquired pneumonia (CAP) is a leading single cause of mortality in children under 5 years of age. In search of new diagnostic markers, soluble urokinase plasminogen activator receptor (suPAR) seems to offer promise as a novel clinical tool. The goal of the present study was to assess the relation between suPAR and the severity of CAP. suPAR was measured in 74 (39 males, 35 females) patients aged from 1 month to about 15 years. Correlation between the level of suPAR and inflammatory markers (white blood cell, neutrophil count, C-reactive protein-CRP, and procalcitonin-PCT) was assessed by Spearmann's rank coefficient. We found that the median suPAR level in children with pneumonia was 8.29 ng/mL (range 2.44-18.31 ng/mL). In the multivariate logit model, age and CRP level were statistically important. The older children (age above the median value) had higher suPAR (above the median value) less frequently than the younger children (OR = 0.31), whereas the children with greater CRP values (above the median value) had higher suPAR levels than the children with lower CRP concentration (under the median value) (OR = 4.54). There was also a positive correlation between suPAR and PCT levels. In conclusion, we demonstrate a positive correlation between serum suPAR and the non-specific inflammatory markers CRP and PCT in the community acquired pneumonia in children.

The role of biomarkers in low respiratory tract infections

Low respiratory tract infections (LRTI) represent the leading infectious cause of death worldwide and account for substantial use of healthcare resources. Physicians must adopt practices focused on improving outcomes and serum biomarker can help them in the management of patients with LRTI. Several studies have been carried out or are currently ongoing to evaluate the role of various biomarkers for the differential diagnosis, definition of prognosis, treatment and duration of antibiotic therapy in respiratory infections. The objective of this position paper of the Italian Society of Respiratory Diseases (SIMER) is to provide evidence-based recommendations for the use of biomarkers in routine clinical practice in the management of adult patients with LRTI. These guidelines capture the use of biomarkers both outside and inside the hospital, focused on community-acquired pneumonia, acute exacerbations of chronic obstructive pulmonary disease, hospital-acquired and ventilator-acquired pneumonia.