Biomarkers in respiratory tract infections: diagnostic guides to antibiotic prescription, prognostic markers and mediators

Mid-regional pro-adrenomedullin: A rapid sepsis biomarker for diagnosing spontaneous bacterial peritonitis in cirrhosis

BACKGROUND

Spontaneous bacterial peritonitis (SBP) is a frequent and life-threatening complication of cirrhosis, contributing to considerable morbidity and mortality.

METHODS

A cross-sectional derivation study was conducted to assess the diagnostic accuracy of two sepsis-related calcitonin peptide family biomarkers, mid-regional pro-adrenomedullin (MR-pro-ADM) and procalcitonin, in ascitic fluid for identifying bacteriologically confirmed SBP (BC-SBP). In a subsequent validation study, the diagnostic performance of the 'SBP score' was evaluated in an independent patient cohort using an absolute polymorphonuclear (PMN) leukocyte count threshold of ≥250 cells/mm3 as the diagnostic benchmark for diagnosing SBP.

RESULTS

In the derivation study, the concentration of MR-pro-ADM in ascitic fluid was significantly higher in patients with BC-SBP compared to those without BC-SBP (3.14 nmol/L [IQR, 2.39-6.74] vs. 1.91 nmol/L [IQR, 1.33-2.80]; p = .0002). Bayesian ANOVA indicated that MR-pro-ADM was highly discriminative for diagnosing BC-SBP, with a substantial Bayes factor (BFM = 2505), whereas procalcitonin exhibited poor discriminatory performance. Receiver-operating characteristic (ROC) analysis identified an optimal MR-pro-ADM cut-off of ≥2.50 nmol/L for diagnosing BC-SBP, with an area under the ROC curve (AUROC) of 0.746 (95% CI, 0.685-0.801; p < .0001). Multivariable logistic regression identified three independent predictors of BC-SBP, which were subsequently incorporated into the 'SBP score' (MR-pro-ADM ≥2.5 nmol/L, absolute PMN count ≥250 cells/mm3 and Child-Pugh score). In the validation study, the 'SBP score' demonstrated an AUROC of 0.993 (95% CI, 0.929-1.000; p < .0001) for diagnosing SBP.

CONCLUSION

MR-pro-ADM in ascitic fluid emerges as a promising biomarker for SBP diagnosis. Combining MR-pro-ADM with absolute PMN count and Child-Pugh score in the 'SBP score' greatly improves the diagnostic accuracy of SBP.

Clinical application of Myxovirus resistance protein A as a diagnostic biomarker to differentiate viral and bacterial respiratory infections in pediatric patients

Background

Differentiating between viral and bacterial respiratory tract infections in pediatric patients remains a significant diagnostic challenge, often leading to the overuse of antibiotics. Myxovirus resistance protein A (MxA) has been identified as a promising biomarker for viral infections. This study aimed to assess the fluctuations in blood MxA levels among children with viral respiratory infections and to explore the differences in MxA levels between viral and bacterial infections, focusing on clinical implications for antibiotic use.

Methods

We conducted a retrospective study using enzyme-linked immunosorbent assay (ELISA) to measure MxA levels in a cohort of 314 children with respiratory tract infections and 89 healthy controls. The study compared MxA levels across children with viral, bacterial, and mixed infections. Diagnostic accuracy was evaluated using receiver operating characteristic (ROC) curve analysis to distinguish between viral and bacterial infections or between viral and co-infections, with additional comparisons to other established infection biomarkers.

Results

MxA levels were significantly elevated in children with viral infections (n=205) compared to bacterial infections (n=21) (p<0.0001). The ROC curve analysis demonstrated that MxA had an area under the curve (AUC) of 0.8019 (95% CI: 0.6989 to 0.9049) for distinguishing viral from bacterial infections. Combining MxA with C-reactive protein (CRP) further enhanced diagnostic performance, achieving an AUC of 0.8713 (95% CI: 0.7916 to 0.9510). However, the use of MxA or MxA/CRP alone is insufficient to differentiate viral and viral - bacterial coinfection. The AUC of MxA is 0.5161 (95% CI: 0.4392 to 0.5930), and the AUC of MxA/CRP is 0.5429 (95% CI: 0.4705 to 0.6153).

Conclusions

This study highlights the diagnostic potential of MxA as a biomarker for differentiating viral from bacterial respiratory infections in children. The combined use of MxA and CRP offers a novel approach to improve diagnostic accuracy. Still, a combination with other clinical and laboratory markers remains required to determine whether to administer antibiotics to children with respiratory tract infections.

Analysis of risk factors related to perioperative neurocognitive disorders in elderly patients with hip fractures

To explore the risk factors related to perioperative neurocognitive disorders (PND) in elderly patients with hip fractures, with perioperative acute pain management as the core. This study used a retrospective case-control study method. 90 elderly patients who underwent artificial femoral head replacement or total hip replacement surgery in our hospital from 2022 to 2023 were collected, and divided into PND group and non-PND group based on the occurrence of PND. Collected data on 17 factors and conducted univariate and multivariate regression analysis to analyze the risk factors and contribution value of PND in elderly patients with hip fractures. Univariate analysis showed that compared with the non-PND group, patients in the PND group showed a significant increase in age, higher ASA class, longer surgical time, increased number of nerve block cases, increased postoperative 12 h visual analogue scale (VAS) scores, increased postoperative 24 h VAS scores, and increased levels of CRP, PCT, and BL-6 (P < 0.05). Multivariate regression analysis found that the risk factors for PND were postoperative 12 h VAS scores, postoperative 24 h VAS scores, CRP, PCT, and BL-6. The protective factors were ASA class III and ASA class II. The risk factors for PND in elderly patients undergoing hip fracture surgery included postoperative 12 h VAS scores (OR = 3.356), postoperative 24 h VAS scores (OR = 2.311), CRP (OR = 1.058), PCT (OR = 18.661), and BL-6 (OR = 1.061). The protective factors were ASA class III (OR = 0.039) and ASA class II (OR = 0.016).

Dependability of Procalcitonin as an Early Predictor of Infection in Open Fractures: An Observational Study

Introduction Open extremity fractures are complex injuries involving soft tissue disruption and bone discontinuity, often associated with significant morbidity and mortality due to complications such as infection. Infection remains a primary concern, exacerbating patient outcomes and increasing healthcare costs. Procalcitonin (PCT) is a biomarker with potential utility for early detection of infection in these cases. Materials and methods This prospective observational study was conducted at Justice K S Hegde Charitable Hospital between October 2022 and April 2024. Forty patients with open fractures who met inclusion criteria were enrolled. PCT levels were measured preoperatively and on postoperative days 1 and 5. Patients were monitored for clinical signs of infection for one month. Data analysis included descriptive and inferential statistics. Results The mean age of the patients was 42.26 ± 16.62 years, with a male predominance of 35 (87.5%) of the total sample size. Preoperative PCT levels were significantly higher in patients who developed infections (mean: 1.02 ng/mL) compared to non-infected patients (mean: 0.13 ng/mL). Postoperative PCT levels continued to rise in all patients but were significantly elevated in the infected group (p < 0.01). Conclusion PCT is a reliable biomarker for the early detection of postoperative infections in open fractures. Elevated preoperative PCT levels (>0.5 ng/mL) predict infection, while non-infected patients showed lower trauma-related increases. Further studies with larger samples are recommended to validate these findings.

Cross-sectional study: can endogenous procalcitonin differentiate between healthy and bovine respiratory disease-affected preweaned dairy calves?

Bovine respiratory disease (BRD) represents a significant challenge in cattle management due to its multifactorial nature and lack of a gold standard diagnostic method. Procalcitonin (PCT) has emerged as a potential biomarker for bacterial infections in various species, including cattle. This study aimed to investigate plasma PCT concentration variations in pre-weaned dairy calves categorized as BRD-positive using clinical scores (WRSC; BRD-positive ≥5), thoracic ultrasonography with two cut-off (TUS; BRD-positive ≥1 or ≥3), or a combination of both methods (WRSC/TUS1cm or WRSC/TUS3cm). Additionally, the accuracy of PCT in diagnosing BRD was evaluated. A cross-sectional study was conducted on a convenience sample of 226 pre-weaned Italian-Friesian female calves. Clinical scoring, TUS, and plasma PCT analysis were performed. Calves were categorized based on TUS findings, clinical scores, or a combination of both methods. Statistical analyses were conducted to assess the differences in PCT concentrations among different groups and to determine the diagnostic accuracy of PCT. Results showed a significant increase in PCT levels in calves with lung consolidation detected by TUS using a 1 cm cutoff. However, the diagnostic accuracy of PCT in discriminating BRD-positive cases was poor (area under the curve 0.62). The optimal cutoff value for PCT was determined to be 86.63 pg/mL, with sensitivity of 49.7%, specificity of 71.8%, positive predictive value of 79.4% and negative predictive value of 39.5%. In conclusion, while PCT showed potential as a biomarker for BRD, its diagnostic accuracy was limited in this study. Future research should focus on integrating PCT measurements with other diagnostic methods and conducting longitudinal cohort studies to better understand its role in BRD diagnosis and management.

Procalcitonin-guided antibiotic treatment in patients with cancer: a patient-level meta-analysis from randomized controlled trials

BACKGROUND

Use of serum procalcitonin (PCT), an inflammatory biomarker for bacterial infections, has shown promising results for early stopping antibiotic treatment among patients with respiratory infections and sepsis. There is need for additional data regarding effectiveness and safety of this concept among patients with cancer.

METHODS

Individual data of patients with a documented diagnosis of cancer and proven or suspected respiratory infection and/or sepsis were extracted from previous trials where adult patients were randomized to receive antibiotic treatment based on a PCT protocol or usual care (control group). The primary efficacy and safety endpoints were antibiotic exposure and 28-day all-cause mortality.

RESULTS

This individual-patient data meta-analysis included 777 patients with a diagnosis of cancer from 15 randomized-controlled trials. Regarding efficacy, there was a 18% reduction in antibiotic exposure in patients randomized to PCT-guided care compared to usual care ([days] 8.2 ± 6.6 vs. 9.8 ± 7.3; adjusted difference, - 1.77 [95% CI, - 2.74 to - 0.80]; p < 0.001). Regarding safety, there were 72 deaths in 379 patients in the PCT-guided group (19.0%) compared to 91 deaths in 398 participants in the usual care group (22.9%) resulting in an adjusted OR of 0.78 (95% CI, 0.60 to 1.02). A subgroup analysis showed a significant reduction in mortality in patients younger than 70 years (adjusted OR, 0.58 [95% CI, 0.40 to 0.86]).

CONCLUSION

Result of this individual patient meta-analysis from 15 previous trials suggests that among patients with cancer and suspected or proven respiratory infection or sepsis, use of PCT to guide antibiotic treatment decisions results in reduced antibiotic exposure with a possible reduction in mortality, particularly among younger patients.

Exosomes as novel biomarkers in sepsis and sepsis related organ failure

Sepsis, a severe and life-threatening condition arising from a dysfunctional host response to infection, presents considerable challenges to the health care system and is characterized by high mortality rates and substantial economic costs. Exosomes have garnered attention as potential diagnostic markers because of their capacity to mirror the pathophysiological milieu of sepsis. This discourse reviews the progression of sepsis classification from Sepsis 1.0 to Sepsis 3.0, highlighting the imperative for sensitive and specific biomarkers to facilitate timely diagnosis and optimize patient outcomes. Existing biomarkers, such as procalcitonin (PCT) and C-reactive protein (CRP), exhibit certain limitations, thereby prompting the quest for more dependable diagnostic indicators. Exosomal cargoes, which encompass proteins and miRNAs, present a trove of biomarker candidates, attributable to their stability, pervasive presence, and indicative nature of the disease status. The potential of exosomal biomarkers in the identification of sepsis-induced organ damage, including cardiomyopathy, acute kidney injury, and acute lung injury, is emphasized, as they provide real-time insights into cardiac and renal impairments. Despite promising prospects, hurdles persist in the standardization of exosome extraction and the need for extensive clinical trials to validate their efficacy. The combination of biomarker development and sophisticated exosome detection techniques represents a pioneering strategy in the realm of sepsis diagnosis and management, underscoring the significance of further research and clinical validation.

Evaluating the utility of procalcitonin and a clinical decision support tool to determine duration of antimicrobial therapy for respiratory tract infections

PURPOSE

Procalcitonin (PCT) levels may play a role in decreasing the duration of antimicrobial therapy in institutions that have long durations of therapy for management of community-acquired pneumonia. We assessed the impact of the combination of pharmacist stewardship interventions assisted by a clinical decision support (CDS) tool and PCT assessment on the antimicrobial days of therapy (DOT) prescribed for respiratory tract infections (RTIs).

METHODS

We conducted a quasi-experimental study in which patients in the preintervention group were admitted between April and June 2021 and patients in the intervention group were admitted between April and June 2022. In the intervention phase, a CDS tool was utilized to alert clinical pharmacists when patients met specific criteria. This alert was programmed to activate for individual patients when a reported PCT level was less than 0.25 ng/mL and the patient was on antimicrobials prescribed for an RTI as indicated by providers in the electronic health record. Stewardship interventions were made by pharmacists via prospective audit and feedback. The primary endpoint was inpatient antimicrobial DOT for RTIs.

RESULTS

There were 90 patients in the preintervention group and 104 patients in the intervention group. Although baseline characteristics were not well matched between the groups, favoring the preintervention group, the median DOT was lower in the intervention group, at 3 days (interquartile range [IQR], 2-4 days), compared to 4 days (IQR, 2.8-5 days) in the preintervention group (P = 0.001).

CONCLUSION

The results of our study demonstrate the utility of pharmacist interventions coupled with CDS and PCT in reducing antimicrobial DOT prescribed for RTIs. Antimicrobial stewardship programs may benefit from implementing a PCT bundle.

Usefulness of mid-regional proadrenomedullin levels in the resuscitation phase of severely burned patients and its utility in early sepsis detection

INTRODUCTION

Mid-regional proadrenomedullin (MR-proADM) reflects the adrenomedullin level, which has vasodilatory activity, decreases endothelial permeability, and downregulates proinflammatory cytokines. Sepsis diagnosis in these patients is difficult, and MR-proADM is a widely studied sepsis biomarker. This study evaluates MR-proADM levels during the resuscitation phase, considering the potential influence of haemodynamic changes and its usefulness for the early sepsis detection in burn patients.

METHODS

A prospective observational study performed in the Critical Burn Unit. Demographic data, burn characteristics, comorbidities, prognostic/severity scales, and haemodynamic parameters were collected. The resuscitation protocol guided by diuresis, transpulmonary thermodilution, and lactate levels was followed. Blood samples were collected at various time points for biomarker measurement. Biomarker levels, including MR-proADM, C-reactive protein, and procalcitonin were measured during the resuscitation phase and septic episodes.

RESULTS

Twenty-seven patients were included, with a mean age of 51 years, a mean total body surface area burn of 41.8%, a mean Abbreviated Burn Severity Index of 9.7, and a mean Baux score of 92. MR-proADM levels were elevated on admission (0.9 ± 0.5 nmol/l) and continued to increase slightly during the resuscitation phase (2.4 ± 2.2 nmol/l). Haemodynamic changes during resuscitation did not significantly affect MR-proADM levels. Twelve of the 27 patients developed sepsis, whose MR-proADM levels were significantly elevated on the day of clinical diagnosis (3.91 ± 2.99 nmol/l) and even the day before (2.57 ± 3.37). Higher MR-proADM levels were associated with greater severity as measured by the Sequential Organ Failure Assessment score. The mean MR-proadrenomedullin values during resuscitation in the patients who died was 3.51 ± 2.30 nmol/l, whereas in the survivors it was 1.28 ± 1.10 nmol/l (p = 0.0001).

CONCLUSION

MR-proadrenomedullin values are elevated after thermal injury but are not affected by haemodynamic changes. During septic episodes in burn patients, MR-proADM rises early (the day before sepsis diagnosis). Higher levels of MR-proADM are associated with greater organ dysfunction and mortality.

Case-Control Study: Endogenous Procalcitonin and Protein Carbonylated Content as a Potential Biomarker of Subclinical Mastitis in Dairy Cows

Procalcitonin (PCT) and protein carbonylated content (PCC) are promising biomarkers for bacterial infection and inflammation in veterinary medicine. This study examined plasma PCT and PCC levels in healthy cows (H) and cows with subclinical mastitis (SCM). A total of 130 cows (65 H and 65 SCM) were included in this study. Blood samples were collected, and plasma was frozen at -80 °C. PCT levels were determined using a bovine procalcitonin ELISA kit, while PCC was measured following the methodology of Levine et al. Statistical analysis revealed a significant difference in PCT levels between H (75.4 pg/mL) and SCM (107.3 pg/mL) cows (p < 0.001) and significantly lower concentrations of PCC in the SCM group (H: 0.102 nmol/mL/mg, SCM: 0.046 nmol/mL/mg; p < 0.001). The PCT cut-off value for distinguishing healthy and subclinical mastitis animals was >89.8 pg/mL (AUC 0.695), with a sensitivity of 66.2% and specificity of 69.2%. PCT showed potential value as a diagnostic tool to help in decision making for subclinical mastitis cases, while PCC requires further studies to investigate the trend of this biomarker during localized pathology.

Mid-Regional Proadrenomedullin Levels in Primary Immunodeficiencies Complicated with Pulmonary Manifestations

The development of lower respiratory complications in children with primary immunodeficiencies characterized by recurrent infections significantly contributes to morbidity and mortality. This is clinically more important and specific in the evaluation of prognosis. The inflammatory response that develops throughout the clinical process can cause the release of several biomarkers. This study aimed to evaluate the inflammatory biomarker "mid-regional pro-adrenomedullin (MR-proADM)" levels by distribution of lower respiratory tract complications. Plasma MR-proADM levels were measured in children with (n = 52) and without (n = 103) lower respiratory tract complications. The complicated group was also evaluated as "infective and non-infective" groups. The median MR-proADM levels were higher in the complicated cases (p = 0.175). It was 205.5 (73.4- 562.6) ng/L in the infective group while it was 96.1 (26.1-43.3) ng/L in the non-infective group and the difference between the two groups was statistically significant (p = 0.003). The predictive value of MR-proADM (AUC = 0.749, p = 0.003) was statistically significant compared to CRP (AUC = 0.330, p = 0.040) and SAA (AUC = 0.261, p = 0.004) in the infective group. This study evidences that the MR-proADM levels are higher in PID cases with infective pulmonary complications. Among other markers, MR-proADM appears to be a particularly good predictive inflammation marker for these children.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12291-022-01061-9.

Detecting Diabetic Ketoacidosis with Infection: Combating a Life-Threatening Emergency with Practical Diagnostic Tools

BACKGROUND

Diabetic ketoacidosis (DKA) is a life-threatening acute complication of diabetes mellitus and can lead to patient demise if not immediately treated. From the recent literature, the diabetic ketoacidosis mortality rate, depending on age, is 2-5%. Insulin discontinuation and infection remain the two most common triggers for diabetic ketoacidosis. About 50% of cases of ketoacidosis result from bacterial infections like urinary tract infections and pneumonia. It is also important to diagnose the presence of infection in diabetic ketoacidosis patients to prevent the excessive use of antibiotics, which may lead to antibiotic resistance. Although performing bacterial culture is confirmatory for the presence or absence of bacterial infection, the time required to obtain the result is long. At the same time, emergency treatment needs to be started as early as possible.

METHODS

This narrative review examines various septic markers to identify the appropriate tools for diagnosis and to distinguish between diabetic ketoacidosis with and without infection. Electronic databases were searched using the Google engine with the keywords "Diabetes Mellitus", "Diabetic Ketoacidosis", "Infection with Diabetic Ketoacidosis", "biomarkers for infection in Diabetic Ketoacidosis", "Procalcitonin", "Inflammatory cytokines in DKA", "Lactic acidosis in DKA", and "White blood cell in infection in DKA".

RESULTS

This narrative review article presents the options for diagnosis and also aims to create awareness regarding the gravity of diabetic ketoacidosis with infection and emphasizes the importance of early diagnosis for appropriate management. Diabetes mellitus is a clinical condition that may lead to several acute and chronic complications. Acute diabetic ketoacidosis is a life-threatening condition in which an excess production of ketone bodies results in acidosis and hypovolemia. Infection is one of the most common triggers of diabetic ketoacidosis. When bacterial infection is present along with diabetic ketoacidosis, the mortality rate is even higher than for patients with diabetic ketoacidosis without infection. The symptoms and biomarkers of diabetic ketoacidosis are similar to that of infection, like fever, C reactive protein, and white blood cell count, since both create an environment of systemic inflammation. It is also essential to distinguish between the presence and absence of bacterial infection to ensure the appropriate use of antibiotics and prevent antimicrobial resistance. A bacterial culture report is confirmatory for the existence of bacterial infection, but this may take up to 24 h. Diagnosis needs to be performed approximately in the emergency room upon admission since there is a need for immediate management. Therefore, researching the possible diagnostic tools for the presence of infection in diabetic ketoacidosis patients is of great importance. Several of such biomarkers have been discussed in this research work.

Profile analysis of emerging respiratory virus in children

Acute respiratory infections (ARIs) are caused by a variety of microorganisms. Of all ARIs, 80% are caused by viruses such as human respiratory syncytial virus, metapneumovirus, influenza, parainfluenza, rhinovirus, and, more recently, Sars-CoV-2, which has been responsible for the COVID-19 pandemic. The objective of our study was to evaluate clinical data from a viral panel performed in children hospitalized with SARS or COVID-19 in the infirmary or ICU of 5 pediatric hospitals in the city of Goiânia, Goiás, Brazil. Demographic, clinical, and laboratory data were collected for analysis, and data on the outcomes underwent statistical treatment. A total of 128 patients were selected for the study, 54% of whom were male and 46% female. The viral panel included rhinovirus, COVID-19, metapneumovirus, adenovirus, and parainfluenza. Descriptive analyses of age profile showed differences in the involvement of particular viruses. The percentage of patients who required hospitalization in the ICU, infirmary, as well as individuals who were discharged after therapy or who died, were described. Our work shows that epidemiological surveillance measures are indispensable, especially if used in the continued analysis of viral panels in all pediatric patients with SARS.

The Potential Use of Saliva as a Biofluid for Systemic Inflammatory Response Monitoring in Children with Pneumonia

OBJECTIVE

To investigate the levels of C-reactive protein, procalcitonin, calprotectin, interleukin 1 beta (IL-1β), IL-6, and tumor necrosis factor-alpha (TNF-α) in both saliva and serum in children with community-acquired pneumonia and to compare the saliva response with the systemic response.

METHODS

Forty hospitalized children with community-acquired pneumonia aged between 1 mo and 15 y; and 40 healthy controls were included. Both serum and saliva samples were collected on admission and at the time of discharge.

RESULTS

Calculated differences between values for each serum and salivary parameter on admission and before discharge named delta (Δ) values were used for correlation analysis. Salivary Δ values of each parameter were moderately/strongly correlated with their corresponding serum Δ levels [IL-1β ÷ (r = 0.554, p < 0.001); IL-6 ÷ (r = 0.484, p = 0.002); PCT ÷ (r = 0.737, p < 0.001); TNF-α ÷ (r = 0.587, p < 0.001); CRP ÷ (r = 0.703, p < 0.001); and calprotectin ÷ (r = 0.774, p < 0.001)].

CONCLUSIONS

This study will evaluate the reflection of systemic changes in saliva and the efficacy of saliva in pediatric patients with pneumonia. Results will highlight saliva potential use as a biofluid for systemic monitoring in this patient group.

Procalcitonin Is Not a Reliable Biomarker of Bacterial Coinfection in People With Coronavirus Disease 2019 Undergoing Microbiological Investigation at the Time of Hospital Admission

Admission procalcitonin measurements and microbiology results were available for 1040 hospitalized adults with coronavirus disease 2019 (from 48 902 included in the International Severe Acute Respiratory and Emerging Infections Consortium World Health Organization Clinical Characterisation Protocol UK study). Although procalcitonin was higher in bacterial coinfection, this was neither clinically significant (median [IQR], 0.33 [0.11-1.70] ng/mL vs 0.24 [0.10-0.90] ng/mL) nor diagnostically useful (area under the receiver operating characteristic curve, 0.56 [95% confidence interval, .51-.60]).

Procalcitonin metabolomics in the critically ill reveal relationships between inflammation intensity and energy utilization pathways

Procalcitonin is a biomarker of systemic inflammation and may have importance in the immune response. The metabolic response to elevated procalcitonin in critical illness is not known. The response to inflammation is vitally important to understanding metabolism alterations during extreme stress. Our aim was to determine if patients with elevated procalcitonin have differences in the metabolomic response to early critical illness. We performed a metabolomics study of the VITdAL-ICU trial where subjects received high dose vitamin D3 or placebo. Mixed-effects modeling was used to study changes in metabolites over time relative to procalcitonin levels adjusted for age, Simplified Acute Physiology Score II, admission diagnosis, day 0 25-hydroxyvitamin D level, and the 25-hydroxyvitamin D response to intervention. With elevated procalcitonin, multiple members of the short and medium chain acylcarnitine, dicarboxylate fatty acid, branched-chain amino acid, and pentose phosphate pathway metabolite classes had significantly positive false discovery rate corrected associations. Further, multiple long chain acylcarnitines and lysophosphatidylcholines had significantly negative false discovery rate corrected associations with elevated procalcitonin. Gaussian graphical model analysis revealed functional modules specific to elevated procalcitonin. Our findings show that metabolite differences exist with increased procalcitonin indicating activation of branched chain amino acid dehydrogenase and a metabolic shift.

Use of a Novel Clinical Decision Support Tool for Pharmacist-Led Antimicrobial Stewardship in Patients with Normal Procalcitonin

In 2018, a clinical decision support (CDS) tool was implemented as part of a "daily checklist" for frontline pharmacists to review patients on antibiotics with procalcitonin (PCT) <0.25 mcg/L. This study used a retrospective cohort design to assess change in antibiotic use from pharmacist interventions after this PCT alert in patients on antibiotics for lower respiratory tract infections (LRTI). The secondary outcome was antibiotic days of therapy (DOT), with a subgroup analysis examining antibiotic use and the length of stay (LOS) in patients with a pharmacist intervention. From 1/2019 to 11/2019, there were 165 alerts in 116 unique patients on antibiotics for LRTI. Pharmacists attempted interventions after 34 (20.6%) of these alerts, with narrowing spectrum or converting to oral being the most common interventions. Pharmacist interventions prevented 125 DOT in the hospital. Vancomycin was the most commonly discontinued antibiotic with an 85.3% use reduction in patients with interventions compared to a 27.4% discontinuation in patients without documented intervention (p = 0.0156). The LOS was similar in both groups (median 6.4 days vs. 7 days, p = 0.81). In conclusion, interventions driven by a CDS tool for pharmacist-driven antimicrobial stewardship in patients with a normal PCT resulted in fewer DOT and significantly higher rates of vancomycin discontinuation.

The Effects of Neutrophil-Lymphocyte Ratio, Platelet-Lymphocyte Ratio and Prognostic Markers in Determining the Mortality in Patients Diagnosed With Pneumonia in Intensive Care

Objective

In this study, we aimed to reveal the level of predicting mortality of the Neutrophil/Lymphocyte (NLR) and Platelet/Lymphocyte Ratios (TLR) calculated in patients hospitalized with the diagnosis of pneumonia in the intensive care unit when compared with other prognostic scores.

Method

The hospital records of 112 patients who were admitted to the intensive care unit between January 2015 and January 2018 and met the inclusion criteria were retrospectively reviewed. The patients’ demographic data, the NLR and PLR levels, and the APACHE II (Acute Physiology and Chronic Health Evaluation II) and SOFA (Sequential Organ Failure Assessment) scores were calculated from the patient files.

Results

Of the 112 patients examined, 70 were males. The risk analysis showed that the male gender had 2.7 times higher risk of mortality. The NLR, PLR, APACHE II, and SOFA values were found statistically significant in predicting mortality (p<0.001). An evaluation of the risk ratios demonstrated that each one point increase in the NLR increased the mortality risk by 5%, and each one point increase in the SOFA score increased the mortality risk by 13% (p<0.05). In the ROC (receiver operating characteristic) analysis, the NLR assessment proved to be the most powerful, most specific, and sensitive test. The cut-off values were 11.3 for the NLR, 227 for the PLR, 29.8 for the APACHE II scores, and 5.5 for the SOFA scores

Conclusion

We believe that NLR and PLR are strong and independent predictors of mortality that can be easily and cost-effectively tested.

One-step-immunoassay of procalcitonin enables rapid and accurate diagnosis of bacterial infection

Procalcitonin (PCT) (i.e. a precursor of calcitonin) attracts much attention as a reliable biomarker of bacterial infections because its concentration increases rapidly in the blood when bacterial infections occur in the body. Sepsis may occur due to indiscriminate and vigorous proliferation of infectious bacteria, and accordingly early diagnosis and treatment of bacterial infection are of crucial importance. However, current diagnostic methods for sepsis suffer from long assay time, multiple and complex assay steps, inaccuracy, and requirement of analytical equipments. The goal of this study is to develop an advanced one-step-immunoassay that enables quick and accurate diagnosis of sepsis through measuring the PCT concentration in patient sera, which is based on self-enhancement of optical detection signals from large gold particles (i.e. clusters of gold nanoparticles) that are formed on the agglomerates of PCT-bound 3-dimensional (3D) probes. The 3D probe is constructed through attaching polyclonal anti-PCT antibodies (IgGs) to the surface of a modified hepatitis B virus (HBV) capsid, where both tandem repeats of the B domain of Staphylococcal protein A (SPA_B) and the hexa-histidine tag are inserted into each HBV core protein (i.e. subunit of HBV capsid). That is, anti-PCT IgGs are attached via strong interaction between the Fc region and surface-exposed SPA_B. Furthermore, hook effect-free and PCT concentration-dependent optical signals were consistently generated by adding both bovine serum albumin (BSA) and nickel ions to patient sera and also by optimally adjusting the 3D probe concentration. Compared to conventional chemiluminescent microparticle immunoassay (CMIA) showing poor linearity of detection signals, this novel immunoassay accurately detected PCT with good linearity between PCT concentrations and optical signals in a wide range of PCT concentrations (0.05–200 ng mL⁻¹) and also showed a sufficiently low limit of detection, resulting in 100% sensitivity and 100% specificity when tested with 30 sepsis patients and 30 healthy individuals.

An advanced one-step-immunoassay enables quick and accurate diagnosis of sepsis with generation of clear optical signals in assay solution, which is based on sensitive detection of procalcitonin in patient sera.

Influence of Prednisone on Inflammatory Biomarkers in Community-Acquired Pneumonia: Secondary Analysis of a Randomized Trial

Glucocorticoids are frequently prescribed in inflammatory diseases and have recently experienced a boom in the treatment of COVID-19. Small studies have shown an effect of glucocorticoids on inflammatory marker levels, but definitive proof is lacking. We investigated the influence of prednisone on inflammatory biomarkers in a previous multicenter, randomized, placebo-controlled trial that compared a 7-day treatment course of 50-mg prednisone to placebo in patients hospitalized with community-acquired pneumonia. We compared levels of C-reactive protein (CRP), procalcitonin (PCT), leukocyte and neutrophil count between patients with and without glucocorticoid treatment at baseline and on days 3, 5, and 7 and at discharge by Wilcoxon tests and analysis of variance. A total of 356 patient data sets in the prednisone group and 355 in the placebo group were available for analysis. Compared to placebo, use of prednisone was associated with reductions in levels of CRP on days 3, 5, and 7 (mean difference of 46%, P < .001 for each time point). For PCT, no such difference was observed. Leukocyte and neutrophil count were higher in the prednisone group at all time points (mean difference of 27% for leukocytes and 33% for neutrophils, P <.001 for all time points). We conclude that after administration of glucocorticoids in community-acquired pneumonia, patients had lower CRP levels and increased leukocyte and neutrophil count as compared to the placebo group. PCT levels were not different between treatment groups. PCT levels thus may more appropriately mirror the resolution of infection compared to more traditional inflammatory markers.

Prognostic Value of Procalcitonin and C-Reactive Protein in 1608 Critically Ill Patients with Severe Influenza Pneumonia

Background: Procalcitonin (PCT) and C-Reactive protein (CRP) are well-established sepsis biomarkers. The association of baseline PCT levels and mortality in pneumonia remains unclear, and we still do not know whether biomarkers levels could be related to the causative microorganism (GPC, GNB). The objective of this study is to address these issues. Methods: a retrospective observational cohort study was conducted in 184 Spanish ICUs (2009–2018). Results: 1608 patients with severe influenza pneumonia with PCT and CRP available levels on admission were included, 1186 with primary viral pneumonia (PVP) and 422 with bacterial Co-infection (BC). Those with BC presented higher PCT levels (4.25 [0.6–19.5] versus 0.6 [0.2–2.3]ng/mL) and CRP (36.7 [20.23–118] versus 28.05 [13.3–109]mg/dL) as compared to PVP (p < 0.001). Deceased patients had higher PCT (ng/mL) when compared with survivors, in PVP (0.82 [0.3–2.8]) versus 0.53 [0.19–2.1], p = 0.001) and BC (6.9 [0.93–28.5] versus 3.8 [0.5–17.37], p = 0.039). However, no significant association with mortality was observed in the multivariate analysis. The PCT levels (ng/mL) were significantly higher in polymicrobial infection (8.4) and GPC (6.9) when compared with GNB (1.2) and Aspergillus (1.7). The AUC-ROC of PCT for GPC was 0.67 and 0.32 for GNB. The AUROC of CRP was 0.56 for GPC and 0.39 for GNB. Conclusions: a single PCT/CRP value at ICU admission was not associated with mortality in severe influenza pneumonia. None of the biomarkers have enough discriminatory power to be used for predicting the causative microorganism of the co-infection.

Analysis of Biochemical Parameters in Children with Chronic Tonsillitis

Chronic tonsillitis are frequent in pediatric pathology with numerous involved risk factors and pathogenic mechanisms. In this study, epidemiological data and biochemical values addressed to inflammation and mineral, lipid and hepatic metabolism were analyzed for 37 children of school age with chronic tonsillitis. We found that in the majority of cases, chronic tonsillitis was associated with increasing number of blood circulating inflammatory cells, high values of transaminases, cholesterol, triglycerides and low values of procalcitonin, C-reactive protein, calcium, vitamin D and serum iron. The results indicated relations of the biochemical profile analyzed with risk factors and systemic mechanisms for initiation and maintenance of chronic tonsillitis, aspects that can be used to optimize the prognosis of chronic tonsillitis in children.

Acute Exacerbations of Chronic Obstructive Pulmonary Disease With a Low Procalcitonin Concentration: Impact of Antibiotic Therapy

BACKGROUND

Patients admitted with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) often are prescribed antibiotics. Studies have shown that the use of procalcitonin (PCT) to guide the decision to initiate antibiotic therapy in AECOPD has resulted in less antibiotic use and similar outcomes compared with standard of care. We evaluated patients with AECOPD and low PCT concentrations to determine whether antibiotic therapy was associated with improved outcomes.

METHODS

We retrospectively evaluated adult patients admitted with AECOPD who had a peak PCT concentration <0.25 µg/mL. Patients were evaluated based on their antibiotic exposure: ≤24 hours vs >24 hours. We also evaluated outcomes based upon the duration of azithromycin therapy: ≤24 hours vs >24 hours. The primary outcome was all-cause 30-day readmissions. Secondary outcomes included length of stay (LOS) and COPD-related 30-day readmissions.

RESULTS

One hundred sixty-one and 195 patients received ≤24 hours vs >24 hours of antibiotic therapy, respectively. The cohort with ≤24 hours of antibiotics had a shorter LOS (2.8 vs 3.7 days; P = .01). There were no differences in all-cause 30-day readmissions (15.5% vs 17.4%; P = .63) or COPD-related 30-day readmissions (11.2% vs 12.3%; P = .74). Additionally, patients receiving ≤24 hours of azithromycin had a shorter LOS (3.0 vs 3.8 days; P = .002) and there were no differences in all-cause 30-day readmissions (16.2% vs 17.1%; P = .82) or COPD-related 30-day readmissions (11.9% vs 11.6%; P = .94).

CONCLUSIONS

For adult patients hospitalized with nonsevere AECOPD and low PCT concentrations, antibiotic therapy beyond 24 hours did not improve outcomes.

Hot topics and current controversies in community-acquired pneumonia

Community-acquired pneumonia (CAP) is one of the most common infectious diseases, as well as a major cause of death both in developed and developing countries, and it remains a challenge for physicians around the world. Several guidelines have been published to guide clinicians in how to diagnose and take care of patients with CAP. However, there are still many areas of debate and uncertainty where research is needed to advance patient care and improve clinical outcomes. In this review we highlight current hot topics in CAP and present updated evidence around these areas of controversy.

Community-acquired pneumonia is the most frequent cause of infectious death worldwide; however, there are several areas of controversy that should be addressed to improve patient care. This review presents the available data on these topics.http://bit.ly/2ShnH7A

Investigating the role of circulating CXCR5-expressing CD8+ T-cells as a biomarker for bacterial infection in subjects with pneumonia

BACKGROUND

Recently, lymphoid follicle-confined and circulating CD8+ T-cells expressing the C-X-C chemokine receptor type 5 (CXCR5) were described, which was involved in anti-virus immune response. However, the dynamics and role of circulating CXCR5-expressing CD8+ T-cells during bacterial infection is unknown. So, we asked whether CXCR5+ CD8+ T cells were also generated during bacterial infections in lower respiratory tract.

METHODS

The clinical data of 65 pneumonia patients were analyzed. The patients were divided into groups as tuberculosis, bronchiectasis and community or hospital acquired pneumonia (CAP, HAP). The sputum/bronchial secretion or bronchoalveolar lavage fluid (BALF) samples were taken for microbiological examination. The procalcitonin (PCT) was used to evaluate disease severity of these groups and compared among patients. We characterized the number and phenotype (PD-1 and CD103) of CXCR5 + CD8+ T cells in the peripheral circulation by flow cytometry in all individuals and analyzed their association with the serum PCT level and disease severity.

RESULTS

Patients were mainly infected with Escherichia coli, Acinetobacter baumannii, Klebsiella pneumonia (K.p), Pseudomonas aeruginosa, and Staphylococcus aureus. Of note is the finding that PCT was weakly correlated with severity of respiratory infections. Furthermore, it was revealed an increase of CXCR5-expressing CD8+ T cells in peripheral blood of un-controlled CAP and progressive HAP compared controlled CAP and HAP, respectively (P < 0.05). Strikingly, the circulating CXCR5-expressing CD8+ T-cells in K.p-infected group was higher than that non-K.p-infected group (P < 0.05). Meanwhile, the ratio of CXCR5 + CD8+/CD8 was positively correlated with PCT level (P < 0.05). In clinic, the determination of CXCR5-expressing CD8+ T-cells showed better results compared to PCT and can be useful for the prediction of exacerbation of CAP or HAP. Phenotypically, CXCR5+ CD8 + T cell expressed comparable level of inhibitory molecules PD-1 and lower CD103 compared to their CXCR5- counterparts.

CONCLUSION

The circulating CXCR5-expressing CD8+ T-cell has diagnostic value for current pneumonia severity, and could act as a biomarker for identifying a bacteria-associated exacerbation. These cells may provide novel insight for the pathogenesis of pneumonia.

Inflammatory biomarkers are associated with aetiology and predict outcomes in community-acquired pneumonia: results of a 5-year follow-up cohort study

Background

Biomarkers may facilitate clinical decisions in order to guide antimicrobial treatment and prediction of prognosis in community-acquired pneumonia (CAP). We measured serum C-reactive protein, procalcitonin (PCT) and calprotectin levels, and plasma pentraxin 3 (PTX3) and presepsin levels, along with whole-blood white cell counts, at three time-points, and examined their association with microbial aetiology and adverse clinical outcomes in CAP.

Methods

Blood samples were obtained at hospital admission, clinical stabilisation and 6-week follow-up from 267 hospitalised adults with CAP. Adverse short-term outcome was defined as intensive care unit admission and 30-day mortality. Long-term outcome was evaluated as 5-year all-cause mortality.

Results

Peak levels of all biomarkers were seen at hospital admission. Increased admission levels of C-reactive protein, PCT and calprotectin were associated with bacterial aetiology of CAP, while increased admission levels of PCT, PTX3 and presepsin were associated with adverse short-term outcome. In univariate and multivariate regression models, white blood cells and calprotectin at 6-week follow-up were predictors of 5-year all-cause mortality.

Conclusions

Calprotectin emerges as both a potential early marker of bacterial aetiology and a predictor for 5-year all-cause mortality in CAP, whereas PCT, PTX3 and presepsin may predict short-term outcome.

In 267 adults with community-acquired pneumonia, systemic calprotectin emerges as an early marker of bacterial aetiology and a predictor of 5-year mortality, whereas systemic procalcitonin, pentraxin 3 and presepsin are predictors of short-term outcomehttp://ow.ly/dz6S30nAFvn

[Place of biomarkers in the management of pulmonary infections]

INTRODUCTION

The management of acute lower respiratory tract infections and, in particular, the decision whether or not to commence antibiotic therapy, still remains difficult in the absence of reliable clinical or radiological criteria allowing confident distinction between bacterial and viral infections. Numerous biomarkers have been developed to help the clinician in his/her diagnostic and therapeutic approach, but the role and significance of each has not been clearly defined.

BACKGROUND

Though procalcitonin (PCT) or C-reactive protein (CRP) seem equal in helping the clinician to decide whether to commence antibiotic therapy or not during the course of an exacerbation of asthma or chronic obstructive pulmonary disease (COPD), PCT is currently the most useful biomarker to distinguish sepsis from other causes of inflammation and to determine the bacterial or viral origin of a pneumonia.

OUTLOOK

The ability of PCT to reduce the global exposure to antibiotics remains uncertain and the results of randomised trials are contradictory.

CONCLUSIONS

Prescription algorithms involving PCT may be used without increased risk for patients even though clinical signs of severity remain important. Changes in PCT also have a prognostic value in identifying those patients with unfavourable outcome.

Serum Procalcitonin and Presepsin Levels in Patients with Generalized Pustular Psoriasis

Patients with generalized pustular psoriasis (GPP) often present with symptoms that must be differentiated from sepsis. Procalcitonin (PCT) and presepsin (P-SEP) are widely used as biomarkers for sepsis; therefore, we examined the serum PCT and P-SEP levels in patients with psoriatic diseases. The enrolled patients included 27 with psoriasis vulgaris (PV) (22 males, 5 females; mean age 47.7 years), 12 with psoriatic arthritis (PsA) (8 males, 4 females; mean age 51.3 years), and 15 with GPP (10 males, 5 females; mean age 63.7 years). The mean serum PCT levels in patients with PV, PsA, and GPP were 0.01 ng/mL (25th–75th percentile; 0.00–0.03), 0.013 ng/mL (0.00–0.03), and 0.12 ng/mL (0.05–0.18), respectively; the levels of PCT were higher for patients with GPP than with PV or PsA but were lower than the PCT cutoff value (0.5 ng/mL) for the diagnosis of infection. The mean serum P-SEP levels in patients with PV, PsA, and GPP were 144.9 pg/mL (25th–75th percentile; 78–181), 168.1 pg/mL (124–203), and 479.9 pg/mL (216–581), respectively. Unexpectedly, the levels of P-SEP in the patients with GPP were as high as the P-SEP cutoff value (317 to 647 pg/mL) used for the diagnosis of infection. We also found that neutrophils produced P-SEP, suggesting that the high serum P-SEP levels in patients with GPP might arise at least in part due to the P-SEP derived from neutrophils activated in GPP. Both serum PCT and P-SEP might therefore be useful as novel serum biomarkers for GPP because their levels were decreased by GPP treatments. However, the measurement of PCT might be more useful than the measurement of P-SEP for discriminating between GPP and sepsis.

The role of serum procalcitonin in the differential diagnosis of pneumonia from pulmonary edema among the patients with pulmonary infiltrates on chest radiography

The aim of this study is to evaluate the usefulness of serum procalcitonin (PCT) as a diagnostic biomarker for distinguishing pneumonia from pulmonary edema in patients presenting with pulmonary infiltrates on chest radiography.A comparative study was performed retrospectively in a university-affiliated hospital, from May, 2013 to April, 2015. Adult patients (≥18 years) who showed pulmonary infiltrates on chest radiography and had blood tests with C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), PCT, and N-terminal pro-b-type natriuretic peptide (NT-proBNP) on admission were included in the study. Clinical parameters collected on admission were compared between the case group (n = 143) with pneumonia and the control group (n = 88) with pulmonary edema alone.During the study period, a total of 1217 patients were identified. Of them, a total of 231 patients were included in analyses based on exclusion criteria. In the multivariate logistic regression analysis, PCT ≥0.25 ng/mL, ESR ≥35 mm/h, CRP ≥18 mg/L, NT-proBNP ≤200 pg/mL, underlying neurologic diseases, fever, sputum, absence of cardiomegaly, and a low Charlson comorbidity index were independently associated with pneumonia. For this model, the sensitivity, specificity, positive predictive value, and negative predictive value in distinguishing between the 2 groups were 90.2%, 79.6%, 87.8%, and 83.3%, respectively, with an area under the curve of 0.93.This study suggests that the practical use of PCT in conjunction with clinical data can be valuable in the differential diagnosis of pulmonary infiltrates and guidance for clinicians to prevent antibiotic misuse.

2018 recommendations for the management of community acquired pneumonia

Community-acquired pneumonia (CAP) is the leading cause of death worldwide. Despite the vast diversity of respiratory microbiota, Streptococcus pneumoniae remains the most prevalent pathogen among etiologic agents. Despite the significant decrease in the mortality rates for lower respiratory tract infections in recent decades, CAP ranks third as a cause of death in Brazil. Since the latest Guidelines on CAP from the Sociedade Brasileira de Pneumologia e Tisiologia (SBPT, Brazilian Thoracic Association) were published (2009), there have been major advances in the application of imaging tests, in etiologic investigation, in risk stratification at admission and prognostic score stratification, in the use of biomarkers, and in the recommendations for antibiotic therapy (and its duration) and prevention through vaccination. To review these topics, the SBPT Committee on Respiratory Infections summoned 13 members with recognized experience in CAP in Brazil who identified issues relevant to clinical practice that require updates given the publication of new epidemiological and scientific evidence. Twelve topics concerning diagnostic, prognostic, therapeutic, and preventive issues were developed. The topics were divided among the authors, who conducted a nonsystematic review of the literature, but giving priority to major publications in the specific areas, including original articles, review articles, and systematic reviews. All authors had the opportunity to review and comment on all questions, producing a single final document that was approved by consensus.

Increased procalcitonin level is a risk factor for prolonged fever in children with Mycoplasma pneumonia

PURPOSE

Macrolide-resistant Mycoplasma pneumoniae pneumonia (MPP) is characterized by prolonged fever and radiological progression despite macrolide treatment. Few studies have examined serum procalcitonin (PCT) level in children with MPP. We aimed to investigate the association of acute inflammation markers including PCT with clinical parameters in children with MPP.

METHODS

A total of 147 children were recruited. The diagnosis of MPP relied on serial measurement of IgM antibody against mycoplasma and/or polymerase chain reaction. We evaluated the relationships between C-reactive protein (CRP), PCT, and lactate dehydrogenase (LDH) levels and white blood cell (WBC) counts, and clinical severity of the disease. We used multivariate logistic regression analysis to estimate the odds ratio for prolonged fever (>3 days after admission) and hospital stay (> 6 days), comparing quintiles 2-5 of the PCT levels with the lowest quintile.

RESULTS

The serum PCT and CRP levels were higher in children with fever and hospital stay than in those with fever lasting ≤ 3 days after admission and hospital stay ≤ 6 days. CRP level was higher in segmental/lobar pneumonia than in bronchopneumonia. The LDH level and WBC counts were higher in children with fever lasting for >3 days before compared to those with fever lasting for ≤ 3 days. The highest quintile of PCT levels was associated with a significantly higher risk of prolonged fever and/or hospital stay than the lowest quintile.

CONCLUSION

Serum PCT and CRP levels on admission day were associated with persistent fever and longer hospitalization in children with MPP.

Impact of Procalcitonin Guidance on Management of Adults Hospitalized with Chronic Obstructive Pulmonary Disease Exacerbations

BACKGROUND

Antibiotics are often prescribed for hospitalized patients with chronic obstructive pulmonary disease (COPD) exacerbations. The use of procalcitonin (PCT) in the management of pneumonia has safely reduced antibiotic durations, but limited data on the impact of PCT guidance on the management of COPD exacerbations remain.

OBJECTIVE

To determine the impact of PCT guidance on antibiotic utilization for hospitalized adults with exacerbations of COPD.

DESIGN

A retrospective, pre-/post-intervention cohort study was conducted to compare the management of patients admitted with COPD exacerbations before and after implementation of PCT guidance. The pre-intervention period was March 1, 2014, through October 31, 2014, and the post-intervention period was March 1, 2015, through October 31, 2015.

PARTICIPANTS

All patients with hospital admissions during the pre- and post-intervention period with COPD exacerbations were included. Patients with concomitant pneumonia were excluded.

INTERVENTION

Availability of PCT laboratory values in tandem with a PCT guidance algorithm and education.

MAIN MEASURES

The primary outcome was duration of antibiotic therapy for COPD. Secondary objectives included duration of inpatient length of stay (LOS) and 30-day readmission rates.

KEY RESULTS

There were a total of 166 and 139 patients in the pre- and post-intervention cohorts, respectively. There were no differences in mean age (66.2 vs. 65.9; P = 0.82) or use of home oxygenation (34% vs. 39%; P = 0.42) in the pre- and post-intervention groups, respectively. PCT guidance was associated with a reduced number of antibiotic days (5.3 vs. 3.0; p = 0.01) and inpatient LOS (4.1 days vs. 2.9 days; P = 0.01). Respiratory-related 30-day readmission rates were unaffected (10.8% vs. 9.4%; P = 0.25).

CONCLUSIONS

Utilizing PCT guidance in the management of COPD exacerbations was associated with a decreased total duration of antibiotic therapy and hospital LOS without negatively impacting hospital readmissions.

Relationship between acute kidney injury and serum procalcitonin (PCT) concentration in critically ill patients with influenza infection

INTRODUCTION

Serum procalcitonin (PCT) concentration could be increased in patients with renal dysfunction in the absence of bacterial infection.

OBJECTIVE

To determine the interactions among serum renal biomarkers of acute kidney injury (AKI) and serum PCT concentration, in patients admitted to the intensive care unit (ICU) due to lung influenza infection.

DESIGN

Secondary analysis of a prospective multicentre observational study.

SETTING

148 Spanish ICUs.

PATIENTS

ICU patients admitted with influenza infection without bacterial co-infection. Clinical, laboratory and hemodynamic variables were recorded. AKI was classified as AKI I or II based on creatinine (Cr) concentrations (≥1.60-2.50mg/dL and Cr≥2.51-3.99mg/dL, respectively). Patients with chronic renal disease, receiving renal replacement treatment or with Cr>4mg/dL were excluded. Spearman's correlation, simple and multiple linear regression analysis were performed.

INTERVENTIONS

None.

RESULTS

Out of 663 patients included in the study, 52 (8.2%) and 10 (1.6%) developed AKI I and II, respectively. Patients with AKI were significantly older, had more comorbid conditions and were more severally ill. PCT concentrations were higher in patients with AKI (2.62 [0.60-10.0]ng/mL vs. 0.40 [0.13-1.20]ng/mL, p=0.002). Weak correlations between Cr/PCT (rho=0.18) and Urea (U)/PCT (rho=0.19) were identified. Simple linear regression showed poor interaction between Cr/U and PCT concentrations (Cr R²=0.03 and U R²=0.018). Similar results were observed during multiple linear regression analysis (Cr R²=0.046 and U R²=0.013).

CONCLUSIONS

Although PCT concentrations were slightly higher in patients with AKI, high PCT concentrations are not explained by AKI and could be warning sign of a potential bacterial infection.

Impact of Procalcitonin Guidance with an Educational Program on Management of Adults Hospitalized with Pneumonia

BACKGROUND

Community-acquired pneumonia and healthcare-associated pneumonia are often treated with prolonged antibiotic therapy. Procalcitonin (PCT) has effectively and safely reduced antibiotic use for pneumonia in controlled studies. However, limited data exist regarding PCT guidance in real-world settings for management of pneumonia.

METHODS

A retrospective, preintervention/postintervention study was conducted to compare management for patients admitted with pneumonia before and after implementation of PCT guidance at 2 teaching hospitals in Pittsburgh, Pennsylvania. The preintervention period was March 1, 2014 through October 31, 2014, and the postintervention period was March, 1 2015 through October 31, 2015.

RESULTS

A total of 152 and 232 patients were included in the preintervention and postintervention cohorts, respectively. When compared with the preintervention group, mean duration of therapy decreased (9.9 vs 6.0 days; P < .001). More patients received an appropriate duration of 7 days or less (26.9% vs 66.4%; P < .001). Additionally, mean hospital length of stay decreased in the postintervention group (4.9 vs 3.5 days; P = .006). Pneumonia-related 30-day readmission rates (7.2% vs 4.3%; P = .26) were unaffected. In the postintervention group, patients with PCT levels <0.25 µg/L received shorter mean duration of therapy compared with patients with levels >0.25 µg/L (4.6 vs 8.0 days; P < .001), as well as reduced hospital length of stay (3.2 vs 3.9 days; P = .02).

CONCLUSIONS

In this real-world study, PCT guidance led to shorter durations of total antibiotic therapy and abridged inpatient length of stay without affecting hospital readmissions.

Role of Single Procalcitonin Test on Admission as a Biomarker for Predicting the Severity of Clostridium difficile Infection

Objective: To evaluate whether serum Procalcitonin (PCT) at the early stage of infection can serve as a potential biomarker for determining Clostridium difficile infection (CDI) severity.

Methods: Fifty-four patients diagnosed with CDI were enrolled in the study. Serum samples were obtained within a median time of 24–48 h of the lab result for presence of C. difficile. PCT levels were measured by chemiluminescence immunoassay. Demographic, clinical, and prognostic data concerning the patients were retrospectively collected from medical records. The illness severity score was determined according to “Score indices for C. difficile infection severity.”

Results: We found that serum PCT levels were significantly higher in patients with moderate disease, compared to patients with mild disease (p = 0.0032). Additionally, PCT was correlated with mortality (p = 0.0002), white blood cell count (p = 0.019), and community-acquired disease (p = 0.0345).

Conclusion: Early measurement of PCT may serve as a biomarker for early prediction of CDI severity, which is of great importance due to the high risk of complications and death.

Prognostic performance of MR-pro-adrenomedullin in patients with community acquired pneumonia in the Emergency Department compared to clinical severity scores PSI and CURB

AIM

(i) evaluate the performance of MR-pro-ADM in reflecting the outcome and risk for CAP patients in the emergency department, and (ii) compare the prognostic performance of MR-pro-ADM with that of clinical scores PSI and CURB65.

METHODS

Observational prospective, single-center study in patients with suspected community acquired pneumonia (CAP). Eighty one patients underwent full clinical and laboratory assessment as by protocol, and were followed up a 28 days. Primary endpoints measured were: death, death at 14 days, non-invasive mechanical ventilation (NIMV), endotracheal intubation (EI), ICU admission, overall hospital stay >10 days, emergency department stay >4 days. The discriminative performance of MR-pro-ADM and clinical scores was assessed by AUROC analysis.

RESULTS

The distribution for MR-pro-ADM followed an upward trend, increasing with the increase of both PSI (p<0.001) and CURB65 (p<0.001) classes. However, the difference between MRproADM values and score classes was significant only in the case of CURB65 classes 0 and 1 (p = 0.046), 2 (p = 0.013), and 3 (p = 0.011); and with PSI classes 5, 3 (p = 0.044), and 1 (p = 0.020). As to the differences among variables for the six end-points, MR-pro-ADM values in the two groups selected for each considered end-point differed in a statistically significant manner for all endpoints. Both PSI and CURB65 differed significantly for all end-points, except for stay in the ED longer than 4 days and the hospital stay longer than 10 days and endotracheal intubation (only PSI classes differed with statistical significance). ROC analyses evidenced that MR-pro-ADM values gave the greatest AUC for the prediction of death, endotracheal intubation, hospital stay >10 days and DE stay >4 days, compared to the PSI and CURB (though difference not statistically significant). For each endpoint measured, the best thresholds values for Mr-pro-ADM were: 1.6 (specificity 76.5%; sensitivity 77.8%) for death; 2.5 (specificity 88.9%; sensitivity 80.0%) for death at 14 days; 1.5 (specificity 77.0%; sensitivity 87.5%) for NIMV; 2.4 (specificity 88.7%; sensitivity 83.3%) for endotracheal intubation; 0.9 (specificity 53.5%; sensitivity 70.6%) for DE stay greater than 4 days; 1.9 (specificity 82.1%; sensitivity 55.3%) for hospital stay greater than 10 days. The AUC for the combination of MR-pro-ADM and PSI was 81.29% [63.41%-99.17%], but not in a statistically significant manner compared to the AUCs of the single predictors. Conversely, the AUC for the combination of MR-pro-ADM and CURB65 was 87.58% [75.54%-99.62%], which was significantly greater than the AUC of CURB65 (p = 0.047) or PSI (p = 0.017) alone.

CONCLUSIONS

The present study confirms that assessment of MR-pro-ADM levels in CAP patients in addition to CURB scores increases the prognostic accuracy of CURB alone and may help rule out discrepancies arising from flawed clinical severity classification. With particular reference to patients scoring in the upper classes of CURB and PSI, MR-pro-ADM values provided additional information towards a better risk stratification of those patients. In particular, our results pointed towards two MR-pro-ADM threshold values that appear to predict with a good degree of accuracy the patient's need for non-invasive mechanical ventilation, endotracheal intubation, or intensive care. This aspect, however, deserves further investigation.

Effect of procalcitonin-guided antibiotic treatment on mortality in acute respiratory infections: a patient level meta-analysis

BACKGROUND

In February, 2017, the US Food and Drug Administration approved the blood infection marker procalcitonin for guiding antibiotic therapy in patients with acute respiratory infections. This meta-analysis of patient data from 26 randomised controlled trials was designed to assess safety of procalcitonin-guided treatment in patients with acute respiratory infections from different clinical settings.

METHODS

Based on a prespecified Cochrane protocol, we did a systematic literature search on the Cochrane Central Register of Controlled Trials, MEDLINE, and Embase, and pooled individual patient data from trials in which patients with respiratory infections were randomly assigned to receive antibiotics based on procalcitonin concentrations (procalcitonin-guided group) or control. The coprimary endpoints were 30-day mortality and setting-specific treatment failure. Secondary endpoints were antibiotic use, length of stay, and antibiotic side-effects.

FINDINGS

We identified 990 records from the literature search, of which 71 articles were assessed for eligibility after exclusion of 919 records. We collected data on 6708 patients from 26 eligible trials in 12 countries. Mortality at 30 days was significantly lower in procalcitonin-guided patients than in control patients (286 [9%] deaths in 3336 procalcitonin-guided patients vs 336 [10%] in 3372 controls; adjusted odds ratio [OR] 0·83 [95% CI 0·70 to 0·99], p=0·037). This mortality benefit was similar across subgroups by setting and type of infection (p_interactions>0·05), although mortality was very low in primary care and in patients with acute bronchitis. Procalcitonin guidance was also associated with a 2·4-day reduction in antibiotic exposure (5·7 vs 8·1 days [95% CI -2·71 to -2·15], p<0·0001) and a reduction in antibiotic-related side-effects (16% vs 22%, adjusted OR 0·68 [95% CI 0·57 to 0·82], p<0·0001).

INTERPRETATION

Use of procalcitonin to guide antibiotic treatment in patients with acute respiratory infections reduces antibiotic exposure and side-effects, and improves survival. Widespread implementation of procalcitonin protocols in patients with acute respiratory infections thus has the potential to improve antibiotic management with positive effects on clinical outcomes and on the current threat of increasing antibiotic multiresistance.

FUNDING

National Institute for Health Research.

Procalcitonin in heart failure: hic et nunc

Although procalcitonin (PCT) was evaluated for the first time in the setting of heart failure (HF) in 1999, its utility in HF patients is still under examination. Patients with HF have significantly higher plasma PCT concentrations than healthy subjects and PCT levels are associated with severity of HF. It has been confirmed that higher levels of PCT are associated with worse outcomes, such as increased mortality and higher rate of rehospitalization, in HF patients with no evidence of infection. Furthermore, it has been approved that PCT-guided antibiotic treatment in HF patients reduces duration of antibiotic therapy and improves outcomes. This review summarizes current evidence from the published literature of the usefulness and limitations of PCT as a biomarker in HF.

Drivers of antibiotic prescribing in children and adolescents with febrile lower respiratory tract infections

BACKGROUND

Knowledge of key drivers for antibiotic prescribing in pediatric lower respiratory tract infection (LRTI) could support rational antibiotic use. Thus, we aimed to determine the impact of clinical and laboratory factors on antibiotic prescribing in children and adolescents with febrile LRTI.

METHODS

Pediatric patients from the standard care control group of a randomized controlled trial (ProPAED) investigating procalcitonin guided antibiotic treatment in febrile LRTI were included in a multivariate logistic regression analysis to evaluate the impact of laboratory and clinical factors on antibiotic prescribing.

RESULTS

The standard care control group of the ProPAED study comprised 165 LRTI patients (median age: 2.7 years, range: 0.1-16), out of which 88 (55%) received antibiotic treatment. Factors significantly associated with antibiotic prescribing in patients with complete clinical and laboratory documentation (n = 158) were C-reactive protein (OR 5.8 for a 10-fold increase, 95%CI 2.2-14.9), white blood count beyond age-dependent reference range (OR 3.9, 95%CI 1.4-11.4), body temperature (OR 1.7 for an increase by 1°C, 95%CI 1.02-2.68), and pleuritic pain (OR 2.8, 95%CI 1.1-7.6). Dyspnea (OR 0.3, 95%CI 0.1-0.7) and wheezing (OR 0.3, 95%CI 0.13-0.95) were inversely associated with antibiotic prescribing.

CONCLUSION

Laboratory markers were strong drivers of antibiotic prescribing in children with febrile lower respiratory tract infections, in spite of their known poor prediction of antibiotic need. Building on current guidelines for antibiotic treatment in children with febrile LRTI, a reliable decision algorithm for safe antibiotic withholding considering the laboratory and clinical factors evaluated in this study has the potential to further reduce antibiotic prescribing.

Bacteria in the respiratory tract-how to treat? Or do not treat?

BACKGROUND

Acute and chronic respiratory tract infections are a common cause of inappropriate antimicrobial prescription. Antimicrobial therapy leads to the development of resistance and the emergence of opportunistic pathogens that substitute the indigenous microbiota.

METHODS

This review explores the major challenges and lines of research to adequately establish the clinical role of bacteria and the indications for antimicrobial treatment, and reviews novel therapeutic approaches.

RESULTS

In patients with chronic pulmonary diseases and structural disturbances of the bronchial tree or the lung parenchyma, clinical and radiographic signs and symptoms are almost constantly present, including a basal inflammatory response. Bacterial adaptative changes and differential phenotypes are described, depending on the clinical role and niche occupied. The respiratory tract has areas that are potentially inaccessible to antimicrobials. Novel therapeutic approaches include new ways of administering antimicrobials that may allow intracellular delivery or delivery across biofilms, targeting the functions essential for infection, such as regulatory systems, or the virulence factors required to cause host damage and disease. Alternatives to antibiotics and antimicrobial adjuvants are under development.

CONCLUSIONS

Prudent treatment, novel targets, and improved drug delivery systems will contribute to reduce the emergence of antimicrobial resistance in lower respiratory tract infections.

Comparison of Procalcitonin Guidance-Administered Antibiotics with Standard Guidelines on Antibiotic Therapy in Children with Lower Respiratory Tract Infections: A Retrospective Study in China

OBJECTIVE

To establish the efficacy of an algorithm based on the biomarker procalcitonin (PCT) to reduce antibiotic exposure in pediatric patients with lower respiratory tract infection (LRTI).

MATERIALS AND METHODS

The clinical data of 357 patients (<14 years of age) who were discharged home with LRTI from January 1, 2010 to July 31, 2016 were analyzed. Antibiotic exposure, antibiotic prescription rate, length of hospital stay, and antibiotic-associated adverse effects were compared between the PCT group (n = 183) and the standard group (n = 174) using SAS 9.1.3 software.

RESULTS

The overall adverse effect rates were similar in both the PCT and standard groups: 42 (22.95%) and 51 (29.31%), respectively. The length of hospital stay was not significantly different between the PCT (9.96 ± 5.81 days) and standard groups (10.58 ± 4.24 days) (difference: -0.62%; 95% CI: -1.68 to 0.43). Antibiotic prescribing rates were significantly different in the PCT group compared to the standard group: 54.64% versus 83.91% (difference: -29.26%; 95% CI: -38.31, -20.22; p = 0.23). Mean duration of antibiotic exposure in the PCT group (3.98 ± 2.17 days) was lower than the standard groups (6.66 ± 5.59 days) (difference: -2.68%; 95% CI: -3.21 to -2.16).

CONCLUSION

This study showed that PCT guidance of antibiotic treatment in children and adolescents with LRTI reduced the duration of antibiotic exposure and antibiotic prescribing rates, but did not affect the adverse effect rate and length of hospital stay.

An update on the pharmacotherapeutic management of lower respiratory tract infections

INTRODUCTION

Our knowledge about lower respiratory tract infections (LRTIs) has improved substantially in the last years, but the management of respiratory infections is still a challenge and we are still far from using precision medicine in their treatment. Areas covered: The approaches developed in recent years to improve the pharmacotherapeutic management of LRTIs, such as novel diagnostic assays to facilitate medical decision-making, attempts for selecting an optimal empiric antibiotic regimen, and the role of new and possibly unproven adjunctive therapies, are described. Expert opinion: Early and appropriate antibiotics remain the cornerstone in the treatment of LRTIs. The updated trend is to apply antimicrobial stewardship principles and initiatives to optimize both the management and the outcomes of LTRIs. Biomarkers, mainly C-reactive protein (CRP) and procalcitonin (PCT), can improve the diagnostic and prognostic assessment of LRTIs and aid to guide antibiotic therapy. The widespread use of antimicrobial agents has greatly contributed to faster development of antibiotic resistance and the emergence of opportunistic pathogens, which substitute the indigenous microbiota. However, very few new antibiotics in development to overcome existing resistance and ensure continued success in the treatment of LRTIs have been approved, likely because antibiotic stewardship programs discourage the use of new agents.