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

Therapeutic Drug Monitoring and Biomarkers; towards Better Dosing of Antimicrobial Therapy

Due to variability in pharmacokinetics and pharmacodynamics, clinical outcomes of antimicrobial drug therapy vary between patients. As such, personalised medication management, considering both pharmacokinetics and pharmacodynamics, is a growing concept of interest in the field of infectious diseases. Therapeutic drug monitoring is used to adjust and individualise drug regimens until predefined pharmacokinetic exposure targets are achieved. Minimum inhibitory concentration (drug susceptibility) is the best available pharmacodynamic parameter but is associated with many limitations. Identification of other pharmacodynamic parameters is necessary. Repurposing diagnostic biomarkers as pharmacodynamic parameters to evaluate treatment response is attractive. When combined with therapeutic drug monitoring, it could facilitate making more informed dosing decisions. We believe the approach has potential and justifies further research.

Evaluation of Serial Procalcitonin Levels for the Optimization of Antibiotic Use in Non-Critically Ill COVID-19 Patients

BACKGROUND

Procalcitonin (PCT) has been used as a biomarker to guide antibiotic therapy in various patient populations. However, its role in optimizing antibiotic use in COVID-19 patients has not been well studied to date. Thus, we aimed to evaluate the use of serial PCT monitoring as an antimicrobial stewardship tool for COVID-19 patients.

METHODS

This retrospective study included 240 COVID-19 patients who were admitted to a tertiary medical institution in Saudi Arabia between January 2020 and February 2022. Patients who received empiric antibiotic therapy for community-acquired pneumonia (CAP) and had serial procalcitonin levels were included. The patients were divided into two groups: the normal procalcitonin arm (PCT level < 0.5 ng/mL) and the elevated PCT arm (PCT level > 0.5 ng/mL). The primary and secondary outcomes were the effect of PCT monitoring on the duration of antibiotic exposure and the length of hospital stay, respectively. To measure the accuracy of PCT, the receiver-operating characteristic area under the curve (ROC-AUC) was determined.

RESULTS

Among the included patients, 142 were in the normal procalcitonin arm (median PCT, 0.12 ng/mL), and 78 were in the elevated PCT arm (median PCT, 4.04 ng/mL). The baseline characteristics were similar between the two arms, except for the higher prevalence of kidney disease in the elevated PCT arm. There was no statistically significant difference in the duration of antibiotic exposure between the normal and elevated PCT arms (median duration: 7 days in both arms). However, the length of hospital stay was significantly shorter in the normal PCT arm (median stay, 9 days) than in the elevated PCT arm (median stay, 13 days; p = 0.028). The ROC-AUC value was 0.54 (95% CI: 0.503-0.595).

CONCLUSIONS

Serial PCT monitoring did not lead to a reduction in the duration of antibiotic exposure in COVID-19 patients. However, it was associated with a shorter hospital stay. These findings suggest that PCT monitoring may be useful for optimizing antibiotic use and improving outcomes in COVID-19 patients. While PCT-guided algorithms have the potential to enable antibiotic stewardship, their role in the context of COVID-19 treatment requires further investigation.

Prognostic value of procalcitonin in patients with cirrhosis hospitalized for acute infection

BACKGROUND

In patients with cirrhosis, infections significantly increase the risk of short and long-term mortality. During infection, the levels of procalcitonin increase, but it has not yet been clarified its prognostic value in subjects with cirrhosis. Therefore, the aim of this study was to evaluate the prognostic role of procalcitonin in patients with liver cirrhosis hospitalized for acute infection, and to compare it with other markers of infection.

PATIENTS

We included 279 patients hospitalized because of infection, 133 with liver cirrhosis. At admission the levels of the main biochemical parameters of infection, i.e. leukocytes, procalcitonin, C reactive protein and lactate, were considered.

RESULTS

The duration of hospitalization and antibiotic therapy were longer in patients with cirrhosis, while no difference was observed for mortality. In both groups, a correlation with the duration of hospitalization and antibiotic therapy was observed for high levels of procalcitonin. In the cirrhotic population, in particular, higher procalcitonin values were associated with an increase in the length of hospitalization and antibiotic therapy, suggesting an even greater predictive value for those patients. High levels of leucocytes and lactate were positively associated with the duration of hospitalization, but not with the duration of antibiotic therapy. For mortality, the strongest correlation was found for high serum lactate levels, regardless of the presence of cirrhosis.

CONCLUSION

In patients with cirrhosis and acute infection, the value of procalcitonin at admission is a good prognostic indicator for the course of hospitalization, and could be useful for guiding the management and treatment of hospitalized patients.

Clinical benefits of therapeutic drug monitoring of vancomycin therapy in patients with postoperative intracerebral hemorrhage: a retrospective cohort study

OBJECTIVE

The objective of this study was to investigate the clinical efficacy and safety of conducting therapeutic drug monitoring (TDM) of vancomycin in patients with postoperative intracerebral haemorrhage.

METHODS

We conducted a retrospective analysis of 435 patients who experienced postoperative cerebral haemorrhage and were treated with vancomycin in the Department of Neurosurgery of Inner Mongolia Autonomous Region People's Hospital from January 2017 to December 2021. Patients were then matched using the propensity score matching method in a ratio of 1:1. Ninety-two pairs of cases were successfully matched, and the data before and after performing vancomycin TDM were analysed.

RESULTS

After PSM, the baseline data of the two groups were balanced. There were no significant differences in the 14-day mortality and length of hospital stay (p>0.05) between the two groups. Compared with the non-TDM group, the TDM group had a higher proportion of patients with normal white blood cells (83.7% vs 56.5%, p=0.000), neutrophil count (57.6% vs 25.0%, p=0.000) and attaining desirable reductions of 80% in procalcitonin (65.2% vs 10.9%, p=0.000) and C-reactive protein (78.3% vs 41.3%, p=0.000) levels. At US$15.82 per additional TDM, TDM significantly promoted patient outcomes, as seen in improvements in the proportion of patients attaining desirable levels of white blood cells, neutrophil count, procalcitonin and C-reactive protein.

CONCLUSIONS

Vancomycin TDM is a safe and effective approach for the treatment of patients with postoperative intracerebral haemorrhage. The empirical use of TDM of vancomycin significantly improved normal values of white blood cells and neutrophil count, achieved desirable reductions of 80% in procalcitonin and C-reactive protein, and reduced nephrotoxicity in patients with postoperative intracerebral haemorrhage.

Prognosis prediction of procalcitonin within 24 h for acute diquat poisoning

BACKGROUND

To explore the predictive value of procalcitonin (PCT) within 24 h after poisoning for prognosis of acute diquat poisoning.

METHODS

This retrospective study included acute diquat poisoning patients in the Nanyang City Hospital between May 2017 and July 2021.

RESULTS

Among the 45 patients included, 27 survived. The maximum PCT value within 24 h after poisoning was significantly higher in the non-survival patients [9.65 (2.63, 22.77) vs. 0.15 (0.10, 0.50) µg/mL, P < 0.001] compared to the survival patients. The area under the ROC curve (AUC) indicated that the maximum PCT value within 24 h had a good predictive value (AUC = 0.905, 95% CI: 0.808-1.000) compared to ingested quantity (AUC = 0.879, 95% CI: 0.776-0.981), serum creatinine (AUC = 0.776, 95% CI: 0.640-0.912), or APACHE II score (AUC = 0.778, 95% CI: 0.631-0.925). The predictive value of maximum PCT value within 24 h was comparable with blood lactate (AUC = 0.904, 95%CI: 0.807-1.000).

CONCLUSIONS

The maximum PCT value within 24 h after poisoning might be a good predictor for the prognosis of patients with acute diquat poisoning.

Association of biomarkers with successful ventilatory weaning in COVID-19 patients: an observational study

OBJECTIVE

To evaluate the association of biomarkers with successful ventilatory weaning in COVID-19 patients.

METHODS

An observational, retrospective, and single-center study was conducted between March 2020 and April 2021. C-reactive protein, total lymphocytes, and the neutrophil/lymphocyte ratio were evaluated during attrition and extubation, and the variation in these biomarker values was measured. The primary outcome was successful extubation. ROC curves were drawn to find the best cutoff points for the biomarkers based on sensitivity and specificity. Statistical analysis was performed using logistic regression.

RESULTS

Of the 2,377 patients admitted to the intensive care unit, 458 were included in the analysis, 356 in the Successful Weaning Group and 102 in the Failure Group. The cutoff points found from the ROC curves were -62.4% for C-reactive protein, +45.7% for total lymphocytes, and -32.9% for neutrophil/lymphocyte ratio. These points were significantly associated with greater extubation success. In the multivariate analysis, only C-reactive protein variation remained statistically significant (OR 2.6; 95%CI 1.51 - 4.5; p < 0.001).

CONCLUSION

In this study, a decrease in C-reactive protein levels was associated with successful extubation in COVID-19 patients. Total lymphocytes and the neutrophil/lymphocyte ratio did not maintain the association after multivariate analysis. However, a decrease in C-reactive protein levels should not be used as a sole variable to identify COVID-19 patients suitable for weaning; as in our study, the area under the ROC curve demonstrated poor accuracy in discriminating extubation outcomes, with low sensitivity and specificity.

Development of quality indicators for antimicrobial stewardship in Belgian hospitals: a RAND - modified Delphi procedure

INTRODUCTION

Inappropriate antibiotic use is a major cause of antibiotic resistance. Therefore, optimizing antibiotic usage is essential. In Belgium, optimization of antimicrobials for the fight against multidrug resistant organisms (MDROs) is followed up by national surveillance by public health authorities. To improve appropriate antimicrobial use in hospitals, an effective national Antimicrobial Stewardship (AMS) program should include indicators for measuring both the quantity and quality of antibiotic use.

OBJECTIVES

The aim of this study was to develop a set of process quality indicators (QIs) to evaluate and improve AMS in hospitals.

METHODS

A RAND-modified Delphi procedure was used. The procedure consisted of a structured narrative literature review to select the QIs, followed by two online questionnaires and an intermediate multidisciplinary panel discussion with experts in infectious diseases from general and teaching hospitals in Belgium.

RESULTS

A total of 38 QIs were selected after the RAND-modified Delphi procedure, from which 11 QIs were selected unanimously. These QIs address compliancy of antibiotic therapy and prophylaxis with local guidelines, documentation of the rationale for antibiotic treatment in the medical record, the availability of AMS Programs and Outpatient Parenteral Antibiotic Therapy, resistance patterns and antimicrobial prescribing during focused ward rounds.

CONCLUSION

Our study selected 38 relevant process QIs, from which 11 were unanimously selected. The QIs can contribute to the improvement of quality of antibiotic use by stimulating hospitals to present better outcomes and by providing a focus on how to intervene and to improve prescribing of antimicrobials.

Detection and Analysis of Commonly Used Infection Indicators in Patients with Acute Urticaria

INTRODUCTION

In this study, we investigated the correlation and clinical significance of peripheral blood leukocytes, neutrophils, C-reactive protein (CRP), and procalcitonin (PCT) in patients with acute urticaria.

METHODS

Complete blood count with differential, CRP, and PCT tests were conducted on patients with acute urticaria. A total of 614 patients with acute urticaria were divided into three groups: the first group consisted of patients with elevated leukocyte and neutrophil count, the second group consisted of patients with normal leukocyte and neutrophil count, and the third group consisted of patients with abnormal leukocyte and neutrophil count. A correlation analysis was conducted to investigate the levels of leukocytes, neutrophils, CRP, and PCT in the three groups.

RESULTS

The results of Kruskal-Wallis' nonparametric test revealed statistically significant variations in leukocytes, neutrophils, CRP, and PCT among the three groups (p < 0.001). However, CRP and PCT showed no statistically significant differences between the second and third groups (p < 0.001, p = 0.0041, p = 0.0032). Additional multiple comparisons in Spearman correlation analysis indicated statistically significant differences (p = 0.55). Across all groups, there was a statistically significant difference in the correlation between CRP-PCT and leukocytes-neutrophils (p = 0.53).

CONCLUSION

Leukocytes and neutrophils are sensitive to the impact of medications and stress on the body. Combining CRP and PCT, as well as routine blood test, may be a comprehensive assessment of infection presence and severity in patients, providing guidance for antibiotic treatment.

A machine learning strategy to mitigate the inappropriateness of procalcitonin request in clinical practice

Aim

The aim of this study was to develop machine learning (ML) models to mitigate the inappropriate request of Procalcitonin (PCT) in clinical wards.

Material and methods

We built six different ML models based on both demographical data, i.e., sex and age, and laboratory parameters, i.e., cell blood count (CBC) parameters, inclusive of monocyte distribution width (MDW), and C-reactive protein (CRP). The dataset included 1667 PCT measurements of different patients. Based on a PCT cut-off of 0.50 ng/mL, we found 1090 negative (65.4%) and 577 positive (34.6%) results. We performed a 70:15:15 train:validation:test splitting based on the outcome.

Results

Random Forest, Support Vector Machine and eXtreme Gradient Boosting showed optimal performances for predicting PCT positivity, with an area under the curve ranging from 0.88 to 0.89.

Conclusions

The ML models developed could represent a useful tool to predict PCT positivity, avoiding unusefulness PCT requests. ML models are based on laboratory tests commonly ordered together with PCT but have the great advantage to be easy to measure and low-cost.

Exploring the Impact of Model-Informed Precision Dosing on Procalcitonin Concentrations in Critically Ill Patients: A Secondary Analysis of the DOLPHIN Trial

Model-informed precision dosing (MIPD) might be used to optimize antibiotic treatment. Procalcitonin (PCT) is a biomarker for severity of infection and response to antibiotic treatment. The aim of this study was to assess the impact of MIPD on the course of PCT and to investigate the association of PCT with pharmacodynamic target (PDT) attainment in critically ill patients. This is a secondary analysis of the DOLPHIN trial, a multicentre, open-label, randomised controlled trial. Patients with a PCT value available at day 1 (T1), day 3 (T3), or day 5 (T5) after randomisation were included. The primary outcome was the absolute difference in PCT concentration at T1, T3, and T5 between the MIPD and the standard dosing group. In total, 662 PCT concentrations from 351 critically ill patients were analysed. There was no statistically significant difference in PCT concentration between the trial arms at T1, T3, or T5. The median PCT concentration was highest in patients who exceeded 10× PDT at T1 [13.15 ng/mL (IQR 5.43-22.75)]. In 28-day non-survivors and in patients that exceeded PDT at T1, PCT decreased significantly between T1 and T3, but plateaued between T3 and T5. PCT concentrations were not significantly different between patients receiving antibiotic treatment with or without MIPD guidance. The potential of PCT to guide antibiotic dosing merits further investigation.

Bacterial infections in patients with COVID-19: the impact of procalcitonin testing on antibiotics prescription in the real world

BACKGROUND

Bacterial infections are not prevalent among patients hospitalized with COVID-19, while unnecessary prescription of antibiotics was commonly observed. This study aimed to determine the impact of procalcitonin testing on antibiotics prescription in the real-world setting.

METHODS

We performed a territory-wide retrospective cohort study involving all laboratory-confirmed patients hospitalized in public hospitals in Hong Kong in 2020 with COVID-19. We determined the prevalence of bacterial co-infections (documented infections within 72 h of admission) and secondary bacterial infections (infections after 72 h of admission) and antibiotics consumption, and the correlation between procalcitonin testing and antibiotics prescription.

RESULTS

The cohort included 8666 patients, with mean age 45.3 ± 19.9 years, 48.5% male, and comorbidities in 26.9%. Among 2688 patients with bacterial cultures performed, 147 (5.5%) had bacterial co-infections, and 222 (8.3%) had secondary bacterial infections. Antibiotics were prescribed for 2773 (32.0%) patients during the hospital admission. Procalcitonin tests were performed for 2543 (29.3%) patients. More patients with procalcitonin testing received antibiotics (65.9% vs. 17.9%, p < 0.001). Procalcitonin testing was associated with 5-fold increased risk of antibiotics prescription after adjusting for confounding variables. At hospital level, procalcitonin testing correlated with antibiotics prescription. Patients with procalcitonin level < 0.5 ng/mL had a lower probability of antibiotics initiation and shorter duration of antibiotics therapy.

CONCLUSIONS

Procalcitonin testing was not associated with lower prescription of antibiotics. Patients with low procalcitonin level had lower antibiotics exposure, supporting the use of procalcitonin to exclude bacterial infections aiding early stopping of antibiotics among patients hospitalized with COVID-19.

Clinical utility of procalcitonin in implementation of procalcitonin-guided antibiotic stewardship in the South-East Asia and India: evidence and consensus-based recommendations

INTRODUCTION

The South-East Asian (SEA) region and India are highly susceptible to antibiotic resistance, which is caused due to lack of antimicrobial stewardship (AMS) knowledge, uncontrolled use of antibiotics, and poor infection control. Nonadherence to national/local guidelines, developed to combat antimicrobial resistance, is a major concern. A virtual advisory board was conducted to understand the current AMS standards and challenges in its implementation in these regions.

AREAS COVERED

Procalcitonin (PCT)-guided antibiotic use was discussed in various clinical conditions across initiation, management, and discontinuation stages. Most experts strongly recommended using PCT-driven antibiotic therapy among patients with lower respiratory tract infections, sepsis, and COVID-19. However, additional research is required to understand the optimal use of PCT in patients with organ transplantation and cancer patients with febrile neutropenia. Implementation of the solutions discussed in this review can help improve PCT utilization in guiding AMS in these regions and reducing challenges.

EXPERT OPINION

Experts strongly support the inclusion of PCT in AMS. They believe that PCT in combination with other clinical data to guide antibiotic therapy may result in more personalized and precise targeted antibiotic treatment. The future of PCT in antibiotic treatment is promising and may result in effective utilization of this biomarker.

Special Issue "Clinical Consequences of COVID-19": Taking a Look at Complexity

The consequences of SARS-CoV-2 infection are far from being fully understood or accounted for [...].

Procalcitonin Guided Antibiotic Stewardship in Pediatric Sepsis and Lower Respiratory Tract Infections

OBJECTIVES

To determine the impact of procalcitonin-guided antibiotic stewardship protocol (PCT-ASP) in children admitted with sepsis and lower respiratory tract infection on the duration of antibiotic therapy and clinical outcome.

METHODS

This was a single-center study involving children with infections treated with antibiotic therapy according to the PCT-ASP as the study group. The control group consisted of children with same age and diagnosis who were treated with antibiotics according to individual unit protocol before the implementation of PCT-ASP. The primary outcome was median duration of antibiotic therapy and hospital stay.

RESULTS

Among 127 patients, 66 were enrolled in the study and 61 in the control group respectively. The median (IQR) PCT values at admission, day 4 and day 6 of antibiotic therapy were 5.59 (61.3), 2.57 (47.35), and 0.35 (0.47) ng/ml respectively, and showed a decreasing trend. All the children in the control group received antibiotics at admission while 12% of children in the study group were not initiated on antibiotics. In the study group, 53% of the children received antibiotics only for three days in the absence of treatment failure. The duration of antibiotics (p = 0.001) and hospital stay (p = 0.03) were less in the study group when compared to the control group.

CONCLUSIONS

PCT-ASP reduces the duration of antibiotics and duration of hospital stay without increasing morbidity and mortality.

Effect of early antibiotic treatment strategy on prognosis of acute pancreatitis

BACKGROUND

Antibiotic use in the early stages of acute pancreatitis is controversial. The purpose of this study was to investigate the effect of early antibiotic application on the prognosis of acute pancreatitis (AP).

MATERIALS AND METHODS

Clinical data of patients with primary AP admitted to our emergency ward within 72 hours of onset were retrospectively collected from January 2016 to December 2020. We classified patients with acute pancreatitis according to etiology and disease severity, and compared the differences in hospital stay, laparotomy rate, and in-hospital mortality among AP patients who received different antibiotic treatment strategies within 72 hours of onset.

RESULTS

A total of 1134 cases were included, with 681 (60.1%) receiving early antibiotic treatment and 453 (39.9%) not receiving it. There were no significant differences in baseline values and outcomes between the two groups. In subgroup analysis, patients with biliary severe acute pancreatitis (SAP) who received early antibiotics had lower rates of laparotomy and invasive mechanical ventilation, as well as shorter hospital stays compared to those who did not receive antibiotics. In logistic regression analysis, the early administration of carbapenem antibiotics in biliary SAP patients was associated with a lower in-hospital mortality rate. Early antibiotic use in biliary moderate-severe acute pancreatitis (MSAP) reduced hospital stays and in-hospital mortality. Quinolone combined with metronidazole treatment in biliary mild acute pancreatitis (MAP) shortened hospital stays. Early antibiotic use does not benefit patients with non-biliary AP.

CONCLUSION

Strategies for antibiotic use in the early stages of AP need to be stratified according to cause and disease severity.

Prevention of surgical site infection and sepsis in pregnant obese women

Obesity is a major determinant of health outcomes and is on the increase in women worldwide. It predisposes to surgical site infection (SSI). Risk factors for the SSI include extremes of age, smoking, comorbidities such as hypertension and diabetes, inappropriate vertical abdominal and or uterine wall incisions, increased operating time, subcutaneous layer of 3 cm or more, and unnecessary use of subcutaneous drain. Most bacteria that cause SSIs are human commensals. Common organisms responsible for SSI include Staphylococcus aureus and coliforms such as Proteus mirabilis, and Escherichia coli. A surgeon's gloves post caesarean section in the obese has a preponderance of Firmicutes and Bacteroidetes, which increases SSI risk. The interaction of skin commensals and vaginal microbiome at the surgical incision site increases the risk of SSI in the obese compared to non-obese. Minimizing the risk of SSI involves modification of risk factors, timely treatment of SSI to prevent sepsis and compliance with the recommended care bundles.

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.

Diagnostic Accuracy of Procalcitonin for Infection After Adult Liver Transplantation: A Meta-Analysis and Systematic Review

Background: Post-operative infection remains a major cause of morbidity and mortality in adults early after liver transplantation (LT). Procalcitonin (PCT) may be a good test method for early diagnosis of post-operative infection and determining its severity. This study was performed to assess the diagnostic accuracy of PCT as a biomarker for infection after LT. Patients and Methods: A meta-analysis and systematic review was conducted for studies reporting diagnostic performance of PCT for infection in adults after LT. Observational studies were evaluated for their reporting of diagnostic accuracy, relevance, and quality. Results: Ten eligible studies assessing 730 patients were included in this meta-analysis and systematic review summarizing the diagnostic value of PCT for post-operative infection in adult liver transplantation. Pooled sensitivity and specificity with corresponding 95% confidence interval were 69% (95% confidence interval [CI], 54-81; heterogeneity I2 = 82.4%) and 88% (95% CI, 82-92; I2 = 52.7%), respectively. The diagnostic odd ratio (DOR) was 16 (95% CI, 10-25; I2 = 76.4%). The summary receiver operator characteristic (SROC) of PCT for post-operative infection was 0.88. There was a wide range of variability in the cutoff values, ranging from 0.22 to 42.80 ng/mL. Heterogeneity was reduced by excluding studies that focused on pediatric LT recipients. Conclusions: Procalcitonin is a moderately accurate diagnostic marker for post-operative infection in adult LT. Additionally, the diagnostic performance can be improved by combining it with other inflammatory biomarkers. This article provides the research direction for post-operative infection control.

Reliability of Admission Procalcitonin Testing for Capturing Bacteremia Across the Sepsis Spectrum: Real-World Utilization and Performance Characteristics, 65 U.S. Hospitals, 2008-2017

OBJECTIVES

Serum procalcitonin is often ordered at admission for patients with suspected sepsis and bloodstream infections (BSIs), although its performance characteristics in this setting remain contested. This study aimed to evaluate use patterns and performance characteristics of procalcitonin-on-admission in patients with suspected BSI, with or without sepsis.

DESIGN

Retrospective cohort study.

SETTING

Cerner HealthFacts Database (2008-2017).

PATIENTS

Adult inpatients (≥ 18 yr) who had blood cultures and procalcitonin drawn within 24 hours of admission.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Testing frequency of procalcitonin was determined. Sensitivity of procalcitonin-on-admission for detecting BSI due to different pathogens was calculated. Area under the receiver operating characteristic curve (AUC) was calculated to assess discrimination by procalcitonin-on-admission for BSI in patients with and without fever/hypothermia, ICU admission and sepsis defined by Centers for Disease Control and Prevention Adult Sepsis Event criteria. AUCs were compared using Wald test and p values were adjusted for multiple comparisons. At 65 procalcitonin-reporting hospitals, 74,958 of 739,130 patients (10.1%) who had admission blood cultures also had admission procalcitonin testing. Most patients (83%) who had admission day procalcitonin testing did not have a repeat procalcitonin test. Median procalcitonin varied considerably by pathogen, BSI source, and acute illness severity. At a greater than or equal to 0.5 ng/mL cutoff, sensitivity for BSI detection was 68.2% overall, ranging between 58.0% for enterococcal BSI without sepsis and 96.4% for pneumococcal sepsis. Procalcitonin-on-admission displayed moderate discrimination at best for overall BSI (AUC, 0.73; 95% CI, 0.72-0.73) and showed no additional utility in key subgroups. Empiric antibiotic use proportions were not different between blood culture sampled patients with a positive procalcitonin (39.7%) and negative procalcitonin (38.4%) at admission.

CONCLUSIONS

At 65 study hospitals, procalcitonin-on-admission demonstrated poor sensitivity in ruling out BSI, moderate-to-poor discrimination for both bacteremic sepsis and occult BSI and did not appear to meaningfully alter empiric antibiotic usage. Diagnostic stewardship of procalcitonin-on-admission and risk assessment of admission procalcitonin-guided clinical decisions is warranted.

Antibiotic use and consumption among medical patients of two hospitals in Sierra Leone: a descriptive report

BACKGROUND

Although one of the main drivers of antimicrobial resistance is inappropriate antibiotic prescribing, there are limited resources to support the surveillance of antibiotic consumption in low-income countries. In this study, we aimed to assess antibiotic use and consumption among medical patients of two hospitals in different geographic regions of Sierra Leone.

METHODS

This is a cross-sectional study of adult (18 years or older) patients receiving medical care at two hospitals (34 Military Hospital-MH and Makeni Government Hospital-MGH) between March 2021 and October 2021. After admission to the medical or intensive care unit, patients were sequentially recruited by a nurse from each hospital. Demographic and clinical characteristics and information on the dose of antibiotics, their routes, and frequency of administration and duration were collected using a questionnaire adapted from previous studies and encrypted in EpiCollect software (Epic, Verona WI). A physician reviews and verifies each completed questionnaire. Data analysis was done using STATA version 16.

RESULTS

The mean age of the 468 patients evaluated in this study was 48.6 years. The majority were women (241, 51.7%) and treated at MGH (245, 52.0%). Clinical diagnosis of bacterial infection was made in only 180 (38.5%) patients. Regardless of the diagnosis, most (442, 94.9%) patients received at least one antibiotic. Of a total 813 doses of antibiotics prescribed by the two hospitals, 424 (52.2%) were administered in MH. Overall, antibiotic consumption was 66.9 defined daily doses (DDDs) per 100 bed-days, with ceftriaxone being the most commonly used antibiotic (277, 34.1%). The ACCESS and WATCH antibiotics accounted for 18.9 DDDs per 100 bed-days (28.2%) and 48.0 DDDs per 100 bed-days (71.7%), respectively. None of the patients were prescribed a RESERVE antibiotics. The antibiotic consumption was lower in MH (61.3 DDDs per 100 bed-days) than MGH (76.5 DDDs per 100 bed-days).

CONCLUSION

Antibiotic consumption was highest with ceftriaxone, followed by levofloxacin and metronidazole. Given the high rate of consumption of antibiotics in the WATCH category of the AWaRe classification, there is a need to initiate surveillance of antibiotic consumption and establish hospital-based antibiotic stewardship in these settings.

Immunoaffinity LC-MS/MS Quantification of the Sepsis Biomarker Procalcitonin Using Magnetic- and Polystyrene-Bead Immobilized Polyclonal Antibodies

Procalcitonin (PCT) is a biomarker for bacterial sepsis, and accurate quantification of PCT is critical for sepsis diagnosis and treatment. Immunological PCT quantification methods are routinely used in clinical laboratories, yet there is a need for harmonization of PCT quantification protocols. An orthogonal method to clinical immunological assays, such as LC-MS/MS, is required. In this study, a highly sensitive and robust immunoaffinity LC-MRM quantitative method for detecting procalcitonin in human serum has been developed. An initial comparison of immunocapture of PCT with a polyclonal anti-PCT antibody immobilized on polystyrene nanoparticles (Latex) and magnetic beads demonstrated superior performance with magnetic beads. Three tryptic PCT peptides from the N- and C-terminal regions of PCT were selected for LC-MS/MS quantification. For PCT quantification, an LLOQ of 0.25 ng/mL of PCT in human serum was achieved using a sample volume of 1 mL. The method's trueness and precision consistently lie within the 15% margin. The parallel measurement of three PCT peptides may allow future differentiation of intact PCT vs other PCT forms originating from potential degradation, processing, or polymorphisms. An established and validated LC-MRM-based quantification of PCT will be relevant as an orthogonal method for harmonization and standardization of clinical assays for PCT.

Procalcitonin Use for Predicting Mortality and Morbidity of Patients Diagnosed With Sepsis Within the Intensive Care Unit

Objective Infections leading to severe sepsis and septic shock are among the top five causes requiring admission to the intensive care unit (ICU). Up to 40% of ICU admissions contain a sepsis diagnosis. Without a clear marker to diagnose and manage sepsis, procalcitonin has been extensively studied for its usefulness in the management of bacterial infections. These studies, however, have been focused toward how it can be used to help guide when antibiotics should be initiated and de-escalated. There, however, has not been a study on how this biomarker could be used to predict mortality, and morbidity and help guide a need for antibiotic escalation. Design A retrospective chart review was conducted on patients admitted to the ICU at Northeast Georgia Medical Center between January 1, 2019, to June 30, 2021. Inclusion criteria were all patients above the age of 18 admitted to the ICU with a diagnosis of sepsis and having at least two procalcitonin drawn within 10 days of each other. Exclusion criteria were any patient with a diagnosis of COVID-19. Data Analysis was conducted to identify how delta procalcitonin could identify mortality and morbidity and if there was any change in antibiotics based on the delta procalcitonin.  Conclusion There was a statistically significant association between a delta positive procalcitonin and increased ICU length of stay. There was no statistical significance in expiration based on the antibiotic change in relationship to delta positive change in procalcitonin.

Decreasing Antibiotic Use in a Community Neonatal Intensive Care Unit: A Quality Improvement Initiative

OBJECTIVE

 In view of the excessive use of antibiotics in our neonatal intensive care unit (NICU), we launched a 5-year multidisciplinary quality improvement (QI) initiative in our NICU in 2018. We had set our aim of decreasing the antibiotic use rate (AUR) from 22 to 17%.

STUDY DESIGN

 The QI initiative was conducted in our 53-bed level 3B NICU. We used the core elements of antibiotic stewardship and focused on improving gaps in knowledge by using updated standards of care and a multidisciplinary approach. Outcome measures included overall AUR in NICU. Statistical control chart (P chart) was used to plot the AUR data quarterly.

RESULTS

 The AUR demonstrated a decline at the onset, and at the end of the initiative the AUR demonstrated a sustained decline to 13.18%, a 40% decrease from the baseline AUR of 22%. The changes that were implemented included development of evidence-based guidelines for babies less than and greater than 35 weeks, daily antibiotic stewardship rounds, sepsis risk calculator, antibiotic stop orders (48-hour stop, 36-hour soft stop, and 36-hour hard stop), and periodic reviews.

CONCLUSION

 Our multidisciplinary approach using all the core elements of an antibiotic stewardship program significantly decreased AUR in our NICU.

KEY POINTS

· Excessive use of antibiotics may cause harm to the infant's health.. · Indiscriminate use of antibiotics can lead to antibiotic resistance.. · Stewardship programs can significantly decrease AUR in NICUs..

Reduced Reliability of Procalcitonin (PCT) as a Biomarker of Bacterial Superinfection: Concerns about PCT-Driven Antibiotic Stewardship in Critically Ill COVID-19 Patients-Results from a Retrospective Observational Study in Intensive Care Units

BACKGROUND

The aim of this study was to assess whether procalcitonin levels is a diagnostic tool capable of accurately identifying sepsis and ventilator-associated pneumonia (VAP) even in critically ill COVID-19 patients.

METHODS

In this retrospective, observational study, all critically ill COVID-19 patients who survived for ≥2 days in a single university hospital and had at least one serum procalcitonin (PCT) value and associated blood culture and/or culture from a lower respiratory tract specimen available were eligible for the study.

RESULTS

Over the research period, 184 patients were recruited; 67 VAP/BSI occurred, with an incidence rate of 21.82 episodes of VAP/BSI (95% CI: 17.18-27.73) per 1000 patient-days among patients who were included. At the time of a positive microbiological culture, an average PCT level of 1.25-3.2 ng/mL was found. Moreover, also in subjects without positive cultures, PCT was altered in 21.7% of determinations, with an average value of 1.04-5.5 ng/mL. Both PCT and PCT-72 h were not linked to a diagnosis of VAP/BSI in COVID-19 patients, according to the multivariable GEE models (aOR 1.13, 95% CI 0.51-2.52 for PCT; aOR 1.32, 95% CI 0.66-2.64 for PCT-72 h).

CONCLUSION

Elevated PCT levels might not always indicate bacterial superinfections or coinfections in a severe COVID-19 setting.

Biomarkers in the intensive care setting: A focus on using procalcitonin and C-reactive protein to optimize antimicrobial duration of therapy

Managing the critically ill patient with infection is complex, requiring clinicians to synthesize considerable information relating to antimicrobial efficacy and treatment duration. The use of biomarkers may play an important role in identifying variation in treatment response and providing information about treatment efficacy. Though a vast number of biomarkers for clinical application have been described, procalcitonin and C-reactive protein (CRP) are the most thoroughly investigated in the critically ill. However, the presence of heterogeneous populations, variable end points, and incongruent methodology in the literature complicates the use of such biomarkers to guide antimicrobial therapy. This review focuses on an appraisal of evidence for use of procalcitonin and CRP to optimize antimicrobial duration of therapy (DOT) in critically ill patients. Procalcitonin-guided antimicrobial therapy in mixed critically ill populations with varying degrees of sepsis appears to be safe and might assist in reducing antimicrobial DOT. Compared to procalcitonin, fewer studies exist examining the impact of CRP on antimicrobial DOT and clinical outcomes in the critically ill. Procalcitonin and CRP have been insufficiently studied in many key intensive care unit populations, including surgical patients with concomitant trauma, renally insufficient populations, the immunocompromised, and patients with septic shock. We believe the available evidence is not strong enough to warrant routine use of procalcitonin or CRP to guide antimicrobial DOT in critically ill patients with infection. So long as its limitations are recognized, procalcitonin could be considered to tailor antimicrobial DOT on a case-by-case basis in the critically ill patient.

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

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

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Procalcitonin as a biomarker to guide treatments for patients with lower respiratory tract infections

INTRODUCTION

Lower respiratory tract infections are amongst the main causes for hospital/intensive care unit admissions and antimicrobial prescriptions. In order to reduce antimicrobial pressure, antibiotic administration could be optimized through procalcitonin-based algorithms.

AREAS COVERED

In this review, we discuss the performances of procalcitonin for the diagnosis and the management of community-acquired and ventilator-associated pneumonia. We provide up-to-date evidence and deliver clear messages regarding the purpose of procalcitonin to reduce unnecessary antimicrobial exposure.

EXPERT OPINION

Antimicrobial pressure and resulting antimicrobial resistances are a major public health issue as well as a daily struggle in the management of patients with severe infectious diseases, especially in intensive care units where antibiotic exposure is high. Procalcitonin-guided antibiotic administration has proven its efficacy in reducing unnecessary antibiotic use in lower respiratory tract infections without excess in mortality, hospital length of stay or disease relapse. Procalcitonin-guided algorithms should be implemented in wards taking care of patients with severe infections. However, procalcitonin performances are different regarding the setting of the infection (community versus hospital-acquired infections) the antibiotic management (start or termination of antibiotic) as well as patient's condition (immunosuppressed or in shock) and we encourage the physicians to be aware of these limitations.

Successful antibiotic stewardship in the electronic era

A multi-faceted antimicrobial stewardship programme contributed to a 17.8% reduction in antibiotic consumption for our English NHS Trust. This dramatic achievement could be partially attributed to an empirical antibiotic guideline change, introduction of procalcitonin testing to guide in antibiotic decisions in SARS-CoV-2 inpatients and use of electronic antibiotic stewardship strategies. In this article, we describe the multifaceted, step-by-step antibiotic stewardship approach that weathered the SARS-CoV-2 pandemic and led to this dramatic improvement. Also included for completeness are interventions that did not pass the plan, do, study, act (PDSA) cycle and were therefore discontinued.

AACC Guidance Document on the Clinical Use of Procalcitonin

BACKGROUND

Procalcitonin (PCT), a peptide precursor of the hormone calcitonin, is a biomarker whose serum concentrations are elevated in response to systemic inflammation caused by bacterial infection and sepsis. Clinical adoption of PCT in the United States has only recently gained traction with an increasing number of Food and Drug Administration-approved assays and expanded indications for use. There is interest in the use of PCT as an outcomes predictor as well as an antibiotic stewardship tool. However, PCT has limitations in specificity, and conclusions surrounding its utility have been mixed. Further, there is a lack of consensus regarding appropriate timing of measurements and interpretation of results. There is also a lack of method harmonization for PCT assays, and questions remain regarding whether the same clinical decision points may be used across different methods.

CONTENT

This guidance document aims to address key questions related to the use of PCT to manage adult, pediatric, and neonatal patients with suspected sepsis and/or bacterial infections, particularly respiratory infections. The document explores the evidence for PCT utility for antimicrobial therapy decisions and outcomes prediction. Additionally, the document discusses analytical and preanalytical considerations for PCT analysis and confounding factors that may affect the interpretation of PCT results.

SUMMARY

While PCT has been studied widely in various clinical settings, there is considerable variability in study designs and study populations. Evidence to support the use of PCT to guide antibiotic cessation is compelling in the critically ill and in some lower respiratory tract infections but is lacking in other clinical scenarios, and evidence is also limited in the pediatric and neonatal populations. Interpretation of PCT results requires guidance from multidisciplinary care teams of clinicians, pharmacists, and clinical laboratorians.

Central role of laboratory medicine in public health and patient care

Clinical laboratories play a vital role in the healthcare system. Objective medical data provided by clinical laboratories supports approximately 60-70% of clinical decisions, however, evidence supporting this claim is poorly documented and laboratories still lack visibility, despite their indisputable impact on patient care and public health. The International Federation for Clinical Chemistry and Laboratory Medicine (IFCC) Task Force on Outcome Studies in Laboratory Medicine (TF-OSLM) was recently developed to support directed research evaluating the role of laboratory medicine on clinical outcomes. Establishing and documenting this evidence is key to enhance visibility of the field in the eye of the public and other healthcare professionals together with optimizing patient outcomes and health care system operations. In this review, we discuss four areas that exemplify the contribution of laboratory medicine directly to patient care. This includes high-sensitivity cardiac troponin (hs-cTn) and N-terminal pro-B-type natriuretic peptide/B-type natriuretic peptides (NT-proBNP/BNP) for the diagnosis and prognosis of myocardial infarction and heart failure, respectively, and procalcitonin for the management of sepsis and antibiotic stewardship. Emerging markers of traumatic brain injury and the role of laboratory medicine in the fight against the COVID-19 pandemic are discussed along with an introduction to plans of IFCC TF-OSLM.

The Role of Procalcitonin as an Antimicrobial Stewardship Tool in Patients Hospitalized with Seasonal Influenza

Background: Up to 60% of the antibiotics prescribed to patients hospitalized with seasonal influenza are unnecessary. Procalcitonin (PCT) has the potential as an antimicrobial stewardship program (ASP) tool because it can differentiate between viral and bacterial etiology. We aimed to explore the role of PCT as an ASP tool in hospitalized seasonal influenza patients. Methods: We prospectively included 116 adults with seasonal influenza from two influenza seasons, 2018–2020. All data was obtained from a single clinical setting and analyzed by descriptive statistics and regression models. Results: In regression analyses, we found a positive association of PCT with 30 days mortality and the amount of antibiotics used. Influenza diagnosis was associated with less antibiotic use if the PCT value was low. Patients with a low initial PCT (<0.25 µg/L) had fewer hospital and intensive care unit (ICU) days and fewer positive chest X-rays. PCT had a negative predictive value of 94% for ICU care stay, 98% for 30 days mortality, and 88% for bacterial coinfection. Conclusion: PCT can be a safe rule-out test for bacterial coinfection. Routine PCT use in seasonal influenza patients with an uncertain clinical picture, and rapid influenza PCR testing, may be efficient as ASP tools.

An algorithm for PCT-guided antimicrobial therapy: a consensus statement by Japanese experts

In Japan, a national antimicrobial resistance (AMR) action plan was adopted in 2016, advocating a 20% reduction in antibiotic consumption by 2020. However, there is still room for improvement to accomplish this goal. Many randomized controlled trials have reported that procalcitonin (PCT)-guided antimicrobial therapy could help to reduce antibiotic consumption without negative health effects, specifically in acute respiratory infections. In September 2018, some experts in Europe and the USA proposed algorithms for PCT-guided antimicrobial therapy in mild to moderate infection cases outside the ICU and severe cases in the ICU (the international experts consensus). Thereafter, a group of Japanese experts, including specialists in intensive care medicine, emergency medicine, respiratory medicine and infectious diseases, created a modified version of a PCT-guided algorithm (Japanese experts consensus). This modified algorithm was adapted to better fit Japanese medical circumstances, since PCT-guided therapy is not widely used in daily clinical practice in Japan. The Japanese algorithm has three specific characteristics. First, the target patients are limited to only hospitalized ICU or non-ICU patients. Second, pneumonia due to Pseudomonas aeruginosa, Staphylococcus aureus and Legionella species are excluded. Finally, a different timing of PCT follow-up measurement was proposed to meet restrictions of the Japanese medical insurance system. The adapted algorithms has high potential to further improve the safe reduction in antibiotic consumption in Japan, while reducing the spread of AMR pathogens.

Pathogen Distribution, Drug Resistance Risk Factors, and Construction of Risk Prediction Model for Drug-Resistant Bacterial Infection in Hospitalized Patients at the Respiratory Department During the COVID-19 Pandemic

Objective

To investigate the distribution and drug resistance of pathogens among hospitalized patients in the respiratory unit during the COVID-19 pandemic, analyze the risk factors of drug resistance, construct a risk prediction model.

Methods

This study isolated 791 strains from 489 patients admitted to the Affiliated Hospital of Chengdu University, who were retrospectively enrolled between December 2019 and June 2021. The patients were divided into training and validation sets based on a random number table method (8:2). The baseline information, clinical characteristics, and culture results were collected using an electronic database and WHONET 5.6 software and compared between the two groups. A risk prediction model for drug-resistant bacteria was constructed using multi-factor logistic regression.

Results

K. pneumoniae (24.78%), P. aeruginosa (17.19%), A. baumannii (10.37%), and E. coli (10.37%) were the most abundant bacterial isolates. 174 isolates of drug-resistant bacteria were collected, ie, Carbapenem-resistant organism-strains, ESBL-producing strains, methicillin-resistant S. aureus, multi-drug resistance constituting 38.51%, 50.57%, 6.32%, 4.60%, respectively. The nosocomial infection prediction model of drug-resistant bacteria was developed based on the combined use of antimicrobials, pharmacological immunosuppression, PCT>0.5 ng/mL, CKD stage 4-5, indwelling catheter, and age > 60 years. The AUC under the ROC curve of the training and validation sets were 0.768 (95% CI: 0.624-0.817) and 0.753 (95% CI: 0.657-0.785), respectively. Our model revealed an acceptable prediction demonstrated by a non-significant Hosmer-Lemeshow test (training set, p=0.54; validation set, p=0.88).

Conclusion

K. pneumoniae, P. aeruginosa, A. baumannii, and E. coli were the most abundant bacterial isolates. Antimicrobial resistance among the common isolates was high for most routinely used antimicrobials and carbapenems. COVID-19 did not increase the drug resistance pressure of the main strains. The risk prediction model of drug-resistant bacterial infection is expected to improve the prevention and control of antibacterial-resistant bacterial infection in hospital settings.

Biomarkers as Prognostic Predictors and Therapeutic Guide in Critically Ill Patients: Clinical Evidence

A biomarker is a molecule that can be measured in a biological sample in an objective, systematic, and precise way, whose levels indicate whether a process is normal or pathological. Knowing the most important biomarkers and their characteristics is the key to precision medicine in intensive and perioperative care. Biomarkers can be used to diagnose, in assessment of disease severity, to stratify risk, to predict and guide clinical decisions, and to guide treatments and response to them. In this review, we will analyze what characteristics a biomarker should have and how to ensure its usefulness, and we will review the biomarkers that in our opinion can make their knowledge more useful to the reader in their clinical practice, with a future perspective. These biomarkers, in our opinion, are lactate, C-Reactive Protein, Troponins T and I, Brain Natriuretic Peptides, Procalcitonin, MR-ProAdrenomedullin and BioAdrenomedullin, Neutrophil/lymphocyte ratio and lymphopenia, Proenkephalin, NefroCheck, Neutrophil gelatinase-associated lipocalin (NGAL), Interleukin 6, Urokinase-type soluble plasminogen activator receptor (suPAR), Presepsin, Pancreatic Stone Protein (PSP), and Dipeptidyl peptidase 3 (DPP3). Finally, we propose an approach to the perioperative evaluation of high-risk patients and critically ill patients in the Intensive Care Unit (ICU) based on biomarkers.

Procalcitonin and Adrenomedullin in Infectious Diseases

Calcitonin (CT) and adrenomedullin (ADM) are members of the CT family. Procalcitonin (PCT) is a prohormone of CT. Elevations in serum PCT and ADM levels are associated with severe sepsis and coronavirus disease 2019 (COVID-19). PCT enhances sepsis mortality and it binds to the CGRP receptor, which is a heterodimer of CT receptor-like receptor and receptor activity-modifying protein 1. The N-terminal truncated form of PCT, PCT3-116, is produced by the cleavage of PCT by dipeptidyl peptidase 4 (DPP-4) and is the main form of PCT in serum during sepsis, inducing microvascular permeability. Mid-regional pro-adrenomedullin (MR-proADM) is used instead of ADM as a biological indicator because ADM is rapidly degraded, and MR-proADM is released at the same rate as ADM. ADM reduces endothelial permeability and promotes endothelial stability. Endothelial dysfunction is responsible for multiple organ failure in sepsis and COVID-19 patients. Therefore, ADM may be an important molecule for improving the severity associated with sepsis and COVID-19. This review focuses on the current knowledge of PCT and ADM in sepsis and COVID-19.

Diagnostic value of procalcitonin, hypersensitive C-reactive protein and neutrophil-to-lymphocyte ratio for bloodstream infections in pediatric tumor patients

OBJECTIVES

Bloodstream infection (BSI) is one of the major causes of death in pediatric tumor patients. Blood samples are relatively easy to obtain and thus provide a ready source of infection-related biological markers for the prompt evaluation of infection risk.

METHODS

A total of 259 pediatric tumor patients were included from May 2019 to March 2022. Patients were divided into BSI group (n=70) and control group (n=189). Clinical and biological data were collected using electronic medical records. Differences in biological markers between BSI group and control group and differences before and during infection in BSI group were analyzed.

RESULTS

The infected group showed higher levels of procalcitonin (PCT) and hypersensitive C-reactive-protein (hsCRP), and lower prealbumin (PA) than the uninfected group. Area under the receiver-operating curve (ROC) curves (AUC) of PCT, hsCRP and NLR (absolute neutrophil count to the absolute lymphocyte count) were 0.756, 0.617 and 0.612. The AUC of other biomarkers was ≤0.6. In addition, PCT, hsCRP, NLR and fibrinogen (Fg) were significantly increased during infection, while PA and lymphocyte (LYM) were significantly decreased. Antibiotic resistant of Gram-positive bacteria to CHL, SXT, OXA and PEN was lower than that of Coagulase-negative Staphylococcus. Resistant of Gram-positive bacteria to CHL was lower, while to SXT was higher than that of Gram-negative bacteria.

CONCLUSIONS

This study explored the utility of biomarkers to assist in diagnosis and found that the PCT had the greatest predictive value for infection in pediatric tumor patients with BSI. Additionally, the PCT, hsCRP, NLR, PA, LYM and Fg were changed by BSI.

The Complexity of the Post-Burn Immune Response: An Overview of the Associated Local and Systemic Complications

Burn injury induces a complex inflammatory response, both locally and systemically, and is not yet completely unravelled and understood. In order to enable the development of accurate treatment options, it is of paramount importance to fully understand post-burn immunology. Research in the last decades describes insights into the prolonged and excessive inflammatory response that could exist after both severe and milder burn trauma and that this response differs from that of none-burn acute trauma. Persistent activity of complement, acute phase proteins and pro- and anti-inflammatory mediators, changes in lymphocyte activity, activation of the stress response and infiltration of immune cells have all been related to post-burn local and systemic pathology. This "narrative" review explores the current state of knowledge, focusing on both the local and systemic immunology post-burn, and further questions how it is linked to the clinical outcome. Moreover, it illustrates the complexity of post-burn immunology and the existing gaps in knowledge on underlying mechanisms of burn pathology.

Consider this tool to reduce antibiotic-associated adverse events in patients with sepsis

Predictive biomarker procalcitonin can aid clinical decision-making on continued antibiotic treatment in this patient population.

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

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

How to best use procalcitonin to diagnose infections and manage antibiotic treatment

Objectives

Procalcitonin (PCT) is a host-response biomarker that has shown clinical value for assessing the likelihood of bacterial infections and guiding antibiotic treatment. Identifying situations where PCT can improve clinical care is therefore highly important.

Methods

The aim of this narrative review is to discuss strategies for the usage and integration of PCT into clinical routine, based on the most recent clinical evidence.

Results

Although PCT should not be viewed as a traditional diagnostic marker, it can help differentiate bacterial from non-bacterial infections and inflammation states – particularly in respiratory illness. Several trials have found that PCT-guided antibiotic stewardship reduces antibiotic exposure and associated side-effects among patients with respiratory infection and sepsis. Studies have demonstrated that patient-specific decisions regarding antibiotic usage is highly complex. Factors to consider include: the clinical situation (with a focus on the pretest probability for bacterial infection), the acuity and severity of presentation, as well as PCT test results. Low PCT levels help rule out bacterial infection in patients with both low pretest probability for bacterial infection and low-risk general condition. In high-risk individuals and/or high pretest probability for infection, empiric antibiotic treatment is mandatory. Subsequent monitoring of PCT helps track the resolution of infection and guide decisions regarding early termination of antibiotic treatment.

Conclusions

PCT possesses high potential to improve decision-making regarding antibiotic treatment – when combined with careful patient assessment, evidence-based clinical algorithms, and continuous notification and regular feedback from all antibiotic stewardship stakeholders. Medical Journals such as Clinical Chemistry and Laboratory Medicine (CCLM) have played a critical role in reviewing and dissemination the high-quality evidence about assays for PCT measurement, observational research regarding association with outcomes among different populations, and interventional research proofing its effectiveness for patient care.

DIAGNOSTIC ACCURACY AND ADDED VALUE OF INFECTION BIOMARKERS IN PATIENTS WITH POSSIBLE SEPSIS IN THE EMERGENCY DEPARTMENT

ABSTRACT

Background: Biomarkers for early recognition of infection are warranted. The hypothesis of this study was that calprotectin, C-reactive protein (CRP), IL-6 and procalcitonin (PCT), alone or in combination, provide clinically useful information to the clinicians for early identification of infection in patients with possible sepsis in the emergency department (ED). Biomarker dynamics in the first week of hospitalization were explored. Methods: Adult patients in rapid response teams in the ED were included in a prospective observational study (n = 391). Patients who received antibiotics after biomarker availability were excluded. The ED clinician (EDC) decision whether to start antibiotics was registered. Calprotectin, CRP, IL-6, and PCT were analyzed in blood samples drawn within 15 min after ED arrival and in a subgroup for 1 week. Infection likelihood was evaluated post hoc . Results: In identifying patients with infection, CRP (area under the receiver operating characteristic curve [AUC], 0.913) and IL-6 (AUC, 0.895) were superior to calprotectin (AUC, 0.777) and PCT (AUC, 0.838). The best regression model predicting infections included EDC, CRP, and IL-6. Using optimal cutoff values, CRP and IL-6 in combination reached 95% positive and 90% negative predictive values for infection. The EDC undertreated or overtreated 65 of 391 patients (17%), and CRP and IL-6 optimal cutoff values could correct this in 32 of 65 patients (49%). Longitudinal samples revealed that IL-6 peaked in the ED, whereas CRP and PCT peaked later. Conclusion: C-reactive protein and IL-6 were superior to calprotectin and PCT for recognizing infection in patients with possible sepsis in the ED. Combining these two biomarkers with different dynamics improved recognition of infection and could aid clinical management in rapid response teams in the ED.

Antimicrobial stewardship

PURPOSE OF REVIEW

The optimal use of antimicrobials is necessary to slow resistance development and improve patient outcomes. Antimicrobial stewardship (AMS) is a bundle of interventions aimed at promoting the responsible use of antiinfectives. The ICU is an important field of activity for AMS because of high rates of antimicrobial use, high prevalence of resistant pathogens and complex pharmacology. This review discusses aims and interventions of AMS with special emphasis on the ICU.

RECENT FINDINGS

AMS-interventions can improve the quality and quantity of antimicrobial prescribing in the ICU without compromising patient outcomes. The de-escalation of empiric therapy according to microbiology results and the limitation of treatment duration are important steps to reduce resistance pressure. Owing to the complex nature of critical illness, the pharmacological optimization of antimicrobial therapy is an important goal in the ICU. AMS-objectives and strategies are also applicable to patients with sepsis. This is reflected in the most recent guidelines by the Surviving Sepsis Campaign. AMS-interventions need to be adapted to their respective setting and be mindful of local prescribing cultures and prescribers' attitudes.

SUMMARY

AMS in the ICU is effective and safe. Intensivists should be actively involved in AMS-programs and propagate responsible use of antimicrobials.

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

Objective

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

Methods

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

Results

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

Conclusions

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

The Etiology of Community-Acquired Pneumonia Correlates with Serum Inflammatory Markers in Children

Community-acquired pneumonia (CAP) severely affects pediatric hospitalizations. This study assessed the contribution of CAP to hospitalizations, its etiology in relationship with age, and the inflammatory markers. Between 2013 and 2018, 1064 CAP patients were hospitalized and diagnosed with bacterial/possibly bacterial pneumonia (BP), viral/possibly viral pneumonia (VP) and atypical pneumonia (AP). The etiology was confirmed using blood/pleural fluid culture/polymerase chain reaction (PCR), rapid antigen test/PCR in nasopharyngeal swabs, or serological studies. CAP accounted for 9.9% of hospitalizations and 14.8% of patient days. BP was diagnosed in 825 (77.5%), VP in 190 (17.9%), and AP in 49 (4.6%) cases; the confirmed etiology (n = 209; 20%) included mostly influenza (39%; n = 82), respiratory syncytial virus (RSV, 35%; n = 72), and Mycoplasma pneumoniae (19%; n = 39). VP frequency decreased with age (41% in < 3 mo to 9% in ≥ 60 mo), in contrast to AP (13% in ≥ 60 mo). Among the analyzed parameters, the best differentiating potential was shown by: C-reactive protein (CRP, AUCBP-VP = 0.675; 95% CI: 0.634−0.715), procalcitonin (AUCBP-AP = 0.73; 95% CI: 0.67−0.794), and CRP/procalcitonin (AUCAP-VP = 0.752; 95% CI: 0.67−0.83); a good positive predictive value (88.8%, 98.3%, and 91.6%, respectively) but a low negative predictive value (29.5%, 13.1%, and 40.7%, respectively) was observed. CAP influences hospital patient days more than the crude number of patients would suggest. On a clinical basis, BP is mainly recognized, although viral pneumonia is confirmed most often. RSV and influenza are responsible for a huge percentage of hospitalized cases, as well as M. pneumoniae in children aged ≥ 5 years. Serum inflammatory markers may help differentiate etiological factors.

Procalcitonin as a predictive marker in COVID-19: A systematic review and meta-analysis

Background

Coronavirus disease 2019 has emerged as a global pandemic causing millions of critical cases and deaths. Early identification of at-risk patients is crucial for planning triage and treatment strategies.

Methods and findings

We performed this systematic review and meta-analysis to determine the pooled prognostic significance of procalcitonin in predicting mortality and severity in patients with COVID-19 using a robust methodology and clear clinical implications.

Design

We used Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Cochrane Handbook for Systematic Reviews of Interventions guidelines. We included thirty-two prospective and retrospective cohort studies involving 13,154 patients.

Results

The diagnostic odds ratio of procalcitonin for predicting mortality were estimated to be 11 (95% CI: 7 to 17) with sensitivity, specificity, and summary area under the curveof 0.83 (95% CI: 0.70 to 0.91), 0.69 (95% CI: 0.58 to 0.79), and 0.83 (95% CI: 0.79 to 0.86) respectively. While for identifying severe cases of COVID-19, the odds ratio was 8.0 (95% CI 5.0 to 12.0) with sensitivity, specificity, and summary area under the curve of 0.73 (95% CI 0.67 to 0.78), 0.74 (0.66 to 0.81), and 0.78 (95% CI 0.74 to 0.82) respectively.

Conclusion

Procalcitonin has good discriminatory power for predicting mortality and disease severity in COVID-19 patients. Therefore, procalcitonin measurement may help identify potentially severe cases and thus decrease mortality by offering early aggressive treatment.

The Sustained and Marked Elevation of Serum Procalcitonin in a Hemodialysis Patient with Tuberculous Lymphadenitis, but Without the Evidence of Sepsis: A Case Report

Background

The elevation of serum procalcitonin (PCT) has been considered as a marker of systemic bacterial infection and sepsis. However, the marked elevation of PCT in non-sepsis conditions was rare. Here, we report a rare case of sustained markedly elevation of serum PCT in a dialysis patient with tuberculosis, but without the evidence of sepsis.

Case Presentation

A 25-year-old man on maintenance hemodialysis was admitted to the hospital for kidney transplantation. On admission, physical examination revealed multiple lymph nodes were palpable on both sides of the neck which was later confirmed as tuberculosis with biopsy pathology. On the 3rd day after admission, the patient suffered from fever with a temperature of 38.8°C. The white blood cells 12.35 × 10⁹/L and the PCT level was 5.73 ng/mL. Lately the PCT increased to 63.10 ng/mL, and the level of C-reactive protein was 186.00 mg/L. After the antibiotics upgraded from cefmetazole to meropenem, and vancomycin was added, the body temperature dropped to the normal range on the 17th day and remained normal thereafter. The PCT level declined gradually to 4.18 ng/mL on the 21st day and an antituberculosis regimen was started. After that, the PCT levels fluctuated between 2.9 ng/mL and 94.9 ng/mL without any manifestation of sepsis. The markedly elevation of serum PCT level persisted despite normal C-reactive protein level and leukocyte counts.

Conclusion

Persistently elevated serum PCT level might occur in conditions without evidence of sepsis. Taking consideration of multiple inflammatory factors to determine infection when the markedly elevated PCT level was not correlated with the clinical manifestations.