Impact of adequate empirical antibiotic therapy on the outcome of patients admitted to the intensive care unit with sepsis

Effects of lung inflammation and injury on pulmonary tissue penetration of meropenem and vancomycin in a model of unilateral lung injury

OBJECTIVE

The timing and dosing of antimicrobial therapy are key in the treatment of pneumonia in critically ill patients. It is uncertain whether the presence of lung inflammation and injury affects tissue penetration of intravenously administered antimicrobial drugs. The effects of lung inflammation and injury on tissue penetration of two antimicrobial drugs commonly used for pneumonia were determined in an established model of unilateral lung injury.

METHODS

Unilateral lung injury was induced in the left lung of 13 healthy pigs through cyclic rinsing; the right healthy lung served as control. Infusions of meropenem and vancomycin were administered and concentrations of these drugs in lung tissue, blood, and epithelial lining fluid (ELF) were compared over a period of 6 h.

RESULTS

Median vancomycin lung tissue concentrations and penetration ratio were higher in inflamed and injured lungs compared with uninflamed and uninjured lungs (AUC0-6h: P = 0.003 and AUCdialysate/AUCplasma ratio: P = 0.003), resulting in higher AUC0-24/MIC. Median meropenem lung tissue concentrations and penetration ratio in inflamed and injured lungs did not differ from that in uninflamed and uninjured lungs (AUC0-6: P = 0.094 and AUCdialysate/AUCplasma ratio: P = 0.173). The penetration ratio for both vancomycin and meropenem into ELF was similar in injured and uninjured lungs.

CONCLUSION

Vancomycin penetration into lung tissue is enhanced by acute inflammation and injury, a phenomenon barely evident with meropenem. Therefore, inflammation in lung tissue influences the penetration into interstitial lung tissue, depending on the chosen antimicrobial drug. Measurement of ELF levels alone might not identify the impact of inflammation and injury.

An insight into MDR Acinetobacter baumannii infection and its pathogenesis: Potential therapeutic targets and challenges

Acinetobacter baumannii is observed as a common species of Gram-negative bacteria that exist in soil and water. Despite being accepted as a typical component of human skin flora, it has become an important opportunistic pathogen, especially in healthcare settings. The pathogenicity of A. baumannii is attributed to its virulence factors, which include adhesins, pili, lipopolysaccharides, outer membrane proteins, iron uptake systems, autotransporter, secretion systems, phospholipases etc. These elements provide the bacterium the ability to cling to and penetrate host cells, get past the host immune system, and destroy tissue. Its infection is a major contributor to human pathophysiological conditions including pneumonia, bloodstream infections, urinary tract infections, and surgical site infections. It is challenging to treat infections brought on by this pathogen since this bacterium has evolved to withstand numerous drugs and further emergence of drug-resistant A. baumannii results in higher rates of morbidity and mortality. The long-term survival of this bacterium on surfaces of medical supplies and hospital furniture facilitates its frequent spread in humans from one habitat to another. There is a need for urgent investigations to find effective drug targets for A. baumannii as well as designing novel drugs to reduce the survival and spread of infection. In the current review, we represent the specific features, pathogenesis, and molecular intricacies of crucial drug targets of A. baumannii. This would also assist in proposing strategies and alternative therapies for the prevention and treatment of A. baumannii infections and their spread.

Lactate Profile Assessment-A Good Predictor of Prognosis in Patients with COVID-19 and Septic Shock Requiring Continuous Renal Therapy

INTRODUCTION

Lactate is a useful prognostic marker, as its level increases in hypoxic tissue and/or during accelerated aerobic glycolysis due to excessive beta-adrenergic stimulation and decreased lactate clearance. The Surviving Sepsis Campaign Bundle 2018 Update suggests premeasurement of lactate within 2-4 h so that physicians perform, assist, administer, and introduce lactate-guided resuscitation to reduce mortality due to sepsis.

METHODS

A total of 108 patients with septic shock who underwent continuous renal replacement therapy (CRRT) for acute kidney injury were enrolled in this observational study. Demographic, clinical, and laboratory data were collected, and patients were divided into two groups: survivors and non-survivors.

RESULTS

Multivariate analysis demonstrated that lactate levels at 24 h after initiation of CRRT treatment, but not lactate levels at intensive care unit (ICU) admission, were associated with mortality. Lactate clearance was associated with lower mortality among the survivors (OR = 0.140) at 6 h after ICU admission and late mortality (OR = 0.260) after 24 h. The area under the ROC curves for mortality was 0.682 for initial lactate; 0.797 for lactate at 24 h; and 0.816 for lactate clearance at 24 h.

CONCLUSIONS

Our result reinforces that the determination of lactate dynamics represents a good predictor for mortality, and serial lactate measurements may be more useful prognostic markers than initial lactate in patients with septic shock.

Usefulness of Procalcitonin Levels for Predicting the Microbiological Orientation in Patients with Sepsis

The main objective of the study was to verify whether levels of procalcitonin (PCT) could guide us toward determining the type of bacteria causing the sepsis and to identify the discriminatory cut-off point in the first urgent laboratory test. This study is a single center retrospective analysis that includes 371 patients with a mean age of 71.7 ± 15.6 years who were diagnosed with sepsis or septic shock. The yield of blood cultures in demonstrating the causative microbiological agent was 24.3% (90), and it was 57, 1% (212) when evaluating all types of cultures. Statistically significant positive differences were observed in the mean value of the PCT between the group that obtained positive cultures and the group that did not (p < 0.0001). The AUC-ROC of PCT values as a guide to the causal bacteria type was 0.68 (95%CI: 0.57-0.78, p < 0.0021). The PCT value that showed the best diagnostic characteristics for identifying Gram-negative rods (GNR) as the causative agent in blood cultures was 2.1 ng/mL. The positive predictive value (PPV) was 78, 9% (66.3-88.1%). The AUC-ROC of the PCT values for sepsis diagnosis, with any positive culture that could be assessed, was 0.67 (95%CI: 0.63-0.73, p < 0.0001). The PCT value that showed the best diagnostic characteristic for predicting sepsis was 3.6 ng/mL.

Machine learning model for the prediction of gram-positive and gram-negative bacterial bloodstream infection based on routine laboratory parameters

BACKGROUND

Bacterial bloodstream infection is responsible for the majority of cases of sepsis and septic shock. Early recognition of the causative pathogen is pivotal for administration of adequate empiric antibiotic therapy and for the survival of the patients. In this study, we developed a feasible machine learning (ML) model to predict gram-positive and gram-negative bacteremia based on routine laboratory parameters.

METHODS

Data for 2118 patients with bacteremia were obtained from the Medical Information Mart for Intensive Care dataset. Patients were randomly split into the training set and test set by stratified sampling, and 374 routine laboratory blood test variables were retrieved. Variables with missing values in more than 40% of the patients were excluded. Pearson correlation test was employed to eliminate redundant features. Five ML algorithms were used to build the model based on the selected features. Additionally, 132 patients with bacteremia who were treated at Qilu Hospital of Shandong University were included in an independent test cohort to evaluate the model.

RESULTS

After feature selection, 32 variables remained. All the five ML algorithms performed well in terms of discriminating between gram-positive and gram-negative bacteremia, but the performance of convolutional neural network (CNN) and random forest (RF) were better than other three algorithms. Consider of the interpretability of models, RF was chosen for further test (ROC-AUC = 0.768; 95%CI = 0.715-0.798, with a sensitivity of 75.20% and a specificity of 63.79%). To expand the application of the model, a decision tree (DT) was built utilizing the major variables, and it achieved an AUC of 0.679 (95%CI = 0.632-0.723), a sensitivity of 66%, and a specificity of 67.82% in the test cohort. When tested in the Qilu Hospital cohort, the ROC-AUC of the RF and DT models were 0.666 (95%CI = 0.579-0.746) and 0.615 (95%CI = 0.526-0.698), respectively. Finally, a software was developed to make the RF- and DT-based prediction models easily accessible.

CONCLUSION

The present ML-based models could effectively discriminate between gram-positive and gram-negative bacteremia based on routine laboratory blood test results. This simple model would be beneficial in terms of guiding timely antibiotic selection and administration in critically ill patients with bacteremia before their pathogen test results are available.

Early discontinuation of combination antibiotic therapy in severe community-acquired pneumonia: a retrospective cohort study

BACKGROUND

Severe community-acquired pneumonia (SCAP) is commonly treated with an empiric combination therapy, including a macrolide, or a quinolone and a β-lactam. However, the risk of Legionella pneumonia may lead to a prolonged combination therapy even after negative urinary antigen tests (UAT).

METHODS

We conducted a retrospective cohort study in a French intensive care unit (ICU) over 6 years and included all the patients admitted with documented SCAP. All patients received an empirical combination therapy with a β-lactam plus a macrolide or quinolone, and a Legionella UAT was performed. Macrolide or quinolone were discontinued when the UAT was confirmed negative. We examined the clinical and epidemiological features of SCAP and analysed the independent factors associated with ICU mortality.

RESULTS

Among the 856 patients with documented SCAP, 26 patients had atypical pneumonia: 18 Legionella pneumophila (LP) serogroup 1, 3 Mycoplasma pneumonia (MP), and 5 Chlamydia psittaci (CP). UAT diagnosed 16 (89%) Legionella pneumonia and PCR confirmed the diagnosis for the other atypical pneumonia. No atypical pneumonia was found by culture only. Type of pathogen was not associated with a higher ICU mortality in the multivariate analysis.

CONCLUSION

Legionella pneumophila UAT proved to be highly effective in detecting the majority of cases, with only a negligible percentage of patients being missed, but is not sufficient to diagnose atypical pneumonia, and culture did not provide any supplementary information. These results suggest that the discontinuation of macrolides or quinolones may be a safe option when Legionella UAT is negative in countries with a low incidence of Legionella pneumonia.

Determinants of Inadequate Empiric Antimicrobial Therapy in ICU Sepsis Patients in Al-Madinah Al-Munawwarah, Saudi Arabia: A Comparison of Artificial Neural Network and Regression Analysis

In the management of sepsis, providing adequate empiric antimicrobial therapy is one of the most important pillars of sepsis management. Therefore, it is important to evaluate the adequacy of empiric antimicrobial therapy (EAMT) in sepsis patients admitted to intensive care units (ICU) and to identify the determinants of inadequate EAMT. The aim of this study was to evaluate the adequacy of empiric antimicrobial therapy in patients admitted to the ICU with sepsis or septic shock, and the determinants of inadequate EAMT. The data of patients admitted to the ICU units due to sepsis or septic shock in two tertiary healthcare facilities in Al-Madinah Al-Munawwarah were retrospectively reviewed. The current study used logistic regression analysis and artificial neural network (ANN) analysis to identify determinants of inadequate empiric antimicrobial therapy, and evaluated the performance of these two approaches in predicting the inadequacy of EAMT. The findings of this study showed that fifty-three per cent of patients received inadequate EAMT. Determinants for inadequate EAMT were APACHE II score, multidrug-resistance organism (MDRO) infections, surgical history (lower limb amputation), and comorbidity (coronary artery disease). ANN performed as well as or better than logistic regression in predicating inadequate EAMT, as the receiver operating characteristic area under the curve (ROC-AUC) of the ANN model was higher when compared with the logistic regression model (LRM): 0.895 vs. 0.854. In addition, the ANN model performed better than LRM in predicting inadequate EAMT in terms of classification accuracy. In addition, ANN analysis revealed that the most important determinants of EAMT adequacy were the APACHE II score and MDRO. In conclusion, more than half of the patients received inadequate EAMT. Determinants of inadequate EAMT were APACHE II score, MDRO infections, comorbidity, and surgical history. This provides valuable inputs to improve the prescription of empiric antimicrobials in Saudi Arabia going forward. In addition, our study demonstrated the potential utility of applying artificial neural network analysis in the prediction of outcomes in healthcare research.

Comparison of the clinical characteristics and clinical outcomes of culture-positive septic shock and culture-negative septic shock among pediatric patients

OBJECTIVES

Among pediatric patients with septic shock, culture-negative septic shock (CNSS) is common but there have been limited data on its clinical characteristics and prognosis. We compared the clinical characteristics and clinical outcomes between culture-positive septic shock (CPSS) and CNSS in pediatric patients.

DESIGN

Retrospective single-center study.

SETTING

Pediatric intensive care unit (PICU) of a tertiary referral hospital.

PATIENTS

All pediatric patients who were admitted to the PICU due to septic shock between January 2010 and November 2021, except for those with fungal or viral infections and those who expired on the day of admittance to the PICU. The primary outcome was 30-day mortality and in-hospital mortality.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 294 patients (CPSS group, n = 185 [62.9%]; CNSS group, n = 109 [37.1%]) were included. The rates of 30-day mortality and in-hospital mortality (30-day mortality 22.7% vs 22%, in-hospital mortality 29.7% vs 25.7%) were not significantly different between the CPSS group and the CNSS group. The two groups showed comparable results in clinical outcomes such as the requirement for mechanical ventilator and renal replacement therapy, PICU stay duration, and the duration of MV and vasopressor/inotrope support. Among the CPSS group, 98 (53%) patients who were infected with multi-drug resistance (MDR) bacteria had significantly higher rates of 30-day mortality and in-hospital mortality than those infected with non-MDR bacteria.

CONCLUSIONS

Among pediatric patients, the CPSS group and CNSS group did not show significant differences in clinical features and mortality. Among the CPSS group, those with MDR bacteria had poorer prognosis.

Rationale and clinical application of antimicrobial stewardship principles in the intensive care unit: a multidisciplinary statement

BACKGROUND

Antimicrobial resistance represents a major critical issue for the management of the critically ill patients hospitalized in the intensive care unit (ICU), since infections by multidrug-resistant bacteria are characterized by high morbidity and mortality, high rates of treatment failure, and increased healthcare costs worldwide. It is also well known that antimicrobial resistance can emerge as a result of inadequate antimicrobial therapy, in terms of drug selection and/or treatment duration. The application of antimicrobial stewardship principles in ICUs improves the quality of antimicrobial therapy management. However, it needs specific considerations related to the critical setting.

METHODS

The aim of this consensus document gathering a multidisciplinary panel of experts was to discuss principles of antimicrobial stewardship in ICU and to produce statements that facilitate their clinical application and optimize their effectiveness. The methodology used was a modified nominal group discussion.

CONCLUSION

The final set of statements underlined the importance of the specific interpretation of antimicrobial stewardship's principles in critically ill patient management, quasi-targeted therapy, the use of rapid diagnostic methods, the personalization of antimicrobial therapies' duration, obtaining microbiological surveillance data, the use of PK/PD targets, and the use of specific indicators in antimicrobial stewardship programs.

Mortality analysis among sepsis patients in and out of intensive care units using the Japanese nationwide medical claims database: a study by the Japan Sepsis Alliance study group

BACKGROUND

A substantial number of sepsis patients require specialized care, including multidisciplinary care, close monitoring, and artificial organ support in the intensive care unit (ICU). However, the efficacy of ICU management on clinical outcomes remains insufficiently researched. Therefore, we tested the hypothesis that ICU admission would increase the survival rate among sepsis patients.

METHODS

We conducted a retrospective study using the nationwide medical claims database of sepsis patients in Japan from 2010 to 2017 with propensity score matching to adjust for baseline imbalances. Patients aged over 20 years, with a combined diagnosis of presumed serious infection and organ failure, were included in this study. The primary outcome studied was the in-hospital mortality among non-ICU and ICU patients. In addition to propensity score matching, we performed a multivariable logistic regression analysis for the primary outcome. As the treatment policy was not extracted from the database, we performed sensitivity analyses to determine mortality differences in adults (20 ≤ age ≤ 64), independent patients, patients without malignant tumors, based on the assumption that treatment intensity is likely to increase in those population.

RESULTS

Among 1,167,901 sepsis patients (974,289 in non-ICU and 193,612 in ICU settings), the unadjusted in-hospital mortality was 22.5% among non-ICU patients and 26.2% among ICU patients (3.7% [95% CI 3.5-3.9]). After propensity score matching, the in-hospital mortality was 29.2% among non-ICU patients and 25.8% among ICU patients ([Formula: see text] 3.4% [95% CI [Formula: see text] 3.7 to [Formula: see text] 3.1]). In-hospital mortality with a multivariable regression analysis ([Formula: see text] 5.0% [95% CI [Formula: see text] 5.2 to [Formula: see text] 4.8]) was comparable with the results of the propensity score matching analysis. In the sensitivity analyses, the mortality differences between non-ICU and ICU in adults, independent patients, and patients without malignant tumors were [Formula: see text] 2.7% [95% CI [Formula: see text] 3.3 to [Formula: see text] 2.2], [Formula: see text] 5.8% [95% CI [Formula: see text] 6.4 to [Formula: see text] 5.2], and [Formula: see text] 1.3% [95% CI [Formula: see text] 1.7 to [Formula: see text] 1.0], respectively.

CONCLUSIONS

Herein, using the nationwide medical claims database, we demonstrated that ICU admission was potentially associated with decreasing in-hospital mortality among sepsis patients. Further investigations are warranted to validate these results and elucidate the mechanisms favoring ICU management on clinical outcomes.

LCMS/MS-based multiplex antibacterial platform for therapeutic drug monitoring in intensive care unit patients

Empirically prescribed standard dosing regimens of antibacterial agents may result in insufficient or excess plasma concentrations with persistently poor clinical outcomes, especially for patients in intensive care units (ICUs). Therapeutic drug monitoring (TDM) of antibacterial agents can guide dose adjustments to benefit patients. In this study, we developed a robust, sensitive, and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) platform for the quantification of 14 antibacterial and antifungal agents (beta-lactams piperacillin, cefoperazone, and meropenem; beta-lactamase inhibitors tazobactam and sulbactam; antifungal agents fluconazole, caspofungin, posaconazole, and voriconazole; and daptomycin, vancomycin, teicoplanin, linezolid, and tigecycline) that can be used for patients with severe infection. This assay requires only 100 µL of serum with rapid protein precipitation. Chromatographic analysis was performed using a Waters Acquity UPLC C8 column. Three stable isotope-labeled antibacterial agents and one analogue were used as internal standards. Calibration curves ranged from 0.1-100 μg/mL, 0.1-50 μg/mL, and 0.3-100 μg/mL for different drugs, and all correlation coefficients were greater than 0.9085. Intra- and inter-day imprecision and inaccuracy values were below 15%. After validation, this new method was successfully employed for TDM in routine practice.

Impact of a Rapid Molecular Test for Klebsiella pneumoniae Carbapenemase and Ceftazidime-Avibactam Use on Outcomes After Bacteremia Caused by Carbapenem-Resistant Enterobacterales

BACKGROUND

Patients with bacteremia due to carbapenem-resistant Enterobacterales (CRE) experience delays until appropriate therapy and high mortality rates. Rapid molecular diagnostics for carbapenemases and new β-lactam/β-lactamase inhibitors may improve outcomes.

METHODS

We conducted an observational study of patients with CRE bacteremia from 2016 to 2018 at 8 New York and New Jersey medical centers and assessed center-specific clinical microbiology practices. We compared time to receipt of active antimicrobial therapy and mortality between patients whose positive blood cultures underwent rapid molecular testing for the Klebsiella pneumoniae carbapenemase (KPC) gene (blaKPC) and patients whose cultures did not undergo this test. CRE isolates underwent antimicrobial susceptibility testing by broth microdilution and carbapenemase profiling by whole-genome sequencing. We also assessed outcomes when ceftazidime-avibactam and polymyxins were used as targeted therapies.

RESULTS

Of 137 patients with CRE bacteremia, 89 (65%) had a KPC-producing organism. Patients whose blood cultures underwent blaKPC PCR testing (n = 51) had shorter time until receipt of active therapy (median: 24 vs 50 hours; P = .009) compared with other patients (n = 86) and decreased 14-day (16% vs 37%; P = .007) and 30-day (24% vs 47%; P = .007) mortality. blaKPC PCR testing was associated with decreased 30-day mortality (adjusted odds ratio: .37; 95% CI: .16-.84) in an adjusted model. The 30-day mortality rate was 10% with ceftazidime-avibactam monotherapy and 31% with polymyxin monotherapy (P = .08).

CONCLUSIONS

In a KPC-endemic area, blaKPC PCR testing of positive blood cultures was associated with decreased time until appropriate therapy and decreased mortality for CRE bacteremia, and ceftazidime-avibactam is a reasonable first-line therapy for these infections.

A culture-free biphasic approach for sensitive and rapid detection of pathogens in dried whole-blood matrix

Blood stream infections (BSIs) cause high mortality, and their rapid detection remains a significant diagnostic challenge. Timely and informed administration of antibiotics can significantly improve patient outcomes. However, blood culture, which takes up to 5 d for a negative result, followed by PCR remains the gold standard in diagnosing BSI. Here, we introduce a new approach to blood-based diagnostics where large blood volumes can be rapidly dried, resulting in inactivation of the inhibitory components in blood. Further thermal treatments then generate a physical microscale and nanoscale fluidic network inside the dried matrix to allow access to target nucleic acid. The amplification enzymes and primers initiate the reaction within the dried blood matrix through these networks, precluding any need for conventional nucleic acid purification. High heme background is confined to the solid phase, while amplicons are enriched in the clear supernatant (liquid phase), giving fluorescence change comparable to purified DNA reactions. We demonstrate single-molecule sensitivity using a loop-mediated isothermal amplification reaction in our platform and detect a broad spectrum of pathogens, including gram-positive methicillin-resistant and methicillin-susceptible Staphylococcus aureus bacteria, gram-negative Escherichia coli bacteria, and Candida albicans (fungus) from whole blood with a limit of detection (LOD) of 1.2 colony-forming units (CFU)/mL from 0.8 to 1 mL of starting blood volume. We validated our assay using 63 clinical samples (100% sensitivity and specificity) and significantly reduced sample-to-result time from over 20 h to <2.5 h. The reduction in instrumentation complexity and costs compared to blood culture and alternate molecular diagnostic platforms can have broad applications in healthcare systems in developed world and resource-limited settings.

Changes in Biomarkers and Hemodynamics According to Antibiotic Susceptibility in a Model of Bacteremia

Proper selection of susceptible antibiotics in drug-resistant bacteria is critical to treat bloodstream infection. Although biomarkers that guide antibiotic therapy have been extensively evaluated, little is known about host biomarkers targeting in vivo antibiotic susceptibility. Therefore, we aimed to evaluate the trends of hemodynamics and biomarkers in a porcine bacteremia model treated with insusceptible antibiotics compared to those in susceptible models. Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli, 5.0 * 10^9 CFU) was intravenously administered to 11 male pigs. One hour after bacterial infusion, pigs were assigned to two groups of antibiotics, ceftriaxone (n = 6) or ertapenem (n = 5). Pigs were monitored up to 7 h after bacterial injection with fluid and vasopressor support to maintain the mean arterial blood pressure over 65 mmHg. Blood sampling for blood culture and plasma acquisition was performed before and every predefined hour after E. coli injection. Cytokine (tumor necrosis factor-α, interleukin [IL]-1β, IL-6, IL-8, IL-10, C-reactive protein, procalcitonin, presepsin, heparan sulfate, syndecan, and soluble triggering receptor expressed on myeloid cells-1 [sTREM-1]) levels in plasma were analyzed using enzyme-linked immunosorbent assays. Bacteremia developed after intravenous injection of E. coli, and negative conversion was confirmed only in the ertapenem group. While trends of other biomarkers failed to show differences, the trend of sTREM-1 was significantly different between the two groups (P = 0.0001, two-way repeated measures analysis of variance). Among hemodynamics and biomarkers, the sTREM-1 level at post 2 h after antibiotics administration represented a significant difference depending on susceptibility, which can be suggested as a biomarker candidate of in vivo antibiotics susceptibility. Further clinical studies are warranted for validation.

IMPORTANCE Early and appropriate antibiotic treatment is a keystone in treating patients with sepsis. Despite its importance, blood culture which requires a few days remains as a pillar of diagnostic method for microorganisms and their antibiotic susceptibility. Whether changes in biomarkers and hemodynamics indicate treatment response of susceptible antibiotic compared to resistant one is not well understood to date. In this study using extended-spectrum β-lactamase -producing E. coli bacteremia porcine model, we have demonstrated the comprehensive cardiovascular hemodynamics and trends of plasma biomarkers in sepsis and compared them between two groups with susceptible and resistant antibiotics. While other hemodynamics and biomarkers have failed to differ, we have identified that levels of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) significantly differed between the two groups over time. Based on the data in this study, trends of sTREM-1 obtained before the antibiotics and 2~4 h after the antibiotics could be a novel host biomarker that triggers the step-up choice of antibiotics.

Temporal trends in the epidemiology, management, and outcome of sepsis-A nationwide observational study

BACKGROUND

Registry-based studies have shown increasing incidence of sepsis and declining mortality rates in recent years, but are inherently at risk of bias. The objectives of this study were to describe 11-year trends in the incidence, treatment and outcome of sepsis using clinical criteria with chart review.

METHODS

This was a retrospective, observational study. All adult admissions to Icelandic ICUs during years 2006, 2008, 2010, 2012, 2014, and 2016 were screened for severe sepsis or septic shock by ACCP/SCCM criteria (sepsis-2). Incidence, patient characteristics, treatment and outcome were compared across the study years.

RESULTS

During the six study years, 9166 patients were admitted to Icelandic ICUs, 971 (10.6%) because of severe sepsis or septic shock. The crude incidence of sepsis requiring admission to ICU remained stable between 0.55 and 0.75 per 1000 inhabitants. No statistically significant trends were observed over time in median patient age (67 years), APACHE II score (21), SOFA score (8) or Charlson Comorbidity Index (4). The time to antibiotic administration (median 1.8 h) in the emergency departments was stable over the study period but the time to lactate measurements decreased from 4.1 h in 2006 to 1.2 h in 2016, p < .001. The 28-day mortality was 25% and 1-year mortality 41%, both with no observed change with time.

CONCLUSIONS

In a nationwide cohort, diagnosed with clinical criteria, the incidence of sepsis requiring intensive care did not change over an 11-year period. Mortality remained stable and only minimal changes were observed in initial resuscitation in the emergency departments.

Population Pharmacokinetics and Dosing Optimization of Gentamicin in Critically Ill Patients Undergoing Continuous Renal Replacement Therapy

Purpose

Appropriate gentamicin dosing in continuous renal replacement therapy (CRRT) patients remains undefined. This study aimed to develop a population pharmacokinetic (PK) model of gentamicin in CRRT patients and to infer the optimal dosing regimen for gentamicin.

Methods

Fourteen CRRT patients dosed with gentamicin were included to establish a population PK model to characterize the variabilities and influential covariates of gentamicin. The pharmacokinetic/pharmacodynamic (PK/PD) target attainment and risk of toxicity for different combinations of gentamicin regimens (3–7 mg/kg q24h) and CRRT effluent doses (30–50 mL/h/kg) were evaluated by Monte Carlo simulation. The probability of target attainment (PTA) was determined for the PK/PD indices of the ratio of drug peak concentration/minimum inhibitory concentration (C_max/MIC > 10) and the ratio of area under the drug concentration–time curve/MIC over 24 h (AUC_0-24h/MIC > 100), and the risk of toxicity was estimated by drug trough concentration thresholds (1 and 2 mg/L).

Results

A one-compartment model adequately described the PK characteristics of gentamicin. Covariates including body weight, age, gender, and CRRT modality did not influence the PK parameters of gentamicin based on our dataset. All studied gentamicin regimens failed to achieve satisfactory PTAs for pathogens with an MIC ≥2 mg/L. A good balance of PK/PD target attainment and risk of toxicity (>2 mg/L) was achieved under 7 mg/kg gentamicin q24h and 40 mL/kg/h CRRT dose for an MIC ≤1 mg/L. CRRT dose intensity had a significant impact on the target attainment of AUC_0-24h/MIC >100 and risk of toxicity.

Conclusion

A combination of 7 mg/kg gentamicin q24h and 40 mL/kg/h CRRT dose might be considered as a starting treatment option for CRRT patients, and drug monitoring is required to manage toxicity.

Enhancing sepsis management through machine learning techniques: A review

Sepsis is a major public health problem and a leading cause of death in the world, where delay in the beginning of treatment, along with clinical guidelines non-adherence have been proved to be associated with higher mortality. Machine Learning is increasingly being adopted in developing innovative Clinical Decision Support Systems in many areas of medicine, showing a great potential for automatic prediction of diverse patient conditions, as well as assistance in clinical decision making. In this context, this work conducts a narrative review to provide an overview of how specific Machine Learning techniques can be used to improve sepsis management, discussing the main tasks addressed, the most popular methods and techniques, as well as the obtained results, in terms of both intelligent system accuracy and clinical outcomes improvement.

Sepsis Management, Controversies, and Advancement in Nanotechnology: A Systematic Review

Sepsis is a potentially dangerous infection that requires prompt identification and treatment. Emergency medicine physicians must grasp the clinical signs and laboratory results of direct and indirect organ failure, the source of infection management, and the criteria for treating sepsis and septic shock. The pathogenesis of sepsis is connected to inflammation and an excess of reactive oxygen and nitrogen species, which activate the pathogen-associated molecular pattern (PAMP)-pattern recognition receptor (PRR) and damage-associated molecular pattern (DAMP)-PRR signaling pathways. The development of rapid, sensitive, and precise techniques for sepsis diagnosis might be aided by nanotechnology, a part of nanomedicine. Nanoparticles (NPs) such as magnetic NPs, gold NPs, fluorescent (silica and quantum dots), and lipid-based NPs have all been discussed to contribute to the detection of sepsis-related microbial infections. Because of the intrinsic and unique features of these nano-sized systems, researchers are evaluating nanotechnology-based alternatives for sepsis control. Recent advances in nanotechnology-based technologies for sepsis detection and management are discussed in this study.

Databases (PubMed, Medline, PMC, Google Scholar) were used to source various studies that were carried out on sepsis in terms of assessment, types, diagnosis, and treatment controversies, with more attention being given with a focus on the most recent data, principles, and management guidelines. Priority was also given to studies published within the last 11 years, using keywords such as "sepsis guidelines," "sepsis clinical," "septic risk factors," "sepsis and nano technology," "nano particles," "sepsis controversies," and "nano diagnostic" in the search. After a filtration process, the eight most relevant studies were selected to be included in this review. The filtration process included the use of both inclusion and exclusion criteria. The excluded studies were pediatric populations, obstetrical populations, and nanotechnology advancements dealing with other fields not relating to sepsis. The selected studies were also undertaken through a quality appraisal process using corresponding assessment tools. The selected articles were all highly informative about sepsis and the processes of diagnosis and treatment that are currently in use as well as those that are still being developed or implemented. Furthermore, we look at how nanomedicine in the application of nanomaterials can be employed to efficiently manage sepsis.

Impact of rapid susceptibility testing on antimicrobial therapy and clinical outcomes in Gram-negative bloodstream infections

Background

Rapid antimicrobial susceptibility testing (rAST) has the potential to improve care of bloodstream infections.

Objectives

The aim of this service evaluation was to assess the impact of rAST on antimicrobial therapy and clinical outcomes in patients with Gram-negative bloodstream infection.

Methods

A prospective service evaluation was conducted from March 2018 to December 2018. A rAST system (Alfred 60AST) was run Monday–Friday before midday and results were communicated to clinicians on the same day as positive blood culture, with subsequent conventional AST performed. Times to antibiotic therapy and clinical outcomes were compared between rAST and conventional AST.

Results

One hundred and ninety-one patients with Gram-negative bacteraemia were included (93 in the rapid group and 98 in the conventional group). Aminoglycoside combination therapy was stopped earlier in the rapid group [32 h (0–795) versus 54 h (4–216), P = 0.002]. The median time to optimal antibiotic based on AST results was significantly shorter than that in the conventional group [50 h (10–339) versus 69.5 h (20–872), P = 0.034]. In the subgroup of patients on ineffective empirical antibiotic, time to effective antibiotic was shorter in the rapid group [39.5 h (32–97) versus 57 h (49–83), P = 0.036]. No differences were found in 28 day mortality or length of stay.

Conclusions

Rapid susceptibility testing resulted in faster discontinuation of aminoglycosides and a shorter time to starting effective and optimal antibiotic when compared with conventional AST results. rAST has potential clinical benefits and points to the need for larger future studies in areas of high antibiotic resistance.

Factors Affecting the Time to First Dose Antibiotic in Sepsis in Acute Emergency

Background

The Surviving Sepsis Campaign recommends the administration of antibiotics within 1 hour of triage time in sepsis patients. The purpose of this study was to determine the factors affecting the time to first dose antibiotics in sepsis patients presenting to the emergency department (ED).

Methods

We conducted a prospective observational study on factors affecting the time to first dose antibiotics in patients with sepsis presenting to the ED over a period of 7 months (July 2019 to January 2020). The purpose of this study was to determine the factors affecting the time to first dose antibiotics in sepsis patients.

Results

During the study period, a total of 410 patients with a mean age of 51.6 years were presented to the ED with sepsis. Majority was triaged to priority 1 (84.8%). The median door to antibiotic time was 50 minutes (IQR, 40–90). Two-thirds (68%) of the patients (279) received antibiotics within 60 minutes. The blood culture positivity rate was 22.9%, and the contamination rate was 6%. The most common factors for the delay were atypical presentation (36.6%) and unknown focus of infection (36.6%). Triage to non-acute areas of the ED (priority 2) was associated with delayed antibiotic administration [odds ratio (OR), 7.3; 95% confidence interval (CI), 4.03–13.36; p-value <0.001]. Patients presented with cellulitis and necrotizing soft tissue infection (NSTI) had received antibiotics within an hour compared to other diagnoses (18.3 vs 8.4%; OR, 2.4; 95% CI, 1.2–4.9; p = 0.009).

Conclusion

Two-thirds of our patients received their first dose of antibiotics within an hour of presentation to the ED. Triage to lower priorities was an independent risk factor for delay in first-dose antibiotic administration, and patients presented with an obvious focus of infections like cellulitis and NSTI received their first dose of antibiotic much earlier when compared to other diagnoses.

How to cite this article

Joseph JV, Madhiyazhagan M, Roshan R, Dhanapal SG, Arul S, Abhilash KPP. Factors Affecting the Time to First Dose Antibiotic in Sepsis in Acute Emergency. Indian J Crit Care Med 2021;25(10):1155–1160.

Biomarker-Guided Individualization of Antibiotic Therapy

Treatment failure of antibiotic therapy due to insufficient efficacy or occurrence of toxicity is a major clinical challenge, and is expected to become even more urgent with the global rise of antibiotic resistance. Strategies to optimize treatment in individual patients are therefore of crucial importance. Currently, therapeutic drug monitoring plays an important role in optimizing antibiotic exposure to reduce treatment failure and toxicity. Biomarker-based strategies may be a powerful tool to further quantify and monitor antibiotic treatment response, and reduce variation in treatment response between patients. Host response biomarkers, such as CRP, procalcitonin, IL-6, and presepsin, could potentially carry significant information to be utilized for treatment individualization. To achieve this, the complex interactions among immune system, pathogen, drug, and biomarker need to be better understood and characterized. The purpose of this tutorial is to discuss the use and evidence of currently available biomarker-based approaches to inform antibiotic treatment. To this end, we also included a discussion on how treatment response biomarker data from preclinical, healthy volunteer, and patient-based studies can be further characterized using pharmacometric and system pharmacology based modeling approaches. As an illustrative example of how such modeling strategies can be used, we describe a case study in which we quantitatively characterize procalcitonin dynamics in relation to antibiotic treatments in patients with sepsis.

Clinical impact of procalcitonin-based algorithms for duration of antibiotic treatment in critically ill adult patients with sepsis: a meta-analysis of randomized clinical trials

Background: Our objective was to assess the impact on mortality, antibacterial therapy duration, and length of stay of using PCT to guide antibiotic cessation in critically ill patients with sepsis or septic shock.Research design and Methods: A systematic literature search was performed in PubMed, Embase, ISI Web of Knowledge, BioMed Central, ScienceDirect and the Cochrane Central Register of Controlled Trials, of clinical trials published in English before December 31, 2019. Eligible studies should be carried out in adults at ICU with sepsis, comparing the PCT-guided antimicrobial therapy with standard of care. A random effects model was used.Results: Twelve studies were eligible with a total of 4292 patients included. The combined relative risk for 28-day mortality was 0.89 (95% CI: 0.79; 0.99), for the duration of antimicrobial therapy was -1.98 days (95% CI: -2.76, -1.21) and for ICU- length of stay was-1.21 days (95% CI: -4.16, 1.74).Conclusions: In critically ill adults with sepsis, a procalcitonin-guided strategy is associated with a significant shorter duration of antimicrobial therapy. This reduction was associated with a significant decrease in mortality although the length of ICU stay was not affected.

Potential Tamoxifen Repurposing to Combat Infections by Multidrug-Resistant Gram-Negative Bacilli

The development of new strategic therapies for multidrug-resistant bacteria, like the use of non-antimicrobial approaches and/or drugs repurposed to be used as monotherapies or in combination with clinically relevant antibiotics, has become urgent. A therapeutic alternative for infections by multidrug-resistant Gram-negative bacilli (MDR-GNB) is immune system modulation to improve the infection clearance. We showed that immunocompetent mice pretreated with tamoxifen at 80 mg/kg/d for three days and infected with Acinetobacter baumannii, Pseudomonas aeruginosa, or Escherichia coli in peritoneal sepsis models showed reduced release of the monocyte chemotactic protein-1 (MCP-1) and its signaling pathway interleukin-18 (IL-18), and phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2). This reduction of MCP-1 induced the reduction of migration of inflammatory monocytes and neutrophils from the bone marrow to the blood. Indeed, pretreatment with tamoxifen in murine peritoneal sepsis models reduced the bacterial load in tissues and blood, and increased mice survival from 0% to 60–100%. Together, these data show that tamoxifen presents therapeutic efficacy against MDR A. baumannii, P. aeruginosa, and E. coli in experimental models of infection and may be a new candidate to be repurposed as a treatment for GNB infections.

Gene Expression Profiling of Pseudomonas aeruginosa Upon Exposure to Colistin and Tobramycin

Pseudomonas aeruginosa (Pae) is notorious for its high-level resistance toward clinically used antibiotics. In fact, Pae has rendered most antimicrobials ineffective, leaving polymyxins and aminoglycosides as last resort antibiotics. Although several resistance mechanisms of Pae are known toward these drugs, a profounder knowledge of hitherto unidentified factors and pathways appears crucial to develop novel strategies to increase their efficacy. Here, we have performed for the first time transcriptome analyses and ribosome profiling in parallel with strain PA14 grown in synthetic cystic fibrosis medium upon exposure to polymyxin E (colistin) and tobramycin. This approach did not only confirm known mechanisms involved in colistin and tobramycin susceptibility but revealed also as yet unknown functions/pathways. Colistin treatment resulted primarily in an anti-oxidative stress response and in the de-regulation of the MexT and AlgU regulons, whereas exposure to tobramycin led predominantly to a rewiring of the expression of multiple amino acid catabolic genes, lower tricarboxylic acid (TCA) cycle genes, type II and VI secretion system genes and genes involved in bacterial motility and attachment, which could potentially lead to a decrease in drug uptake. Moreover, we report that the adverse effects of tobramycin on translation are countered with enhanced expression of genes involved in stalled ribosome rescue, tRNA methylation and type II toxin-antitoxin (TA) systems.

Revisiting the epidemiology of bloodstream infections and healthcare-associated episodes: results from a multicentre prospective cohort in Spain (PRO-BAC Study)

The epidemiology of bloodstream infections (BSIs) is dynamic as it depends on microbiological, host and healthcare system factors. The aim of this study was to update the information regarding the epidemiology of BSIs in Spain considering the type of acquisition. An observational, prospective cohort study in 26 Spanish hospitals from October 2016 through March 2017 including all episodes of BSI in adults was performed. Bivariate analyses stratified by type of acquisition were performed. Multivariate analyses were performed by logistic regression. Overall, 6345 BSI episodes were included; 2510 (39.8%) were community-acquired (CA), 1661 (26.3%) were healthcare-associated (HCA) and 2056 (32.6%) hospital-acquired (HA). The 30-day mortality rates were 11.6%, 19.5% and 22.0%, respectively. The median age of patients was 71 years (interquartile range 60-81 years) and 3656 (58.3%; 95% confidence interval 57.1-59.6%) occurred in males. The proportions according to patient sex varied according to age strata. Escherichia coli (43.8%), Klebsiella spp. (8.9%), Staphylococcus aureus (8.9%) and coagulase-negative staphylococci (7.4%) were the most frequent pathogens. Multivariate analyses confirmed important differences between CA and HCA episodes, but also between HCA and HA episodes, in demographics, underlying conditions and aetiology. In conclusion, we have updated the epidemiological information regarding patients' profiles, underlying conditions, frequency of acquisition types and aetiological agents of BSI in Spain. HCA is confirmed as a distinct type of acquisition.

Sepsis after elective surgery - Incidence, aetiology and outcome

BACKGROUND

Sepsis requiring admission to intensive care (ICU) is a rare complication of elective surgery, but is associated with high morbidity and mortality. The aim of this study was to describe the incidence and outcome of sepsis following elective surgery.

METHODS

This was a retrospective, observational study where all admissions to Icelandic ICUs during calendar years 2006, 2008, 2010, 2012, 2014 and 2016 were screened, identifing patients with sepsis following elective surgery (ACCP/SCCM criteria). The number of elective operations performed at the largest center (Landspitali) during the study years were collected. Descriptive statistics were used to assess the incidence and outcome of patients with sepsis after elective surgery.

RESULTS

During the study years, 88 patients were admitted to Icelandic ICUs with sepsis following elective surgery. Of those, 80 were operated at Landspitali, where the incidence of sepsis was 0.19% per elective procedure, highest following pancreaticoduodenectomies (14%, CI 6-25) and esophagectomies (13%, CI 4-27), but the greatest number of patients (30% (26/88)) developed sepsis after a colorectal procedure. The most common infection sources were the abdomen (65% (57/88)) and lungs/mediastinum (22% (19/88)), frequently polymicrobial (58% (36/62) of patients with cultures). The incidence of insufficient empirical antibiotics was high (50% (30/60)). The median ICU and hospital length-of-stay were 5.5 and 26 days and the 28-day and 1-year mortality rates were 16% (14/88) and 41% (36/87), respectively.

CONCLUSIONS

Incidence of sepsis following elective surgery is low in Iceland but mortality is high. Initial antimicrobial therapy needs careful consideration in these hospital-acquired, often polymicrobial infections.

Advances in sepsis diagnosis and management: a paradigm shift towards nanotechnology

Sepsis, a dysregulated immune response due to life-threatening organ dysfunction, caused by drug-resistant pathogens, is a major global health threat contributing to high disease burden. Clinical outcomes in sepsis depend on timely diagnosis and appropriate early therapeutic intervention. There is a growing interest in the evaluation of nanotechnology-based solutions for sepsis management due to the inherent and unique properties of these nano-sized systems. This review presents recent advancements in nanotechnology-based solutions for sepsis diagnosis and management. Development of nanosensors based on electrochemical, immunological or magnetic principals provide highly sensitive, selective and rapid detection of sepsis biomarkers such as procalcitonin and C-reactive protein and are reviewed extensively. Nanoparticle-based drug delivery of antibiotics in sepsis models have shown promising results in combating drug resistance. Surface functionalization with antimicrobial peptides further enhances efficacy by targeting pathogens or specific microenvironments. Various strategies in nanoformulations have demonstrated the ability to deliver antibiotics and anti-inflammatory agents, simultaneously, have been reviewed. The critical role of nanoformulations of other adjuvant therapies including antioxidant, antitoxins and extracorporeal blood purification in sepsis management are also highlighted. Nanodiagnostics and nanotherapeutics in sepsis have enormous potential and provide new perspectives in sepsis management, supported by promising future biomedical applications included in the review.

Bacterial and Fungal Etiology of Sepsis in Children in the United States: Reconsidering Empiric Therapy

OBJECTIVES

Timely empiric antimicrobial therapy is associated with improved outcomes in pediatric sepsis, but minimal data exist to guide empiric therapy. We sought to describe the prevalence of four pathogens that are not part of routine empiric coverage (e.g., Staphylococcus aureus, Pseudomonas aeruginosa, Clostridium difficile, and fungal infections) in pediatric sepsis patients in a contemporary nationally representative sample.

DESIGN

This was a retrospective cohort study using administrative data.

SETTING

We used the Nationwide Readmissions Database from 2014, which is a nationally representative dataset that contains data from nearly half of all discharges from nonfederal hospitals in the United States.

PATIENTS

Discharges of patients who were less than 19 years old at discharge and were not neonatal with a discharge diagnosis of sepsis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of the 19,113 pediatric admissions with sepsis (6,300 [33%] previously healthy and 12,813 [67%] with a chronic disease), 31% received mechanical ventilation, 19% had shock, and 588 (3.1%) died during their hospitalization. Among all admissions, 8,204 (42.9%) had a bacterial or fungal pathogen identified. S. aureus was the most common pathogen identified in previously healthy patients (n = 593, 9.4%) and those with any chronic disease (n = 1,430, 11.1%). Methicillin-resistant S. aureus, P. aeruginosa, C. difficile, and fungal infections all had high prevalence in specific chronic diseases associated with frequent contact with the healthcare system, early surgery, indwelling devices, or immunosuppression.

CONCLUSIONS

In this nationally representative administrative database, the most common identified pathogen was S. aureus in previously healthy and chronically ill children. In addition, a high proportion of children with sepsis and select chronic diseases had infections with methicillin-resistant S. aureus, fungal infections, Pseudomonas infections, and C. difficile. Clinicians caring for pediatric patients should consider coverage of these organisms when administering empiric antimicrobials for sepsis.

Bacterial Isolation Microwell-Plug (μWELLplug) for Rapid Antibiotic Susceptibility Testing Using Morphology Analysis

The rapid and accurate diagnosis of infectious diseases with high morbidity rates is crucial because it can minimize the misuse and overuse of antibiotics and increase survival rates in dreadful conditions. The conventional antibiotic susceptibility test (AST) systems used to choose appropriate antibiotics require long wait times to obtain results and cannot prevent the misuse or overuse of antibiotics by clinicians who need to quickly treat patients and cannot wait to identify the underlying cause of their symptoms. Therefore, several rapid AST (rAST) methods have been developed to provide quick test results, but they are complicated to operate, require additional equipment or materials, and give less accurate results than the conventional AST methods. In this study, we propose an rAST method that can obtain precise outcomes from a simple process with a short running time using a bacterial isolation microwell-plug (μWELLplug) in a conventional 96-well plate. The specifically designed hydrogel component of the μWELLplug provides a simple process for cell isolation and the observation of bacterial growth and morphological changes induced by a variety of antibiotic concentrations. The μWELLplug is placed over each well of the 96-well plate, and then bacterial or eukaryotic cells are isolated in the microwells and treated with different antibiotic concentrations to observe their effects. Saccharomyces cerevisiae (yeast, eukaryote), Streptomyces atratus (actinomycetes, prokaryote), Escherichia coli, Staphylococcus aureus, and methicillin-resistant S. aureus were cultivated and tested using the μWELLplug. The minimum inhibitory concentration values from this system were obtained in 3-4 h and correlated well with those from the conventional AST methods whose running time is 18-24 h.

A retrospective observational study of antibiotics treatment for sepsis using a nationwide claim database in Japan

Survival Sepsis Campaign (SSC) guidelines have recommended broad-spectrum antibiotics prescriptions to cover the possible pathogenic microorganisms. However, mortality from sepsis is still high, as about one quarter of cases are thought to result in death. We analyzed nationwide health claims data of universal health insurance systems in Japan. Our aim was to describe the antibiotics prescriptions and underlying conditions of Japanese sepsis patients. In addition, we analyzed the factors associated with 30-day mortality. A total of 1188 patients aged ≥15 years were entered, of which 80.1% were ≥65 years old. Broad-spectrum antibiotics were prescribed for 53.8%. Carbapenem, Piperacillin Tazobactam and Anti-pseudomonas Cephalosporin were prescribed for 30.8%, 13.0% and 12.2% of the patients, respectively. (Some patients were counted twice) The overall 30-day mortality rate was 21.3%. Risk factors associated with 30-day mortality were examined by Cox proportional hazards regression analysis. Age of ≥85 years, malignancy, chronic kidney disease (CKD), shock and respiratory failure were selected as risk factors, but broad-spectrum antibiotics was not included. Sepsis is mostly observed in those aged 65 years and over. The rates of broad-spectrum antibiotics were restricted, and antibiotics were also not necessarily prescribed on the basis of SSC guidelines. However, broad-spectrum antibiotics did not improve the treatment outcome. Aging and underlying conditions like malignancy, CKD, shock and respiratory failure were poor prognostic factors.

In-vitro Investigation of Antibiotics Efficacy Against Uropathogenic Escherichia coli Biofilms and Antibiotic Induced Biofilm Formation at Sub-Minimum Inhibitory Concentration of Ciprofloxacin

Background

Community-acquired urinary tract infections are associated with significant morbidity, and uropathogenic Escherichia coli (UPEC) alone causes 90% of urinary tract infections. This bacterium retains a diverse armament of virulence factors including fimbria, hemolysins, and siderophores production. In a post invasion scenario, formation of intracellular communities mimic biofilm-like characteristics and are linked to recurrent urinary tract infections. We investigated the effects of different frontline antibiotics on the formation, inhibition, and eradication of biofilms of virulent UPEC strains.

Materials and Methods

A total of 155 UPEC strains were scrutinized for various virulence factors including gelatinase, cell surface hydrophobicity, hemagglutination, and serum bactericidal activity. Biofilm formation was confirmed by three different methods: Congo red agar, test tube, and tissue culture plate method. Biofilm inhibition and eradication assays were performed according to the standard protocols. Topographical analysis of biofilms was done by scanning electronic microscopy (SEM).

Results

Out of 155 strains, 113 (73%) were strong biofilm formesr, while 37 (24%) produced biofilms at moderate level. Significant differences were observed between MICs of planktonic cells (MIC-p) and MICs of UPEC biofilms (MIC-b). Among tested frontline antibiotics, levofloxacin successfully inhibited biofilms at a concentration of 32 µg/mL, while trimethoprim eradicated biofilms at higher concentrations (512–1024 µg/mL). Ciprofloxacin treatment at sub-MIC level significantly enhanced biofilm formation (P<0.05).

Conclusion

The majority of UPEC strains are strong biofilm formers and show higher tolerance towards frontline antibiotics in biofilm form. We observed significant inhibitory effects of levofloxacin (32 µg/mL) on UPEC biofilms, while treatment with sub-minimal concentrations of ciprofloxacin significantly enhanced biofilm formation. Out of all tested antibiotics, trimethoprim (512–1024 µg/mL) eradicated UPEC biofilms.

Antibiotic treatment in patients with sepsis: a narrative review

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

Enhancing sepsis management through machine learning techniques: A review

Sepsis is a major public health problem and a leading cause of death in the world, where delay in the beginning of treatment, along with clinical guidelines non-adherence have been proved to be associated with higher mortality. Machine Learning is increasingly being adopted in developing innovative Clinical Decision Support Systems in many areas of medicine, showing a great potential for automatic prediction of diverse patient conditions, as well as assistance in clinical decision making. In this context, this work conducts a narrative review to provide an overview of how specific Machine Learning techniques can be used to improve sepsis management, discussing the main tasks addressed, the most popular methods and techniques, as well as the obtained results, in terms of both intelligent system accuracy and clinical outcomes improvement.

ERS International Congress, Madrid, 2019: highlights from the Respiratory Infections Assembly

The European Respiratory Society (ERS) International Congress organised in Madrid, Spain, in 2019 welcomed >22 000 participants from 134 countries. For each ERS assembly, an impressive number of abstracts were submitted. The topics covered by Assembly 10 (Respiratory Infections and Tuberculosis) were included this year in the top five research areas with the most submitted abstracts, with a total of 424 abstracts accepted for presentation. As it would be difficult for any delegate to stay up to date with all the scientific advances in the field, we wanted to highlight three of the Congress sessions that included presentations on respiratory infections and tuberculosis that we deemed as important and we hope the readers will consider this material of great interest.

Clinical Performance of the Novel GenMark Dx ePlex Blood Culture ID Gram-Positive Panel

Rapid identification from positive blood cultures is standard of care (SOC) in many clinical microbiology laboratories. The GenMark Dx ePlex Blood Culture Identification Gram-Positive (BCID-GP) Panel is a multiplex nucleic acid amplification assay based on competitive DNA hybridization and electrochemical detection using eSensor technology. This multicenter study compared the investigational-use-only (IUO) BCID-GP Panel to other methods of identification of 20 Gram-positive bacteria, four antimicrobial resistance genes, and both Pan Candida and Pan Gram-Negative targets that are unique to the BCID-GP Panel.

Rapid identification from positive blood cultures is standard of care (SOC) in many clinical microbiology laboratories. The GenMark Dx ePlex Blood Culture Identification Gram-Positive (BCID-GP) Panel is a multiplex nucleic acid amplification assay based on competitive DNA hybridization and electrochemical detection using eSensor technology. This multicenter study compared the investigational-use-only (IUO) BCID-GP Panel to other methods of identification of 20 Gram-positive bacteria, four antimicrobial resistance genes, and both Pan Candida and Pan Gram-Negative targets that are unique to the BCID-GP Panel. Ten microbiology laboratories throughout the United States collected residual, deidentified positive blood culture samples for analysis. Five laboratories tested both clinical and contrived samples with the BCID-GP Panel. Comparator identification methods included each laboratory’s SOC, which included matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) and automated identification systems as well as targeted PCR/analytically validated real-time PCR (qPCR) with bidirectional sequencing. A total of 2,342 evaluable samples (1,777 clinical and 565 contrived) were tested with the BCID-GP Panel. The overall sample accuracy for on-panel organisms was 89% before resolution of discordant results. For pathogenic Gram-positive targets (Bacillus cereus group, Enterococcus spp., Enterococcus faecalis, Enterococcus faecium, Staphylococcus spp., Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus lugdunensis, Listeria spp., Listeria monocytogenes, Streptococcus spp., Streptococcus agalactiae, Streptococcus anginosus group, Streptococcus pneumoniae, and Streptococcus pyogenes), positive percent agreement (PPA) and negative percent agreement (NPA) ranged from 93.1% to 100% and 98.8% to 100%, respectively. For contamination rule-out targets (Bacillus subtilis group, Corynebacterium, Cutibacterium acnes, Lactobacillus, and Micrococcus), PPA and NPA ranged from 84.5% to 100% and 99.9% to 100%, respectively. Positive percent agreement and NPA for the Pan Candida and Pan Gram-Negative targets were 92.4% and 95.7% for the former and 99.9% and 99.6% for the latter. The PPAs for resistance markers were as follows: mecA, 97.2%; mecC, 100%; vanA, 96.8%; and vanB, 100%. Negative percent agreement ranged from 96.6% to 100%. In conclusion, the ePlex BCID-GP Panel compares favorably to SOC and targeted molecular methods for the identification of 20 Gram-positive pathogens and four antimicrobial resistance genes in positive blood culture bottles. This panel detects a broad range of pathogens and mixed infections with yeast and Gram-negative organisms from the same positive blood culture bottle.

Appropriateness of empirical antibiotics: risk factors of adult patients with sepsis in the ICU

Background The appropriateness of antibiotics is the basis for improving the survival of patients with sepsis. Objective This study aimed to determine the appropriateness of empirical antibiotics, reasons for non-appropriate empirical antibiotics, risk factors of mortality, length of stay in intensive care unit (ICU-LOS) and Acute Physiology And Chronic Health Evaluation II (APACHE II) score predictors in adult patients with sepsis. Setting An adult ICU of a tertiary hospital in  Malaysia. Methods A retrospective cohort study was conducted amongst patients with sepsis. Data were retrieved from the patients' files and computer system. Each case was reviewed for the appropriateness of empirical antibiotics based on ICU local guidelines, bacterial sensitivity, dose, frequency, creatinine clearance and time of administration of empirical antibiotics. Multivariable logistic and Cox regression modelling were performed to compute the adjusted association of receiving appropriate or inappropriate empirical antibiotics with ICU mortality. Multivariable linear regression modelling was performed using ICU-LOS and APACHE II scores. Main outcome measures were ICU mortality, severity score (APACHE II scores) and ICU-LOS. Results The total mortality rate amongst the 228 adult ICU patients was 84.6%. Males showed a higher mortality rate (119 [52.2%]) than females (74 [32.5%]). Inappropriate empirical antibiotics were significantly associated with mortality and ICU-LOS (P < 0.005). Results from multivariable logistic regression showed that the appropriateness of empirical antibiotics model was a potential predictor for survival (OR 0.395, 95% CI 0.184-0.850, P < 0.005). Results from simple linear regression indicated that the appropriateness of empirical antibiotics model was a remarkable predictor of decreasing ICU-LOS (R² = 0.055, 95% CI - 7.184 to - 2.114, P < 0.001). Results from simple Cox regression suggested that the appropriateness of empirical antibiotics was a protective factor for ICU mortality (HR 0.610, 95% CI 0.433-0.858, P = 0.005). Multivariable Cox regression revealed that the administration of antibiotics exceeding the recommended dose based on creatinine clearance was a protective factor (HR 0.186, 95% CI 0.040-0.868, P = 0.032). Conclusion The appropriateness of empirical antibiotics is a good predictor for improving survival and decreasing ICU-LOS. Effective appropriateness of empirical antibiotics use and close adherence to the recommended dose can prevent the early mortality of patients with sepsis and acute renal failure.

An approach to antibiotic treatment in patients with sepsis

Sepsis is a medical emergency and life-threatening condition due to a dysregulated host response to infection, which is time-dependent and associated with unacceptably high mortality. Thus, when treating suspicious or confirmed cases of sepsis, clinicians must initiate broad-spectrum antimicrobials within the first hour of diagnosis. Optimizing antibiotic use is essential to ensure successful outcomes and to reduce adverse antibiotic effects, as well as preventing drug resistance. All likely pathogens involved should be considered to provide an appropriate antibiotic coverage. Clinicians must investigate on the previous risk of multidrug-resistant (MDR) pathogens, and the principle of individualized dosing should replace the principle of standard dosing. The loading dose is an initial higher dose of an antibiotic for all patients, yet an individualized treatment approach for further doses should be implemented according to pharmacokinetics (PK)/pharmacodynamics (PD) and the presence of renal/liver dysfunction. Extended or continuous infusion of beta-lactams and therapeutic drug monitoring (TDM) can help to achieve therapeutic levels of antimicrobials. Reevaluation of duration and appropriateness of treatment at regular intervals are also necessary. De-escalation and shortened courses of antimicrobials must be considered for most patients, except in some justified circumstances. Leadership, teamwork, antimicrobial stewardship (AS) frameworks, guideline’s recommendations on the optimal duration of treatments, de-escalation, and novel diagnostic stewardship approaches will help us to improve patients’ quality of care.

Carbapenem Treatment and Outcomes Among Patients With Culture-Positive Complicated Intra-abdominal Infections in US Hospitals: A Retrospective Cohort Study

Background

Carbapenems are a frequent firstline therapy in complicated intra-abdominal infections (cIAIs). We examined the microbiology, epidemiology, and outcomes among patients hospitalized in the United States with culture-positive cIAIs in the context of their exposure to empiric carbapenem treatment (ECT).

Methods

We performed a multicenter retrospective cohort study of Premier database of ~180 hospitals, 2013–2017. Using an International Classification of Diseases (ICD)-9/10-based algorithm, we identified all culture-positive adult patients hospitalized with cIAI and examined their microbiology, epidemiology, and outcomes.

Results

Among 4453 patients with cIAIs, 3771 (84.7%) had a gram-negative (GN) and 1782 (40.0%) a gram-positive organism; 1185 (26.6%) received ECT. Compared with those on non-ECT, patients on ECT were less frequently admitted from home (82.5% vs 86.0%) or emergently (76.0% vs 81.4%; P < .05 for each); E. coli were less frequent, whereas P. aeruginosa and Enterococcus spp. were more prevalent and resistance to third-generation cephalosporins (C3R; 10.1% vs 5.1%; P < .001) and carbapenems (CR; 3.6% vs 1.2%; P < .001) was more common. In adjusted analyses, ECT was associated with no rise in mortality, shorter postinfection length of stay (–0.59 days; 95% confidence interval [CI], –1.15 to –0.03), but higher postinfection costs ($3844; 95% CI, $1921 to $5767) and risk of Clostridioides difficile (odds ratio, 2.15; 95% CI, 1.02 to 4.50).

Conclusions

Among patients hospitalized with cIAI, the majority were gram-negative. Despite a 10% prevalence of C3R, fully one-quarter of all empiric regimens contained a carbapenem. ECT was a marker for slightly lower postinfection length of stay, but higher costs and risk of hospital complications.

Determination of optimal loading and maintenance doses for continuous infusion of vancomycin in critically ill patients: Population pharmacokinetic modelling and simulations for improved dosing schemes

OBJECTIVES

Despite extensive clinical use, limited data are available on optimal loading and maintenance doses of vancomycin in critically ill patients. This study aimed to develop a rational approach for optimised dosage of vancomycin given in a continuous infusion in critically ill patients.

METHODS

Vancomycin pharmacokinetic (PK) data (total serum concentrations) were obtained from 55 intensive care unit (ICU) patients (Bach Mai Hospital, Hanoi, Vietnam) receiving a 20 mg/kg loading dose followed by continuous infusion stratified by creatinine clearance (CLCr). Population PK modelling and Monte Carlo simulations were performed using a nonlinear mixed-effects modelling (NONMEM) program for a target of 20-30 mg/L to optimise efficacy and minimise nephrotoxicity.

RESULTS

A two-compartment model with first-order elimination best fitted the PK data with central and peripheral volumes of distribution of 1.01 and 2.39 L/kg, respectively (allometric scaling to a 70 kg standard subject). The population total clearance of 3.63 L/h was only explained by renal function in the covariate and final model. The simulations showed that a 25-mg/kg loading dose infused over 90 minutes was optimal to reach the target range. The optimal maintenance dose for low renal function (CLCr < 45 mL/min) was 1000-1500 mg/day. For augmented renal clearance (CLCr > 130 mL/min) the dose should be up to 3500 mg/day or even 4500 mg/day to achieve adequate exposure. These simulated maintenance doses were larger than previously proposed for non-ICU patients.

CONCLUSION

Large loading and maintenance doses of vancomycin are generally needed in critically ill patients. Because of high interindividual variability in vancomycin PK, drug monitoring may still be necessary.

Differential roles of comorbidity burden and functional status in elderly and non-elderly patients with infections in general wards

BACKGROUND

Differential roles of comorbidity burden, functional status and severity of illness in elderly and non-elderly patients admitted to general wards with infections in terms of short-term and long-term mortality remain poorly understood and worth further investigation.

METHODS

From 2011 to 2013, patients admitted to general wards with a main diagnosis of infections were included and their Barthel index, Charlson comorbidity index and Pitt bacteremia score were collected to evaluate their association with in-hospital and 1-year outcomes of the study cohort. Age stratification was applied for all outcome analysis.

RESULTS

A total of 2481 patients were identified, with main diagnoses of pneumonia (57%), urinary tract infection (28%) and intra-abdominal infection (18%). In-hospital mortality occurred in 291 (12%) of the population and was independently predicted by Barthel index ≤50 (odds ratio [OR] 5.67 and 2.73, respectively) and Charlson comorbidity index >2 (OR 1.49 and 2.87, respectively) in both elderly and non-elderly patients. Among 2190 hospital survivors, Barthel index ≤50 (hazard ratio [HR] 1.38) and Charlson comorbidity index >2 (HR 1.96) were associated with a higher hazard of 1-year mortality in elderly patients. However, only Charlson comorbidity index >2 (HR 2.87) was a significant characteristic of non-elderly patients to be correlated with higher 1-year mortality.

CONCLUSION

This study found that functional status on admission was predictive of in-hospital mortality of general patients with infections irrespective of age groups; however, it played a differential role in 1-year mortality in between elderly and non-elderly patients, emphasizing the importance of functional assessment among the elderly.

Repeated determination of moxifloxacin concentrations in interstitial space fluid of muscle and subcutis in septic patients

BACKGROUND

For an effective antimicrobial treatment, it is crucial that antibiotics reach sufficient concentrations in plasma and tissue. Currently no data exist regarding moxifloxacin plasma concentrations and exposure levels in tissue under septic conditions.

OBJECTIVES

To determine the pharmacokinetics of moxifloxacin in plasma and interstitial space fluid over a prolonged period.

PATIENTS AND METHODS

Ten septic patients were treated with 400 mg of moxifloxacin once a day; on days 1, 3 and 5 of treatment plasma sampling and microdialysis in the subcutis and muscle of the upper thigh were performed to determine concentrations of moxifloxacin in different compartments. This trial was registered in the German Clinical Trials Register (DRKS, register number DRKS00012985).

RESULTS

Mean unbound fraction of moxifloxacin in plasma was 85.5±3.4%. On day 1, Cmax in subcutis and muscle was 2.8±1.8 and 2.5±1.3 mg/L, respectively, AUC was 24.8±15.1 and 21.3±10.5 mg·h/L, respectively, and fAUC0-24/MIC was 100.9±62.9 and 86.5±38.3 h, respectively. Cmax for unbound moxifloxacin in plasma was 3.5±0.9 mg/L, AUC was 23.5±7.5 mg·h/L and fAUC0-24/MIC was 91.6±24.8 h. Key pharmacokinetic parameters on days 3 and 5 showed no significant differences. Clearance was higher than in healthy adults, but tissue concentrations were comparable, most likely due to a lower protein binding.

CONCLUSIONS

Surprisingly, the first dose already achieved exposure comparable to steady-state conditions. The approved daily dose of 400 mg was adequate in our patient population. Thus, it seems that in septic patients a loading dose on the first day of treatment with moxifloxacin is not required.

Real World Patterns of Antimicrobial Use and Microbiology Investigations in Patients with Sepsis outside the Critical Care Unit: Secondary Analysis of Three Nation-Wide Point Prevalence Studies

Recent description of the microbiology of sepsis on the wards or information on the real-life antibiotic choices used in sepsis is lacking. There is growing concern of the indiscriminate use of antibiotics and omission of microbiological investigations in the management of septic patients. We performed a secondary analysis of three annual 24-h point-prevalence studies on the general wards across all Welsh acute hospitals in years 2016–2018. Data were collected on patient demographics, as well as radiological, laboratory and microbiological data within 48-h of the study. We screened 19,453 patients over the three 24 h study periods and recruited 1252 patients who fulfilled the entry criteria. 775 (64.9%) patients were treated with intravenous antibiotics. Only in 33.65% (421/1252) of all recruited patients did healthcare providers obtain blood cultures; in 25.64% (321/1252) urine cultures; in 8.63% (108/1252) sputum cultures; in 6.79% (85/1252) wound cultures; in 15.25% (191/1252) other cultures. Out of the recruited patients, 59.1% (740/1252) fulfilled SEPSIS-3 criteria. Patients with SEPSIS-3 criteria were significantly more likely to receive antibiotics than the non-septic cohort (p < 0.0001). In a multivariable regression analysis increase in SOFA score, increased number of SIRS criteria and the use of the official sepsis screening tool were associated with antibiotic administration, however obtaining microbiology cultures was not. Our study shows that antibiotics prescription practice is not accompanied by microbiological investigations. A significant proportion of sepsis patients are still at risk of not receiving appropriate antibiotics treatment and microbiological investigations; this may be improved by a more thorough implementation of sepsis screening tools.

Community versus hospital-acquired pneumonia in patients requiring extracorporeal membrane oxygenation

Background:

Bacterial pneumonia is a major cause of acute respiratory distress syndrome (ARDS) requiring extracorporeal membrane oxygenation (ECMO) support. However, it is unknown whether the type of pneumonia, community-acquired pneumonia (CAP) versus hospital-acquired pneumonia (HAP), should be considered when predicting outcomes for ARDS patients treated with ECMO.

Methods:

We divided a sample of adult patients receiving ECMO for acute respiratory distress syndrome caused by bacterial pneumonia between January 2012 and December 2016 into CAP (n = 21) and HAP (n = 35) groups and compared clinical and bacteriological characteristics and outcomes.

Results:

The median acute physiology and chronic health evaluation II and sequential organ failure assessment scores were 22 and 8, respectively, in the CAP and HAP groups. The most commonly identified organism in the CAP group was Streptococcus pneumonia (n = 12, 57.1%), while Acinectobacter baumanii was the most commonly identified in the HAP group (n = 13, 37.1%). However, the incidence of multidrug resistant bacteria was not different between groups (57.1% versus 74.3%, p = 0.125). Of the 56 patients in the study, 26 were successfully weaned from ECMO, and 20 were discharged from the hospital. There were no significant differences in ECMO weaning rate (47.6% versus 45.7%, p > 0.999) or survival to discharge rate (33.3% versus 37.1%, p > 0.999) between the two groups. The 30-day and 90-day mortality rates were also similar.

Conclusion:

Patients with CAP and HAP who received ECMO for respiratory support had similar characteristics and clinical outcomes.

When not to start antibiotics: avoiding antibiotic overuse in the intensive care unit

BACKGROUND

Most intensive care unit (ICU) patients receive broad-spectrum antibiotics. While lifesaving in some, in others these treatments may be unnecessary and place patients at risk of antibiotic-associated harms.

OBJECTIVES

To review the literature exploring how we diagnose infection in patients in the ICU and address the safety and utility of a 'watchful waiting' approach to antibiotic initiation with selected patients in the ICU.

SOURCES

A semi-structured search of PubMed and Cochrane Library databases for articles published in English during the past 15 years was conducted.

CONTENT

Distinguishing infection from non-infectious mimics in ICU patients is uniquely challenging. At present, we do not have access to a rapid point-of-care test that reliably differentiates between individuals who need antibiotics and those who do not. A small number of studies have attempted to compare early aggressive versus conservative antimicrobial strategies in the ICU. However, this body of literature is small and not robust enough to guide practice.

IMPLICATIONS

This issue will not likely be resolved until there are diagnostic tests that rapidly and reliably identify the presence or absence of infection in the ICU population. In the meantime, prospective trials that identify clinical situations wherein it is safe to delay or withhold antibiotic initiation in the ICU until the presence of an infection is proven are warranted.