Early antimicrobial therapy in severe sepsis and septic shock

Early Versus Late Antipseudomonal β-Lactam Antibiotic Dose Adjustment in Critically Ill Sepsis Patients With Acute Kidney Injury: A Prospective Observational Cohort Study

Background

Acute kidney injury (AKI) is a common complication of sepsis, contributing to an increased mortality rate. However, some studies have demonstrated that renal function improves in sepsis patients with AKI within 48 hours, raising questions about the necessity for early antibiotic adjustment. This study evaluates the association between the timing of antipseudomonal β-lactam dose adjustment and the outcomes of critically ill sepsis patients with AKI.

Methods

A prospective, multicenter observational study of critically ill patients aged ≥18 years admitted to the intensive care unit with sepsis and AKI and started on antipseudomonal β-lactam therapy. After the initial dose, eligible patients were grouped as early β-lactam antibiotic (E-BLA) or late β-lactam antibiotic (L-BLA) dose adjustments based on the administration of subsequent renally adjusted doses within 24 hours and after 24 hours of sepsis recognition, respectively. The main outcome of interest was in-hospital mortality.

Results

Among 1185 patients screened, 224 (mean age, 62.7 ± 16.8 years; 62% were male) met inclusion criteria. Eighty-four and 140 patients were included in the E-BLA and L-BLA groups, respectively. Approximately half of the cohort presented with AKI stage II, and piperacillin-tazobactam was prescribed as initial empirical therapy in more than 50% of the cohort. In the multivariable Cox proportional hazards model, L-BLA was associated with a significant reduction in in-hospital mortality compared to E-BLA (hazard ratio, 0.588 [95% confidence interval, .355-.974]).

Conclusions

In sepsis patients with AKI, L-BLA was associated with in-hospital mortality benefits.

Shortening identification times: comparative observational study of three early blood culture testing protocols

Background

While early appropriate antibiotic therapy is a proven means of limiting the progression of infections, especially bacteremia, empirical antibiotic therapy in sepsis is ineffective up to 30%. The aim of this study was to compare early blood culture testing protocols in terms of their ability to shorten the delay between blood sampling and appropriate antibiotic therapy.

Methods

In this french observational study, we compared three blood culture testing protocols. Positive blood cultures were tested using either GenMark ePlex panels (multiplex PCR period), a combination of MRSA/SA PCR, β-Lacta and oxidase tests (multitest period), or conventional identification and susceptibility tests only (reference period). Conventional identification and susceptibility tests were performed in parallel for all samples, as the gold standard.

Results

Among the 270 patients with positive blood cultures included, early and conventional results were in good agreement, especially for the multitest period. The delay between a blood culture positivity and initial results was 3.8 (2.9-6.9) h in the multiplex PCR period, 2.6 (1.3-4.5) h in the multitest period and 3.7 (1.8-8.2) h in the reference period (p<0.01). Antibiotic therapy was initiated or adjusted in 68 patients based on early analysis results. The proportion of patients receiving appropriate antibiotic therapy within 48 h of blood sampling was higher in the multiplex PCR and multitest periods, (respectively 90% and 88%) than in the reference period (71%).

Conclusion

These results suggest rapid bacterial identification and antibiotic resistance tests are feasible, efficient and can expedite appropriate antibiotic therapy.

Optimization of Empirical Antimicrobial Therapy in Enterobacterales Bloodstream Infection Using the Extended-Spectrum Beta-Lactamase Prediction Score

Clinical tools for the prediction of antimicrobial resistance have been derived and validated without examination of their implementation in clinical practice. This study examined the impact of utilization of the extended-spectrum beta-lactamase (ESBL) prediction score on the time to initiation of appropriate antimicrobial therapy for bloodstream infection (BSI). The quasi-experimental cohort study included hospitalized adults with BSI due to ceftriaxone-resistant (CRO-R) Enterobacterales at three community hospitals in Columbia, South Carolina, USA before (January 2010 to December 2013) and after (January 2014 to December 2019) implementation of an antimicrobial stewardship intervention. In total, 45 and 101 patients with BSI due to CRO-R Enterobacterales were included before and after the intervention, respectively. Overall, the median age was 66 years, 85 (58%) were men, and 86 (59%) had a urinary source of infection. The mean time to appropriate antimicrobial therapy was 78 h before and 46 h after implementation of the antimicrobial stewardship intervention (p = 0.04). Application of the ESBL prediction score as part of an antimicrobial stewardship intervention was associated with a significant reduction in time to appropriate antimicrobial therapy in patients with BSI due to CRO-R Enterobacterales. Utilization of advanced rapid diagnostics may be necessary for a further reduction in time to appropriate antimicrobial therapy in this population.

Is procalcitonin a reliable indicator of sepsis in spinal cord injury patients: an observational cohort study

STUDY DESIGN

Prospective observational cohort study.

OBJECTIVE

To understand if serum procalcitonin (PCT) is a reliable indicator of sepsis in spinal cord injury (SCI) patients for better prognosis and earlier diagnosis when compared with other common biomarkers such as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood cells (WBC), blood culture and body temperature.

METHODS

From March 2021 to August 2022, data were collected for SCI patients who developed septicaemia. In addition to neurology and admission, the following blood samples were collected on day one of infection: PCT, CRP and WBC. Linear regression analysis was performed to determine the relationship between PCT, CRP and WBC.

RESULTS

A total of 27 SCI patients had an infection during their stay in the regional centre; however, only 10 developed septicaemias. 100% of SCI individuals with sepsis had elevated PCT levels, whilst 60% had elevated CRP and 30% had elevated WBC levels. There was a strong positive correlation between PCT and CRP (R2 = 0.673, CI = 95%, 5.5-22.8, p < 0.05) and a weaker positive correlation between PCT and WBC (R2 = 0.110, CI = 95%, 4.2-10.9, p < 0.05).

CONCLUSION

In SCI individuals, there was a correlation between serum PCT levels and septicaemia. Alongside this, PCT appeared to be more consistent throughout the study population when compared with CRP and WBC. However, this was a preliminary study and further research is required on a larger scale.

Identification of bacterial and fungal pathogens directly from clinical blood cultures using whole genome sequencing

Bloodstream infections are a major cause of morbidity and mortality worldwide. Early administration of appropriate antimicrobial therapy can improve patient survival and prevent antimicrobial resistance (AMR). Whole genome sequencing (WGS) can provide information for pathogen identification, AMR prediction and sequence typing earlier than current phenotypic diagnostic methods. WGS was performed on 97 clinical blood specimens and matched culture isolate pairs. Specimen/isolate pairs were MLST sequence-typed and further characterization was performed on Streptococcus species. WGS correctly identified 91.7% of clinical specimens and 93.2% of matched isolates representing 35 different microbial species. MLST types were assigned for 89.9% of matched cultures and 21.7% of blood specimens, with higher success for blood culture specimens extracted within 3 days (52% characterized) than 7 days (9.3%). This study demonstrates the potential use of WGS for identification and characterization of pathogens directly from blood culture specimens to facilitate timely initiation of appropriate antimicrobial therapies.

Antimicrobial residual drug error in the intensive care unit; a single blinded prospective observational study

OBJECTIVE

To determine the percentage of drug remaining in discarded antibiotic vials after use.

DESIGN

Blinded prospective observational trial.

SETTING

26-bed Australian metropolitan tertiary referral intensive care unit.

MAIN OUTCOME MEASURES

Percentage of labelled dose remaining in the vial after discard.

METHOD

Discarded antibiotic vials collected over a 7-day period in an adult intensive care unit were analysed. Each collected vial had any drug remnant washed out and made up to a known volume. A 1 ml aliquot of each vials washings was analysed using high performance liquid chromatography. From this concentration, the percentage of the drug remaining in the vial after discard was calculated. Additionally, each vial was weighed before and after washing to determine the weight of the remnant in each vial.

RESULTS

A total of 311 vials comprising of 11 different drugs and 14 individual vial types were collected. The median residual drug error across all vials was 3.7 %. The drug with the highest median was piperacillin at 6.1 % (IQR 4.3) and the lowest was amoxicillin 0.2 % (IQR 0.1). The single highest value for a given vial was vancomycin (500 mg) with 33.2 % and the lowest for a given vial was 0.1 % amoxicillin (1 g). These two drugs also exhibited the greatest range between the maximum and minimum value for any drug being 32 % and 0.9 % respectively.

CONCLUSIONS

Our study shows that up to a third of the intended dose may fail to reach the patient, highlighting a significant factor in the administration of antibiotics to the critically ill population.

IMPLICATIONS FOR CLINICAL PRACTICE

Residual drug often remains in antibiotic vials meaning that drug is not reaching the patient. There is considerable variation in the method by which medications are reconstituted in clinical settings. Two person checks should be completed after reconstitution in order to ensure that the medication is fully reconstituted and extracted from the vial.

Therapeutic drug monitoring of meropenem and pharmacokinetic-pharmacodynamic target assessment in critically ill pediatric patients from a prospective observational study

OBJECTIVES

To compare the unbound plasma meropenem concentrations at mid-dosing intervals (C_mid, 50%fT), end-dosing intervals (C_trough, 100%fT), and proportions of patients achieving 50%fT and 100%fT above MIC (50%fT_>MIC and 100%fT_>MIC) between extended infusion (EI) and intermittent bolus (IB) administration in a therapeutic drug monitoring (TDM) program in children.

METHODS

A prospective observational study was conducted in children aged 1 month to 18 years receiving meropenem every 8 h by either EI or IB. Meropenem C_mid, C_trough, and proportions of patients achieving 50%fT_>MIC and 100%fT_>MIC were compared.

RESULTS

TDM data from 72 patients with a median age (IQR) of 12 months (3-37) were used. Meropenem dose was 120 and 60 mg/kg/day in EI and IB groups, respectively. Geometric mean (95% CI) C_mid of EI versus IB was 17.3 mg/L (13.7-21.8) versus 3.4 mg/L (1.7-6.7) (P<0.001). Geometric mean (95% CI) C_trough of EI versus IB was 2.3 mg/L (1.6-3.4) versus 0.8 mg/L (0.4-1.5) (P=0.005). Greater proportions of patients achieving 50%fT_>MIC and 100%fT_>MIC were observed in the EI group.

CONCLUSIONS

A meropenem dose of 20 mg/kg/dose given by IB should not be used in critically ill children, even if they are not suspected of having a CNS infection. A dose of 40 mg/kg/dose given by EI resulted in higher C_mid, C_trough, and proportions of patients achieving 50%fT_>MIC and 100%fT_>MIC.

A sensitive and selective HPLC-MS3 method for therapeutic drug monitoring of meropenem and its validation by comparison with HPLC-MS2 methods

Meropenem, a representative β-lactam antibiotic, is widely used to treat complicated and serious infections. Therefore, it is a great significance to monitor the plasma drug concentration for individualized antimicrobial therapy. This study first describes the development and validation of high performance liquid chromatography-tandem mass spectrometry cubed method for monitoring meropenem in human plasma. Protein precipitation with methanol and a chromatographic analysis time of 7 min make this method is simple and high-throughput. Meropenem was extracted from human plasma with recoveries greater than 94.1%. Calibration curves were linear (R² >0.995) in the concentration range of 0.5-50 μg/mL. Overall accuracy and precision did not exceed 8.0% as well as no significant matrix effect was observed. The novelty of this method is that the triple-stage MS technology improves the selectivity and sensitivity. A comparison of the presented method and traditional liquid chromatography-tandem mass spectrometry method was assessed in 44 patients treated with meropenem and Passing-Bablok regression coefficients and Bland-Altman plots showed that no significant difference between the two methods. So the triple-stage MS method developed in this study is appropriate and practical for the monitor of meropenem in the daily clinical laboratory practice. This article is protected by copyright. All rights reserved.

Duplex dPCR System for Rapid Identification of Gram-Negative Pathogens in the Blood of Patients with Bloodstream Infection: A Culture-Independent Approach

Early and accurate detection of pathogens is important to improve clinical outcomes of bloodstream infections (BSI), especially in the case of drug-resistant pathogens. In this study, we aimed to develop a culture-independent digital PCR (dPCR) system for multiplex detection of major sepsiscausing gram-negative pathogens and antimicrobial resistance genes using plasma DNA from BSI patients. Our duplex dPCR system successfully detected nine targets (five bacteria-specific targets and four antimicrobial resistance genes) through five reactions within 3 hours. The minimum detection limit was 50 ag of bacterial DNA, suggesting that 1 CFU/ml of bacteria in the blood can be detected. To validate the clinical applicability, cell-free DNA samples from febrile patients were tested with our system and confirmed high consistency with conventional blood culture. This system can support early identification of some drug-resistant gram-negative pathogens, which can help improving treatment outcomes of BSI.

Can the cytokine adsorber CytoSorb® help to mitigate cytokine storm and reduce mortality in critically ill patients? A propensity score matching analysis

Background

A cytokine storm is life threatening for critically ill patients and is mainly caused by sepsis or severe trauma. In combination with supportive therapy, the cytokine adsorber Cytosorb^® (CS) is increasingly used for the treatment of cytokine storm. However, it is questionable whether its use is actually beneficial in these patients.

Methods

Patients with an interleukin-6 (IL-6) > 10,000 pg/ml were retrospectively included between October 2014 and May 2020 and were divided into two groups (group 1: CS therapy; group 2: no CS therapy). Inclusion criteria were a regularly measured IL-6 and, for patients allocated to group 1, CS therapy for at least 90 min. A propensity score (PS) matching analysis with significant baseline differences as predictors (Simplified Acute Physiology Score (SAPS) II, extracorporeal membrane oxygenation, renal replacement therapy, IL-6, lactate and norepinephrine demand) was performed to compare both groups (adjustment tolerance: < 0.05; standardization tolerance: < 10%). U-test and Fisher’s-test were used for independent variables and the Wilcoxon test was used for dependent variables.

Results

In total, 143 patients were included in the initial evaluation (group 1: 38; group 2: 105). Nineteen comparable pairings could be formed (mean initial IL-6: 58,385 vs. 59,812 pg/ml; mean SAPS II: 77 vs. 75). There was a significant reduction in IL-6 in patients with (p < 0.001) and without CS treatment (p = 0.005). However, there was no significant difference (p = 0.708) in the median relative reduction in both groups (89% vs. 80%). Furthermore, there was no significant difference in the relative change in C-reactive protein, lactate, or norepinephrine demand in either group and the in-hospital mortality was similar between groups (73.7%).

Conclusion

Our study showed no difference in IL-6 reduction, hemodynamic stabilization, or mortality in patients with Cytosorb^® treatment compared to a matched patient population.

Physicochemical Assessment of Branded and Generic Linezolid Injection from Different Pharmaceutical Manufacturers

Background:

Up to date, generic linezolid injections produced by Chinese manufacturers were not widely used in clinics in China. Quality evaluation of linezolid injections produced in China is a prerequisite, which has rarely been performed.

Objective:

This study aimed to evaluate the quality of branded and generic injections from different manufacturers and to provide a basis for quality control.

Methods:

In this study, the content of linezolid, related impurities and enantiomer of linezolid were determined by high-performance liquid chromatography. The content of glucose was determined by the iodine method. The insoluble particles and visible and sub-visible particles were determined by light blockage and lamp test, respectively. Osmotic pressure was determined by the freezing point depression method. The standard solution control method was used to check the color of the injection. Linezolid injections from different manufacturers were evaluated uniformly.

Results:

No significant difference was found in the content of linezolid, glucose, related impurities, visible particles, insoluble particles, pH value, and solution color between branded and generic drugs from different manufacturers in China.

Conclusion:

The quality of samples from different manufacturers is consistent. Although the physicochemical similarity does not guarantee the bioequivalence of studied branded and generic linezolid injections, the results provide references for further bioequivalence study. Generic injections offer more affordable treatment options for patients with infections than expensive branded drugs.

Pharmacokinetics of meropenem in children with sepsis undergoing extracorporeal life support: A prospective observational study

What is known and Objective

Meropenem, a broad‐spectrum carbapenem, is frequently used to treat severe bacterial infections in critically ill children. Recommendations for meropenem doses in adult infections are available; however, few studies have been published regarding the use of meropenem in children with sepsis, especially in those receiving continuous renal replacement therapy (CRRT) and extracorporeal membrane oxygenation (ECMO). We aimed to investigate the pharmacokinetic (PK) parameters of meropenem in children with sepsis receiving extracorporeal life support (ECLS).

Methods

This was a prospective observational clinical study of children with sepsis receiving ECMO or CRRT in the paediatric intensive care unit (PICU) of a children's hospital. The enrolled children received 20 mg/kg meropenem infusion over 1 hour, every 8 hours, and were grouped into children receiving ECMO, children receiving CRRT and children receiving neither ECMO nor CRRT. Plasma meropenem concentrations were determined using a validated high‐performance liquid chromatography‐tandem mass spectrometry (HPLC‐MS/MS). The key PK parameters were determined using the non‐compartmental approach.

Results and discussion

Twenty‐seven patients were finally enrolled. The eCLCR of the CRRT group was lower than that of the ECMO group. The values of elimination half‐life (t_1/2), area under the plasma concentration‐time curve (AUC_tau), area under the plasma concentration‐time curve from time zero to infinity (AUC_0‐∞), and total clearance (CL) in the ECMO group were not different from those of the other groups (all p > 0.05). However, the AUC_tau (p = 0.0137) and AUC_0‐∞ (p = 0.0234) significantly decreased after filtration through a hemofiltration membrane in patients receiving CRRT.

What is new and Conclusion

No significant alterations in the PK parameters of meropenem occurred in children with sepsis administered ECMO and/or CRRT. Further investigations including PK modelling could provide evidence for appropriate meropenem dosing regimens during ECLS administration.

Physiologically Based Population Pharmacokinetic Modeling Approach for Ciprofloxacin in Bone of Patients Undergoing Orthopedic Surgery

Ciprofloxacin is highly active against bacteria that commonly cause bone infections. However, the time-course of ciprofloxacin in bone has not been characterized using population pharmacokinetic modeling. Thirty-nine patients received a 1-h infusion of 400 mg of ciprofloxacin before orthopedic surgery. Blood and bone samples were collected at 0.5 to 20 h following the start of the infusion. Bone samples were separated into cortical and cancellous bone and pulverized under liquid nitrogen using a cryogenic mill. Ciprofloxacin in plasma, and cortical and cancellous bone was quantified by liquid chromatography-tandem mass spectrometry. A physiologically based pharmacokinetic modeling approach was utilized to describe the concentration-time profiles in plasma and bone. Ciprofloxacin concentrations ranged from 0.176 to 5.98 mg/L (median, 1.67; density, 1.99 g/cm³) in cortical, and 0.224 to 14.6 mg/L (median, 1.22; 1.92 g/cm³) in cancellous bone. The average observed cortical bone/plasma concentration ratio was 0.67 at 0.5 to 2 h (n = 7) and 5.1 at 13 to 20 h (n = 9). For cancellous bone the respective average ratios were 0.77 and 4.4. The population PK model included a central (blood) compartment, two peripheral tissue compartments, and compartments for the organic and inorganic (hydroxyapatite) matrix in cortical and cancellous bone. The population mean ciprofloxacin clearance was 20.7 L/h. The estimated partition coefficients of the organic bone matrix were 3.39 for cortical and 5.11 for cancellous bone. Ciprofloxacin achieved higher concentrations in bone than plasma. Slow redistribution from bone to plasma may have been due to binding to the inorganic bone matrix. The developed model presents a step toward optimized antibiotic dosing in osteomyelitis.

Therapeutic Drug Monitoring of Meropenem and Piperacillin in Critical Illness-Experience and Recommendations from One Year in Routine Clinical Practice

Various studies have reported insufficient beta-lactam concentrations in critically ill patients. The extent to which therapeutic drug monitoring (TDM) in clinical practice can reduce insufficient antibiotic concentrations is an ongoing matter of investigation. We retrospectively evaluated routine meropenem and piperacillin measurements in critically ill patients who received antibiotics as short infusions in the first year after initiating a beta-lactam TDM program. Total trough concentrations above 8.0 mg/L for meropenem and above 22.5 mg/L for piperacillin were defined as the breakpoints for target attainment. We included 1832 meropenem samples and 636 piperacillin samples. We found that 39.3% of meropenem and 33.6% of piperacillin samples did not reach the target concentrations. We observed a clear correlation between renal function and antibiotic concentration (meropenem, r = 0.53; piperacillin, r = 0.63). Patients with renal replacement therapy or creatinine clearance (CrCl) of <70 mL/min had high rates of target attainment with the standard dosing regimens. There was a low number of patients with a CrCl >100 mL/min that achieved the target concentrations with the maximum recommended dosage. Patients with impaired renal function only required TDM if toxic side effects were noted. In contrast, patients with normal renal function required different dosage regimens and TDM-guided therapy to reach the breakpoints of target attainment.

How should microbiology laboratories interpret cultures of the sonicate of closed needleless connectors?

INTRODUCTION

Our objective was to determine whether there is a cut-off in the needleless connectors' (NCs) cultures that when combined with skin cultures it was as efficient as conventional superficial cultures to rule-out catheter colonization (CC) and catheter-related bloodstream infection (CRBSI).

METHODS

During 10 months, we collected samples and then we analyzed the validity values of skin+NCs cultures for CC and CRBSI considering the best cut-off showing at least >90% of specificity to have a high negative predictive value using a ROC curve.

RESULTS

We collected a total of 167 catheters. The optimal cut-off of NCs culture was 1000cfu/NC. The validity values for CC and CRBSI combining skin cultures and NCs cultures using the selected cut-off were, respectively: S, 42.9%/16.7%; SP, 83.6%/75.8%; PPV, 27.3%/2.5%; and NPV, 91.0%/96.0%.

CONCLUSIONS

The combination of skin cultures and quantitative NCs cultures could be used for ruling-out CC and CRBSI.

Direct-from-blood RNA sequencing identifies the cause of post-bronchoscopy fever

Background

Antibiotic resistance is rising at disturbing rates and contributes to the deaths of millions of people yearly. Antibiotic resistant infections disproportionately affect those with immunocompromising conditions, chronic colonization, and frequent antibiotic use such as transplant patients or those with cystic fibrosis. However, clinicians lack the diagnostic tools to confidently diagnose and treat infections, leading to widespread use of empiric broad spectrum antimicrobials, often for prolonged duration.

Case presentation

A 22 year-old Caucasian female with cystic fibrosis received a bilateral orthotopic lung transplantation 5 months prior to the index hospitalization. She underwent routine surveillance bronchoscopy and was admitted for post-procedure fever. A clear cause of infection was not identified by routine methods. Imaging and bronchoscopic lung biopsy did not identify an infectious agent or rejection. She was treated with a prolonged course of antimicrobials targeting known colonizing organisms from prior bronchoalveolar lavage cultures (Pseudomonas, Staphylococcus aureus, and Aspergillus). However, we identified Stenotrophomonas maltophilia in two independent whole blood samples using direct-pathogen sequencing, which was not identified by other methods.

Conclusions

This case represents a common clinical conundrum: identification of infection in a high-risk, complex patient. Here, direct-pathogen sequencing identified a pathogen that would not otherwise have been identified by common techniques. Had results been clinically available, treatment could have been customized, avoiding a prolonged course of broad spectrum antimicrobials that would only exacerbate resistance. Direct-pathogen sequencing is poised to fill a diagnostic gap for pathogen identification, allowing early identification and customization of treatment in a culture-independent, pathogen-agnostic manner.

Development of a dosing algorithm for meropenem in critically ill patients based on a population pharmacokinetic/pharmacodynamic analysis

Effective antibiotic dosing is vital for therapeutic success in critically ill patients. This work aimed to develop an algorithm to identify appropriate meropenem dosing in critically ill patients. Population pharmacokinetic (PK) modelling was performed in NONMEM®7.3 based on densely sampled meropenem serum samples (n_patients = 48; n_samples = 1376) and included a systematic analysis of 27 pre-selected covariates to identify factors influencing meropenem exposure. Using Monte Carlo simulations newly considering the uncertainty of PK parameter estimates, standard meropenem dosing was evaluated with respect to attainment of the pharmacokinetic/pharmacodynamic (PK/PD) target and was compared with alternative infusion regimens (short-term, prolonged, continuous; daily dose, 2000-6000 mg). Subsequently, a dosing algorithm was developed to identify appropriate dosing regimens. The two-compartment population PK model included three factors influencing meropenem pharmacokinetics: the Cockcroft-Gault creatinine clearance (CLCR_CG) on meropenem clearance; and body weight and albumin on the central and peripheral volume of distribution, respectively; of these, only CLCR_CG was identified as a vital influencing factor on PK/PD target attainment. A three-level dosing algorithm was developed (considering PK parameter uncertainty), suggesting dosing regimens depending on renal function and the level (L) of knowledge about the infecting pathogen (L1, pathogen unknown; L2, pathogen known; L3_(-MIC), pathogen and susceptibility known; L3_(+MIC), MIC known). Whereas patients with higher CLCR_CG and lower pathogen susceptibility required mainly intensified dosing regimens, lower than standard doses appeared sufficient for highly susceptible pathogens. In conclusion, a versatile meropenem dosing algorithm for critically ill patients is proposed, indicating appropriate dosing regimens based on patient- and pathogen-specific information.

Rapid Diagnostics for Blood Cultures: Supporting Decisions for Antimicrobial Therapy and Value-Based Care

Bacteremia and sepsis are critically important syndromes with high mortality, morbidity, and associated costs. Bloodstream infections and sepsis are among the top causes of mortality in the US, with >600 deaths each day. Most septic patients can be found in emergency medicine departments or critical care units, settings in which rapid administration of targeted antibiotic therapy can reduce mortality. Unfortunately, routine blood cultures are not rapid enough to aid in the decision of therapeutic intervention at the onset of bacteremia. As a result, empiric, broad-spectrum treatment is common-a costly approach that may fail to target the correct microbe effectively, may inadvertently harm patients via antimicrobial toxicity, and may contribute to the evolution of drug-resistant microbes. To overcome these challenges, laboratorians must understand the complexity of diagnosing and treating septic patients, focus on creating algorithms that rapidly support decisions for targeted antibiotic therapy, and synergize with existing emergency department and critical care clinical practices put forth in the Surviving Sepsis Guidelines.

Multiplex identification of sepsis-causing Gram-negative pathogens from the plasma of infected blood

Early and accurate detection of bacterial pathogens in the blood is the most crucial step for sepsis management. Gram-negative bacteria are the most common organisms causing severe sepsis and responsible for high morbidity and mortality. We aimed to develop a method for rapid multiplex identification of clinically important Gram-negative pathogens and also validated whether our system can identify Gram-negative pathogens with the cell-free plasm DNA from infected blood. We designed five MLPA probe sets targeting the genes specific to major Gram-negative pathogens (uidA and lacY for E. coli, ompA for A. baumannii, phoE for K. pneumoniae, and ecfX for P. aeruginosa) and one set targeting the CTX-M group 1 to identify the ESBL producing Gram-negative pathogens. All six target-specific peaks were clearly separated without any non-specific peaks in a multiplex reaction condition. The minimum detection limit was 100 fg of pathogen DNA. When we tested 28 Gram-negative clinical isolates, all of them were successfully identified without any non-specific peaks. To evaluate the clinical applicability, we tested seven blood samples from febrile patients. Three blood culture positive cases showed E. coli specific peaks, while no peak was detected in the other four culture negative samples. This technology can be useful for detection of major sepsis-causing, drug-resistant Gram-negative pathogens and also the major ESBL producing Gram-negatives from the blood of sepsis patients in a clinical setting. This system can help early initiation of effective antimicrobial treatment against Gram-negative pathogens for sepsis patients, which is very crucial for better treatment outcomes.

Role of renal function in risk assessment of target non-attainment after standard dosing of meropenem in critically ill patients: a prospective observational study

Background

Severe bacterial infections remain a major challenge in intensive care units because of their high prevalence and mortality. Adequate antibiotic exposure has been associated with clinical success in critically ill patients. The objective of this study was to investigate the target attainment of standard meropenem dosing in a heterogeneous critically ill population, to quantify the impact of the full renal function spectrum on meropenem exposure and target attainment, and ultimately to translate the findings into a tool for practical application.

Methods

A prospective observational single-centre study was performed with critically ill patients with severe infections receiving standard dosing of meropenem. Serial blood samples were drawn over 4 study days to determine meropenem serum concentrations. Renal function was assessed by creatinine clearance according to the Cockcroft and Gault equation (CLCR_CG). Variability in meropenem serum concentrations was quantified at the middle and end of each monitored dosing interval. The attainment of two pharmacokinetic/pharmacodynamic targets (100%T_>MIC, 50%T_>4×MIC) was evaluated for minimum inhibitory concentration (MIC) values of 2 mg/L and 8 mg/L and standard meropenem dosing (1000 mg, 30-minute infusion, every 8 h). Furthermore, we assessed the impact of CLCR_CG on meropenem concentrations and target attainment and developed a tool for risk assessment of target non-attainment.

Results

Large inter- and intra-patient variability in meropenem concentrations was observed in the critically ill population (n = 48). Attainment of the target 100%T_>MIC was merely 48.4% and 20.6%, given MIC values of 2 mg/L and 8 mg/L, respectively, and similar for the target 50%T_>4×MIC. A hyperbolic relationship between CLCR_CG (25–255 ml/minute) and meropenem serum concentrations at the end of the dosing interval (C_8h) was derived. For infections with pathogens of MIC 2 mg/L, mild renal impairment up to augmented renal function was identified as a risk factor for target non-attainment (for MIC 8 mg/L, additionally, moderate renal impairment).

Conclusions

The investigated standard meropenem dosing regimen appeared to result in insufficient meropenem exposure in a considerable fraction of critically ill patients. An easy- and free-to-use tool (the MeroRisk Calculator) for assessing the risk of target non-attainment for a given renal function and MIC value was developed.

Trial registration

Clinicaltrials.gov, NCT01793012. Registered on 24 January 2013.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1829-4) contains supplementary material, which is available to authorized users.

Effectiveness and safety of procalcitonin evaluation for reducing mortality in adults with sepsis, severe sepsis or septic shock

BACKGROUND

Serum procalcitonin (PCT) evaluation has been proposed for early diagnosis and accurate staging and to guide decisions regarding patients with sepsis, severe sepsis and septic shock, with possible reduction in mortality.

OBJECTIVES

To assess the effectiveness and safety of serum PCT evaluation for reducing mortality and duration of antimicrobial therapy in adults with sepsis, severe sepsis or septic shock.

SEARCH METHODS

We searched the Central Register of Controlled Trials (CENTRAL; 2015, Issue 7); MEDLINE (1950 to July 2015); Embase (Ovid SP, 1980 to July 2015); Latin American Caribbean Health Sciences Literature (LILACS via BIREME, 1982 to July 2015); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; EBSCO host, 1982 to July 2015), and trial registers (ISRCTN registry, ClinicalTrials.gov and CenterWatch, to July 2015). We reran the search in October 2016. We added three studies of interest to a list of 'Studies awaiting classification' and will incorporate these into formal review findings during the review update.

SELECTION CRITERIA

We included only randomized controlled trials (RCTs) testing PCT-guided decisions in at least one of the comparison arms for adults (≥ 18 years old) with sepsis, severe sepsis or septic shock, according to international definitions and irrespective of the setting.

DATA COLLECTION AND ANALYSIS

Two review authors extracted study data and assessed the methodological quality of included studies. We conducted meta-analysis with random-effects models for the following primary outcomes: mortality and time spent receiving antimicrobial therapy in hospital and in the intensive care unit (ICU), as well as time spent on mechanical ventilation and change in antimicrobial regimen from a broad to a narrower spectrum.

MAIN RESULTS

We included 10 trials with 1215 participants. Low-quality evidence showed no significant differences in mortality at longest follow-up (risk ratio (RR) 0.81, 95% confidence interval (CI) 0.65 to 1.01; I2 = 10%; 10 trials; N = 1156), at 28 days (RR 0.89, 95% CI 0.61 to 1.31; I2 = 0%; four trials; N = 316), at ICU discharge (RR 1.03, 95% CI 0.50 to 2.11; I2 = 49%; three trials; N = 506) and at hospital discharge (RR 0.98, 95% CI 0.75 to 1.27; I2 = 0%; seven trials; N = 805; moderate-quality evidence). However, mean time receiving antimicrobial therapy in the intervention groups was -1.28 days (95% CI to -1.95 to -0.61; I2 = 86%; four trials; N = 313; very low-quality evidence). No primary study has analysed the change in antimicrobial regimen from a broad to a narrower spectrum.

AUTHORS' CONCLUSIONS

Up-to-date evidence of very low to moderate quality, with insufficient sample power per outcome, does not clearly support the use of procalcitonin-guided antimicrobial therapy to minimize mortality, mechanical ventilation, clinical severity, reinfection or duration of antimicrobial therapy of patients with septic conditions.

Multiplex identification of drug-resistant Gram-positive pathogens using stuffer-free MLPA system

Early detection of pathogens from blood and identification of their drug resistance are essential for sepsis management. However, conventional culture-based methods require relatively longer time to identify drug-resistant pathogens, which delays therapeutic decisions. For precise multiplex detection of drug-resistant Gram-positive pathogens, we developed a method by using stuffer-free multiplex ligation-dependent probe amplification (MLPA) coupled with high-resolution CE single-strand conformation polymorphisms (CE-SSCP) system. We designed three probe sets for genes specific to Gram-positive species (Staphylococcus aureus: nuc, Enterococcus faecium: sodA, and Streptococcus pneumoniae: lytA) and two sets for genes associated with drug resistance (mecA and vanA) to discriminate major Gram-positive pathogens with the resistance. A total of 94 different strains (34 reference strains and 60 clinical isolates) were used to validate this method and strain-specific peaks were successfully observed for all the strains. To improve sensitivity of the method, a target-specific preamplification step was introduced and, consequently, the sensitivity increased from 10 pg to 100 fg. We also reduced a total assay time to 8 h by optimizing hybridization time without compromising test sensitivity. Taken together, our multiplex detection system can improve detection of drug-resistant Gram-positive pathogens from sepsis patients' blood.

Uncertainty in Antibiotic Dosing in Critically Ill Neonate and Pediatric Patients: Can Microsampling Provide the Answers?

PURPOSE

With a decreasing supply of antibiotics that are effective against the pathogens that cause sepsis, it is critical that we learn to use currently available antibiotics optimally. Pharmacokinetic studies provide an evidence base from which we can optimize antibiotic dosing. However, these studies are challenging in critically ill neonate and pediatric patients due to the small blood volumes and associated risks and burden to the patient from taking blood. We investigate whether microsampling, that is, obtaining a biologic sample of low volume (<50 μL), can improve opportunities to conduct pharmacokinetic studies.

METHODS

We performed a literature search to find relevant articles using the following search terms: sepsis, critically ill, severe infection, intensive care AND antibiotic, pharmacokinetic, p(a)ediatric, neonate. For microsampling, we performed a search using antibiotics AND dried blood spots OR dried plasma spots OR volumetric absorptive microsampling OR solid-phase microextraction OR capillary microsampling OR microsampling. Databases searched include Web of Knowledge, PubMed, and EMbase.

FINDINGS

Of the 32 antibiotic pharmacokinetic studies performed on critically ill neonate or pediatric patients in this review, most of the authors identified changes to the pharmacokinetic properties in their patient group and recommended either further investigations into this patient population or therapeutic drug monitoring to ensure antibiotic doses are suitable. There remain considerable gaps in knowledge regarding the pharmacokinetic properties of antibiotics in critically ill pediatric patients. Implementing microsampling in an antibiotic pharmacokinetic study is contingent on the properties of the antibiotic, the pathophysiology of the patient (and how this can affect the microsample), and the location of the patient. A validation of the sampling technique is required before implementation.

IMPLICATIONS

Current antibiotic regimens for critically ill neonate and pediatric patients are frequently suboptimal due to a poor understanding of altered pharmacokinetic properties. An assessment of the suitability of microsampling for pharmacokinetic studies in neonate and pediatric patients is recommended before wider use. The method of sampling, as well as the method of bioanalysis, also requires validation to ensure the data obtained reflect the true result.

Severe sepsis in older adults

Severe sepsis may be underrecognized in older adults. Therefore, the purpose of this article is to review special considerations related to early detection of severe sepsis in older adults. Normal organ changes attributed to aging may delay early detection of sepsis at the time when interventions have the greatest potential to improve patient outcomes. Systems are reviewed for changes. For example, the cardiovascular system may have a limited or absent compensatory response to inflammation after an infectious insult, and the febrile response and recruitment of white blood cells may be blunted because of immunosenescence in aging. Three of the 4 hallmark responses (temperature, heart rate, and white blood cell count) to systemic inflammation may be diminished in older adults as compared with younger adults. It is important to consider that older adults may not always manifest the typical systemic inflammatory response syndrome. Atypical signs such as confusion, decreased appetite, and unsteady gait may occur before sepsis related organ failure. Systemic inflammatory response syndrome criteria and a comparison of organ failure criteria were reviewed. Mortality rates in sepsis and severe sepsis remain high and are often complicated by multiple organ failures. As the numbers of older adults increase, early identification and prompt treatment is crucial in improving patient outcomes.

Decreased serum concentrations of sphingosine-1-phosphate in sepsis

Introduction

Sphingosine-1-phosphate (S1P) is a signaling lipid that regulates pathophysiological processes involved in sepsis progression, including endothelial permeability, cytokine release, and vascular tone. The aim of this study was to investigate whether serum-S1P concentrations are associated with disease severity in patients with sepsis.

Methods

This single-center prospective-observational study includes 100 patients with systemic inflammatory response syndrome (SIRS) plus infection (n = 40), severe sepsis (n = 30), or septic shock (n = 30) and 214 healthy blood donors as controls. Serum-S1P was measured by mass spectrometry. Blood parameters, including C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6), lactate, and white blood cells (WBCs), were determined by routine assays. The Sequential Organ Failure Assessment (SOFA) score was generated and used to evaluate disease severity.

Results

Serum-S1P concentrations were lower in patients than in controls (P < 0.01), and the greatest difference was between the control and the septic shock groups (P < 0.01). Serum-S1P levels were inversely correlated with disease severity as determined by the SOFA score (P < 0.01) as well as with IL-6, PCT, CRP, creatinine, lactate, and fluid balance. A receiver operating characteristic analysis for the presence or absence of septic shock revealed equally high sensitivity and specificity for S1P compared with the SOFA score. In a multivariate logistic regression model calculated for prediction of septic shock, S1P emerged as the strongest predictor (P < 0.001).

Conclusions

In patients with sepsis, serum-S1P levels are dramatically decreased and are inversely associated with disease severity. Since S1P is a potent regulator of endothelial integrity, low S1P levels may contribute to capillary leakage, impaired tissue perfusion, and organ failure in sepsis.

Antibiotic stewardship in the intensive care unit

The rapid emergence and dissemination of antimicrobial-resistant microorganisms in ICUs worldwide constitute a problem of crisis dimensions. The root causes of this problem are multifactorial, but the core issues are clear. The emergence of antibiotic resistance is highly correlated with selective pressure resulting from inappropriate use of these drugs. Appropriate antibiotic stewardship in ICUs includes not only rapid identification and optimal treatment of bacterial infections in these critically ill patients, based on pharmacokinetic-pharmacodynamic characteristics, but also improving our ability to avoid administering unnecessary broad-spectrum antibiotics, shortening the duration of their administration, and reducing the numbers of patients receiving undue antibiotic therapy. Either we will be able to implement such a policy or we and our patients will face an uncontrollable surge of very difficult-to-treat pathogens.

The meta-genome of sepsis: host genetics, pathogens and the acute immune response

Severe infection and the patient response constitute sepsis. Here, we review the meta-genome (patient genetics, pathogen communities and host response) and its impact upon the outcome of severe sepsis. Patient genetics, both predisposition for infection and the subsequent response to infection are reviewed. The pathogen is discussed with particular emphasis upon the modern era of microbiome analysis and nucleic acid diagnostics. Finally, we discuss the host clinical and immune responses and present new data to suggest that the immune response is the key to understanding sepsis and improving a death rate of nearly 30%.

Diagnostic accuracy of three different methods of temperature measurement in acutely ill geriatric patients

OBJECTIVE

we examined the diagnostic accuracy of different methods of body temperature measurement to diagnose infection in geriatric patients presenting to the emergency department (ED).

METHODS

this observational study was done in consecutive patients ≥75 years old presenting to the ED. Body temperature was determined by tympanal thermometry, temporal artery thermometry and rectal temperature measurement. Adjudicated final diagnosis of infection was done by two experts including patient history, clinical and laboratory findings as well as radiographic studies.

RESULTS

a total of 427 patients were included in the data analysis (age: 82.7 ± 5.1 years). Infection was present in 105 patients (24.6%). Respiratory rate, heart rate and body temperature were significantly higher in patients with infection, blood pressure was lower (P < 0.01). Body temperature measured by tympanal and temporal artery thermometry was correlated with rectal thermometry. Body temperature was significantly higher in patients with infection compared with those without infection independent of the method of body temperature measurement (P < 0.001). The diagnostic accuracy for infection quantified by the area under curve (AUC) was comparable among rectal [AUC: 0.72 (95% CI: 0.65-0.80)] and tympanal thermometry [AUC: 0.73 (95% CI: 0.66-0.81)], but significantly lower in temporal artery thermometry [AUC: 0.65 (95% CI: 0.57-0.73; P < 0.001)]. Compared with rectal measurement tympanal thermometry showed a higher bias than temporal artery thermometry (0.54 versus 0.03°C), while its limits of agreement were more narrow (-0.14 to 1.21°C versus -0.94-1.01°C).

CONCLUSION

diagnostic accuracy for the identification of infection was comparable among tympanal and rectal thermometry and lower for temporal artery thermometry. Different cut-off points should be used to identify infection using tympanal (37.3°C) or rectal (37.9°C) thermometry. In general, temperature measurement is an insensitive method to identify geriatric patients with infection. Registration number clinicaltrials.com: KSMC-tempger-1.

Influence of multidrug resistance and appropriate empirical therapy on the 30-day mortality rate of Pseudomonas aeruginosa bacteremia

Infections due to multidrug-resistant (MDR) Pseudomonas aeruginosa are increasing. The aim of our study was to evaluate the influences of appropriate empirical antibiotic therapy and multidrug resistance on mortality in patients with bacteremia due to P. aeruginosa (PAB). Episodes of PAB were prospectively registered from 2000 to 2008. MDR was considered when the strain was resistant to ≥3 antipseudomonal antibiotics. Univariate and multivariate analyses were performed. A total of 709 episodes of PAB were studied. MDR PAB (n = 127 [17.9%]) was more frequently nosocomial and associated with longer hospitalization, bladder catheter use, steroid and antibiotic therapy, receipt of inappropriate empirical antibiotic therapy, and a higher mortality. Factors independently associated with mortality were age (odds ratio [OR], 1.02; 95% confidence interval [CI], 1.002 to 1.033), shock (OR, 6.6; 95% CI, 4 to 10.8), cirrhosis (OR, 3.3; 95% CI, 1.4 to 7.6), intermediate-risk sources (OR, 2.5; 95% CI, 1.4 to 4.3) or high-risk sources (OR, 7.3; 95% CI, 4.1 to 12.9), and inappropriate empirical therapy (OR, 2.1; 95% CI, 1.3 to 3.5). To analyze the interaction between empirical therapy and MDR, a variable combining both was introduced in the multivariate analysis. Inappropriate therapy was significantly associated with higher mortality regardless of the susceptibility pattern, and there was a trend toward higher mortality in patients receiving appropriate therapy for MDR than in those appropriately treated for non-MDR strains (OR, 2.2; 95% CI, 0.9 to 5.4). In 47.9% of MDR PAB episodes, appropriate therapy consisted of monotherapy with amikacin. In conclusion, MDR PAB is associated with a higher mortality than non-MDR PAB. This may be related to a higher rate of inappropriate empirical therapy and probably also to amikacin as frequently the only appropriate empirical therapy given to patients with MDR PAB.