Effects of prophylactic antibiotic therapy with mezlocillin plus sulbactam on the incidence and height of fever after severe acute ischemic stroke: the Mannheim infection in stroke study (MISS)

Comparing Early National Institutes of Health Stroke Scale Versus 90-Day Modified Rankin Scale Outcomes in Acute Ischemic Stroke Trials: A Systematic Review and Analysis

BACKGROUND

Early National Institutes of Health Stroke Scale (NIHSS) assessment may provide practical benefits over 90-day modified Rankin Scale (mRS), but it is unclear how it compares in adjudicating randomized clinical trial (RCT) results in acute ischemic stroke.

METHODS AND RESULTS

We searched Ovid Medline (inception to April 1, 2023) and included RCTs of acute therapies for acute ischemic stroke with data for both 90-day mRS and NIHSS within 7 days. Primary outcome was agreement between trial results (classified as positive, negative, or neutral) based on 24-hour NIHSS and 90-day mRS scores. We additionally assessed agreement for 2-hour, 48-hour, 72- to 96-hour, and 5- to 7-day NIHSS scores. We aimed to validate our findings using individual patient data from the ESCAPE (Randomized Assessment of Rapid Endovascular Treatment of Ischemic Stroke) and ESCAPE-NA1 (Safety and Efficacy of Nerinetide [NA-1] in Subjects Undergoing Endovascular Thrombectomy for Stroke) RCTs. We included 116 trials (44 387 patients), contributing 165 NIHSS assessments. The 24-hour NIHSS scores resulted in the same classification as 90-day mRS scores in 61/73 (83.6%) trials (Cohen's kappa, 0.64 [95% CI: 0.45-0.83] and Gwet's agreement coefficient 1, 0.79 [95% CI: 0.67-0.90]). Agreement was not statistically different by timing of NIHSS assessments (range 75%-100%, P=0.33). Individual patient data showed higher agreement for assessments between 48 hours and 7 days, varying by NIHSS dichotomization cutoffs (NIHSS score, 0-2; 2 hours, 56.6%; 24 hours, 66.6%; 48 hours, 71.8%; 5-7 days: 76.5%, P<0.01; NIHSS score, 0-7; 2 hours, 72.8%; 24 hours, 80.5%; 48 hours, 83.1%; 5-7 days: 84.7%, P<0.01).

CONCLUSIONS

The 24-hour NIHSS scores aligned with 90-day mRS scores in 84% of RCT results, indicating intermediate-to-good agreement. However, individual patient data showed that early NIHSS risks misclassifying around 1/4 patients. These data contribute to a better understanding of the nuances of early NIHSS score as an outcome in acute ischemic stroke RCTs.

The efficacy and safety of prophylactic antibiotics for post-acute stroke infection: A systematic review and meta-analysis

AIMS

Infections are common complications after stroke and associated with unfavourable outcomes. We aimed to evaluate the efficacy and safety of prophylactic antibiotics for post-acute stroke infection.

METHODS

We searched PubMed, Embase, the Cochrane Library, SinoMed, China National Knowledge Infrastructure, WanFang Data, China Science and Technology Journal Database, and clinical trial register platforms from inception to 15 February 2022. We included randomized clinical trials that evaluated the efficacy and safety of prophylactic antibiotics. Primary outcomes were mortality rate and incidence of pneumonia. The pooled risk ratio (RR) and mean differences with 95% confidence interval (CI) were calculated using the random or fixed-effect model depending on heterogeneity. The quality of evidence was evaluated using the Grading of Recommendations, Assessment, Development and Evaluations.

RESULTS

Twelve studies (4809 participants) were included. There was no significant difference in the mortality rate (12 trials, n = 4740, RR 1.03 [95% Cl: 0.91-1.16], high-quality evidence), incidence of pneumonia (7 trials, n = 4352, RR 0.94 [95% CI: 0.79-1.11], high-quality evidence) and the incidence of adverse events between the prophylactic antibiotics and control groups. Prophylactic antibiotics significantly reduced the incidence of infections (8 trials, n = 4517, RR 0.72 [95% CI: 0.58-0.89], moderate-quality evidence) and urinary tract infections (7 trials, n = 4352, RR 0.39 [95% CI: 0.3-0.49], moderate-quality evidence). None of the subgroup analyses showed a significant difference in mortality or the incidence of pneumonia.

CONCLUSION

For acute stroke patients, prophylactic antibiotics were significantly associated with fewer incidences of any infections and urinary tract infections without significant differences in mortality rate and pneumonia.

Inflammatory response biomarkers nomogram for predicting pneumonia in patients with spontaneous intracerebral hemorrhage

Objectives

Inflammatory response biomarkers are promising prognostic factors to improve the prognosis of stroke-associated pneumonia (SAP) after ischemic stroke. This study aimed to investigate the prognostic significance of inflammatory response biomarkers on admission in SAP after spontaneous intracerebral hemorrhage (SICH) and establish a corresponding nomogram.

Methods

The data of 378 patients with SICH receiving conservative treatment from January 2019 to December 2021 at Taizhou People's Hospital were selected. All eligible patients were randomized into the training (70%, 265) and validation cohorts (30%, 113). In the training cohort, multivariate logistic regression analysis was used to establish an optimal nomogram, including inflammatory response biomarkers and clinical risk factors. The area under the receiver operating characteristic (ROC) curve (AUC), calibration curve, and decision curve analysis (DCA) were used to evaluate the nomogram's discrimination, calibration, and performance, respectively. Moreover, this model was further validated in a validation cohort.

Results

A logistic regression analysis showed that intraventricular hemorrhage (IVH), hypertension, dysphagia, Glasgow Coma Scale (GCS), National Institute of Health Stroke Scale (NIHSS), systemic inflammation response index (SIRI), and platelet/lymphocyte ratio (PLR) were correlated with SAP after SICH (P < 0.05). The nomogram was composed of all these statistically significant factors. The inflammatory marker-based nomogram showed strong prognostic power compared with the conventional factors, with an AUC of 0.886 (95% CI: 0.841-0.921) and 0.848 (95% CI: 0.799-0.899). The calibration curves demonstrated good homogeneity between the predicted risks and the observed outcomes. In addition, the model has a significant net benefit for SAP, according to DCA. Also, internal validation demonstrated the reliability of the prediction nomogram. The length of hospital stay was shorter in the non-SAP group than in the SAP group. At the 3-month follow-up, clinical outcomes were worse in the SAP group (P < 0.001).

Conclusion

SIRI and PLR at admission can be utilized as prognostic inflammatory biomarkers in patients with SICH in the upper brain treated with SAP. A nomogram covering SIRI and PLR can more accurately predict SAP in patients' supratentorial SICH. SAP can influence the length of hospital stay and the clinical outcome.

Preventive ceftriaxone in patients at high risk of stroke-associated pneumonia. A post-hoc analysis of the PASS trial

BACKGROUND

Infections complicate the acute phase of stroke in one third of patients and especially pneumonia is associated with increased risk of death or dependency. In randomized trials of stroke patients, preventive antibiotics reduced overall infections, but did not reduce pneumonia or improve outcome. This may be explained by broad selection criteria, including many patients with a low risk of pneumonia. To assess the potential of selection of patients at high risk of pneumonia, we performed a post-hoc analysis in the Preventive Antibiotics in Stroke Study (PASS).

METHODS

PASS was a multicentre phase 3 trial in acute stroke patients who were randomized to preventive ceftriaxone for four days within 24 hours or standard care. For this analysis patients were divided based on the ISAN risk score for pneumonia as follows: low (0-6), medium (7-14) and high (15-21). Primary outcomes were pneumonia rate during admission as judged by the treating physician, and by an independent committee; secondary outcomes were overall infections and unfavorable outcome (modified Rankin Scale ≥3). We adjusted with multivariable regression for possible confounders: age, stroke subtype and severity, pre-stroke dependency and diabetes.

RESULTS

Pneumonia occurred more frequently in higher risk groups (25.7% (high), 9.0% (medium) 1.5%, (low)). The absolute difference in pneumonia rate between patients treated with ceftriaxone or standard care increased with the ISAN score (low: 0.5%, medium: 1.2%, high: 10.1%). After adjustment ceftriaxone reduced overall infections in the low and medium groups, not in the high-risk group. There was a trend towards reduction of pneumonia as judged by the committee (3.7% vs 13.6%, aOR = 0.164, p = 0.063) in the high-risk group.

CONCLUSIONS

This post-hoc analysis of PASS confirmed higher rates of pneumonia with higher ISAN scores, and suggests that in acute stroke patients with an ISAN score of ≥15, preventive ceftriaxone for four days may reduce pneumonia rate.

Circulating Inflammatory Biomarkers in Early Prediction of Stroke-Associated Infections

(1) Background: Patients with acute ischaemic stroke (AIS) are at high risk for stroke-associated infections (SAIs). We hypothesised that increased concentrations of systemic inflammation markers predict SAIs and unfavourable outcomes; (2) Methods: In 223 patients with AIS, blood samples were taken at ≤24 h, 3 d and 7d after a stroke, to determine IL-6, IL-10, CRP and LBP. The outcome was assessed using the modified Rankin Scale at 90 d. Patients were thoroughly examined regarding the development of SAIs; (3) Results: 47 patients developed SAIs, including 15 lower respiratory tract infections (LRTIs). IL-6 and LBP at 24 h differed, between patients with and without SAIs (IL-6: p < 0.001; LBP: p = 0.042). However, these associations could not be confirmed after adjustment for age, white blood cell count, reduced consciousness and NIHSS. When considering the subgroup of LRTIs, in patients who presented early (≤12 h after stroke, n = 139), IL-6 was independently associated with LRTIs (OR: 1.073, 95% CI: 1.002−1.148). The ROC-analysis for prediction of LRTIs showed an AUC of 0.918 for the combination of IL-6 and clinical factors; (4) Conclusions: Blood biomarkers were not predictive for total SAIs. At early stages, IL-6 was independently associated with outcome-relevant LRTIs. Further studies need to clarify the use of biochemical markers to identify patients prone to SAIs.

Preventive antibiotic therapy in acute stroke patients: A systematic review and meta-analysis of individual patient data of randomized controlled trials

Introduction

Infection after stroke is associated with unfavorable outcome. Randomized controlled studies did not show benefit of preventive antibiotics in stroke but lacked power for subgroup analyses. Aim of this study is to assess whether preventive antibiotic therapy after stroke improves functional outcome for specific patient groups in an individual patient data meta-analysis.

Patients and methods

We searched MEDLINE (1946–7 May 2021), Embase (1947–7 May 2021), CENTRAL (17th September 2021), trial registries, cross-checked references and contacted researchers for randomized controlled trials of preventive antibiotic therapy versus placebo or standard care in ischemic or hemorrhagic stroke patients. Meta-analysis was performed by a one-step and two-step approach. Primary outcome was functional outcome adjusted for age and stroke severity. Secondary outcomes were infections and mortality.

Results

4197 patients from nine trials were included. Preventive antibiotic therapy was not associated with a shift in functional outcome (mRS) at 3 months (OR1.13, 95%CI 0.98–1.31) or unfavorable functional outcome (mRS 3–6) (OR0.85, 95%CI 0.60–1.19). Preventive antibiotics did not improve functional outcome in pre-defined subgroups (age, stroke severity, timing and type of antibiotic therapy, pneumonia prediction scores, dysphagia, type of stroke, and type of trial). Preventive antibiotics reduced infections (276/2066 (13.4%) in the preventive antibiotic group vs. 417/2059 (20.3%) in the control group, OR 0.60, 95% CI 0.51–0.71, p < 0.001), but not pneumonia (191/2066 (9.2%) in the preventive antibiotic group vs. 205/2061 (9.9%) in the control group (OR 0.92 (0.75–1.14), p = 0.450).

Discussion and conclusion

Preventive antibiotic therapy did not benefit any subgroup of patients with acute stroke and currently cannot be recommended.

European Stroke Organisation and European Society for Swallowing Disorders guideline for the diagnosis and treatment of post-stroke dysphagia

Post-stroke dysphagia (PSD) is present in more than 50% of acute stroke patients, increases the risk of complications, in particular aspiration pneumonia, malnutrition and dehydration, and is linked to poor outcome and mortality. The aim of this guideline is to assist all members of the multidisciplinary team in their management of patients with PSD. These guidelines were developed based on the European Stroke Organisation (ESO) standard operating procedure and followed the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. An interdisciplinary working group identified 20 relevant questions, performed systematic reviews and meta-analyses of the literature, assessed the quality of the available evidence and wrote evidence-based recommendations. Expert opinion was provided if not enough evidence was available to provide recommendations based on the GRADE approach. We found moderate quality of evidence to recommend dysphagia screening in all stroke patients to prevent post-stroke pneumonia and to early mortality and low quality of evidence to suggest dysphagia assessment in stroke patients having been identified at being at risk of PSD. We found low to moderate quality of evidence for a variety of treatment options to improve swallowing physiology and swallowing safety. These options include dietary interventions, behavioural swallowing treatment including acupuncture, nutritional interventions, oral health care, different pharmacological agents and different types of neurostimulation treatment. Some of the studied interventions also had an impact on other clinical endpoints such as feedings status or pneumonia. Overall, further randomized trials are needed to improve the quality of evidence for the treatment of PSD.

Prophylactic Antibiotics, the Mediator of Post-Stroke Infections: A Systematic Review

Infections frequently complicate an acute stroke and have been associated with an unfavorable prognosis among patients. The use of prophylactic antibiotics seems rational, however, its efficacy has remained obscure. This systematic review aims to offer more clarity to this established dilemma. PubMed and Google Scholar were explored to gain access to studies on post-stroke infection. A systematic review was carried out to analyze how profitable it would be to offer preventive antibiotics immediately after an acute stroke. Five randomized control trials were obtained and analyzed the efficacy of antibiotics in acute stroke according to their intrinsic effects on the infection rate, functionality, and mortality benefits. Based on our findings, we discovered that antibiotics reduce the onset of early infections, especially urinary tract infections, but have absolutely no effect on the functionality and offer no mortality benefit. These results were emphatically shown in two large, open-labeled randomized controlled trials involved in this systematic review. Prophylactic antibiotics provide no additional benefits to the standard of care and should not be used following an acute stroke. They may decrease the incidence of acute infections, especially urinary tract infections, but have no effects on functional outcome and mortality.

Effects of a 4-Step Standard Operating Procedure for the Treatment of Fever in Patients With Acute Stroke

Background and Purpose: Fever in the acute phase of stroke leads to an unfavorable clinical outcome and increased mortality. However, no specific form of effective fever treatment has been established, so far. We analyzed the effectiveness of our in-house standard operating procedure (SOP) of fever treatment. Methods: This SOP was analyzed for a period of 33 weeks. Patients with cerebral ischemia (ischemic stroke, transient ischemic attack) or cerebral hemorrhage (intracerebral, subarachnoid) and body temperature elevation of ≥ 37.5°C within the first 6 days after admission were eligible for inclusion in the analysis. The results of SOP group, who's data have been collected prospectively were then compared with a historical control group that had been treated conventionally 1 year earlier in the same period. The data of control group have been collected in retrospect. The primary endpoint was the total duration of the fever for the first 6 days after admission to the stroke unit. Results: A total of 130 patients (mean age of 78 ± 12) received 370 antipyretic interventions. Sequential application of paracetamol (n = 245), metamizole (n = 53) and calf compress (n = 15) led to significant reduction in body temperature. In patients who did not respond to these applications, normothermia could be achieved after infusion of the cooled saline solution. Normothermia could be achieved within 120 min in more than 90% of the cases treated by the SOP. The SOP reduced the fever duration in the 6 days significantly, from 12.2 ± 2.7 h [95% confidence interval (CI) for mean] in the control group to 3.9 ± 1.0 h (95% CI) in the SOP group (p < 0.001). The SOP was rated to be reasonable and effective. Conclusion: Our in-house SOP is cost-efficient and effective for fever treatment in stroke patients, that can be implemented by local health care professionals.

CNS and peripheral immunity in cerebral ischemia: partition and interaction

Stroke elicits excessive immune activation in the injured brain tissue. This well-recognized neural inflammation in the brain is not just an intrinsic organ response but also a result of additional intricate interactions between infiltrating peripheral immune cells and the resident immune cells in the affected areas. Given that there is a finite number of immune cells in the organism at the time of stroke, the partitioned immune systems of the central nervous system (CNS) and periphery must appropriately distribute the limited pool of immune cells between the two domains, mounting a necessary post-stroke inflammatory response by supplying a sufficient number of immune cells into the brain while maintaining peripheral immunity. Stroke pathophysiology has mainly been neurocentric in focus, but understanding the distinct roles of the CNS and peripheral immunity in their concerted action against ischemic insults is crucial. This review will discuss stroke-induced influences of the peripheral immune system on CNS injury/repair and of neural inflammation on peripheral immunity, and how comorbidity influences each.

Assessment, typo error on Author's response of Post Ischemic Stroke Infections

Background

Infection is a common complication in acute phase after stroke, and even in specialized stroke units, it remains one of the major complications. The relationship between infections and acute ischemic stroke is complex and bidirectional. Infections can result in ischemic stroke, and the rate of infection is increased after ischemic stroke.

Aim of work

The aim of this study is to estimate the incidence of post-stroke infections in the Egyptian patients, with determination of the most common infections, possible risk factors, and their clinical implications.

Methods

The study was conducted on one hundred adult patients with acute ischemic stroke, full medical history, thorough clinical examination, routine laboratory investigations, estimation of erythrocyte sedimentation rate and C-reactive protein, abdominal ultrasound, plain X-ray of the chest, culture and sensitivity, non-contrast computed tomography, magnetic resonance imaging for patients with normal CT studies of the brain, duplex study of both carotids and vertebral, ECG, and echocardiography, any further investigations needed and lastly collected data statistically analyzed.

Results

The results of our study showed that 32 patients (32%) developed post-stroke infection. Post-stroke infections increased with higher age and female gender. Post-stroke infections were strongly correlated to the presence of atrial fibrillation, previous stroke, or transient ischemic attacks. The occurrence of post-stroke infection was significantly correlated to stroke severity, size of infarction, and carotid stenosis. Post-stroke infection was also correlated with the occurrence of multiple post-stroke neurological complications. Infections that occurred post-stroke were pneumonia (21%) and urinary tract infection (15%), blood (5%), and subcutaneous infection (3%).

Conclusion

Stroke is a major health problem, and infection is one of the commonest post-stroke complications. Post-stroke infection significantly affects clinical outcome and being strongly associated with occurrence of neurological complications.

Abstract: study was conducted on one hundred adult patients with acute ischemic stroke, full medical history, thorough clinical examination, routine laboratory investigations, estimation of erythrocyte sedimentation rate and C-reactive protein, abdominal ultrasound, plain X-ray of the chest, culture and sensitivity, non-contrast computed tomography (CT), magnetic resonance imaging (MRI) for patients with normal CT studies of the brain, duplex study of both carotids and vertebral, electrocardiography (ECG), and echocardiography, any further investigations needed and lastly collected data statistically analyzed.

Predictors of urinary tract infection in acute stroke patients: A cohort study

Patients with stroke have a high risk of infection which may be predicted by age, procalcitonin, interleukin-6, C-reactive protein, National Institute of Health stroke scale (NHSS) score, diabetes, etc. These prediction methods can reduce unfavourable outcome by preventing the occurrence of infection.We aim to identify early predictors for urinary tract infection in patients after stroke.In 186 collected acute stroke patients, we divided them into urinary tract infection group, other infection type groups, and non-infected group. Data were recorded at admission. Independent risk factors and infection prediction model were determined using Logistic regression analyses. Likelihood ratio test was used to detect the prediction effect of the model. Receiver operating characteristic curve and the corresponding area under the curve were used to measure the predictive accuracy of indicators for urinary tract infection.Of the 186 subjects, there were 35 cases of urinary tract infection. Elevated interleukin-6, higher NIHSS, and decreased hemoglobin may be used to predict urinary tract infection. And the predictive model for urinary tract infection (including sex, NIHSS, interleukin-6, and hemoglobin) have the best predictive effect.This study is the first to discover that decreased hemoglobin at admission may predict urinary tract infection. The prediction model shows the best accuracy.

The Local and Peripheral Immune Responses to Stroke: Implications for Therapeutic Development

The immune response to stroke is an exciting target for future stroke therapies. Stroke is a leading cause of morbidity and mortality worldwide, and clot removal (mechanical or pharmacological) to achieve tissue reperfusion is the only therapy currently approved for patient use. Due to a short therapeutic window and incomplete effectiveness, however, many patients are left with infarcted tissue that stimulates inflammation. Although this is critical to promote repair, it can also damage surrounding healthy brain tissue. In addition, acute immunodepression and subsequent infections are common and are associated with worse patient outcomes. Thus, the acute immune response is a major focus of researchers attempting to identify ways to amplify its benefits and suppress its negative effects to improve short-term recovery of patients. Here we review what is known about this powerful process. This includes the role of brain resident cells such as microglia, peripherally activated cells such as macrophages and neutrophils, and activated endothelium. The role of systemic immune activation and subsequent immunodepression in the days after stroke is also discussed, as is the chronic immune responses and its effects on cognitive function. The biphasic role of inflammation, as well as complex timelines of cell production, differentiation, and trafficking, suggests that the relationship between the acute and chronic phases of stroke recovery is complex. Gaining a more complete understanding of this intricate process by which inflammation is initiated, propagated, and terminated may potentially lead to therapeutics that can treat a larger population of stroke patients than what is currently available. The immune response plays a critical role in patient recovery in both the acute and chronic phases after stroke. In patients, the immune response can be beneficial by promoting repair and recovery, and also detrimental by propagating a pro-inflammatory microenvironment. Thus, it is critical to understand the mechanisms of immune activation following stroke in order to successfully design therapeutics.

Role of Prophylactic Antibiotics in Critical Care of Stroke Patients - A Preventive Approach to Post-stroke Infections?

Post-stroke complications are very common worldwide and the most common complication is infection. This contributes the most to the mortality rate in stroke patients. Among the infections, pneumonia and urinary tract infections are most common. Hyperthermia following stroke is associated with neuronal damage and worse outcomes. Post-stroke immunosuppression and activation of inflammatory mediators also cause infections. Based on the high mortality caused by post-stroke infections, various trials were done to seek the advantage that prophylactic antibiotics can give in the critical care of stroke patients. Antibiotics, including ceftriaxone (cephalosporin), levofloxacin (fluoroquinolone), penicillin, and minocycline (tetracycline), were used and the stroke patients were followed up to analyze the primary and secondary outcomes. It was concluded that early antibiotic therapy (mostly within 24 hours) leads to a reduced rate of post-stroke infections and reduced fever spikes, whereas follow-up for a longer period of time showed no better functional outcome. Furthermore, mortality and morbidity benefits were also not seen with prophylactic antibiotic therapy. This review helped us to put a nail in the coffin to the earlier thoughts that prophylactic antibiotics are necessary for the critical care of stroke patients.

Infection Prevention in the Neurointensive Care Unit: A Systematic Review

Hospital-acquired infections are common in neurointensive care units. We sought to review interventions which may reduce infection rates in neurocritically ill populations. We conducted a systematic review of studies targeting adult patients in neuro-intensive care units (neuro-ICUs) with an intervention designed to prevent ICU-acquired infections. Our outcome of interest was change in the prevalence or rates of infection between active and control arms of these studies. We excluded studies based on the following criteria: no English full-text version available; pediatric population; non-neurosciences ICU population; pre- or intraoperative methods to prevent infection; lack of discrete data for infection rates/prevalence; studies that were purely observational in nature and did not test an intervention; and studies performed in resource limited settings. We initially retrieved 3716 results by searching the following databases: PubMed/MEDLINE, EMBASE via Ovid, and Cochrane CENTRAL via Ovid. No date or language limits were used in the search. Computerized deduplication was conducted using EndNote followed by a confirmatory manual review resulting in 3414 citations. An additional 19 manuscripts were identified through review of references. The screening process followed a standard protocol, using two screeners at the title/abstract level to determine relevance and at the full-text level to determine eligibility for inclusion. The 3427 titles/abstracts were independently screened by two board-certified neurointensivists to determine relevance for full-text review, and 3248 were rejected. The remaining 179 abstracts were reviewed in full text using predetermined inclusion/exclusion criteria. Ultimately, 75 articles met our inclusion criteria and were utilized in the final analysis. The reviewed literature highlights the need for collaborative, multi-disciplinary, and multi-pronged approaches to reduce infections. Rates of VRI, SSI, VAP, CAUTI, and CLABSI can approach zero with persistence and a team-based approach.

Antibiotic Class and Outcome in Post-stroke Infections: An Individual Participant Data Pooled Analysis of VISTA-Acute

Introduction: Antibiotics used to treat post-stroke infections have differing antimicrobial and anti-inflammatory effects. Our aim was to investigate whether antibiotic class was associated with outcome after post-stroke infection. Methods: We analyzed pooled individual participant data from the Virtual International Stroke Trials Archive (VISTA)-Acute. Patients with ischemic stroke and with an infection treated with systemic antibiotic therapy during the first 2 weeks after stroke onset were eligible. Antibiotics were grouped into eight classes, according to antimicrobial mechanism and prevalence. The primary analysis investigated whether antibiotic class for any infection, or for pneumonia, was independently associated with a shift in 90 day modified Rankin Scale (mRS) using ordinal logistic regression. Results: 2,708 patients were eligible (median age [IQR] = 74 [65 to 80] y; 51% female; median [IQR] NIHSS score = 15 [11 to 19]). Pneumonia occurred in 35%. Treatment with macrolides (5% of any infections; 9% of pneumonias) was independently associated with more favorable mRS distribution for any infection [OR (95% CI) = 0.59 (0.42 to 0.83), p = 0.004] and for pneumonia [OR (95% CI) = 0.46 (0.29 to 0.73), p = 0.001]. Unfavorable mRS distribution was independently associated with treatment of any infection either with carbapenems, cephalosporins or monobactams [OR (95% CI) = 1.62 (1.33 to 1.97), p < 0.001], penicillin plus β-lactamase inhibitors [OR (95% CI) = 1.26 (1.03 to 1.54), p = 0.025] or with aminoglycosides [OR (95% CI) = 1.73 (1.22 to 2.46), p = 0.002]. Conclusion: This retrospective study has several limitations including effect modification and confounding by indication. Macrolides may have favorable immune-modulatory effects in stroke-associated infections. Prospective evaluation of the impact of antibiotic class on treatment of post-stroke infections is warranted.

Preventive Antibiotics for Poststroke Infection in Patients With Acute Stroke: A Systematic Review and Meta-analysis

AIMS

To determine if preventive antibiotics is effective in poststroke infection in patients with acute stroke in comparison with no prophylaxis.

MATERIALS AND METHODS

MEDLINE (1950 to January 2017), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2017) and EMBASE (1974 to January 2017) databases were used to search for randomized controlled trials with intervening measures related to the preventive antibiotics in patients with acute stroke. Besides, the reference lists of the retrieved publications were manually searched to explore other relevant studies.

RESULTS

We included 6 randomized controlled trials involving 4110 stroke patients. The study population, study design, intervening measures, and definition of infection were different. Preventive antibiotics significantly reduced the incidence of algorithm-defined infection in patients with acute stroke from 11.14% (220/1975) to 7.43% (149/2006); odds ratio (OR)=0.41; 95% confidence interval (CI), 0.20-0.87; P=0.02. There was no difference in mortality between 2 groups, the mortality in preventive antibiotics group was 17.03% (347/2037) and control group was 16.10% (328/2037); OR=1.07; 95% CI, 0.90-1.27; P=0.44. And preventive antibiotics did not improve the proportion of good outcome, the proportion of good outcome in preventive antibiotics group was 45.47% (909/1999) and control group was 45.76% (913/1995); OR=0.89; 95% CI, 0.62-1.28; P=0.53. None of the studies reported severe adverse relevant to the study antibiotics.

CONCLUSIONS

Preventive antibiotics significantly reduced the incidence of algorithm-defined infection in patients with acute stroke, but did not decrease the mortality or improve the proportion of good outcome. Future research should aim to identify the group of stroke patients who will benefit most from antibiotic prophylaxis.

Effectiveness and Safety of Antibiotics for Preventing Pneumonia and Improving Outcome after Acute Stroke: Systematic Review and Meta-analysis

BACKGROUND

Pneumonia is a common complication after stroke which increases morbidity and mortality. This systematic review was conducted to evaluate the efficacy and safety of antibiotics for the prevention of pneumonia after acute stroke.

METHODS

Medline, EMBASE, and Cochrane databases were searched for randomized controlled trials comparing preventive antibiotics to placebo or no antibiotics after acute stroke. The primary outcome was poststroke pneumonia. Secondary outcomes were all infections, urinary tract infections, death, dependency, length of hospital stay, and adverse events. Treatment effects were summarized using random effects metaanalysis.

RESULTS

Six trials (4111 patients) were eligible for inclusion. The median National Institute of Health Stroke Scale score in included trials ranged from 5 to 16.5. The proportion of dysphagia ranged from 26% to 100%. Preventive antibiotics were commenced within 48hours after acute stroke. Compared to control, preventive antibiotics reduced the risk of poststroke pneumonia (RR .75, 95%CI ·.57-.99), and all infections (RR .58, 95%CI .48-.69). There was no significant difference in the risks of dependency (RR 0.99, 95%CI 0·80-1·11), or mortality (RR .96, 95%CI .78-1.19) between the preventive antibiotics and control groups. Preventive antibiotics did not increase the risk of elevated liver enzymes (RR 1.20, 95% CI .97-1.49). Preventive antibiotics had uncertain effects on the risks of other adverse events.

CONCLUSION

Preventive antibiotics reduced the risk of post-stroke pneumonia. However, there is insufficient evidence to currently recommend routine use of preventive antibiotics after acute stroke.

Stroke-induced immunosuppression and poststroke infection

Infections occur commonly after stroke and are strongly associated with an unfavourable functional outcome of these patients. Approaches for effective management of poststroke infection remain scarce, presenting an urgent need for preventive anti-infection strategies for patients who have suffered a stroke. Emerging evidence indicates that stroke impairs systemic immune responses and increases the susceptibility to infections, suggesting that the modification of impaired immune defence could be beneficial. In this review, we summarised previous attempts to prevent poststroke infections using prophylactic antibiotics and the current understanding of stroke-induced immunosuppression. Further elucidation of the immune mechanisms of stroke will pave the way to tailored design of new treatment to combat poststroke infection via modifying the immune system.

Antibiotic therapy for preventing infections in people with acute stroke

BACKGROUND

Stroke is the main cause of disability in high-income countries and ranks second as a cause of death worldwide. Infections occur frequently after stroke and may adversely affect outcome. Preventive antibiotic therapy in the acute phase of stroke may reduce the incidence of infections and improve outcome. In the previous version of this Cochrane Review, published in 2012, we found that antibiotics did reduce the risk of infection but did not reduce the number of dependent or deceased patients. However, included studies were small and heterogeneous. In 2015, two large clinical trials were published, warranting an update of this Review.

OBJECTIVES

To assess the effectiveness and safety of preventive antibiotic therapy in people with ischaemic or haemorrhagic stroke. We wished to determine whether preventive antibiotic therapy in people with acute stroke:• reduces the risk of a poor functional outcome (dependency and/or death) at follow-up;• reduces the occurrence of infections in the acute phase of stroke;• reduces the occurrence of elevated body temperature (temperature ≥ 38° C) in the acute phase of stroke;• reduces length of hospital stay; or• leads to an increased rate of serious adverse events, such as anaphylactic shock, skin rash, or colonisation with antibiotic-resistant micro-organisms.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (25 June 2017); the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 5; 25 June 2017) in the Cochrane Library; MEDLINE Ovid (1950 to 11 May 2017), and Embase Ovid (1980 to 11 May 2017). In an effort to identify further published, unpublished, and ongoing trials, we searched trials and research registers, scanned reference lists, and contacted trial authors, colleagues, and researchers in the field.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of preventive antibiotic therapy versus control (placebo or open control) in people with acute ischaemic or haemorrhagic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected articles and extracted data; we discussed and resolved discrepancies at a consensus meeting with a third review author. We contacted study authors to obtain missing data when required. An independent review author assessed risk of bias using the Cochrane 'Risk of bias' tool. We calculated risk ratios (RRs) for dichotomous outcomes, assessed heterogeneity amongst included studies, and performed subgroup analyses on study quality.

MAIN RESULTS

We included eight studies involving 4488 participants. Regarding quality of evidence, trials showed differences in study population, study design, type of antibiotic, and definition of infection; however, primary outcomes among the included studies were consistent. Mortality rate in the preventive antibiotic group was not significantly different from that in the control group (373/2208 (17%) vs 360/2214 (16%); RR 1.03, 95% confidence interval (CI) 0.87 to 1.21; high-quality evidence). The number of participants with a poor functional outcome (death or dependency) in the preventive antibiotic therapy group was also not significantly different from that in the control group (1158/2168 (53%) vs 1182/2164 (55%); RR 0.99, 95% CI 0.89 to 1.10; moderate-quality evidence). However, preventive antibiotic therapy did significantly reduce the incidence of 'overall' infections in participants with acute stroke from 26% to 19% (408/2161 (19%) vs 558/2156 (26%); RR 0.71, 95% CI 0.58 to 0.88; high-quality evidence). This finding was highly significant for urinary tract infections (81/2131 (4%) vs 204/2126 (10%); RR 0.40, 95% CI 0.32 to 0.51; high-quality evidence), whereas no preventive effect for pneumonia was found (222/2131 (10%) vs 235/2126 (11%); RR 0.95, 95% CI 0.80 to 1.13; high-quality evidence). No major side effects of preventive antibiotic therapy were reported. Only two studies qualitatively assessed the occurrence of elevated body temperature; therefore, these results could not be pooled. Only one study reported length of hospital stay.

AUTHORS' CONCLUSIONS

Preventive antibiotics had no effect on functional outcome or mortality, but significantly reduced the risk of 'overall' infections. This reduction was driven mainly by prevention of urinary tract infection; no effect for pneumonia was found.

Activation of the sympathetic nervous system modulates neutrophil function

Emerging evidence has revealed that noradrenaline (NA), the main neurotransmitter of the sympathetic nervous system (SNS), regulates a variety of immune functions via binding to adrenergic receptors present on immune cells. In this study, we examined the role of NA in the regulation of neutrophil functions. Neutrophils were isolated from the bone marrow of naïve mice and treated with NA at various concentrations to assess the effect on various neutrophil functions. Additionally, we performed cremaster intravital microscopy to examine neutrophil‐endothelial cell interactions following NA superfusion in vivo. In a separate group of animals, mice were subjected to an experimental model of stroke and at 4 and 24 h neutrophils were isolated for assessment on their ability to migrate toward various chemokines. Treatment of neutrophils with NA for 4 h significantly impaired neutrophil chemotaxis and induced an N2 neutrophil phenotype with reduced expression of the genes critical for cytoskeleton remodeling and inflammation. Prolonged NA administration promoted neutrophils to release myeloperoxidase and IL‐6, but suppressed the production of interferon‐γ and IL‐10, reduced neutrophil activation and phagocytosis. Superfusion of NA over the cremaster muscle almost completely inhibited fMLP‐induced neutrophil adhesion/arrest and transmigration. Furthermore, using a mouse model of stroke, a pathological condition in which SNS activation is evident, neutrophils isolated from poststroke mice showed markedly reduced chemotaxis toward all of the chemokines tested. The findings from our study indicate that neutrophil chemotaxis, activation, and phagocytosis can all be negatively regulated in an NA‐dependent manner. A better understanding of the relationship between sympathetic activation and neutrophil function will be important for the development of effective antibacterial interventions.

Should preventive antibiotics be used in patients with acute stroke? A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Infection is a common complication in acute stroke. Whether or not preventive antibiotics reduce the risk of infection or even lead to a favorable outcome and reduction of mortality after a stroke still remains equivocal. This review was performed to update the current knowledge on the effect and possible benefits of prophylactic antibiotic therapy in patients with stroke.

METHODS

A systematic review and meta-analysis of preventive antibiotics`effect on the incidence of infection, favorable outcome (mRS≤2) and mortality in patients with acute stroke is performed with relevant randomized controlled trials.

RESULTS

Six studies were identified, involving 4125 participants. Compared with the control group, the treated groups were significantly less prone to suffer from early overall infections [RR = 0.52, 95%CI (0.39, 0.70), p<0.0001], early pneumonia [RR = 0.64, 95%CI (0.42, 0.96), p = 0.03] and early urinary tract infections [RR = 0.35, 95%CI (0.25, 0.48), p<0.00001]. However, there was no significant difference in overall mortality [RR = 1.07, 95%CI (0.90, 1.27), p = 0.44], early mortality [RR = 0.99, 95%CI (0.78, 1.26), p = 0.92], late mortality [RR = 1.12, 95%CI (0.94, 1.35), p = 0.21] or favorable outcome [RR = 1.00, 95%CI (0.92, 1.08), p = 0.98].

CONCLUSION

Although preventive antibiotic treatment did reduce the occurrence of early overall infections, early pneumonia and early urinary tract infection in patients with acute stroke, this advantage was not eventually translated to a favorable outcome and reduction in mortality. Future studies are warranted to identify any subgroup of stroke patients who might benefit from preventive antibiotic treatment.

Antibiotic prophylaxis for infections in patients with acute stroke: a systematic review and meta-analysis of randomized controlled trials

Objective

Infections are frequent after stroke and lead to increased mortality and neurological disability. Antibiotic prophylaxis has potential of decreasing the risk of infections and mortality and improving poor functional outcome. Several studies evaluated antibiotic prophylaxis for infections in acute stroke patients have generated conflicting results. The systematic review of randomized clinical trials (RCTs) aimed at comprehensively assessing the evidence of antibiotic prophylaxis for the treatment of acute stroke patients.

Materials and Methods

PubMed, EMBASE, the Cochrane library and the reference lists of eligible articles were searched to identify all potential studies. We included the studies that investigated the efficacy and safety of antibiotic prophylaxis for the treatment of acute stroke patients. The primary outcome included mortality and infection rate. The secondary outcomes included poor functional outcome and adverse events.

Results

Seven trials randomizing 4,261 patients were included. Pooled analyses showed that antibiotic prophylaxis did not improve the mortality (risk ratio (RR) = 1.03, 95% confidence interval (CI) 0.84 to 1.26, p = 0.78, I² = 25%) and poor functional outcome (RR = 0.93, 95% CI 0.80 to 1.08, p = 0.32, I² = 80%), but reduced the incidence of infection (RR = 0.67, 95% CI 0.53 to 0.84, p = 0.0007, I² = 49%). No major side effects were reported. Sensitivity analyses confirmed the results of infection rate and poor functional outcome.

Conclusions

Antibiotic prophylaxis can be used to treat the infectious events of acute stroke patients although it has no potential of decreased mortality and improved functional outcome.

The Efficacy of Prophylactic Antibiotics on Post-Stroke Infections: An Updated Systematic Review and Meta-Analysis

Post-stroke infections are common complications in acute stroke patients and are associated with an unfavorable functional outcome. However, reports on the effects of prophylactic antibiotics treatment on post-stroke infections are conflicting, especially those on post-stroke pneumonia and outcomes. We searched the PubMed, Embase, and Web of Knowledge databases up through March 11^th, 2016. Seven randomized controlled trials including 4261 patients were analyzed among this systematic review and meta-analysis. We found preventive antibiotics treatment at the time of stroke onset did reduce the incidence of infections in adults with acute stroke (OR = 0.57, 95% CI: 0.38–0.85, P = 0.005), including reducing the number of urinary tract infections (OR = 0.34, 95% CI: 0.26–0.46, P < 0.001), but did not significantly decrease the rate of post-stroke pneumonia (OR = 0.91, 95% CI: 0.73–1.13, P = 0.385). Importantly, antibiotics treatment also showed no significant effect on the number of fatalities among stroke patients (OR = 1.07, 95% CI: 0.90–1.26, P = 0.743) and functional outcome scores on the modified Rankin Scale (OR = 1.76, 95% CI: 0.86–3.63, p = 0.124). Our study indicated that preventive antibiotics treatment not reduced the rate of post-stroke pneumonia or mortality, even though decreased the risk of infections, especially urinary tract infections. Thus, preventive antibiotics treatment may not be recommended for acute stroke patients.

Immunity and stroke, the hurdles of stroke research translation

Immunomodulatory therapies after stroke have the potential to provide clinical benefit to a subset of patients, but risk subverting the protective, healing aspects of the innate immune response. Neutrophils clear necrotic cerebral tissue and are important in immunomodulation, but can also contribute to tissue injury. Human trials for immunomodulatory stroke treatments in the sub-acute time frame have attempted to prevent peripheral neutrophil infiltration, but none have been successful and one trial demonstrated harm. These unselected trials had broad inclusion criteria and appear to not have had a specific treatment target. Unfortunately, due to the heterogeneous nature of brain ischemia in humans resulting in variation in clinical severity, the negative effect of thrombolytic drugs on the blood-brain barrier, and the heterogeneity of immune response, it may only be a subset of stroke patients who can realistically benefit from immunomodulation therapies. Translational research strategies require both an understanding of lab practices which create highly controlled environments in contrast to clinical practice where the diagnosis of stroke does not require the identification of a vessel occlusion. These differences between lab and clinical practices can be resolved through the integration of appropriate patient selection criteria and use of advanced imaging and ridged patient selection practices in clinical trials which will be an important part to the success of any future trials of translational research such as immunomodulation.

Prophylactic Antibiotic Therapy for Preventing Poststroke Infection

Infections, in particular pneumonia, are common complications in patients with acute stroke and are associated with a less favorable neurologic and functional outcome. Patients with severe stroke and dysphagia are at highest risk of infection. Experimental and clinical data suggest stroke-induced immunodeficiency as a major factor contributing to the high incidence of infection after stroke. Preclinical studies support the potential benefit of preventive antibiotic therapy in acute stroke for lowering the incidence of infection and improving clinical outcome. Several smaller clinical trials on preventive antibiotic therapy in patients with stroke conducted during the last 10 years yielded inconclusive results. Recently, 2 large, open-label, controlled trials failed to demonstrate an improved clinical outcome after preventive antibiotic therapy in patients with acute stroke treated in specialized stroke units. In the "Preventive Antibiotics in Stroke Study", antibiotic therapy lowered the rate of infection but did not influence outcome. In the STROKE-INF study, performed in patients with dysphagia after stroke, antibiotic therapy did not lower the incidence of pneumonia and had no prognostic significance. At present, preventive antibiotic therapy cannot be recommended as a therapeutic option for acute stroke.

Prophylactic antibiotic treatment in severe acute ischemic stroke: the Antimicrobial chemopRrophylaxis for Ischemic STrokE In MaceDonIa-Thrace Study (ARISTEIDIS)

Infections represent a leading cause of mortality in patients with acute ischemic stroke, but it is unclear whether prophylactic antibiotic treatment improves the outcome. We aimed to evaluate the effects of this treatment on infection incidence and short-term mortality. This was a pragmatic, prospective multicenter real-world analysis of previously independent consecutive patients with acute ischemic stroke who were >18 years, and who had at admission National Institutes of Health Stroke Scale (NIHSS) >11. Patients with infection at admission or during the preceding month, with axillary temperature at admission >37 °C, with chronic inflammatory diseases or under treatment with corticosteroids were excluded from the study. Among 110 patients (44.5 % males, 80.2 ± 6.8 years), 31 (28.2 %) received prophylactic antibiotic treatment, mostly cefuroxime (n = 21). Prophylactic antibiotic treatment was administered to 51.4 % of patients who developed infection, and to 16.4 % of patients who did not (p < 0.001). Independent predictors of infection were NIHSS at admission [relative risk (RR) 1.16, 95 % confidence interval (CI) 1.08-1.26, p < 0.001] and prophylactic antibiotic treatment (RR 5.84, 95 % CI 2.03-16.79, p < 0.001). The proportion of patients who received prophylactic antibiotic treatment did not differ between patients who died during hospitalization and those discharged, or between patients who died during hospitalization or during follow-up and those who were alive 3 months after discharge. Prophylactic administration of antibiotics in patients with severe acute ischemic stroke is associated with an increased risk of infection during hospitalization, and does not affect short-term mortality risk.

Progress in Research on the Mechanism and Treatment of Post-stroke Infection

Post-stroke infection hinders the recovery of stroke patients and can even cause death. The main mechanism of post-stroke infection is related with the post-stroke center, the activation of the peripheral immune system, and the release of inflammatory factors caused by the lesion area and pathophysiological changes in the body. Therefore, elucidating the body’s abnormal immune inflammatory responses after stroke is crucial for the prevention, treatment, and alleviation of post-stroke infection.

Preventive Ceftriaxone in Patients with Stroke Treated with Intravenous Thrombolysis: Post Hoc Analysis of the Preventive Antibiotics in Stroke Study

BACKGROUND

The Preventive Antibiotics in Stroke Study (PASS), a randomized open-label masked endpoint trial, showed that preventive ceftriaxone did not improve functional outcome at 3 months in patients with acute stroke (adjusted common OR 0.95; 95% CI 0.82-1.09). Post-hoc analyses showed that among patients who received intravenous thrombolysis (IVT), patients who received ceftriaxone had a significantly better outcome as compared with the control group. This study aimed to gain more insight into the characteristics of these patients.

METHODS

In PASS, 2,550 patients were randomly assigned to preventive antibiotic treatment with ceftriaxone or standard care. In current post-hoc analysis, 836 patients who received IVT were included. Primary outcome included functional status on the modified Rankin Scale, analyzed with adjusted ordinal regression. Secondary outcomes included infection rate and symptomatic intracerebral hemorrhage (sICH) rate.

RESULTS

For all patients in PASS, the p value for the interaction between IVT and preventive ceftriaxone regarding functional outcome was 0.03. Of the 836 IVT-treated patients, 437 were administered ceftriaxone and 399 were allocated to the control group. Baseline characteristics were similar. In the IVT subgroup, preventive ceftriaxone was associated with a significant reduction in unfavorable outcome (adjusted common OR 0.77; 95% CI 0.61-0.99; p = 0.04). Mortality at 3 months was similar (OR 0.75; 95% CI 0.48-1.18). Preventive ceftriaxone was associated with a reduction in infections (OR 0.43; 95% CI 0.28-0.66), and a trend towards an increased risk for sICH (OR 3.09; 95% CI 0.85-11.31). Timing of ceftriaxone administration did not influence the outcome (aOR 1.00; 95% CI 0.98-1.03; p = 0.85).

CONCLUSIONS

According to the post-hoc analysis of PASS, preventive ceftriaxone may improve the functional outcome in IVT-treated patients with acute stroke, despite a trend towards an increased rate of post-IVT-sICH.

The contribution of antibiotics, pneumonia and the immune response to stroke outcome

BACKGROUND

Infections are common following stroke and associated with worse outcome. Using an animal model of pneumonia, we assessed the effect of infection and its treatment on the immune response and stroke outcome.

METHODS

Lewis rats were subjected to transient cerebral ischemia and survived for 4weeks. One day after stroke animals were exposed to aerosolized Staphylococcus aureus, Pseudomonas aeruginosa or saline. Antibiotics (ceftiofur or enrofloxacin) were started immediately after exposure or delayed for 3days. Behavioral tests were performed weekly. ELISPOT assays were done on lymphocytes from spleen and brain to assess autoimmune responses to myelin basic protein (MBP).

RESULTS

Among animals that received immediate antibiotic therapy, infection was associated with worse outcome in ceftiofur but not enrofloxacin treated animals. (The outcome with immediate enrofloxacin therapy was so impaired that further worsening may have been difficult to detect.) A delay in antibiotic therapy was associated with better outcomes in both ceftiofur and enrofloxacin treated animals. Infection was associated with an increased likelihood of developing Th1(+) responses to MBP in non-infarcted brain (OR=2.94 [1.07, 8.12]; P=0.04), and Th1(+) responses to MBP in spleen and non-infarcted brain were independently associated with a decreased likelihood of stroke recovery (OR=0.16 [0.05, 0.51; P=0.002 and OR=0.32 [0.12, 0.84]; P=0.02, respectively).

CONCLUSIONS

Infection worsens stroke outcome in ceftiofur treated animals and increases Th1 responses to MBP. These data may help explain how infection worsens stroke outcome and suggest that treatment of infection may contribute to this outcome.

Ischemic stroke outcome: A review of the influence of post-stroke complications within the different scenarios of stroke care

Stroke remains one of the main causes of death and disability worldwide. The challenge of predicting stroke outcome has been traditionally assessed from a general point of view, where baseline non-modifiable factors such as age or stroke severity are considered the most relevant factors. However, after stroke occurrence, some specific complications such as hemorrhagic transformations or post stroke infections, which lead to a poor outcome, could be developed. An early prediction or identification of these circumstances, based on predictive models including clinical information, could be useful for physicians to individualize and improve stroke care. Furthermore, the addition of biological information such as blood biomarkers or genetic polymorphisms over these predictive models could improve their prognostic value. In this review, we focus on describing the different post-stroke complications that have an impact in short and long-term outcome across different time points in its natural history and on the clinical-biological information that might be useful in their prediction.

Ischemia, Immunosuppression and Infection--Tackling the Predicaments of Post-Stroke Complications

The incidence of stroke has risen over the past decade and will continue to be one of the leading causes of death and disability worldwide. While a large portion of immediate death following stroke is due to cerebral infarction and neurological complications, the most common medical complication in stroke patients is infection. In fact, infections, such as pneumonia and urinary tract infections, greatly worsen the clinical outcome of stroke patients. Recent evidence suggests that the disrupted interplay between the central nervous system and immune system contributes to the development of infection after stroke. The suppression of systemic immunity by the nervous system is thought to protect the brain from further inflammatory insult, yet this comes at the cost of increased susceptibility to infection after stroke. To improve patient outcome, there have been attempts to lessen the stroke-associated bacterial burden through the prophylactic use of broad-spectrum antibiotics. However, preventative antibiotic treatments have been unsuccessful, and therefore have been discouraged. Additionally, with the ever-rising obstacle of antibiotic-resistance, future therapeutic options to reverse immune impairment after stroke by augmentation of host immunity may be a viable alternative option. However, cautionary steps are required to ensure that collateral ischemic damage caused by cerebral inflammation remains minimal.

Measuring Serum Amyloid A for Infection Prediction in Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is associated with high rates of mortality and morbidity. Nosocomial infections, such as pneumonia or urinary tract infections, are among the main causes of worsening outcomes and death. The aim of this study was to discover a biomarker to predict infection in aSAH patients. For this purpose, the plasma of infected and noninfected patients was compared using quantitative mass spectrometry. The most interesting differentially expressed proteins were selected for validation by immunoassays on plasma samples taken from patients (n = 81) over 10 days of hospitalization. Predictive performances were established using Mann-Whitney U tests and receiver operating characteristic curves. Quantitative proteomics identified 17 significantly regulated proteins. Of these, levels of serum amyloid A (SAA) were significantly higher in infected patients (p < 0.007). ELISA confirmed that the concentrations were significantly higher (p < 0.002) already at hospital admission in patients who subsequently developed an infection during their hospitalization, (AUC of 76%) for a cutoff value of 90.9 μg/mL. Our data suggested that measuring SAA could be an efficient means of detecting patients susceptible of developing an infection during hospitalization after an aSAH. Its predictive capacity could lead to earlier antibiotherapy, improved patient management, and potentially better long-term outcomes.

Reduction of the systemic inflammatory induced by acute cerebral infarction through ultra-early thrombolytic therapy

Acute ischemic stroke induces systemic inflammation, exhibited as changes in body temperature, white blood cell counts and C-reactive protein (CRP) levels. The aim of the present study was to observe the effects of intravenous thrombolytic therapy on inflammatory indices in order to investigate the hypothesis that post-stroke systemic inflammatory response occurs in response to the necrosis of brain tissues. In this study, 62 patients with acute cerebral infarction and indications for intravenous thrombolysis were divided into three groups on the basis of their treatment and response: Successful thrombolysis (n=36), failed thrombolysis (n=12) and control (n=14) groups. The body temperature, white blood cell counts and high-sensitivity (hs)-CRP levels were recorded pre-treatment and on post-stroke days 1, 3, 5 and 7. Spearman's correlation analysis showed that the pre-treatment National Institutes of Health Stroke Scale (NIHSS) score positively correlated with body temperature, white blood cell count and hs-CRP levels. On day 3 of effective intravenous thrombolysis, the body temperature and white blood cell were decreased and on days 3 and 5, the serum levels of hs-CRP were reduced compared with those in the failed thrombolysis and control groups. The results indicate that the systemic inflammatory response following acute cerebral infarction was mainly caused by ischemic injury of local brain tissue; the more serious the stroke, the stronger the inflammatory response. Ultra-early thrombolytic therapy may inhibit the necrosis of brain tissue and thereby reduce the inflammatory response.

Effect of Antibiotic Class on Stroke Outcome

BACKGROUND AND PURPOSE

Infections are common after stroke and associated with worse outcome. Clinical trials evaluating the benefit of prophylactic antibiotics have produced mixed results. This study explores the possibility that antibiotics of different classes may differentially affect stroke outcome.

METHODS

Lewis rats were subjected to transient cerebral ischemia (2 hours) and survived for 1 month. The day after stroke they were randomized to therapy with ceftiofur (a β-lactam antibiotic), enrofloxacin (a fluoroquinolone antibiotic), or vehicle (as controls) and underwent the equivalent of 7 days of treatment. Behavioral tests were performed weekly until euthanization. In a subset of animals, histology was done.

RESULTS

There were no differences in outcomes at 24 hours or 1 week after stroke among the different groups. At 1 month after stroke, however, performance on the rotarod was worse in enrofloxacin-treated animals when compared with control animals.

CONCLUSIONS

Independent of infection, the antibiotic enrofloxacin was associated with worse stroke outcome. These data echo the clinical observations to date and suggest that the secondary effects of antibiotics on stroke outcome should be considered when treating infection in subjects with stroke. The mechanism by which this antibiotic affects outcome needs to be elucidated.

The Preventive Antibiotics in Stroke Study (PASS): a pragmatic randomised open-label masked endpoint clinical trial

BACKGROUND

In adults with acute stroke, infections occur commonly and are associated with an unfavourable functional outcome. In the Preventive Antibiotics in Stroke Study (PASS) we aimed to establish whether or not preventive antimicrobial therapy with a third-generation cephalosporin, ceftriaxone, improves functional outcome in patients with acute stroke.

METHODS

In this multicentre, randomised, open-label trial with masked endpoint assessment, patients with acute stroke were randomly assigned to intravenous ceftriaxone at a dose of 2 g, given every 24 h intravenously for 4 days, in addition to stroke unit care, or standard stroke unit care without preventive antimicrobial therapy; assignments were made within 24 h after symptom onset. The primary endpoint was functional outcome at 3 months, defined according to the modified Rankin Scale and analysed by intention to treat. The primary analysis was by ordinal regression of the primary outcome. Secondary outcomes included death, infection rates, antimicrobial use, and length of hospital stay. Participants and caregivers were aware of treatment allocation but assessors of outcome were masked to group assignment. This trial is registered with controlled-trials.com, number ISRCTN66140176.

FINDINGS

Between July 6, 2010, and March 23, 2014, a total of 2550 patients from 30 sites in the Netherlands, including academic and non-academic medical centres, were randomly assigned to the two treatment groups: 1275 patients to ceftriaxone and 1275 patients to standard treatment (control group). 12 patients (seven in the ceftriaxone group and five in the control group) withdrew consent immediately after randomisation, leaving 2538 patients available for the intention-to-treat-analysis (1268 in the ceftriaxone group and 1270 in the control group). 2514 (99%) of 2538 patients (1257 in each group) completed 3-month follow-up. Preventive ceftriaxone did not affect the distribution of functional outcome scores on the modified Rankin Scale at 3 months (adjusted common odds ratio 0·95 [95% CI 0·82-1·09], p=0·46). Preventive ceftriaxone did not result in an increased occurrence of adverse events. Overgrowth infection with Clostridium difficile occurred in two patients (<1%) in the ceftriaxone group and none in the control group.

INTERPRETATION

Preventive ceftriaxone does not improve functional outcome at 3 months in adults with acute stroke. The results of our trial do not support the use of preventive antibiotics in adults with acute stroke.

FUNDING

Netherlands Organization for Health Research and Development, Netherlands Heart Foundation, and the European Research Council.

Lipopolysaccharide binding protein, interleukin-10, interleukin-6 and C-reactive protein blood levels in acute ischemic stroke patients with post-stroke infection

Background

Ischemic stroke patients are prone to infection by stroke-induced immunodepression. We hypothesized that levels of lipopolysaccharide binding protein (LBP), interleukin-10 (IL-10), IL-6 and C-reactive protein (CRP) are early predictors for the development of stroke-associated infection.

Methods

Fifty-six patients with ischemic stroke (n = 51) and transient ischemic attack (TIA) (n = 5) who presented within 6 hours after symptom onset and who were free of detectable infection on admission were included in the study. Of these, 20 developed early infections during the first week. Blood samples were taken at 6, 12, and 24 hours and at 3 and 7 days after stroke onset. Levels of LBP, Il-10, IL-6 and CRP, as well as S100B, were measured as markers of inflammation and brain damage by commercially available immunometric tests.

Results

In the univariate analysis, levels of LBP, IL-10, IL-6 and CRP significantly differed between patients who developed an infection and those who did not. In the binary logistic regression analysis, which was adjusted for National Institutes of Health Stroke Scale (NIHSS) on admission, stroke subtype and S100B peak levels, as indicator of the extent of brain damage, IL-10 at 6 hours, CRP at 6 hours and NIHSS on admission were identified as independent predictors of infection (IL-10: P = 0.009; CRP: P = 0.018; NIHSS: P = 0.041). The area under the curve (AUC) of the receiver operating characteristic (ROC) curves in relation to the dichotomized status of the infection (infection versus no infection) was 0.74 (95% confidence interval: 0.59 to 0.88) for CRP at 6 hours, 0.76 (0.61 to 0.9) for IL-10 at 6 hours, 0.83 (0.71 to 0.94) for NIHSS on admission and 0.94 (0.88 to 1) for the combination of CRP, IL-10 and NIHSS. In a subanalysis, 16 patients with early infections were matched with 16 patients without infection according to S100B peak levels. Here, the temporal pattern of LBP, IL-10, IL-6 and CRP significantly differed between the patient groups.

Conclusions

Our data show that blood levels of inflammation markers may be used as early predictors of stroke-associated infection. We propose prospective studies to investigate if the calculated cut-offs of CRP, IL-10 and NIHSS might help to identify patients who should receive early preventive antibiotic treatment.

Daily National Institutes of Health Stroke Scale examinations at stroke centers: why not do them?

The National Institutes of Health Stroke Scale was originally designed to stratify patients according to stroke severity for clinical trials, and now it is used to predict disposition and prognosticate functional outcome. Many researchers have also adopted it to trend patient progress over time and detect early neurologic deterioration. However, few investigators have reported its utility in monitoring the daily progress of patients hospitalized for stroke. In the present article, the authors discuss the advantages of daily National Institutes of Health Stroke Scale assessments and our clinical experience with this invaluable tool.

Immunological consequences of ischemic stroke

The treatment of ischemic stroke is one of the great challenges in modern neurology. The localization and the size of the infarct determine the long-term disability of stroke survivors. Recent observations have revealed that stroke also alters the function of the immune system and vice versa: At the site of the infarct, a local inflammatory response develops that enhances brain lesion development. In experimental stroke, proof-of-concept studies confirm that inhibition of this immune response reduces lesion volume and improves outcome. In the peripheral blood of stroke patients, though, lymphocytopenia and monocyte dysfunction develop. These changes reflect a clinically relevant impairment of bacterial defense mechanisms because they are associated with an enhanced risk to acquire post-stroke infections. Stress hormones have been identified as important mediators of stroke-induced immune suppression. The pharmacological inhibition of beta adrenergic receptors, but not the inhibition of steroids, is effective in reducing infection and improving clinical outcome in experimental stroke; catecholamine release therefore appears causally related to stroke-induced immune suppression. Strong evidence supports the hypothesis that these immune alterations impact the clinical course of stroke patients. Thus, the development of new therapeutic strategies targeted to alter the immunological consequences of stroke appears promising. However, to date, the beneficial effects seen in experimental stroke have not been successfully translated into a clinical trial. This brief review summarizes the current understanding of the immunological consequences of ischemic stroke. Finally, we propose a concept that links the peripheral immune suppression with the development of local inflammation.

Is early clinical evidence of autonomic shift predictive of infection after aneurysmal subarachnoid hemorrhage

BACKGROUND

Autonomic shift (AS), characterized by increased sympathetic nervous system activation, has been implicated in neurologically mediated cardiopulmonary dysfunction and immunodepression after stroke. We investigated the prevalence of AS defined by readily available clinical parameters and determined the association of AS with subsequent infection in a cohort of patients with aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

Data were obtained from a single-center cohort study of aSAH patients admitted from January 1, 2007, through April 1, 2012. AS was defined as at least 1 early (<72 hours) routine clinical marker of neurologically mediated cardiopulmonary dysfunction based on electrocardiogram, echocardiogram, cardiac enzymes, or neurogenic pulmonary edema. Multivariable logistic regression models were developed to evaluate the association between AS and subsequent infection after adjusting for other covariates.

RESULTS

A total of 167 patients were included in the analysis (mean age 56, 27% men). AS was seen in 66 of 167 patients (40%; 95% confidence interval [CI], 32%-47%), and infection was seen in 80 of 167 patients (48%; 95% CI, 40%-55%). AS was associated with subsequent infection on unadjusted analysis (odds ratio [OR] 2.11; 95% CI, 1.12-3.97); however, this association was no longer significant when adjusting for other predictors of infection (OR 1.36; 95% CI, .67-2.76). Age, clinical grade, and aneurysm location were all independent predictors of infection after aSAH.

CONCLUSIONS

We identified AS based on readily available clinical markers in 40% of patients with aSAH, though AS defined by these clinical criteria was not an independent predictor of infection. Additional studies may be warranted to determine the optimal definition of AS and the clinical significance of this finding.

Predicting post-stroke pneumonia: the PANTHERIS score

OBJECTIVES

Stroke-associated pneumonia (SAP) is a common complication with a known negative impact on neurological outcome. We developed a score to identify patients at highest risk of SAP in order to promote prophylactic measures.

MATERIALS AND METHODS

We conducted a cohort study on a neurological intensive care unit in patients suffering from acute ischemic MCA infarction. Association of predefined demographics, comorbidities, and clinical characteristics with SAP was investigated using logistic regression analysis.

RESULTS

Between 2003 and 2010, a total of 335 patients were included in this analysis. Frequency of SAP was 31.3%. A 12-point scoring system was developed based on the following factors: Glasgow Coma Scale (GCS) [GCS < 9 = 5, GCS 9-12 = 2, GCS > 12 = 0], age [<60 = 0, 60-80 = 1, >80 = 2], increase in systolic arterial blood pressure >200 mmHg within the first 24 h after admission [no = 0, yes = 2], and white blood cell count >11.000/μl [no = 0, yes = 3]. The score revealed excellent discrimination (AUC = 0.85) and calibration (Nagelkerke's R² = 0.46) properties. Predictive properties were reproduced in an internal validation group.

CONCLUSIONS

The PANTHERIS score is a simple scoring system for the prediction of SAP based on easy-to-assess parameters. By identifying patients at high risk, it may guide intense monitoring or prophylactic measures. This score needs to be validated within external datasets.

Superiority of preventive antibiotic treatment compared with standard treatment of poststroke pneumonia in experimental stroke: a bed to bench approach

Stroke patients are prone to life-threatening bacterial pneumonia. Previous experimental stroke studies have demonstrated that preventive antibiotic treatment (PAT) improves outcome compared with placebo treatment, which however does not model the clinical setting properly. Here we investigate whether PAT is superior to the current clinical 'gold standard' for treating poststroke infections. Therefore, we modeled stroke care according to the current stroke guidelines recommending early antibiotic treatment after diagnosing infections. To reliably diagnose pneumonia in living mice, we established a general health score and a magnetic resonance imaging protocol for radiologic confirmation. Compared with standard treatment after diagnosis by these methods, PAT not only abolished pneumonia successfully but also improved general medical outcome. Both, preventive and standard antibiotic treatment using enrofloxacin improved survival in a similar way compared with placebo treatment. However, in contrast to standard treatment, only PAT improved functional outcome assessed by gait analysis. In conclusion, standard and preventive treatment approach reduced poststroke mortality, however at the cost of a worse neurologic outcome compared with preventive approach. These data support the concept of PAT for treating patients at risk for poststroke infections and warrant phase III trials to prove this concept in clinical setting.

Stroke-associated pneumonia: major advances and obstacles

BACKGROUND

Stroke-associated pneumonia (SAP) has been implicated in the morbidity, mortality and increased medical cost after acute ischemic stroke. The annual cost of SAP during hospitalization in the United States approaches USD 459 million. The incidence and prognosis of SAP among intensive care unit (ICU) patients have not been thoroughly investigated. We reviewed the pathophysiology, microbiology, incidence, risk factors, outcomes and prophylaxis of SAP with special attention to ICU studies.

METHODS

To determine the incidence, risk factors and prognosis of acute SAP, PubMed was searched using the terms 'pneumonia' AND 'neurology intensive unit' and the MeSH terms 'stroke' AND 'pneumonia'. Non-English literature, case reports and chronic SAP studies were excluded. Studies were classified into 5 categories according to the setting they were performed in: neurological intensive care units (NICUs), medical intensive care units (MICUs), stroke units, mixed studies combining more than one setting or when the settings were not specified and rehabilitation studies.

RESULTS

The incidences of SAP in the following settings were: NICUs 4.1-56.6%, MICUs 17-50%, stroke units 3.9-44%, mixed studies 3.9-23.8% and rehabilitation 3.2-11%. The majority of NICU and MICU studies were heterogeneous including different neurovascular diseases, which partly explains the wide range of SAP incidence. The higher incidence in the majority of ICU studies compared to stroke units or acute floor studies is likely explained by the presence of mechanical ventilation, higher stroke severity causing higher rates of aspiration and stroke-induced immunodepression among ICU patients. The short-term mortality of SAP was increased among the mixed and stroke unit studies ranging between 10.1 and 37.3%. SAP was associated with worse functional outcome in the majority of stroke unit and floor studies. Mortality was less consistent among NICU and MICU studies. This difference could be due to the heterogeneity of ICU studies and the effect of small sample size or other independent risk factors for mortality such as the larger neurological deficit, mechanical ventilation, and age, which may simultaneously increase the risk of SAP and mortality confounding the outcomes of SAP itself. The pathophysiology of SAP is likely explained by aspiration combined with stroke-induced immunodepression through complex humeral and neural pathways that include the hypothalamic-pituitary-adrenal axis, parasympathetic and sympathetic systems.

CONCLUSIONS

A unified definition of SAP, strict inclusion criteria, and the presence of a long-term follow-up need to be applied to the future prospective studies to better identify the incidence and prognosis of SAP, especially among ICU patients.

Correlation between inflammatory factors and post-stroke pneumonia in diabetic patients

Pneumonia is the most common cause of mortality in stroke patients and it has been demonstrated to contribute to mortality and poor functional outcome following stroke in the majority of clinical studies. The risk of infection may be attributed to stroke-induced immunodepression syndrome (SIDS). Cytokine production is increased in SIDS. However, the correlation between biomarkers and the risk of post-stroke pneumonia in patients with diabetes mellitus is not clear. The aim of this study was to determine the correlation between pneumonia and the levels of C-reactive protein (CRP) and interleukin-6 (IL-6), as well as to identify early predictors of pneumonia in acute ischemic stroke patients with diabetes mellitus. Additionally, we investigated the impact of pneumonia on functional outcome after 1 month. A total of 106 ischemic stroke patients with diabetes mellitus who were admitted after the onset of symptoms were included in the study. They were divided into two groups, the pneumonia and non-pneumonia groups. CRP, IL-6, white blood cells (WBCs), mean body temperature and National Institutes of Health Stroke Scale (NIHSS) score were measured at the time of admission. The modified Rankin Scale score was assessed at 30 days. The levels of IL-6, CRP and WBCs, as well as mean body temperature were significantly higher in the patients with pneumonia than in the patients without pneumonia. There were also significant differences between the pneumonia and non-pneumonia groups in age, admission NIHSS score, length of hospital stay and dysphagia. Pneumonia patients had worse outcomes compared with patients without pneumonia at 1 month. Age, NIHSS score and dysphagia were significantly associated with pneumonia. WBCs and mean body temperature were not significant predictors of pneumonia. Older patients with more severe ischemic stroke are more susceptible to the development of pneumonia during the stay in hospital. Pneumonia contributes to poor functional outcome. IL-6, CRP, age, NIHSS score and dysphagia may predict the occurrence of pneumonia on the day of stroke symptom onset.

Do stroke models model stroke?

Stroke is one of the leading causes of death worldwide and the biggest reason for long-term disability. Basic research has formed the modern understanding of stroke pathophysiology, and has revealed important molecular, cellular and systemic mechanisms. However, despite decades of research, most translational stroke trials that aim to introduce basic research findings into clinical treatment strategies - most notably in the field of neuroprotection - have failed. Among other obstacles, poor methodological and statistical standards, negative publication bias, and incomplete preclinical testing have been proposed as 'translational roadblocks'. In this article, we introduce the models commonly used in preclinical stroke research, discuss some of the causes of failed translational success and review potential remedies. We further introduce the concept of modeling 'care' of stroke patients, because current preclinical research models the disorder but does not model care or state-of-the-art clinical testing. Stringent statistical methods and controlled preclinical trials have been suggested to counteract weaknesses in preclinical research. We conclude that preclinical stroke research requires (1) appropriate modeling of the disorder, (2) appropriate modeling of the care of stroke patients and (3) an approach to preclinical testing that is similar to clinical testing, including Phase 3 randomized controlled preclinical trials as necessary additional steps before new therapies enter clinical testing.

Immunological biomarkers improve the accuracy of clinical risk models of infection in the acute phase of ischemic stroke

Infection is an independent risk factor for adverse outcome in stroke patients. The risk of developing an infection in this setting is partly related to a stroke-induced immunodepression, in which a shift to a predominant Th2 (immunosuppressive) phenotype has been postulated to play a major role. Our aim was to study whether clinical variables or changes in plasma cytokine expression can predict poststroke infections.

PATIENTS AND METHODS

Medical records of 92 stroke patients were reviewed, and the baseline concentration of cytokines from the Th1/Th2 system was determined. Clinical and serological predictors of incident infections and their prognostic significance were sought by means of univariate and multivariate analysis, and two predictive models for developing an infection were constructed by combining independent predictors (strictly clinical in one, and both clinical and serological in the other) for this outcome. The improvement conferred by the addition of immunological markers to the clinical model was assessed by comparing their respective ROC curves and by improvement (Net Reclassification Index and Integrated Discriminator Improvement) analysis.

RESULTS

Nineteen patients (20.7% of the study sample) developed an infection. Ongoing antiplatelet therapy at symptom onset (OR 0.02, 95% CI 0.001-0.23, p = 0.001), diabetes mellitus (OR 9.96, 95% CI 1.32-75.29, p = 0.03), IL-13 level <33 pg/ml (OR 84.16, 95% CI 2.53-2795.18, p = 0.01) and interferon-γ level >8.4 pg/ml (OR 60.17, 95% CI 1.78-2037.23, p = 0.02) were independently associated with the development of infections during hospital admission. The combined regression model predicted infection with an accuracy of 93.4%, an improvement in the predictive capacity of 17% (p < 0.001). Infection was associated with a worse neurological status at hospital discharge (median NIHSS score 11 (6-18) vs. 4 (1-11.5), p = 0.014).

CONCLUSIONS

This study shows that bloodstream biomarkers are useful to improve the accuracy of clinical prognostic models for infection in the acute phase of stroke. The clinical predictors of infection in the acute phase of stroke are relatively well established in the medical literature, but further research to identify the optimal combination of biomarkers (possibly inflammatory and stress markers) to be included in a clinically useful model is needed. Such a model could be subsequently used in clinical trials to assess the effect of prophylactic and/or early antibiotic therapy in this setting, a currently controversial issue in this field.