A Retrospective Evaluation of Critical Care Blood Culture Yield - Do Support Services Contribute to the "Weekend Effect"?

Time Is of the Essence: Achieving Prompt and Effective Antimicrobial Therapy of Bloodstream Infection With Advanced Hospital Information Systems

The early administration of appropriate antibiotic therapy is crucial for the survival of patients with bacteremia. Current research focuses on improving analytical times through technology, whereas there have been very few efforts to improve postanalytical times even though they represent 40% of the time between blood taking and appropriate treatment administration. One of the clues is the efficiency and appropriateness of the result communication system. Here, we review all delays in the entire process with the aim of improving time to appropriate treatment administration. We discuss causes for long times to adjust treatment once microbiological results are released. We argue that the pervasive health information system in this organization serves as both a bottleneck and a rigid framework. Finally, we explore how next-generation hospital information systems should be designed to effectively assist the doctors in treating patients with bacteremia.

Weekend Admission Increases Risk of Readmissions Following Elective Thoracolumbar Spinal Fusion

STUDY DESIGN

Retrospective database study.

OBJECTIVES

The goal of this study was to assess the influence of weekend admission on patients undergoing elective thoracolumbar spinal fusion by investigating hospital readmission outcomes and analyzing differences in demographics, comorbidities, and postoperative factors.

METHODS

The 2016-2018 Nationwide Readmission Database was used to identify adult patients who underwent elective thoracolumbar spinal fusion. The sample was divided into weekday and weekend admission patients. Demographics, comorbidities, complications, and discharge status data were compiled. The primary outcomes were 30-day and 90-day readmission. Univariate logistic regression analyzed the relationship between weekday or weekend admission and 30- or 90-day readmission, and multivariate regression determined the impact of covariates.

RESULTS

177,847 patients were identified in total, with 176,842 in the weekday cohort and 1005 in the weekend cohort. Multivariate regression analysis found that 30-day readmissions were significantly greater for the weekend cohort after adjusting for sex, age, Medicare or Medicaid status, and comorbidity status (OR 2.00, 95% CI: 1.60-2.48; P < .001), and 90-day readmissions were also greater for the weekend cohort after adjustment (OR 2.01, 95% CI: 1.68-2.40, P < .001).

CONCLUSIONS

Patients undergoing elective thoracolumbar spinal fusion surgery who are initially admitted on weekends are more likely to experience hospital readmission. These patients have increased incidence of deep vein thrombosis, postoperative infection, and non-routine discharge status. These factors are potential areas of focus for reducing the impact of the "weekend effect" and improving outcomes for elective thoracolumbar spinal fusion.

An assessment of the downstream implications of blood culture collection and transit

The implications of the variables within the pre-analytical phase of blood culture processing are poorly understood. This study aims to explore the effect of transit times (TT) and culture volume, on time to microbiological diagnosis and patient outcomes. Blood cultures received between 1st March and 31st July 2020/21 were identified. TT, time in incubator (TII), and for positive samples, request to positivity times (RPT) were calculated. Demographic details were recorded for all samples, and culture volume, length of stay (LoS), and 30-day mortality for patients with positive samples. Statistical analysis examined how culture volume and TT effected culture positivity and outcome; in the context of the 4-h national TT target. Totally, 14,375 blood culture bottles were received from 7367 patients; 988 (13.4%) were positive for organisms. There was no significant difference between TT of negative and positive samples. The RPT was significantly lower for samples with TT < 4 h (p < 0.001). Culture bottle volume did not affect RPT (p = 0.482) or TII (p = 0.367). A prolonged TT was associated with a longer length-of-stay in those with a bacteraemia with a significant organism (p = 0.001). We found shorter blood culture transportation time was associated with a significantly faster time of positive culture reporting, while optimal blood culture volume did not make a significant impact. Delays in reporting for significant organisms correspond to a prolonged LoS. Laboratory centralisation makes achieving the 4-h target a logistical challenge; however, this data suggests such targets have significant microbiological and clinical impacts.

Weekend Admission Increases Risk of Readmissions Following Elective Cervical Spinal Fusion

Objective: The “weekend effect” occurs when patients cared for during weekends versus weekdays experience worse outcomes. But reasons for this effect are unclear, especially amongst patients undergoing elective cervical spinal fusion (ECSF). Our aim was to analyze whether index weekend admission affects 30- and 90-day readmission rates post-ECSF.Methods: All ECSF patients > 18 years were retrospectively identified from the 2016–2018 Healthcare Cost and Utilization Project Nationwide Readmissions Database (NRD), using unique patient linkage codes and International Classification of Diseases, Tenth Revision codes. Patient demographics, comorbidities, and outcomes were analyzed. Univariate logistic regression analyzed primary outcomes of 30- and 90-day readmission rates in weekday or weekend groups. Multivariate regression determined the impact of complications on readmission rates.Results: Compared to the weekday group (n = 125,590), the weekend group (n = 1,026) held a higher percentage of Medicare/Medicaid insurance, incurred higher costs, had longer length of stay, and fewer routine home discharge (all p < 0.001). There was no difference in comorbidity burden between weekend versus weekday admissions, as measured by the Elixhauser Comorbidity Index (p = 0.527). Weekend admissions had higher 30-day (4.30% vs. 7.60%, p < 0.001) and 90-day (7.80% vs. 16.10%, p < 0.001) readmission rates, even after adjusting for sex, age, insurance status, and comorbidities. All-cause complication rates were higher for weekend admissions (8.62% vs. 12.7%, p < 0.001), specifically deep vein thrombosis, infection, neurological conditions, and pulmonary embolism.Conclusion: Index weekend admission increases 30- and 90-day readmission rates after ECSF. In patients undergoing ECSF on weekends, postoperative care for patients at risk for specific complications will allow for improved outcomes and health care utilization.

24/7 workflow for bloodstream infection diagnostics in microbiology laboratories: the first step to improve clinical management

OBJECTIVES

We aimed to evaluate the impact of an uninterrupted workflow regarding blood cultures on turnaround time and antibiotic prescription.

METHODS

Monomicrobial episodes of bacteremia were retrospectively evaluated before and after a continuous 24/7 workflow was implemented in our clinical microbiology laboratory (pre- and post-intervention periods; PREIP and POSTIP). Primary outcome was the time from specimen collection to the first change in antibiotic therapy. Secondary outcomes included the time from specimen collection to effective antibiotic therapy and to antibiotic susceptibility testing results (or turnaround time), as well as hospital length of stay and all-cause mortality at 30 days.

RESULTS

A total of 548 episodes of bacteremia were included in the final analysis. There was no difference in PREIP and POSTIP regarding patient characteristics and causative bacteria. In POSTIP, the mean time to the first change in antibiotic therapy was reduced by 10.4 h (p<0.001). The time to effective antibiotic therapy and the turnaround time were respectively reduced by 4.8 h (p<0.001) and 5.1 h (p=0.006) in POSTIP. There was no difference in mean hospital length of stay or mortality between the two groups.

CONCLUSIONS

Around the clock processing of blood cultures allows for a reduction in turnaround time, which in turn reduces the delay until effective antibiotic therapy prescription.

[Infective Endocarditis with Unknown Etiology: Possibilities of Conquering and Role of Microbiologistics]

Current infectious endocarditis (IE) is characterized by changes in its etiological and epidemiological profiles associated with increased incidence of IE of undetermined etiology. This requires a search for ways to enhance the effectivity of diagnosis. Microbiologistics along with high-tech methods becomes decisively important for identifying the pathogen by studying cultures of blood and tissues from the affected heart valve. This determines timely diagnosis and treatment to be introduced to medical practice as a component of personalized medicine. The article focuses on the validity and features of microbiological (cultural), immunochemical, and molecular biological [MALDI-TOF MS (matrix-activated laser desorption/ionization with time-of-flight mass spectrometry), polymerase chain reaction, sequencing] studies.

Blood culture quality assurance: what Australasian laboratories are measuring and opportunities for improvement

Blood cultures are among the most important specimen types received and processed by the microbiology laboratory. Several publications list which variables should be measured to ensure quality. We undertook a qualitative structured questionnaire of Australian and New Zealand clinical microbiology laboratories to document current blood culture practices and to determine whether expected quality standards are being met. Questions included a wide range of pre-analytical, analytical, and post-analytical aspects of blood cultures from adults. The responses from 71 laboratories were analysed. Compliance was high for use of a biological safety cabinet (90%), incubating for 5 days (86%), and commenting on likely contaminants (85%). While Gram stains were reported within 2 hours during normal hours (93%), reporting was slower after hours (59%), p<0.001. The volume of blood collected for a clinical episode was poorly monitored with only 11% (n=8) of laboratories regularly auditing the number of blood culture sets and 3% (n=2) monitoring adequacy of fill. Most laboratories received blood cultures from off-site with just 34% (n=21) meeting guidance for loading bottles onto the analyser within 4 hours. More laboratories met standards for loading bottles onto the analyser during working hours than after hours: 87% vs 56%, p<0.001. Most laboratories did not monitor the contamination rate, 56% (n=40), and only 27% (n=19) knew their rate was below the guidance threshold of less than -3%. Considerable opportunities exist to improve quality assurance of blood culture practice in Australia and New Zealand, especially for the most critical aspect affecting culture sensitivity, the volume of blood collected.

Laboratory and clinical impacts of an overnight laboratory service

Delayed initiation of effective antimicrobial therapy for sepsis is associated with increased mortality. Whilst automated blood culture machines operate continuously, this does not align with conventional staff working hours and so turn-around-times (TAT) for reporting gram stains to clinicians are 3-7 times longer for blood cultures that flag positive overnight. We retrospectively compared laboratory TATs and clinical outcomes for blood cultures from 183 patients that flagged positive overnight during a 4-month period before and after the implementation of an overnight laboratory service. Enterobacterales and urinary tract infections were the most frequent pathogens and clinical syndrome respectively, and the prevalence of multi-resistant organisms was 15%. Compared with the pre-implementation period, the post-implementation period was associated with shorter median time from blood culture positivity to gram stain (7.4 vs 1.2 h), first genus level identification (7.2 vs 5.8 h) and first antimicrobial susceptibility result (24.1 vs 7.9 h). Similarly, the median time from blood culture positivity to clinicians first being informed was significantly shorter (9.2 vs 1.3 h). After removal of likely contaminants, 78% of patients were on effective empiric antimicrobials and for patients on ineffective empiric antimicrobials, effective therapy was initiated a median of 3.2 h sooner during the post-implementation period, without impact on mortality. Implementation of an overnight laboratory service was associated with significantly faster TAT for reporting blood culture results and more prompt initiation of effective antimicrobials for patients receiving ineffective empiric therapy, improving attainment of sepsis management goals.

Collection, transport and storage procedures for blood culture specimens in adult patients: recommendations from a board of Italian experts

Bloodstream infections (BSIs) remain a potentially life-threatening condition. The gold standard for the diagnosis of BSI is still blood cultures (BCs), and the diagnostic yield depends on clinical and technical factors that have an impact on collection and transportation. Hence, monitoring of the entire pre-analytical process from blood collection to transportation to the microbiology laboratory is critical. To optimize the clinical impact of the diagnostic and therapeutic procedures, a multidisciplinary approach and univocal protocols are mandatory. A board of specialists discussed the available evidence on the pre-analytical process and produced the present document to guide physicians and nurses on the ideal execution of BC: (1) timing and preparation for blood collection; (2) skin antisepsis; (3) blood volume; (4) sampling method and safety; (5) medium to be used; (6) time to BC transportation; and (7) quality assurance and quality management.

On-site blood culture incubation shortens the time to knowledge of positivity and microbiological results in septic patients

Introduction

To determine whether on-site incubation of blood cultures at the intensive care unit (ICU) improves not only the time to incubation but also time to positivity, time to knowledge of positivity and time to results (identification and antibiotic susceptibility testing).

Methods

This observational single-centre study in ICU patients with severe sepsis and septic shock investigated the impact of blood culture incubation immediately on-site at the ICU (ICU group) by comparison with traditional processing in a remote laboratory (LAB group) on different time intervals of blood culture diagnostics from obtaining blood to clinician notification of final result. The effect of on-site incubation was evaluated in Kaplan-Meier estimates for the time to positivity, time to knowledge of positivity and time to microbiological results and a linear mixed model was built.

Results

A total of 3,549 blood culture sets from 657 ICU patients were analysed: 2,381 in the LAB group and 1,168 in the ICU group. Overall, 660 (18.6%) blood culture sets were positive and 2,889 (81.4%) sets remained negative. On-site incubation was associated with reduced time to knowledge of positivity (46.9 h [CI 43.4–50.8 h] vs. 28.0 h [CI 23.6–32.2 h], p < 0.001) and reduced time to result (61.4 h [CI 58.4–64.8 h] vs. 42.1 h [CI 39.1–47.5 h], p < 0.001). In blood cultures processed instantaneously at the ICU compared to incubation in the remote laboratory within 4 h, the time to microbiological result was significantly reduced by 8.5 h (p < 0.001). Pre-existing anti-infective therapy had no significant impact on diagnostic time intervals.

Conclusions

Instantaneous incubation of blood cultures in the ICU compared to incubation in a remote laboratory significantly improves time to knowledge to positivity and time to result. These effects are even more pronounced during off-hours of the microbiological laboratory. The results underline the importance of 24/7 diagnostics to provide round-the-clock processing of blood culture samples in patients with sepsis and septic shock and an immediate to communication of the results to the clinicians.

In-Hospital and Postdischarge Mortality Among Patients With Acute Decompensated Heart Failure Hospitalizations Ending on the Weekend Versus Weekday: The ARIC Study Community Surveillance

Background

Hospital staffing is usually reduced on weekends, potentially impacting inpatient care and postdischarge coordination of care for patients with acute decompensated heart failure (ADHF). However, investigations of in‐hospital mortality on the weekend versus weekday, and post‐hospital outcomes of weekend versus weekday discharge are scarce.

Methods and Results

Hospitalizations for ADHF were sampled by stratified design from 4 US areas by the Community Surveillance component of the ARIC (Atherosclerosis Risk in Communities) study. ADHF was classified by a standardized computer algorithm and physician review of the medical records. Discharges or deaths on Saturday, Sunday, or national holidays were considered to occur on the “weekend.” In‐hospital mortality was compared between hospitalizations ending on a weekend versus weekday. Post‐hospital (28‐day) mortality was compared among patients discharged alive on a weekend versus weekday. From 2005 to 2014, 39 699 weighted ADHF hospitalizations were identified (19% terminating on a weekend). Demographics, comorbidities, length of stay, and guideline‐directed therapies were similar for patients with hospitalizations ending on a weekend versus weekday. In‐hospital death doubled on the weekend compared with weekday (12% versus 6%) and was not attenuated by adjustment for potential confounders (odds ratio, 2.37; 95% CI, 1.93–2.91). There was no association between weekend discharge and 28‐day mortality among patients discharged alive.

Conclusions

The risk of in‐hospital death among patients admitted with ADHF appears to be doubled on the weekends when hospital staffing is usually reduced. However, among patients discharged alive, hospital discharge on a weekend is not adversely associated with mortality.

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Microbiological diagnostics of bloodstream infections in Europe-an ESGBIES survey

OBJECTIVES

High-quality diagnosis of bloodstream infections (BSI) is important for successful patient management. As knowledge on current practices of microbiological BSI diagnostics is limited, this project aimed to assess its current state in European microbiological laboratories.

METHODS

We performed an online questionnaire-based cross-sectional survey comprising 34 questions on practices of microbiological BSI diagnostics. The ESCMID Study Group for Bloodstream Infections, Endocarditis and Sepsis (ESGBIES) was the primary platform to engage national coordinators who recruited laboratories within their countries.

RESULTS

Responses were received from 209 laboratories in 25 European countries. Although 32.5% (68/209) of laboratories only used the classical processing of positive blood cultures (BC), two-thirds applied rapid technologies. Of laboratories that provided data, 42.2% (78/185) were able to start incubating BC in automated BC incubators around-the-clock, and only 13% (25/192) had established a 24-h service to start immediate processing of positive BC. Only 4.7% (9/190) of laboratories validated and transmitted the results of identification and antimicrobial susceptibility testing (AST) of BC pathogens to clinicians 24 h/day. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry from briefly incubated sub-cultures on solid media was the most commonly used approach to rapid pathogen identification from positive BC, and direct disc diffusion was the most common rapid AST method from positive BC.

CONCLUSIONS

Laboratories have started to implement novel technologies for rapid identification and AST for positive BC. However, progress is severely compromised by limited operating hours such that current practice of BC diagnostics in Europe complies only partly with the requirements for optimal BSI management.

Evaluation of blood culture epidemiology and efficiency in a large European teaching hospital

Background

Blood cultures remain the gold standard for detecting bacteremia despite their limitations. The current practice of blood culture collection is still inefficient with low yields. Limited focus has been given to the association between timing of specimen collection at different time points during admission and their yield.

Methods

We carried out a retrospective observational study by analyzing all 3,890 sets of cultures collected from the 1,962 admitted patients over the seven-month period of this study. We compared the blood culture yield between the early group (≤24 hours after admission) and the late group (> 24 hours of admission). We also investigated the effect of prehospital oral antibiotics and pre-analytical time on the first cultures in the emergency department. Epidemiology and efficiency of blood cultures were studied for each medical specialty.

Results

In total, 3,349(86.1%) blood cultures were negative and 541(13.9%) were positive for one or more microorganisms. After correcting for contamination, the overall yield was 290 (7.5%). The early group (n = 1,490) yielded significantly more true-positive cultures (10.1% versus 5.8%, P<0.001) than the late group (n = 2,400). The emergency department had a significantly higher yield than general wards, 11.2% versus 5.7% (p<0.001). Prehospital oral antibiotic use and pre-analytical time did not affect the yield of first cultures at the emergency department (p = 0.735 and 0.816 respectively). The number of tests needed to obtain one true-positive culture varied between departments, ranging from 7 to 45.

Conclusion

This study showed that blood cultures are inefficient in detecting bacteremia. Cultures collected during 24 hours after admission yielded more positive results than those collected later. Significant variations in blood culture epidemiology and efficiency per specialty suggest that guidelines should be reevaluated. Future studies should aim at improving blood culture yield, implementing educational programs to reduce contamination and cost-effective application of modern molecular diagnostic technologies.

Effect of a training programme on blood culture contamination rate in critical care

Blood culture contamination can occur from extraction to processing; its rate should not exceed 3%.

OBJECTIVE

To evaluate the impact of a training programme on the rate of contaminated blood cultures after the implementation of sample extraction recommendations based on the best evidence.

METHOD

Prospective before-after study in a polyvalent intensive care unit with 18 beds. Two phases were established (January-June 2012, October 2012-October 2015) with a training period between them. Main recommendations: sterile technique, surgical mask, double skin disinfection (70° alcohol and 2% alcoholic chlorhexidine), 70° alcohol disinfection of culture flasks and injection of samples without changing needles. Including all blood cultures of patients with extraction request.

VARIABLES

demographic, severity, pathology, reason for admission, stay and results of blood cultures (negative, positive and contaminated). Basic descriptive statistics: mean (standard deviation), median (interquartile range) and percentage (95% confidence interval). Calculated contamination rates per 100 blood cultures extracted. Bivariate analysis between periods.

RESULTS

Four hundred and eight patients were included. Eight hundred and forty-one blood cultures were taken, 33 of which were contaminated. In the demographic variables, severity, diagnosis and stay of patients with contaminated samples, no differences were observed from those with uncontaminated samples. Pre-training vs post-training contamination rates: 14 vs 5.6 per 100 blood cultures extracted (P=.00003).

CONCLUSION

An evidence-based training programme reduced the contamination of samples. It is necessary to continue working on the planning of activities and care to improve the detection of pollutants and prevent contamination of samples.

How to: accreditation of blood cultures' proceedings. A clinical microbiology approach for adding value to patient care

BACKGROUND

Quality assurance and quality management are driving forces for controlling blood culture best practices but should not be disconnected from the end-point target, i.e. patient value.

AIMS

This article is intended to help microbiologists implement blood culture accreditation that is actually beneficial to patient management.

SOURCES

Experience from a nationwide taskforce for promoting quality assurance and competence in clinical microbiology laboratories, guidelines on blood culture.

CONTENT

Experience in blood culture accreditation according to International standard ISO 15189 standards is provided in this review, with a particular focus on critical points that are specific to blood culture (e.g. excluding strain identification or antimicrobial susceptibility testing). Blood culture test method verification is based on risk analysis, and evaluation of the test method's performance is based on the literature review and suppliers' data. In addition, blood culture performance relies largely on the quality of its pre-analytical phase, and the test method should be monitored based on key performance indicators such as the volume of blood cultured, the contamination rate and time to transportation. Other critical key indicators include the rate of false-positive signals, the rate of positive blood cultures, the ecology associated with positive results, and the timely communication of the results to the ward during the post-analytical phase. Finally, a critical analysis of quality controls and of the tools needed to improve blood culture monitoring in the future is provided.

IMPLICATION

Appropriate quality assurance should focus on patient value rather than technical details to provide an appropriate clinical service.

Different utilization of intensive care services (ICSs) for patients dying of hemorrhagic and ischemic stroke, a hospital-based survey

The intensive care service (ICS) saves lives and rescues the neurological function of stroke patients. We wondered the different utilization of ICS for patients with ischemic and hemorrhagic stroke, especially those who died within 30 days after stroke.Sixty-seven patients died during 2011 to 2015 due to acute stroke (42 due to intracranial hemorrhage [ICH]; 25 due to cerebral infarct [CI]). The durations of hospital stay (hospital staying days [HSDs]) and ICS staying days (ISDs) and codes of the do-not-resuscitate (DNR) were surveyed among these medical records. Statistics included chi-square and descriptive analyses.In this study, CI patients had a longer HSD (mean 14.3 days), as compared with ICH patients (mean 8.3 days); however, the ICH patients had a higher percentage of early entry within the first 24 hours of admission into ICS than CI group (95.1% vs 60.0%, P = .003). A higher rate of CI patients died in holidays or weekends than those with ICH (44.0% vs 21.4%, P = .051). DNR, requested mainly from direct descendants (children or grandchildren), was coded in all 25 CI patients (100.0%) and 38 ICH patients (90.5%). More cases with early DNR coded within 24 hours after admission occurred in ICH group (47%, 12% in CI patients, P = .003). None of the stroke patient had living wills. Withhold of endotracheal intubation (ETI) occurred among CI patients, more than for ICH patients (76.0% vs 18.4%, P < .005).In conclusion, CI patients longer HSD, ISD, higher mortality within holidays or weekends, and higher ETI withhold; but less percentage of ICS utilization expressed by a lower ISD/HSD ratio. This ICS utilization is a key issue of medical quality for stroke care.

Impact of Pre-Analytical Time on the Recovery of Pathogens from Blood Cultures: Results from a Large Retrospective Survey

BACKGROUND

Prompt identification of bloodstream pathogens is essential for optimal management of patients. Significant changes in analytical methods have improved the turnaround time for laboratory diagnosis. Less attention has been paid to the time elapsing from blood collection to incubation and to its potential effect on recovery of pathogens. We evaluated the performance of blood cultures collected under typical hospital conditions in relation to the length of their pre-analytical time.

METHODS

We carried out a large retrospective study including 50,955 blood cultures collected, over a 30-month period, from 7,035 adult septic patients. Cultures were accepted by the laboratory only during opening time (Mon-Fri: 8am-4pm; Sat: 8am-2pm). Samples collected outside laboratory hours were stored at room temperature at clinical wards. All cultures were processed by automated culture systems. Day and time of blood collection and of culture incubation were known for all samples.

RESULTS

A maximum pre-analytical interval of 2 hours is recommended by guidelines. When the laboratory was open, 57% of cultures were processed within 2 h. When the laboratory was closed, 4.9% of cultures were processed within 2 h (P<0.001). Samples collected when the laboratory was closed showed pre-analytical times significantly longer than those collected when laboratory was open (median time: 13 h and 1 h, respectively, P<0.001). The prevalence of positive cultures was significantly lower for samples collected when the laboratory was closed compared to open (11% vs 13%, P<0.001). The probability of a positive result decreased of 16% when the laboratory was closed (OR:0.84; 95%CI:0.80-0.89, P<0.001). Further, each hour elapsed from blood collection to incubation resulted associated with a decrease of 0.3% (OR:0.997; 95%CI:0.994-0.999, P<0.001) in the probability of a positive result.

DISCUSSION

Delayed insertions of cultures into automated systems was associated with lower detection rates, with potentially important consequences for patients. In each hospital setting the logistic factors able to shorten pre-analytical time should be carefully investigated and specifically targeted.

Augmented Passive Immunotherapy with P4 Peptide Improves Phagocyte Activity in Severe Sepsis

INTRODUCTION

Antimicrobial resistance threatens to undermine treatment of severe infection; new therapeutic strategies are urgently needed. Preclinical work shows that augmented passive immunotherapy with P4 peptide increases phagocytic activity and shows promise as a novel therapeutic strategy. Our aim was to determine ex vivo P4 activity in a target population of patients admitted to critical care with severe infection.

METHODS

We prospectively recruited UK critical care unit patients with severe sepsis and observed clinical course (≥3 months postdischarge). Blood samples were taken in early (≤48 h postdiagnosis, n = 54), latent (7 days postdiagnosis, n = 39), and convalescent (3-6 months postdiagnosis, n = 18) phases of disease. The primary outcome measure was killing of opsonized Streptococcus pneumoniae by neutrophils with and without P4 peptide stimulation. We also used a flow cytometric whole blood phagocytosis assay to determine phagocyte association and oxidation of intraphagosomal reporter beads.

RESULTS

P4 peptide increased neutrophil killing of opsonized pneumococci by 8.6% (confidence interval 6.35-10.76, P < 0.001) in all phases of sepsis, independent of infection source and microbiological status. This represented a 54.9% increase in bacterial killing compared with unstimulated neutrophils (15.6%) in early phase samples. Similarly, P4 peptide treatment significantly increased neutrophil and monocyte intraphagosomal reporter bead association and oxidation, independent of infection source.

CONCLUSIONS

We have extended preclinical work to demonstrate that P4 peptide significantly increases phagocytosis and bacterial killing in samples from a target patient population with severe sepsis. This study supports the rationale for augmented passive immunotherapy as a therapeutic strategy in severe sepsis.

Comparison of BACTEC™ blood culture media for the detection of fungemia

The aim of the present study was to investigate whether addition of the BACTEC™ Mycosis bottle to the standard BACTEC™ aerobic and anaerobic bottles contributed to a higher detection rate and a faster time to detection (TTD) of fungi. This was a retrospective cohort study of all patients with a positive blood culture with Candida species delivered to the Department of Clinical Microbiology, Herlev and Gentofte Hospital, Denmark in the 8-year period 2006 through 2014. The patients had at least one BACTEC™ aerobic and one Mycosis bottle sampled at the same time and at least one of the bottles yielded growth of fungi. Among 184 patients included, 173 were examined using BACTEC™ aerobic, anaerobic and Mycosis bottles. The anaerobic vial generally had the lowest detection rate and the longest TTD. The detection rate of BACTEC™ aerobic plus anaerobic with the BACTEC™ Mycosis bottle was significantly higher than the detection rate of BACTEC™ aerobic plus anaerobic without BACTEC™ Mycosis bottle for all species after 1-5 days, and specially for Candida glabrata at 2, 3, 4 and 5 days. TTD for C. glabrata was significantly shorter for BACTEC™ Mycosis than TTD for BACTEC™ aerobic or anaerobic bottles after ½ to 4 days. When combining "first or only" detection, the BACTEC™ Mycosis bottle had a significantly higher detection as compared to the aerobic bottle. Addition of the BACTEC™ Mycosis bottle to the standard BACTEC™ aerobic and anaerobic bottles significantly contributed to a higher detection rate and a faster TTD of fungemia.

Weekend specialist intensity and admission mortality in acute hospital trusts in England: a cross-sectional study

BACKGROUND

Increased mortality rates associated with weekend hospital admission (the so-called weekend effect) have been attributed to suboptimum staffing levels of specialist consultants. However, evidence for a causal association is elusive, and the magnitude of the weekend specialist deficit remains unquantified. This uncertainty could hamper efforts by national health systems to introduce 7 day health services. We aimed to examine preliminary associations between specialist intensity and weekend admission mortality across the English National Health Service.

METHODS

Eligible hospital trusts were those in England receiving unselected emergency admissions. On Sunday June 15 and Wednesday June 18, 2014, we undertook a point prevalence survey of hospital specialists (consultants) to obtain data relating to the care of patients admitted as emergencies. We defined specialist intensity at each trust as the self-reported estimated number of specialist hours per ten emergency admissions between 0800 h and 2000 h on Sunday and Wednesday. With use of data for all adult emergency admissions for financial year 2013-14, we compared weekend to weekday admission risk of mortality with the Sunday to Wednesday specialist intensity ratio within each trust. We stratified trusts by size quintile.

FINDINGS

127 of 141 eligible acute hospital trusts agreed to participate; 115 (91%) trusts contributed data to the point prevalence survey. Of 34,350 clinicians surveyed, 15,537 (45%) responded. Substantially fewer specialists were present providing care to emergency admissions on Sunday (1667 [11%]) than on Wednesday (6105 [42%]). Specialists present on Sunday spent 40% more time caring for emergency patients than did those present on Wednesday (mean 5·74 h [SD 3·39] vs 3·97 h [3·31]); however, the median specialist intensity on Sunday was only 48% (IQR 40-58) of that on Wednesday. The Sunday to Wednesday intensity ratio was less than 0·7 in 104 (90%) of the contributing trusts. Mortality risk among patients admitted at weekends was higher than among those admitted on weekdays (adjusted odds ratio 1·10, 95% CI 1·08-1·11; p<0·0001). There was no significant association between Sunday to Wednesday specialist intensity ratios and weekend to weekday mortality ratios (r -0·042; p=0·654).

INTERPRETATION

This cross-sectional analysis did not detect a correlation between weekend staffing of hospital specialists and mortality risk for emergency admissions. Further investigation is needed to evaluate whole-system secular change during the implementation of 7 day services. Policy makers should exercise caution before attributing the weekend effect mainly to differences in specialist staffing.

FUNDING

National Institute for Health Research Health Services and Delivery Research Programme.

How to Optimize the Use of Blood Cultures for the Diagnosis of Bloodstream Infections? A State-of-the Art

Bloodstream infection (BSI) is a major cause of death in developed countries and the detection of microorganisms is essential in managing patients. Despite major progress has been made to improve identification of microorganisms, blood culture (BC) remains the gold standard and the first line tool for detecting BSIs. Consensus guidelines are available to ensure optimal BSI procedures, but BC practices often deviate from the recommendations. This review provides an update on clinical and technical issues related to blood collection and to BC performance, with a special focus on the blood sample strategy to optimize the sensitivity and specificity of BCs.