Impact of blood cultures drawn by phlebotomy on contamination rates and health care costs in a hospital emergency department

An emergency department intervention to improve earlier detection of community-onset bloodstream infection among hospitalized patients

BACKGROUND

Blood cultures (BCs) are essential microbiologic tests, but blood culturing diagnostic stewardship is frequently poor. We aimed to study the process-related failures and to evaluate the effect of an emergency department (ED) intervention on BCs collection practices and yield.

METHODS

We implemented an ED-quality improvement intervention including educational sessions, phlebotomists addition, promoting single-site strategy for BC-collection and preanalytical data feedback. BC-bottles collected, positive BCs, blood volumes and documentation of collection times were measured, before (December 2021-August 2022) and after (September 2022-July 2023) intervention. Results were corrected to hospitalizations admissions or days. We used interrupted-time series analyses for comparisons.

RESULTS

A total of 64,295 BC bottles were evaluated, 26,261 before and 38,034 postintervention. The median ED-BCs collected per week increased from 88 to 105 BCs (P < .0001), resulting from increased early sampling (P = .0001). Solitary BCs decreased (95%-28%), documented times increased (2.8%-25%), and average blood volume increased (3 mL to 4.5 mL) postintervention. Community-onset Bloodstream infections (BSIs) increased (39.6-52 bottles/1,000 admissions, P = .0001), while Health care-associated BSIs decreased (39-27 bottles/10,000 days, P = .0042). Contamination rates did not change.

CONCLUSIONS

An ED-focused intervention based on the education sessions and single-site strategy improved culturing stewardship and facilitated the early identification of BSI without an increase in contamination.

Diagnostic performance of the time to positivity of blood cultures to distinguish true bacteremia from contaminants based on an automated system

OBJECTIVE.

To determine the diagnostic performance of blood culture positivity times for distinguishing true bacteremia from contaminants in the automated "BACT/ALERT®" system.

MATERIALS AND METHODS.

A cross-sectional, diagnostic test-type study was conducted from a database of blood culture samples processed between January 2016 and August 2021. All blood culture samples from patients with suspected bacteremia were included; blood culture samples were entered into the "BACT/ALERT®" system to differentiate true bacteremia from contaminants.

RESULTS.

We obtained 33,951 blood cultures samples, of which 3875 were positive. Of the total number of positive blood cultures, 75.2% (n=2913) were true bacteremia and 24.8% (n=962) were contaminants. The median time to positivity in blood cultures with true bacteremia was significantly shorter (16.3 hours; IQR: 11.2 - 24.9) than the median time to positivity of blood cultures with contaminants (22.5 hours; IQR: 18.4 - 31.8; p<0.001). The positivity time showed the capacity to differentiate true bacteremia from contaminants, with an AUC-ROC of 0.73 (95%CI: 0.71 - 0.75), with 85% and 63% sensitivity and specificity respectively for the diagnosis of contaminants when the positivity time exceeds 16.5 hours. The use of antibiotics prior to sampling delayed the time to positivity, while having fever before sampling shortened the time to positivity.

CONCLUSIONS.

Our results show good diagnostic performance of blood culture positivity times to differentiate true bacteremia from contaminants using the "BACT/ALERT®" system when the positivity time was longer than 16.5 hours.

Effectiveness of Multimodal Intervention to Improve Blood Culture Collection in a Tertiary Care Hospital

Introduction and methods Blood culturing has become one of the backbone investigations for septicemia, fever of unknown origin, etc. This study was conducted to test the effect of multimodal interventions on the practical skills of healthcare workers (HCWs), raise awareness regarding the importance of aseptic blood culture collection practices, and increase compliance with the specific steps to be followed. Hence, this current interventional study was aimed at comparing the rate of isolation of contaminants grown among the blood culture specimens, assessing the knowledge, attitude, and practice (KAP) of HCWs collecting the blood culture specimen on various aspects of sample collection, educating the nursing staff regarding blood sample collection using a structured, pre-formed checklist, and emphasizing best practices for blood culture collection. All of the study's objectives were successfully met within the time frame specified. Using a pre-formed checklist and a Google form for KAP analysis eased the calculation. Results On analysis, the blood culture contamination rate in the pre-interventional phase dropped drastically from 6.16% to 3.03% in the post-interventional phase. The educational sessions conducted are a paramount reason for the reduction in the contamination rate. The HCWs were the least compliant towards the eighth step in the checklist (regarding palpation of skin); however, that too increased from 66.93% and 64.51% to a whopping 82.25% and 83.06%, respectively, with a chi-square value of 0.03 and a p-value of 0.85 (not significant). Conclusion Implementation of interventional studies as an audit like this in tertiary care hospitals can result in a significant reduction in blood culture contamination rates and can also improve the compliance of HCWs with blood culture protocols. This, in turn, can overall improve the effectiveness of blood culture (BC) testing and reduce mortality and morbidity in tertiary care hospitals. Further research can be conducted to brainstorm more methods to increase the compliance of HCWs. Better monitoring strategies can also be set to ensure low contamination rates. Additionally, some other methods can be derived to locate the source of contamination within the hospital environment and thus eliminate it. Similar interventions can be conducted for a longer duration of time to further reduce the blood culture contamination rate below 3% (as per the recommendations).

The use of a diversion tube to reduce blood culture contamination: A "real-life" quality improvement intervention study

BACKGROUND

Blood culture contamination is associated with health care costs and potential patient harm. Diversion of the initial blood specimen reduces blood culture contamination. We report results of the "real-life" clinical implementation of this technique.

METHODS

Following an educational campaign, use of a dedicated diversion tube was recommended prior to all blood cultures. Blood culture sets taken from adults using a diversion tube were defined as "diversion sets," those without, "non-diversion" sets. Blood culture contamination and true positive rates were compared for diversion and nondiversion sets and to nondiversion historical controls. A secondary analysis investigated efficacy of diversion by patient age.

RESULTS

Out of 20,107 blood culture sets drawn, the diversion group included 12,774 (60.5%) and the nondiversion group 8,333 (39.5%) sets. The historical control group included 32,472 sets. Comparing nondiversion to diversion, contamination decreased by 31% (5.5% [461/8333] to 3.8% [489/12744], P < .0001]. Contamination was also 12% lower in diversion than historical controls [3.8% (489/12744) vs 4.3% (1,396/33,174) P = .02)]. The rate of true bacteremia was similar. In older patients, contamination rate was higher, and the relative reduction associated with diversion decreased (54.3% amongst 20-40-year-olds vs 14.5% amongst >80-year-olds).

CONCLUSIONS

Use of a diversion tube in the ED reduced blood culture contamination in this large real life observational study. Efficacy decreased with increasing age, which requires further investigation.

Direct-from-Blood Detection of Pathogens: a Review of Technology and Challenges

Blood cultures have been the staple of clinical microbiology laboratories for well over half a century, but gaps remain in our ability to identify the causative agent in patients presenting with signs and symptoms of sepsis. Molecular technologies have revolutionized the clinical microbiology laboratory in many areas but have yet to present a viable alternative to blood cultures. There has been a recent surge of interest in utilizing novel approaches to address this challenge. In this minireview, I discuss whether molecular tools will finally give us the answers we need and the practical challenges of incorporating them into the diagnostic algorithm.

ISO 9001:2015 Internal Audits for Financial and Strategic Decisions in Reducing Blood Culture Contamination

BACKGROUND AND OBJECTIVES

Blood cultures are vital diagnostic tests that detect harmful pathogens in a patient's bloodstream. In this study, we implemented a process-driven quality improvement program to reduce blood culture contamination rates.

METHODS

St Joseph Health (SJH) utilized the ISO 9001:2015 Internal Audit tool, failure mode effect analyses, and the Centers for Disease Control and Prevention's Hierarchy of Controls to identify opportunities for improvement and design effective corrective and preventive action plans. These actions included reeducation and ongoing coaching of staff on the blood culture collection process, reorganizing blood culture supplies on the nursing units, and adding multiple layers of supervision.

RESULTS

A statistically significant relationship was identified between 2 variables ("contamination rate" and "cumulative cost difference"). The 2 variables had a negative association, demonstrating that as the contamination rate decreased, the cumulative cost difference increased, indicating potential cost savings.

CONCLUSION

The estimated value added to the institution through this initiative was approximately $215 743 to $228 543 in potential cost savings. SJH significantly reduced the number of blood culture contaminations in the critical care division, evidenced by a controlled 6-month mean below 1%. Review of the 6-month mean as a reference point demonstrated the sustainability of the implemented corrective and preventive measures.

Increasing clinical impact and microbiological difficulties in diagnosing coagulase-negative staphylococci in infective endocarditis - a review starting from a series of cases

Coagulase-negative staphylococci (CoNS) are an emergent aetiology of infective endocarditis (IE) on native valves in previously healthy individuals, its presence is associated with prosthetic valves or with other cardiac implants. The identification of CoNS in cultures was customarily seen as contamination, but more recent epidemiological studies have revealed an increasing number of causative and virulent new CoNS species. Starting from two clinical cases of community-acquired CoNS IE on native valves, the review debates the difficulties in identifying CoNS as the causal pathogens, comprising differentiation of contamination from infection in IE, alongside the challenges raised by antibiotic resistance. Even if the risk of CoNS IE is more increased in subjects with prosthetic materials or other foreign devices and immunodeficiencies, native valve infections with these staphylococci are increasing and should be considered important pathogens in IE. Despite the lack of sensitive and specific tools to correctly differentiate contamination from infection in CoNS endocarditis, a comprehensive evaluation with clinical and paraclinical data accurately succeeds in establishing the diagnosis. The genetic profile of CoNS predisposes to antibiotic multi-resistance, making the treatment of IE challenging; the rapid identification of antibiotic susceptibility is essential to prescribe the appropriate therapy and improve outcomes.

Changes in Use of Blood Cultures in a COVID-19-Dedicated Tertiary Hospital

Blood cultures should be collected within an hour in the setting of sepsis/septic shock. The contamination rate should be below 3%. Worldwide reports have described an increase in blood contamination rates during the COVID-19 pandemic. We performed a retrospective analysis of the blood cultures collected during a 10-month period (March−December 2020) at NIID “Prof. Dr. Matei Balș”. The results were compared with data from the pre-pandemic period (March−December 2016) and with the existing data in the literature. During the pandemic, there was a significant decrease in the number of blood cultures collected (1274 blood cultures in 2020 vs. 5399 in 2016). The contamination rate was higher in 2020 (11.7%) compared to 2016 (8.2%), p < 0.001. The rate of infectious episodes in which the etiological agent was identified was constant: 11% in 2020 versus 11.9% in 2016, p = 0.479, but there were fewer invasive bacterial/fungal infections: 0.95/1000 patient days in 2020 vs. 2.39/1000 patient days in 2016, p < 0.001. We observed a change in the species distribution. The Gram-negative isolate’s proportion increased from 50.6% to 63.1% and the gram-positive isolate’s proportion decreased from 31.8% to 19%. Collection of a low number of blood cultures and a high contamination rate was identified in our clinic. In order to improve the usefulness of blood cultures as a diagnostic method, at least two sets should be collected in aseptic conditions.

Analysis of Blood Culture Collection and Laboratory Processing Practices in Israel

IMPORTANCE

Blood culturing is a critical diagnostic procedure affecting patient outcomes and antibiotic stewardship. Although there are standards for blood culturing, the process is not often measured.

OBJECTIVES

To evaluate processes related to the diagnosis of bloodstream infection and compare them with best practices.

DESIGN, SETTING, AND PARTICIPANTS

A quality improvement study using laboratory data from January 1 to June 30, 2019, was conducted in 28 (96.6%) Israeli acute care hospitals. All blood cultures (BCs) performed on samples from adults and children in a period of 147 hospital-months were analyzed. Data analysis was performed from April 12, 2021, to September 9, 2022.

MAIN OUTCOMES AND MEASURES

True pathogen detection rate, contamination rate, proportion of adults with blood cultures performed, proportion of adult culturing episodes with only 1 set or bottle used, and median time of steps from sample collection to pathogen identification.

RESULTS

The data set consisted of 348 987 BC bottles. Bloodstream infection was detected in a median of 6.7% (IQR, 5.8%-8.2%) of adult culturing episodes and 1.1% (IQR, 0.7%-1.9%) of pediatric episodes. Eleven of 27 hospitals (40.7%) with adult patients met the standard of a contamination rate of less than 3% and only 2 hospitals (7.4%) met the more stringent standard of less than or equal to 1% contamination rate. The percentage of adults with blood cultures ranged from 2.7% to 29.0% (mean [SD], 15.7% [6.0%]). There was an association between sampling rate and pathogen detection until BCs were performed in 17% of adult admissions. The percentage of solitary BCs ranged from 47.8% to 94.4%. An estimated 1745 of 7436 (23.5%) adult bloodstream infections went undetected because solitary BCs were performed, anaerobic bottles were not used, or BCs were not performed. Median processing time was 51.2 (IQR, 33.9-78.0) hours, 3 times the optimal time: 4.4 (IQR, 1.7-12.5) hours for the preanalytical stage, 15.9 (IQR, 10.2-23.6) hours from incubation to growth detection, 4.5 (IQR, 1.5-10.7) hours from detection to Gram stain, and 30.9 (IQR, 22.0-41.9) hours from detection to isolate identification. An 8.6-hour delay was related to off-hours operating of laboratories.

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that the multistep process of blood culturing is not managed comprehensively in Israel, leading to poor clinical practices and delayed results.

Initial Specimen Diversion Device Utilization Mitigates Blood Culture Contamination Across Regional Community Hospital and Acute Care Facility

A West Virginia regional community hospital incorporated an initial specimen diversion device (ISDD) into conventional blood culture protocol with the objective to bring the hospital-wide blood culture contamination (BCC) rate from a 3.06% preintervention rate to a target performance level below 1%. Emergency department staff, laboratory phlebotomists, and nursing staff on acute-critical care floors were trained on ISDD (Steripath Gen2, Magnolia Medical Technologies, Inc., Seattle, WA) operating procedure and utilized the device for blood culture sample collection with adult patients from September 2020 through April 2021. Of 5642 blood culture sets collected hospital-wide, 4631 were collected with the ISDD, whereas the remaining sets were collected via the conventional method. The ISDD BCC rate of 0.78% differed from the conventional method BCC rate of 4.06% observed during the intervention period (chi-squared test P < 0.00001). The ISDD group attained a sub-1% BCC rate to satisfy the intervention objective.

Identification of the main contributors to blood culture contamination at a tertiary care academic medical center

Background

Blood culture contamination poses an issue to all hospital systems worldwide because of the associated costs of extended length of stays, unnecessary antibiotic therapy, and additional laboratory testing that are preventable with proper handling and collection techniques.

Methods

In our study, multiple units, staff, and collection methods were compared to determine the primary culprits of contamination from a tertiary care academic medical center, which includes a pediatric hospital and both adult and pediatric emergency departments.

Results

Over 33 months, 2,083 out of 88,322 total blood cultures collected were contaminated, with an overall contamination rate of 2.4%. A moderate positive correlation was found between the monthly total number of cultures and monthly contamination rate (r = 0.411 P < .01). The most notable factors associated with contamination were found to be phlebotomy teams (2.7%) (P < .01), peripheral draws (2.3%) (P <.01), adult emergency departments (2.6%) (P < .01), and pediatric intensive care units (2.7%) (P < .01). A positive correlation was present between the number of hospital beds per unit and unit contamination rates (r = 0.429 P < .01).

Conclusion

Our results were used to make recommendations for decreasing the rate of blood culture contamination in this institution, which includes acknowledgement of an overwhelmed staff and mandatory periodic training on acceptable aseptic technique and contamination awareness. Understanding the factors contributing to blood culture contamination can aid efforts to reduce contamination rates.

Comparing blood culture contamination rates by different sampling methods in a paediatric emergency department

AIM

Blood culture contamination (BCC) can cause unnecessary hospitalisations and inappropriate use of antibiotics. The aim of this study was to find risk factors associated with BCCs in children and to compare contamination rates between open and closed blood culture collection systems.

METHODS

Data were prospectively collected regarding blood cultures obtained in the paediatric emergency department from February 26, 2020, to September 30, 2020, based on the method of drawing blood reported by the obtaining physician. A comparison between contaminated and non-contaminated blood cultures was performed. We also compared the composition of the contaminations in the study period to the same period in 2019.

RESULTS

A total of 512 blood cultures were included, 33 (6.4%) of which were contaminated. The only parameter that was associated with an increased rate of contamination by 2.34 fold (95% CI 1.1-4.99, P = 0.028) was obtaining blood through an 'open' system, using a syringe connected to a needle in order to draw blood from an open ended needle. The proportion of contaminations originating from oral flora decreased in the study period by 44.7% as compared to the same period in the previous year (13% vs. 23.5%, P = 0.056).

CONCLUSIONS

'Open system' method, which is commonly used in paediatric emergency departments for blood culture obtainment, was associated with an increase in BCC. Adherence to blood cultures obtainment guidelines, even at the price of two different blood tests, is important in order to reduce BCC rates in children.

Blood Culture Utilization in the Hospital Setting: a Call for Diagnostic Stewardship

There has been significant progress in detection of bloodstream pathogens in recent decades with the development of more sensitive automated blood culture detection systems and the availability of rapid molecular tests for faster organism identification and detection of resistance genes. However, most blood cultures in clinical practice do not grow organisms, suggesting that suboptimal blood culture collection practices (e.g., suboptimal blood volume) or suboptimal selection of patients to culture (i.e., blood cultures ordered for patients with low likelihood of bacteremia) may be occurring. A national blood culture utilization benchmark does not exist, nor do specific guidelines on when blood cultures are appropriate or when blood cultures are of low value and waste resources. Studies evaluating the potential harm associated with excessive blood cultures have focused on blood culture contamination, which has been associated with significant increases in health care costs and negative consequences for patients related to exposure to unnecessary antibiotics and additional testing. Optimizing blood culture performance is important to ensure bloodstream infections (BSIs) are diagnosed while minimizing adverse events from overuse. In this review, we discuss key factors that influence blood culture performance, with a focus on the preanalytical phase, including technical aspects of the blood culture collection process and blood culture indications. We highlight areas for improvement and make recommendations to improve current blood culture practices among hospitalized patients.

Blood Culture Contamination: A Single General Hospital Experience of 2-Year Retrospective Study

In the event of blood culture contamination (BCC), blood culture (BC) needs to be repeated. This may delay appropriate treatment, prolong hospitalization and, consequently, increase its costs. The aim of the study was to assess the frequency of BCC and associated factors in a general hospital in Poland based on reports of BC in samples submitted for laboratory testing in 2019−2020. BCC is recognized when bacteria (especially those belonging to natural human microbiota) are isolated from a single sample and no clinical signs indicated infection. True positive BC is confirmed by the growth of bacteria in more than one set of blood samples with the corresponding clinical signs present. The structure of BC sets, microorganisms, and laboratory costs of BCC were analyzed. Out of 2274 total BC cases, 11.5% were true positive BC and 9.5% were BCC. Of all the BCC identified in the entire hospital, 72% was from Internal Medicine (IM) and Intensive Care Unit (ICU) combined. When single sets for BC were used in IM in 2020, the use increased to 85% compared with 2019 (p < 0.05). The predominant isolates were coagulase-negative staphylococci (84%). The estimated extra laboratory costs of BCC exceeded EUR 268,000. The BCC was a more serious problem than expected, including non-recommended using of single BC sets. Compliance with the BC collection procedure should be increased in order to reduce BCC and thus extra hospital costs.

Bacteremia in Adults Admitted from the Emergency Department with Laboratory-Confirmed Respiratory Syncytial Virus

BACKGROUND

Collecting blood cultures from patients admitted from the emergency department (ED) with acute respiratory infection (ARI) is common, but the rate of secondary bacteremia in adult patients admitted from the ED with ARI associated with respiratory syncytial virus (RSV) is unknown. Indiscriminate collection of blood cultures can be associated with contaminated blood cultures and increased inappropriate antimicrobial use and health care costs.

OBJECTIVE

This study sought to determine the rate and etiology of secondary bacteremia, factors associated with secondary bacteremia, and factors associated with collecting blood cultures in the ED, in adults hospitalized with RSV.

METHODS

We performed a retrospective substudy using data from a prospective study of adults admitted with RSV infections during two respiratory seasons (October 2017 to April 2018 and October 2018 to April 2019). Blood cultures were collected at the discretion of ED providers. We compared demographic and clinical characteristics among those with and without secondary bacteremia and among those with and without blood cultures collected using multivariate logistic regression models.

RESULTS

Of the 365 hospitalized RSV-positive patients (mean age 68.8 years), 269 (73.7%) had blood cultures collected in the ED and 18 (6.7%) patients had secondary bacteremia, most commonly from a nonrespiratory source (n = 13). Patients with asthma and chronic obstructive pulmonary disease were significantly less likely to have secondary bacteremia. Patients who were immunocompromised, met systemic inflammatory response syndrome criteria, or had pneumonia described on chest x-ray reports were more likely to have blood cultures collected.

CONCLUSIONS

Overall, 6.7% of adults hospitalized with RSV infections had secondary bacteremia, more commonly from nonrespiratory sources.

Effectiveness of multimodal intervention to improve blood culture collection in the emergency department

Introduction:

The blood culture (BC) contamination was a significant problem in our hospital, especially in the emergency department (ED). The study, therefore, was undertaken to improve the BC collection in the ED.

Methods:

The study was conducted for 1 year divided into two phases of 6 months each: Preintervention phase and intervention phase (regular and phlebotomist groups). The interventions comprised implementing standard protocol for BC collection and conducting educational sessions. In preintervention and regular groups, the BCs were collected by interns and technicians, while dedicated phlebotomist did so in the phlebotomist group. Data were analyzed and interpreted for the contamination rate as well as compliance in adequate filling of the requisition form. Statistical Package for the Social Sciences (SPSS) version 22. A value of P < 0.005 was considered statistically significant, and P < 0.01 was considered statistically significant.

Results:

In the preintervention group, 13.7% of specimens were reported as contaminated which was reduced to 4.2% and 3.2% in the regular and phlebotomist group, respectively, after intervention. Compliance of health-care workers to various elements of BC collection protocol was also found to be significantly improved in the intervention phase compared to the preintervention phase (P < 0.001).

Conclusions:

Implementation of this multimodal intervention resulted in a drastic reduction in BC contamination and improvement in compliance to BC collection protocol and filling of various parameters in the BC requisition form, thus improving the overall effectiveness of BC testing. It was also noted that the contamination rate was further reduced by implementing dedicated phlebotomist.

Impact of sterile gloves on blood-culture contamination rates: A randomized clinical trial

BACKGROUND

Reducing the blood-culture contamination rate is a constant challenge for health services. This study aimed to analyze whether blood-culture (BC) collection using sterile gloves reduces the contamination rate when compared to the non-sterile gloves, and to compare baseline and intervention periods.

METHODS

A randomized clinical trial, performed in an intensive care unit in Brazil and paired in two groups: sterile (BCs obtained with modified sterile technique: only sterile gloves; no fenestrated drape or dedicated sterile collection kit) and clean (clean technique: usual care with non-sterile gloves). Two paired blood samples were obtained from each patient by trained and calibrated nurses. BCs were processed by conventional microbiological methods and the results were issued by blinded microbiologists.

RESULTS

There was no difference (P = 1.00) in the contamination rate of BC between the sterile (1%) and clean (1%) groups. However, there was a significant difference (P = 0.05; relative risk: 0.17; 95% confidence interval: 0.04-0.70) in the contamination rate between baseline (6.1%; 20/330) and intervention (1%; 2/200).

CONCLUSIONS

This study suggests that the aseptic care provided in obtaining samples is more important than the sterile technique itself, and highlights the value of standardizing the practices, qualification and calibration of phlebotomists.

Differences in the sequence of PlcR transcriptional regulator binding site affect sphingomyelinase production in Bacillus cereus

Bacillus cereus is an opportunistic pathogen that often causes severe infections such as bacteremia, with sphingomyelinase (SMase) being a crucial virulence factor. Although many strains of B. cereus carry the SMase gene, they are classified as SMase-producing and non-producing strains. The reason for different SMase production among B. cereus strains remains unknown. In this study, we investigated the relationship between SMase and the PlcR transcriptional regulation system to clarify the mechanism leading to varied SMase production among B. cereus strains. We analyzed the sequence of the PlcR box, which is a transcriptional regulator binding site, located at the promoter region of SMase and phosphatidylcholine-specific phospholipase C. Based on differences in the PlcR box sequences, we classified the B. cereus strains into three groups (I, II, and III). SMase expression and activity were hardly detected in Group III strains. In Group I strains, SMase activity and its expression were maximal at the onset of the stationary phase and decreased during the stationary phase, whereas those were maintained during the stationary phase in Group II stains. On injection of B. cereus strains into mice or incubation with macrophages for phagocytosis assay, the SMase-producing Group I and II strains showed higher pathogenicity than Group III strains. These findings suggest that PlcR box sequence in B. cereus affects the production of SMase, which may provide important clinical information for the detection of highly pathogenic B. cereus strains. This article is protected by copyright. All rights reserved.

Impact of Direct From Blood Culture Identification of Pathogens Paired With Antimicrobial Stewardship Interventions in a Pediatric Hospital

OBJECTIVE

Identification of organisms directly from positive blood culture by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has the potential for improved clinical outcomes through earlier organism identification and shorter time to appropriate clinical intervention. The uses of this technology in pediatric patients and its impact in this patient population have not been well described.

METHODS

Direct from positive blood culture organism identification via MALDI-TOF was implemented in September 2019. A quality improvement project was performed to assess its impact on admissions for contaminant blood cultures and time to effective and optimal antimicrobials and clinical decision-making. A pre- and post-implementation retrospective review for consecutive September through February time periods, was conducted on patients with positive monomicrobial blood cultures. Statistics were evaluated using Mann-Whitney U and χ² tests.

RESULTS

One hundred nineteen patients with 131 unique blood cultures (65 in pre- and 66 in post-implementation) were identified. Time to identification was shorter, median 35.4 hours (IQR, 22.7-54.3) versus 42.3 hours (IQR, 36.5-49) in post- and pre-groups, respectively (p = 0.02). Patients were less likely to be admitted for a contaminated blood culture in the post-implementation, 26% versus 11% in the pre-implementation (p = 0.03) group. In patients treated for bacteremia, there was a shorter time to optimal therapy from Gram stain reporting in the post-implementation (median 42.7 hours [IQR, 27.2-72]) versus pre-implementation (median 60.8 hours [IQR, 42.9-80.6]) (p = 0.03).

CONCLUSIONS

Direct from positive blood culture identification by MALDI-TOF decreased time to effective and optimal antimicrobials and decreased unnecessary admission in pediatric patients for contaminated blood cultures.

Initial Specimen Diversion Device® Reduces Blood Culture Contamination and Vancomycin Use in Academic Medical Center

BACKGROUND

In suspected bloodstream infections, accurate blood culture results are critical to timely diagnoses and appropriate antibiotic administration.

AIM

An Initial Specimen Diversion Device®, Steripath®, (Magnolia Medical Technologies, Seattle, WA) was evaluated for efficacy in reducing blood culture contamination at Brooke Army Medical Center (6.8% six-month contamination rate prior to intervention) in a six-month quality improvement project.

METHODS

Blood cultures in the emergency department were collected using either Steripath® or the standard method. 20 mL of blood was cultured into an aerobic and anaerobic medium and incubated for five days using an automated microbial detection system immediately after collection. Positive bottles were Gram stained and plated. Rapid molecular PCR identification was performed on all first positive bottles within a blood culture set for each admission or ED visit. Speciation was deduced during antimicrobial sensitivity testing using the Vitek-2 instrument.

FINDINGS

Seven (7/1016, 0.69%) contamination events occurred when using Steripath® vs. 53 (53/800, 6.6%) contamination events when using the standard method. Steripath® use was associated with a 90% lower incidence of blood culture contamination vs. the standard method. Post-study, Steripath® use was implemented as standard practice hospital-wide, and a retrospective data analysis attributed a 31.4% decrease in vancomycin days of therapy to Steripath® adoption.

CONCLUSION

Using Steripath® significantly decreased blood culture contamination events for bacterial bloodstream infections compared to the standard method. Subsequent adoption of Steripath® reduced overall vancomycin usage. With widescale implementation Steripath® could bolster antibiotic stewardship, mitigating antibiotic resistance caused by unnecessary antibacterial treatments.

Use of a Sterile Collection Process to Reduce Contaminated Peripheral Blood Cultures

BACKGROUND

Contaminated blood cultures pose a significant burden by subjecting children to unnecessary testing, procedures, and antibiotics and increasing health care costs. The aim of our quality improvement (QI) initiative was to decrease the percentage of contaminated peripheral blood cultures in our pediatric emergency department (ED) from an average of 6.7% to <3% over a 16-month period.

METHODS

The QI initiative was implemented in the pediatric ED of a tertiary care children's hospital. Interventions included change of the peripheral blood culture collection from a clean to a sterile process, nursing education, and individualized feedback. The primary outcome measure was the percentage of contaminated peripheral blood cultures. The process measure was the percentage of nurses who completed 75% to 100% of the steps of the sterile collection process, as measured by self-reporting in audit cards. The balancing measures were time from antibiotic ordering to time of administration and ED length of stay.

RESULTS

We decreased the percentage of contaminated peripheral blood cultures threefold from a baseline (June 2, 2018, to December 31, 2018) of 6.7% to 2.1% during the intervention period (January 1, 2019, to April 30, 2020). Ninety-eight percent of nurses who completed audit cards reported performing 75% to 100% of the steps of the new sterile process. There was no significant difference in the average time from antibiotic ordering to antibiotic administration or ED length of stay between the baseline and intervention periods.

CONCLUSIONS

Use of a sterile blood culture collection process, in addition to nursing education and individualized feedback, is an effective method to decrease peripheral blood culture contamination rates in a pediatric ED.

Fully Automated, Sample-to-Answer Leukocyte Functional Assessment Platform for Continuous Sepsis Monitoring via Microliters of Blood

We report a fully automated, sample-to-answer, and label-free leukocyte activation analysis platform for monitoring immune responses in sepsis, by integrating the multidimensional double spiral (MDDS) and isodielectric separation (IDS) subplatforms. The integrated platform can provide rapid and fully automated identification of clinically diagnosed sepsis patients from only 50 μL of peripheral blood volume within 25 min. Many critical innovations were implemented in direct interconnection between the two subplatforms, such as intermediate sample storage and sample transfer, addressing flow rate mismatch (from mL/min to μL/min), and integration of a ridge array for upstream cell focusing in the IDS subplatform. The ridge array in the IDS subplatform can prevent the distortion of electrical profiling due to the residual red blood cells even after the MDDS process. We showed that the integrated platform can separate leukocytes (up to >99.9% red blood cell removal) in the MDDS subplatform and automatically transfer them to the downstream ridge-integrated IDS subplatform for their activation analysis without any apparent ex vivo cell activation and any human intervention. We also demonstrated that the integrated platform can identify differences between leukocytes from human sepsis and healthy subjects significantly (p = 0.0024, 95% confidence interval) by looking into differences in the intrinsic electrical properties of leukocytes. The integrated platform could enable monitoring of host leukocyte function daily or even hourly as a bedside assessment tool, which is currently a critical yet unmet need for managing many critical care patients.

More than Just Contaminants: Frequency and Characterization of Polymicrobial Blood Cultures from a Central Clinical Microbiology Laboratory Serving a Large Healthcare System

BACKGROUND

Polymicrobial blood stream infection is often considered uncommon, and corresponding cultures may be assumed to represent contamination. Here we characterized the prevalence and epidemiology of these cultures submitted to a central clinical microbiology laboratory.

METHODS

Blood cultures from 2017 to 2018 (n = 104 547) were evaluated. Polymicrobial blood cultures were defined by the presence of more than one organism in a blood culture set (set = one aerobic and one anaerobic bottle). Data were stratified by patient location and characteristics of the microbiota detected.

RESULTS

Of all blood culture sets, 14 600 (14.0%) were positive. Among these, 1651 sets (11.3% of positive cultures; 1.6% of total cultures) were polymicrobial. Most cultures (85.2%) grew two microorganisms; the greatest number of microorganisms in a culture was 6. The most common microorganism pairs were (a) two coagulase-negative staphylococci (CoNS), (b) Corynebacterium and CoNS, and (c) S. aureus and CoNS. Microorganisms in polymicrobial cultures represented microbiota from skin (46.1%), the gastrointestinal (GI) tract (33.9%), strict anaerobes (1.4%), and "other" microorganisms (18.6%). Most cultures with GI microbiota originated from an adult academic medical center compared to community or pediatric settings (40.5% of polymicrobial cultures vs 27.2% and 25.8%, P < 0.0001). Within the academic medical center, patients in an intensive care unit (ICU) or who had bone marrow transplants (BMT) had more cultures suggestive of GI microbiota compared to those from the emergency department (ED) (50.8% and 52.8% vs 31.2%, P < 0.0001).

CONCLUSIONS

Polymicrobial blood cultures are common in a variety of healthcare settings and the recovered microorganisms can be clinically relevant.

The Development and Validation of a Machine Learning Model to Predict Bacteremia and Fungemia in Hospitalized Patients Using Electronic Health Record Data

OBJECTIVES

Bacteremia and fungemia can cause life-threatening illness with high mortality rates, which increase with delays in antimicrobial therapy. The objective of this study is to develop machine learning models to predict blood culture results at the time of the blood culture order using routine data in the electronic health record.

DESIGN

Retrospective analysis of a large, multicenter inpatient data.

SETTING

Two academic tertiary medical centers between the years 2007 and 2018.

SUBJECTS

All hospitalized patients who received a blood culture during hospitalization.

INTERVENTIONS

The dataset was partitioned temporally into development and validation cohorts: the logistic regression and gradient boosting machine models were trained on the earliest 80% of hospital admissions and validated on the most recent 20%.

MEASUREMENTS AND MAIN RESULTS

There were 252,569 blood culture days-defined as nonoverlapping 24-hour periods in which one or more blood cultures were ordered. In the validation cohort, there were 50,514 blood culture days, with 3,762 cases of bacteremia (7.5%) and 370 cases of fungemia (0.7%). The gradient boosting machine model for bacteremia had significantly higher area under the receiver operating characteristic curve (0.78 [95% CI 0.77-0.78]) than the logistic regression model (0.73 [0.72-0.74]) (p < 0.001). The model identified a high-risk group with over 30 times the occurrence rate of bacteremia in the low-risk group (27.4% vs 0.9%; p < 0.001). Using the low-risk cut-off, the model identifies bacteremia with 98.7% sensitivity. The gradient boosting machine model for fungemia had high discrimination (area under the receiver operating characteristic curve 0.88 [95% CI 0.86-0.90]). The high-risk fungemia group had 252 fungemic cultures compared with one fungemic culture in the low-risk group (5.0% vs 0.02%; p < 0.001). Further, the high-risk group had a mortality rate 60 times higher than the low-risk group (28.2% vs 0.4%; p < 0.001).

CONCLUSIONS

Our novel models identified patients at low and high-risk for bacteremia and fungemia using routinely collected electronic health record data. Further research is needed to evaluate the cost-effectiveness and impact of model implementation in clinical practice.

A Quality Improvement Initiative to Reduce Blood Culture Contamination in the Neonatal Unit

Peripheral blood culture contamination (BCC) can lead to an initiation of unnecessary antimicrobial treatment, further laboratory tests, increased length of stay, and increased costs. This study describes a 12-month quality improvement (QI) program to reduce the BCC rate in a neonatal unit by 50%.

Methods

The QI team focused on standardizing processes to align with best practices using process mapping and cause and effect diagrams. Plan-Do-Study-Act (PDSA) 1: inoculation of blood culture bottles with the introduction of transfer device; PDSA 2: preparation of the skin for peripheral intravenous cannula insertion; PDSA 3: aseptic technique education package; and PDSA 4: optimizing blood volume of blood collected for culture. The team used statistical process control methodology to detect special cause variation.

Results

Compliance with the standard processes as part of PSDA 1 improved from a mean level of 50% to 100% and for PDSA 2 improved from a mean level of 50% to 95%. After implementation of PDSA 3, scores on a relevant knowledge test increased from a mean of 39% (pretraining test; n = 10) to 92% (posttraining test; n = 10) (P < 0.001). Postimplementation of the processes for PDSA 4, a minimum of 1 mL was collected in 94% of blood culture collection events (n = 450) (mean 1.1 mL; range 0.5-3.5 mL). Special cause variation occurred after the implementation of the PDSA cycles. During the baseline period, the BCC rate was 2.0% and decreased to 1.0% postinterventions implementation.

Conclusions

Interventions focused on standardizing practices around collection of blood cultures in neonates were associated with fewer contaminants.This study is reported according to the SQUIRE 2.0 guidelines.

Modification of Blood Test Draw Order to Reduce Blood Culture Contamination: A Randomized Clinical Trial

BACKGROUND

Blood culture contamination leads to unnecessary interventions and costs. It may be caused by bacteria in deep skin structures unsusceptible to surface decontamination. This study was designed to test whether diversion of blood obtained at venipuncture into a lithium heparin tube prior to aspiration of blood culture reduces contamination.

METHODS

The order of blood draws for biochemistry and blood cultures was randomized. Following standard disinfection and venipuncture, blood was either aspirated into a sterile lithium heparin tube before blood culture bottles (diversion group) or blood cultures first and then lithium heparin tube (control group). All study personnel were blinded with the exception of the phlebotomist.

RESULTS

After exclusions, 970 blood culture/biochemistry sets were analyzed. Contamination occurred in 24 of 480 (5.0%) control vs 10 of 490 (2.0%) diversion group cultures (P = .01). True pathogens were identified in 26 of 480 (5.4%) control vs 18 of 490 (3.7%) diversion cultures (P = .22). Despite randomization, demographic differences were apparent between the 2 groups. A post hoc analysis of 637 cultures from 610 medical patients admitted from home neutralized demographic differences. Culture contamination remained more frequent in the control vs diversion group (17/312 [5%] vs 7/325 [2%]; P = .03). Fewer diversion group patients were admitted to hospital (control: 200/299 [66.9%] vs diversion: 182/311 [58.5%]; P = .03), and length of stay was shorter (control: 30 hours [interquartile range {IQR}, 6-122] vs diversion: 22 [IQR, 5-97]; P = .02).

CONCLUSIONS

Use of lithium heparin tubes for diversion prior to obtaining blood cultures led to a 60% decrease in contamination. This technique is easy and inexpensive and might decrease overall hospital length of stay.

CLINICAL TRIALS REGISTRATION

NCT03966534.

Risk factors and clinical outcomes associated with blood culture contamination

OBJECTIVE

To determine patient-specific risk factors and clinical outcomes associated with contaminated blood cultures.

DESIGN

A single-center, retrospective case-control risk factor and clinical outcome analysis performed on inpatients with blood cultures collected in the emergency department, 2014-2018. Patients with contaminated blood cultures (cases) were compared to patients with negative blood cultures (controls).

SETTING

A 509-bed tertiary-care university hospital.

METHODS

Risk factors independently associated with blood-culture contamination were determined using multivariable logistic regression. The impacts of contamination on clinical outcomes were assessed using linear regression, logistic regression, and generalized linear model with γ log link.

RESULTS

Of 13,782 blood cultures, 1,504 (10.9%) true positives were excluded, leaving 1,012 (7.3%) cases and 11,266 (81.7%) controls. The following factors were independently associated with blood-culture contamination: increasing age (adjusted odds ratio [aOR], 1.01; 95% confidence interval [CI], 1.01-1.01), black race (aOR, 1.32; 95% CI, 1.15-1.51), increased body mass index (BMI; aOR, 1.01; 95% CI, 1.00-1.02), chronic obstructive pulmonary disease (aOR, 1.16; 95% CI, 1.02-1.33), paralysis (aOR 1.64; 95% CI, 1.26-2.14) and sepsis plus shock (aOR, 1.26; 95% CI, 1.07-1.49). After controlling for age, race, BMI, and sepsis, blood-culture contamination increased length of stay (LOS; β = 1.24 ± 0.24; P < .0001), length of antibiotic treatment (LOT; β = 1.01 ± 0.20; P < .001), hospital charges (β = 0.22 ± 0.03; P < .0001), acute kidney injury (AKI; aOR, 1.60; 95% CI, 1.40-1.83), echocardiogram orders (aOR, 1.51; 95% CI, 1.30-1.75) and in-hospital mortality (aOR, 1.69; 95% CI, 1.31-2.16).

CONCLUSIONS

These unique risk factors identify high-risk individuals for blood-culture contamination. After controlling for confounders, contamination significantly increased LOS, LOT, hospital charges, AKI, echocardiograms, and in-hospital mortality.

Evaluation of an Initial Specimen Diversion Device (ISDD) on Rates of Blood Culture Contamination in the Emergency Department

Introduction

Blood cultures are the gold standard for identifying bloodstream infections. The Clinical and Laboratory Standards Institute recommends a blood culture contamination rate of less than 3%. Contamination can lead to misdiagnosis, increased length of stay and hospital costs, unnecessary testing, and antibiotic use. These reasons led to the development of initial specimen diversion devices (ISDD). The purpose of this study was to evaluate the impact of an initial specimen diversion device on rates of blood culture contamination in the emergency department.

Methods

This was a retrospective, multi-site study including patients who had blood cultures drawn in an emergency department. February 2018 to April 2018, when an ISDD was not utilized, was compared with June 2019 to August 2019, when an ISDD was being used. The primary outcome was total blood culture contamination. Secondary outcomes were total hospital cost, hospital and intensive care unit length of stay, vancomycin duration of use, vancomycin serum concentrations obtained, and repeat blood cultures obtained.

Results

A statistically significant difference was found in blood culture contamination rates in the pre-ISDD group vs. the ISDD group (7.47% vs. 2.59%, p < 0.001). None of the secondary endpoints showed a statistically significant difference.

Conclusions

Implementation of an ISDD reduced blood culture contamination. When implementing the ISDD to a healthcare system, compliance is important and will affect contamination rates dramatically.

Evaluation of Optimal Blood Culture Incubation Time To Maximize Clinically Relevant Results from a Contemporary Blood Culture Instrument and Media System

Timely diagnosis of microorganisms in blood cultures is necessary to optimize therapy. Although blood culture media and systems have evolved for decades, the standard interval for incubation prior to being discarded as negative has remained 5 days. Here, we evaluated the optimal incubation time for the BacT/Alert Virtuo blood culture detection system (bioMérieux) using FA Plus (aerobic) and FN Plus (anaerobic) resin culture bottles in routine clinical use.

Timely diagnosis of microorganisms in blood cultures is necessary to optimize therapy. Although blood culture media and systems have evolved for decades, the standard interval for incubation prior to being discarded as negative has remained 5 days. Here, we evaluated the optimal incubation time for the BacT/Alert Virtuo blood culture detection system (bioMérieux) using FA Plus (aerobic) and FN Plus (anaerobic) resin culture bottles in routine clinical use. Following institutional review board (IRB) approval, a retrospective review evaluated the outcomes of 158,710 bottles collected between November 2018 and October 2019. The number of positive blood bottles was 13,592 (8.6%); 99% of positive aerobic and anaerobic bottles flagged positive by 91.5 and 108 h, respectively. The mean (median) times to positivity were 18.4 h (15.6 h) for Staphylococcus aureus, 12.3 h (9.5 h) for Escherichia coli, 22.2 h (15.9 h) for Pseudomonas aeruginosa, and 48.9 h (42.9 h) for Candida spp. Only 175 bottles (0.1% of all bottles) flagged positive after 4 days of incubation; 89 (51%) of these bottles grew Cutibacterium (Propionibacterium) species. Chart review of blood cultures positive after 4 days (96 h) rarely had a clinical impact and sometimes had a negative impact on patient care. Finally, a seeded study of the HACEK group (i.e., Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, and Kingella), historically associated with delayed blood culture positivity, demonstrated no benefit to extended incubation beyond 4 days. Collectively, these findings demonstrated that a 4-day incubation time was sufficient for the Virtuo system and media. Implementation of the 4-day incubation time could enhance clinically relevant results by reducing recovery of contaminants and finalizing blood cultures 1 day earlier.

Asynchronous Testing of 2 Specimen-Diversion Devices to Reduce Blood Culture Contamination: A Single-Site Product Supply Quality Improvement Project

OBJECTIVE

Blood culture contamination above the national threshold has been a consistent clinical issue in the ED setting. Two commercially available devices were examined that divert an initial small volume of the specimen before the collection of blood culture to reduce skin contamination.

METHODS

Prospectively, 2 different blood culture-diversion devices were made available in the unit supplies to ED clinicians at a single site during 2 different periods of time as a follow-up strategy to an ongoing quality improvement project. Blood samples were collected in the emergency department over a period of 16 months. A retrospective record review study was conducted comparing the use of the 2 specimen-diversion devices with no device (control group) for blood culture contamination rates. The main outcome of monthly blood culture contamination per device was tested using a Bayesian Poisson multilevel regression model.

RESULTS

A total of 4030 blood samples were collected and analyzed from November 2017 to February 2019. The model estimated that the mean incidence of contaminated blood draws in the device A group was 0.29 (0.14-0.55) times the incidence of contaminated draws in the control group. The mean incidence of contaminated blood draws in the device B group was 0.23 (0.13-0.37) times the incidence of contaminated draws in the control group, suggesting that initial-diversion methods reduced blood culture contamination.

CONCLUSION

Initial specimen-diversion devices supplement present standard phlebotomy protocols to bring down the blood culture contamination rate.

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.

Procalcitonin as an early indicator of urosepsis following prostate biopsy

BACKGROUND

To investigate the usefulness of serum procalcitonin (PCT) in the early diagnosis of urinary tract infection (UTI) and urosepsis following transrectal prostate biopsy.

METHODS

In this prospective observational study, 227 patients who underwent transrectal ultrasound-guided prostate biopsy were evaluated. The relationship between urosepsis and age, serum PCT, C-reactive protein, prostate-specific antigen (PSA), prostate volume, PSA density and pathologic results following biopsy was assessed. Serum PCT level was measured in all patients immediately before the biopsy and at the post-biopsy day 2.

RESULTS

Of the 227 patients, 11 (4.8%) developed UTI with positive urine culture without urosepsis and 5 (2.2%) developed urosepsis within 30 days after biopsy. The concentration of PCT was within the normal range before the biopsy. Procalcitonin concentration at post-biopsy day 2 was significantly higher in patients who developed urosepsis (1.91 ± 2.99 ng/ml vs. 0.05 ± 0.08 ng/ml; p = .004) compared with non-UTI patients. Only elevated PCT level at post-biopsy day 2 was a statistically significant independent predictor of post-biopsy urosepsis. The area under the ROC curve for the prediction of urosepsis was 0.976 (95%CI: 0.941-1.000) and a cut-off 0.095 ng/ml in the level of PCT at post-biopsy day 2 yielded a sensitivity of 100% and specificity of 93.8% in detecting urosepsis following biopsy.

CONCLUSIONS

Procalcitonin appears to be a useful early biomarker to predict the urosepsis following prostate biopsy. Patients with elevated PCT value should be closely monitored after the biopsy.

Collaborative Antimicrobial Stewardship in the Emergency Department

Given the large number of patients seen in the emergency department (ED) and concerns with antibiotic overprescribing, the ED is an important setting to target for antimicrobial stewardship (AS) initiatives. The ED is positioned between ambulatory and inpatient settings, making AS collaboration with clinicians and other health care providers in the hospital, long-term care facilities, and ambulatory settings critical to success. This article details ED-focused AS strategies on empiric antimicrobial selection, prompt administration, preventing ED return and readmissions, suggested collaborations between ED AS leadership and other key partners, and potential future strategies for expansion.

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.

Impact of Contaminated Blood Cultures on Children, Families, and the Health Care System

BACKGROUND

Contaminated blood cultures pose a significant burden. We sought to determine the impact of contaminated peripheral blood cultures on patients, families, and the health care system.

METHODS

In this retrospective case-control study from January 1, 2014, to December 31, 2017, we compared the hospital course, return visits and/or admissions, charges, and length of stay of patients with contaminated peripheral blood cultures (case patients) with those of patients with negative cultures (controls). Patients were categorized into those evaluated and discharged from the emergency department (ED) (ED patients) and those who were hospitalized (inpatients).

RESULTS

A total of 104 ED case patients were matched with 208 ED control patients. A total of 343 case inpatients were matched with 686 inpatient controls. There was no significant difference between case and control patient demographics, ED, or hospital course at presentation. Fifty-five percent of discharged ED patients returned to the hospital for evaluation and/or admission versus 4% of controls. There was a significant (P < .0001) increase in repeat blood cultures (43% vs 1%), consultations obtained (21% vs 2%), cerebrospinal fluid studies (10% vs 0%), and antibiotic administration (27% vs 1%) in ED patients compared with controls. Each ED patient requiring revisit to the hospital incurred, on average, $4660 in additional charges. There was a significant (P < .04) increase in repeat blood cultures (57% vs 7%), consultations obtained (35% vs 28%), broadening of antibiotic coverage (18% vs 11%), median length of stay (75 vs 64 hours), and median laboratory charges ($3723 vs $3296) in case inpatients compared with controls.

CONCLUSIONS

Contaminated blood cultures result in increased readmissions, testing and/or procedures, length of stay, and hospital charges in children.

Efficient Early Diagnosis of Sepsis Using Whole-Blood PCR-Reverse Blot Hybridization Assay Depending on Serum Procalcitonin Levels

Sepsis is one of the medical emergencies, and its early detection, within the first hours of development, and proper management improve outcomes. Molecular diagnostic assays using whole blood collected from patients with suspected sepsis have been developed, but the decision making is difficult because of the possibility of false positives, due to contamination. Here, we evaluated the performance of the reverse blot hybridization assay (REBA) Sepsis-ID test for the detection of sepsis-causing microorganisms using whole-blood samples. In addition, the concentrations of C-reactive protein (CRP) and procalcitonin (PCT) were determined to evaluate whether these biomarkers can provide criteria for performing REBA Sepsis-ID in clinical settings. For this study, EDTA-anticoagulated whole blood was simultaneously collected for REBA Sepsis-ID and blood culture from 440 patients with suspected sepsis, from January to October 2015. In addition, CRP and PCT concentrations were measured in 227 patients. The overall positive rates of REBA Sepsis-ID and blood culture were 16.6% (73/440) and 13.9% (61/440), respectively. The pathogen-positive rates of REBA Sepsis-ID and blood culture were 9.8% (43/440) and 9.5% (42/440), respectively. The areas under the receiver operating characteristic (AUROC) curves of PCT and CRP for predicting pathogen-positive results of REBA Sepsis-ID were 0.72 and 0.69, respectively. The PCT concentrations in the group of patients aged ≥50 years were significantly higher than those in the group aged <50 years. After adjusting for age, the PCT AUROC value was 0.77 for predicting pathogen-positive results of REBA Sepsis-ID. The optimal cutoff values of PCT concentrations for subsequent application of REBA Sepsis-ID were 0.12 ng/mL in all patients and 0.22 ng/mL in patients aged ≥50 years. Our observations showed that REBA Sepsis-ID using whole blood was advantageous for the early detection of sepsis-causing microorganisms, and the PCT concentration could be used to determine the necessity of using REBA Sepsis-ID in clinical settings. The application of REBA Sepsis-ID using whole blood, based on the PCT concentration, may contribute to a highly efficient detection of sepsis-causing microorganisms.

Reduction in the processing of possible blood culture contaminants by the application of a selection criterion

Possible blood culture (BC) contaminants are generally considered to be skin flora species including coagulase-negative Staphylococci (CNS), Corynebacterium species, Micrococcus species, Bacillus species and Propionibacterium acnes. Prior to October 1, 2016 all possible BC contaminants were fully processed (identification, susceptibility testing) in our laboratory. In order to reduce the laboratory workload from October 1, 2016 a possible contaminant was only processed if it was present in more than one BC pair drawn from the same patient within the same day. The two-year study period was divided in two periods namely period A from January 1, 2016 to September 30, 2016 (first 9 months) and period B from October 1, 2016 to December 31, 2017 (last 15 months). A series of indices (INs) were calculated including among others the Working Rate IN (WR) defined as the total isolates divided to the total number of BCs submitted per month and the CNS Rate (CNSR) defined as the total number of CNS processed divided to the total number of BCs submitted per month. A 23.08% reduction in the CNSR was noted (from 3.51% in period A to 2.70% in period B) whereas the overall WR was reduced from 7.19% in period A to 6.84% in period B. Furthermore, the total number of contaminants processed per month divided to the total number of isolates processed per month was reduced from 54.50% in period A to 42.41% in period B. The reduction in the INs recorded is of great value since it was achieved by the implementation of a simple criterion easily applicable and without any cost.

Reducing Blood Culture Contamination Rates: Experiences of Four Hospital Systems

INTRODUCTION

Blood cultures (BCs) frequently become contaminated during the pre-analytic phase of collection leading to downstream ramifications. We present a summary of performance improvement (PI) interventions provided by four hospital systems and common factors that contributed to decreased blood culture contamination (BCC) rates.

METHODS

Each hospital independently formed a multidisciplinary team and action plan for implementation of their intervention, focusing on the use of educational and training tools. Their goal was to significantly decrease their BCC rates. Pre- and post-intervention data were compared during the sustainment period to determine their success.

RESULTS

All hospitals met their goals of post-intervention BCC rates and with most achieving and sustaining BCC rates ≤ 1.0-2.0%.

CONCLUSION

Our report highlights how four hospitals independently achieved their objective to decrease their BCC rate with the support of a multidisciplinary team. We propose a benchmark for BCC rates of 1.5 to < 2.0% as achievable and sustainable.

A cross-sectional study of prevalence, distribution, cause, and impact of blood product recalls in the United States

Defective blood products that are recalled because of safety or potency deviations can trigger adverse health events and constrict the nation's blood supply chain. However, the underlying characteristics and impact of blood product recalls are not fully understood. In this study, we identified 4700 recall events, 7 reasons for recall, and 144 346 units affected by recalls. Using geospatial mapping of the newly defined county-level recall event density, we discovered hot spots with high prevalence and likelihood of blood product recall events. Distribution patterns and distribution distances of recalled blood products vary significantly between product types. Blood plasma is the most recalled product (87 980 units), and leukocyte-reduced products (34 230 units) are recalled in larger numbers than non-leukocyte-reduced products (8076 units). Donor-related reasons (92 382 units) and sterility deviations (22 408 units) are the major cause of blood product recalls. Monetary loss resulting from blood product recalls is estimated to be $17.9 million, and economic sensitivity tests show that donor-related reasons and sterility deviations contribute most to the overall monetary burden. A total of 2.8 million days was required to resolve recall events, and probabilistic survival time analysis shows that sterility deviations and contamination took longer to resolve because of their systemic effect on blood collection and processing. Our studies demonstrate that better donor screening procedures, rigorous sterility requirements, improved containment methods, and mitigation of recall events in high-prevalence regions will enable a more robust blood supply chain.

Evaluation of two rapid molecular test systems to establish an algorithm for fast identification of bacterial pathogens from positive blood cultures

Fast identification of pathogens directly from positive blood cultures is of highest importance to supply an adequate therapy of bloodstream infections (BSI). There are several platforms providing molecular-based identification, detection of antimicrobial resistance genes, or even a full antimicrobial susceptibility testing (AST). Two of such test systems allowing rapid diagnostics were assessed in this study: The Biofire FilmArray® and the Genmark ePlex®, both fully automated test system with a minimum of hands-on time. Overall 137 BSI episodes were included in our study and compared to conventional culture–based reference methods. The FilmArray® is using one catridge including a panel for the most common bacterial and fungal BSI pathogens as well as selected resistance markers. The ePlex® offers three different cartridges for detection of Gram-positives, Gram-negatives, and fungi resulting in a broader panel including also rare pathogens, putative contaminants, and more genetic resistance markers. The FilmArray® and ePlex® were evaluated for all 137 BSI episodes with FilmArray® detecting 119 and ePlex® detecting 128 of these. For targets on the respective panel of the system, the FilmArray® generated a sensitivity of 98.9% with 100% specificity on Gram-positive isolates. The ePlex® system generated a sensitivity of 94.7% and a specificity of 90.7% on Gram-positive isolates. In each case, the two systems performed with 100% sensitivity and specificity for the detection of Gram-negative specimens covered by each panel. In summary, both evaluated test systems showed a satisfying overall performance for fast pathogen identification and are beneficial tools for accelerating blood culture diagnostics of sepsis patients.

Compliance of clinical microbiology laboratories with recommendations for the diagnosis of bloodstream infections: Data from a nationwide survey in Italy

In 2014, the Italian Working Group for Infections in Critically Ill Patient of the Italian Association of Clinical Microbiologists updated the recommendations for the diagnostic workflow for bloodstream infections (BSI). Two years after publication, a nationwide survey was conducted to assess the compliance with the updated recommendations by clinical microbiology laboratories. A total of 168 microbiologists from 168 laboratories, serving 204 acute care hospitals and postacute care facilities, were interviewed during the period January–October 2016 using a questionnaire consisting of nineteen questions which assessed the level of adherence to various recommendations. The most critical issues were as follows: (a) The number of sets of blood cultures (BC) per 1,000 hospitalization days was acceptable in only 11% of laboratories; (b) the minority of laboratories (42%) was able to monitor whether BCs were over or under‐inoculated; (c) among the laboratories monitoring BC contamination (80%), the rate of contaminated samples was acceptable in only 12% of cases;(d) the Gram‐staining results were reported within 1 hr since BC positivity in less than 50% of laboratories. By contrast, most laboratories received vials within 2–4 hr from withdrawal (65%) and incubated vials as soon as they were received in the laboratory (95%). The study revealed that compliance with the recommendations is still partial. Further surveys will be needed to monitor the situation in the future.

Practical Guidance for Clinical Microbiology Laboratories: A Comprehensive Update on the Problem of Blood Culture Contamination and a Discussion of Methods for Addressing the Problem

In this review, we present a comprehensive discussion of matters related to the problem of blood culture contamination. Issues addressed include the scope and magnitude of the problem, the bacteria most often recognized as contaminants, the impact of blood culture contamination on clinical microbiology laboratory function, the economic and clinical ramifications of contamination, and, perhaps most importantly, a systematic discussion of solutions to the problem. We conclude by providing a series of unanswered questions that pertain to this important issue.

Successful Reduction of Blood Culture Contamination in an Emergency Department by Monitoring and Feedback

Background:

Blood Culture (BC) contamination is a common problem in the Emergency Department (ED) and is associated with prolonged length of patient stay and excess costs.

Objective:

The study aimed to investigate the impact of monthly monitoring and feedback of BC results on contamination rates.

Methods:

Data from a previous study showed that the contamination rate in the ED consistently exceeded the recommended level. This triggered an ad hoc Quality Improvement team to develop and implement a corrective action plan. In 2017, BC contamination rates were reported to the ED on a monthly basis. In response to this, ED staff conducted intensified educational workshops, followed by private counselling and competency assessment of nurses who collected contaminated BCs.

Results:

A total of 12 educational workshops were conducted in February and March, 2017. The intervention resulted in >60% reduction in the contamination rate, from 8.6% baseline level to less than 3%. Of the 2660 BC sets drawn in 2017 from 1318 patients, 128 (4.8%) were contaminated, accounting for 39.5% of the total number of positive cultures. Sixty percent of the contaminated BCs grew Coagulase-negativeStaphylococcusspecies; other contaminants includedCorynebacteriumspp.,Micrococcusspp.,Propionibacteriumspp.,viridansStreptococcus, andNeisseriaspp.

Conclusion:

Continuous monitoring and feedback of contamination rates reduced BC contamination.

ESKAPE Pathogens in Bloodstream Infections Are Associated With Higher Cost and Mortality but Can Be Predicted Using Diagnoses Upon Admission

Background

ESKAPE bacteria are thought to be especially resistant to antibiotics, and their resistance and prevalence in bloodstream infections are rising. Large studies are needed to better characterize the clinical impact of these bacteria and to develop algorithms that alert clinicians when patients are at high risk of an ESKAPE infection.

Methods

From a US data set of >1.1 M patient encounters, we evaluated if ESKAPE pathogens produced worse outcomes than non-ESKAPE pathogens and if an ESKAPE infection could be predicted using simple word group algorithms built from decision trees.

Results

We found that ESKAPE pathogens represented 42.2% of species isolated from bloodstream infections and, compared with non-ESKAPE pathogens, were associated with a 3.3-day increase in length of stay, a $5500 increase in cost of care, and a 2.1% absolute increase in mortality (P < 1e-99). ESKAPE pathogens were not universally more resistant to antibiotics, but only to select antibiotics (P < 5e-6), particularly against common empiric therapies. In addition, simple word group algorithms predicted ESKAPE pathogens with a positive predictive value of 7.9% to 56.2%, exceeding 4.8% by random guessing (P < 1e-99).

Conclusions

Taken together, these data highlight the pathogenicity of ESKAPE bacteria, potential mechanisms of their pathogenicity, and the potential to predict ESKAPE infections upon admission. Implementing word group algorithms could enable earlier and targeted therapies against ESKAPE bacteria and thus reduce their burden on the health care system.

Direct Detection of Pathogens in Bloodstream During Sepsis: Are We There Yet?

Background

Advances in medicine have improved our understanding of sepsis, but it remains a major cause of morbidity and mortality. The detection of pathogens that cause sepsis remains a challenge for clinical microbiology laboratories.

Content

Routine blood cultures are time-consuming and are negative in a large proportion of cases, leading to excessive use of broad-spectrum antimicrobials. Molecular testing direct from patient blood without the need for incubation has the potential to fill the gaps in our diagnostic armament and complement blood cultures to provide results in a timely manner. Currently available platforms show promise but have yet to definitively address gaps in sensitivity and specificity.

Summary

Significant strides have been made in the detection of pathogens directly from blood. A number of hurdles, however, remain before this technology can be adapted for routine use.