The preanalytical optimization of blood cultures: a review and the clinical importance of benchmarking in 5 Belgian hospitals

Bloodstream infections in a rural hospital in Sierra Leone: a retrospective database study

Background. The health system in Sierra Leone has limited infrastructure to provide data on the epidemiology of infectious diseases and to inform clinical decision-making. The diagnostic and research laboratory capacity at Masanga Teaching Hospital was systematically expanded with microbiology infrastructure-building as one of the centrepieces.Objective. This study aims to report the spectrum of bacterial pathogens from bloodstream infections (BSIs) in a rural hospital in Sierra Leone during the first year after the implementation of a blood culture infrastructure and characterize the detected antimicrobial resistances.Patients and methods. Patients treated at Masanga Hospital (Sierra Leone, March 2023-March 2024) were included in this database analysis if they were tested for BSI (BD BACTEC). Demographic and medical data were recorded for each patient. Antimicrobial susceptibility testing was done following EUCAST clinical guidelines.Results. Of the 340 blood cultures, 34 (10%) were positive for obligate pathogens. The three most frequent pathogens were Escherichia coli (n=8), followed by Burkholderia cepacia complex (n=7) and Salmonella enterica (n=5). Almost all Klebsiella pneumoniae (n=3/3) and E. coli (n=7/8) were resistant to third-generation cephalosporins. All four Staphylococcus aureus isolates were methicillin susceptible (mecA negative). Carbapenem resistance was detected in Acinetobacter baumannii complex (bla NDM)Conclusion. The proportion of positive blood cultures with obligate pathogens (10%) was within the suggested benchmark (5-15%). Gram-negative bacteria dominated the pathogen spectrum of BSI with high resistance rates to third-generation cephalosporins.

Occurrence of bacteremia, bacteriuria and bacteriuria-related bacteremia in dogs and cats with chronic kidney disease. A pilot study

In human medicine, major infections are the most significant and critical non-cardiovascular complications in patients affected by chronic kidney disease (CKD), with bacteriuria being the primary source of bloodstream infections and its evolution toward sepsis. The availability of data on prevalence of bacteremia and its association with bacteriuria in dogs and cats with CKD is limited. The aim of this observational cross-sectional study was to determine the occurrence of bacteremia, bacteriuria, and bacteriuria-related bacteremia in dogs and cats affected by CKD. Client-owned dogs and cats with a documented history of CKD undergoing disease follow-up were enrolled. Each included animal underwent a comprehensive physical examination, clinico-pathological and microbiological analyses of blood and urine, along with molecular detection of the 16S rRNA bacterial gene in blood. Aseptically collected blood and urine were obtained through jugular venipuncture and cystocentesis, respectively. After collection, blood and urine samples underwent bacteriological culture within one hour. In the population enrolled, 2/47 dogs and 1/41 cats presented bacteriemia. Moreover, 8/47 dogs and 6/41 cats presented a positive urine culture. Additionally, in one out of the 47 dogs, the same pathogen was identified from blood and urine samples, with a final diagnosis of urosepsis. No instances of bacteriuria-related bacteriemia were observed in the cat population. In conclusion, this study shows a low prevalence of bacteremia and confirms a high prevalence of bacteriuria in companion animals affected by CKD. Moreover, a low prevalence of bacteriuria-related bacteremia was also found.

Bacteriological profile and antibiotic sensitivity pattern of bloodstream infections from a teaching institution in Eastern Uttar Pradesh, North India

Introduction

Bloodstream infections (BSIs), encompassing both self-limiting bacteremia and potentially fatal septicaemia, make up the majority of healthcare-associated ailments worldwide. The organisms encountered are mostly multidrug-resistant (MDROs), leading to increased hospital stays. Our study aims to collect data about blood culture isolates from a medical college in eastern Uttar Pradesh, India.

Materials and Methods

A retrospective analysis of blood culture isolates obtained at our laboratory for ten months from patients with clinical suspicion of sepsis or infection with the possibility of haematogenous spread was done. We only considered consecutive and patient-specific, non-duplicate isolates. Blood samples were initially incubated in BacT/ALERT® and then manually processed once they flagged positive.

Results

A total of 1,033 blood samples were received, of which 217 (21%) showed the growth of a pathogenic organism. The positivity rate varied significantly across different age groups, locations, and departments (P value < 0.001). It was higher among in-patients, those with central venous access, and patients with diabetes mellitus (DM). Staphylococcus aureus [n = 105, 48.38%] was isolated most commonly, with a high prevalence of methicillin resistance (83%). Enterococcus demonstrated a high degree of resistance. MDROs accounted for 68% of the detected Gram-negatives.

Discussion

This study comprehensively analyses blood culture results from a diverse group of patients and emphasizes the association between risk factors and positive blood cultures. Gram-positive and Gram-negative isolates demonstrated low sensitivity to common antibiotics, urging vigilant monitoring and specific therapy.

Conclusion

Our study reveals important insights guiding clinical practices, antimicrobial stewardship, and infection control strategies.

Benchmarking blood culture quality in the emergency department: Contamination, single sets and positivity

OBJECTIVE

To benchmark blood culture (BC) quality in an Australian ED, explore groups at risk of suboptimal BC collection, and identify potential areas for improvement.

METHODS

This retrospective observational study was undertaken to benchmark quality of BCs in a tertiary adult ED in terms of number of BC sets per patient and proportion of patients with false positive (contaminated) BC results.

RESULTS

A single BC set was taken for 55% of patients, with lower acuity patients being more likely to have a single BC set taken. BC false positives occurred in 3.4% of presentations, with higher frequency in some critically unwell patient groups. The true positive BC rate was 10.9%, with pathogens most frequently isolated in older patients, those with a haematological condition or genitourinary source, and those admitted to inpatient wards. Hospital length of stay did not differ between patients with negative and patients with false positive BCs.

CONCLUSIONS

BC quality standards in the ED such as false positive rate <3% and single culture rate <20% are required to facilitate benchmarking and prospective quality improvement. The sensitivity and specificity of this common and critical test can be improved. Patient subgroups associated with poor-quality BC collection can be identified and should be a focus of future work.

Improving Blood Culture Quality with a Medical Staff Educational Program: A Prospective Cohort Study

Purpose

Blood cultures (BCs) are essential laboratory tests for diagnosing blood stream infections. BC diagnostic improvement depends on several factors during the preanalytical phase outside of innovative technologies. In order to evaluate the impact of an educational program on BC quality improvement, a total of 11 hospitals across China were included from June 1st 2020 to January 31st 2021.

Methods

Each hospital recruited 3 to 4 wards to participate. The project was divided into three different periods, pre-implementation (baseline), implementation (educational activities administered to the medical staff) and post-implementation (experimental group). The educational program was led by hospital microbiologists and included professional presentations, morning meetings, academic salons, seminars, posters and procedural feedback.

Results

The total number of valid BC case report forms was 6299, including 2739 sets during the pre-implementation period and 3560 sets during the post-implementation period. Compared with the pre-implementation period, some indicators, such as the proportion of patients who had 2 sets or more, volume of blood cultured, and BC sets per 1000 patient days, were improved in the post-implementation period (61.2% vs 49.8%, 18.56 vs 16.09 sets, and 8.0 vs 9.0mL). While BC positivity and contamination rates did not change following the educational intervention (10.44% vs 11.97%, 1.86% vs 1.94%, respectively), the proportion of coagulase negative staphylococci-positive samples decreased in BSI patients (6.87% vs 4.28%).

Conclusion

Therefore, medical staff education can improve BC quality, especially increasing volume of blood cultured as the most important variable to determine BC positivity, which may lead to improved BSI diagnosis.

Verification of quality assurance for blood culture surveillance using 6 years of data from the Japan Infection Prevention and Control Conference for National and Public University Hospitals

The importance of blood culture has been widely recognized, and there is a need for monitoring to evaluate the accuracy of blood culture that reflects domestic healthcare systems. In this study, we assessed 6-year trends in blood culture quality assurance data. The Japan Infection Prevention and Control Conference for National and Public University Hospitals conducted yearly blood culture surveillance at 52 national public university hospitals from 2015 to 2020. Statistical analysis showed that comparison with the previous year showed significant differences in the number of blood cultures per 1000 patient-days in all years. The number of blood cultures per 1000 admissions was not significantly different in 2017 and 2018, but significant differences were shown in all other years. The multiple blood culture set rate was significantly different between non-pediatric inpatients and outpatients but not between pediatric inpatients and outpatients. The contamination rate did not differ significantly. For all parameters, significant differences were found when comparing 2015 and 2020. Our survey showed that although the sample number improved over time, even the most recent values for 2020 were lower than Cumitech's targets. It is difficult to assess whether these sample numbers are appropriate because target values have not been set for the various types of hospitals in Japan. Surveillance is a useful tool for monitoring quality assurance for blood culture. All parameters improved over the 6-year period, but it is necessary to establish a benchmark for evaluating optimization. We will continue to monitor quality assurance and work on setting benchmarks.

Evaluation of hospital blood culture utilization rates to identify opportunities for diagnostic stewardship

OBJECTIVES

To evaluate the pattern of blood-culture utilization among a cohort of 6 hospitals to identify potential opportunities for diagnostic stewardship.

METHODS

We completed a retrospective analysis of blood-culture utilization during adult inpatient or emergency department (ED) encounters in 6 hospitals from May 2019 to April 2020. We investigated 2 measures of blood-culture utilization rates (BCURs): the total number of blood cultures, defined as a unique accession number per 1,000 patient days (BCX) and a new metric of blood-culture events per 1,000 patient days to account for paired culture practices. We defined a blood-culture event as an initial blood culture and all subsequent samples for culture drawn within 12 hours for patients with an inpatient or ED encounter. Cultures were evaluated by unit type, positivity and contamination rates, and other markers evaluating the quality of blood-culture collection.

RESULTS

In total, 111,520 blood cultures, 52,550 blood culture events, 165,456 inpatient admissions, and 568,928 patient days were analyzed. Overall, the mean BCUR was 196 blood cultures per 1,000 patient days, with 92 blood culture events per 1,000 patient days (range, 64-155 among hospitals). Furthermore, 7% of blood-culture events were single culture events, 55% began in the ED, and 77% occurred in the first 3 hospital days. Among all blood cultures, 7.7% grew a likely pathogen, 2.1% were contaminated, and 5.9% of first blood cultures were collected after the initiation of antibiotics.

CONCLUSIONS

Blood-culture utilization varied by hospital and was heavily influenced by ED culture volumes. Hospital comparisons of blood-culture metrics can assist in identifying opportunities to optimize blood-culture collection practices.

Clinical Performance of Nanopore Targeted Sequencing for Diagnosing Infectious Diseases

The gold standard for confirming bacterial infections is culture-positive, which has a long sample-to-result turnaround time and poor sensitivity for unculturable and fastidious pathogens; therefore, it is hard to guide early, targeted antimicrobial therapy and reduce overuse of broad-spectrum antibiotics. Nanopore targeted sequencing (NTS) is reported to be advantageous in detection speed and range over culture in prior published reports. However, investigation of the clinical performance of NTS is deficient at present. Thus, we assessed the feasibility of NTS for the first time with cohort and systematic comparisons with traditional culture assays and PCR followed by Sanger sequencing. This retrospective study was performed on 472 samples, including 6 specimen types from 436 patients, to evaluate the clinical performance of NTS designed for identifying the microbial composition of various infections. Of these samples, 86.7% were found to be NTS positive, which was significantly higher than culture-positive (26.7%). A total of 425 significant human opportunistic bacteria and fungi detected by NTS were selected to go through validation with PCR followed by Sanger sequencing. The average accuracy rate was 85.2% (maximum 100% created by Cryptococcus neoformans, the last one 66.7% provided by both Staphylococcus haemolyticus and Moraxella osloensis, minimum 0% produced by Burkholderia cepacia). The accuracy rate also varied with sample type; the highest accuracy rate was found in pleural and ascites fluid (95.8%) followed by bronchoalveolar lavage fluid (88.7%), urine (86.8%), and wound secretions (85.0%), while the lowest was present in cerebrospinal fluid (58.8%). NTS had a diagnostic sensitivity of 94.5% and specificity of 31.8%. The positive and negative predictive values of NTS were 79.9% and 66.7%, respectively. For diagnosis of infectious diseases, the sensitivity was greatly increased by 56.7% in NTS compared with culture (94.5% vs 37.8%). Therefore, NTS can accurately detect the causative pathogens in infectious samples, particularly in pleural and ascites fluid, bronchoalveolar lavage fluid, urine, and wound secretions, with a short turnaround time of 8-14 h, and might innovatively contribute to personalizing antibiotic treatments for individuals with standardized protocols in clinical practices. IMPORTANCE Nanopore targeted sequencing (NTS) is reported to be advantageous in detection speed and range over culture in prior published reports. Investigation of the clinical performance of NTS is deficient at present. In our study, cohort and systematic comparisons among three assays (culture, NTS, and Sanger sequencing) were analyzed retrospectively for the first time. We found that NTS undoubtedly has incomparable advantages in accurately detecting the causative pathogens in infectious samples, particularly in pleural and ascites fluid, bronchoalveolar lavage fluid, urine, and wound secretions, with a short turnaround time of 8-14 h. For sterile specimens like blood and cerebrospinal fluid (CSF), the NTS outcomes should be validated using other nucleic acid based detection technology. Overall, NTS might innovatively contribute to guiding early, targeted antimicrobial therapy with lower cost and reduce overuse of broad-spectrum antibiotics.

Single-site sampling versus multi-site sampling for blood cultures; A retrospective clinical study

Objectives The performance of blood cultures (BC) relies on optimal sampling. Sepsis guidelines do not specify which sampling protocol to use, but recommend two sets of BC bottles, each set containing one aerobic and one anaerobic bottle. For the single-site sampling (SSS) protocol, only one venipuncture is performed for all four bottles. The predominating multi-site sampling (MSS) protocol implies that BC bottles are collected from two separate venipuncture sites. The aim of this study was to compare SSS and MSS. Primary outcomes were number of BC sets collected, sample volume and diagnostic performance. Methods This was a retrospective clinical study comparing BC results in an emergency department before and after changing the sampling protocol to SSS from MSS. All BC samples were incubated in the BacT/ALERT BC system. Results The analysis included 5,248 patients before and 5,364 patients after the implementation of SSS. There was a significantly higher proportion of positive BCs sampled with SSS compared to MSS, 1,049/5,364 (19.56%) and 932/5,248 (17.76%) respectively (P=0.018). This difference was due to a higher proportion of solitary BC sets (two BC bottles) in MSS. Analyzing only patients with the recommended four BC bottles, there was no difference in positivity. SSS had a higher proportion of BC bottles with the recommended sample volumes of 8-12 ml than MSS (P<0.001). Conclusions Changing the sampling protocol to SSS from MSS resulted in higher positivity rates, higher sample volume and fewer solitary BC sets. These advantages of SSS should be considered in future sepsis guidelines.

Nonautomated Blood Cultures in a Low-Resource Setting: Optimizing the Timing of Blind Subculture

Laboratory procedures for blood cultures in a hospital in Phnom Penh were adapted to optimize detection of Burkholderia pseudomallei, an important pathogen in this setting. The effects of these changes are analyzed in this study. Blood cultures consisted of two BacT/ALERT bottles (bioMérieux, Marcy-l’Etoile, France). Growth was detected visually by daily inspection of the bottles. In 2016, the aerobic–anaerobic pair (FA/FN FAN) was substituted by an aerobic pair of BacT/ALERT FA Plus bottles. Blind subculture (BS) (subculture in the absence of visual growth) was advanced from day 3 to day 2 of incubation in July 2016. In July 2018, it was further advanced to day 1 of incubation. From July 2016 to October 2019, 9,760 blood cultures were sampled. The proportion of cultures showing pathogen growth decreased from 9.6% to 6.8% after the implementation of the laboratory changes (P < 0.001). Advancing the BS from day 3 to day 2 led to an increased proportion of pathogens detected by day 3 (92.8% versus 82.3%; P < 0.001); for B. pseudomallei, this increase was even more remarkable (92.0% versus 18.2%). Blind subculture on day 1 similarly increased the proportion of pathogens detected by day 2 (82.9% versus 69.0% overall, 66.7% versus 10.0% for B. pseudomallei; both P < 0.001). However, after implementation of day 1 subculture, a decrease in recovery of B. pseudomallei was observed (12.4% of all pathogens versus 4.3%; P < 0.001). In conclusion, earlier subculture significantly shortens time to detection and time to actionable results. Some organisms may be missed by performing an early subculture, especially those that grow more slowly.

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.

The impact of delayed analysis of positive blood cultures on the performance of short-term culture followed by MALDI-TOF MS

BACKGROUND

Short-term culture followed by MALDI-TOF MS is one of the most widely used methods for fast identification of microorganisms from blood cultures. The method identifies the vast majority of bloodstream infection pathogens in 2-6 h after positive blood culture. Transport time of blood culture bottles to laboratories is a major problem affecting total turnaround time. Therefore, many central laboratories establish satellite blood culture systems in other clinics and hospitals to allow blood culture bottles to be incubated immediately after sampling. However, positive blood culture bottles still need to be transported to the clinical microbiology laboratory for analysis. The aim of this study was to investigate how delayed analysis of positive blood culture bottles would affect the short-term culture followed by MALDI-TOF MS method.

MATERIALS/METHODS

To simulate the effect of transportation and delayed analysis of blood culture bottles, 51 simulated blood culture bottles were incubated for 0, 2, 4 and 24 h at room temperature. After each time interval, a 2 to 4 h short-term culture followed by MALDI-TOF MS was performed. In addition, 257 prospective clinical positive blood culture bottles were analysed with the same method after a 24 h incubation at room temperature.

RESULTS

In simulated samples, all (120/120) Gram-negative bacteria and 77/84 (91.6%) Gram-positive bacteria were accurately identified at species-level after a 2 h short-term culture, regardless of the duration of simulated transport time. In the clinical samples, 100/116 (86.2%) Gram-negative, and 44/141 (31.2%) Gram-positive bacteria were accurately identified at species-level after a 2 h short-term culture. After contaminants were excluded, 39/71 (54.9%) Gram-positive bacteria could be identified after 2 h. After a 4 h short-term culture, 112/116 (96.6%) Gram-negative, and 108/141 (76.6%) Gram-positive bacteria were accurately identified at species-level. Of the clinically relevant Gram-positive bacteria, 68/71 (95.8%) were identified at species-level after 4 h.

CONCLUSIONS

Short-term culture followed by MALDI-TOF MS can provide fast and accurate results for identification of clinically relevant bacteria, despite long transportation times from satellite laboratories. The present data shows that the method can be used for identification of microorganisms from positive blood cultures transported from satellite blood culture systems.

Improved blood culture workflow in the time to detection of microorganisms placing incubators systems outside of microbiology laboratory

PURPOSE

We analyzed the workflow of the blood culture procedure with one blood culture incubator in the microbiology laboratory, in comparison with the workflow with the incubators systems placing outside, and in a microbiology laboratory without 24-h staffing.

METHODS

We assessed the elapsed time (ET) and time-to-result (TTR) in the two laboratory workflows during 1 month period in consecutive years. First period with one BACT/ALERT 3D module located in the microbiology laboratory (ML) (access 8 a.m. to 10 p.m.) and second period with three BACT/ALERT VIRTUO modules (one located in ML and two in the core sample laboratory, access 24 h).

RESULTS

The mean ET with BACT/ALERT 3D was 7.09 ± 6.15 h and 1.32 ± 3.14 h with BACT/ALERT VIRTUO. During the 8:00 a.m. to 10:00 p.m. shift, the average ETs were 3.54 ± 5.06 vs 1.59 ± 1.29 h for the two time periods, respectively. Since the automated loading of bottles on the BACT/ALERT VIRTUO allows processing of blood cultures during the night shift, there was a significant reduction of time during the 10:00 p.m. to 8:00 a.m. shift, where the average ET was 10.52 ± 5.23 vs 1.00 ± 4.40 h, respectively. The percentage of positivity in the first period was 9.03% and 11.18% in the second (p = 0.0003). The average TTR in the first period was 24.78 ± 15.9 h and 16.85 ± 14.13 h in the second (p < 0.0001).

CONCLUSIONS

Easy 24-h access to blood culture incubators resulted in significant improvement in the workflow of blood culture, decreasing ET, and therefore decreasing the time to positivity and the efficiency of recovery.

How the Pathologist Can Help the Surgeon Collect Better Specimens for Microbiology Culture

CONTEXT.—

Specimen quality is paramount for microbiology culture in order to ensure the testing is performed appropriately and the results, generated accurately, reflect the patient's clinical situation and guide proper treatment. Several factors play a critical role in guaranteeing the accuracy of the culture results, including adequate specimen collection by the surgeon, proper labeling, and timely transport to the laboratory.

OBJECTIVE.—

To educate pathologists, surgeons, and other medical personnel involved in the collection and processing of surgical specimens submitted for microbiologic culture. To assure the pathogen is correctly identified, proper protocols must be followed. The accurate identification of the infectious microorganisms from surgical specimens is vital for the treating clinician to ensure the correct antimicrobial therapy is administered.

DATA SOURCES.—

An analysis of relevant literature was performed by using PubMed. Articles were selected on the basis of their relevance to the topic as well as their date of publication. Articles published between 2000 and 2018 were deemed sufficient for inclusion, while older references, regardless of relevance, were excluded.

CONCLUSIONS.—

The process of properly obtaining specimens for microbiology culture from the operating room is a complex process that requires collaboration between the collecting surgeon and the pathologist and microbiology laboratory in order to provide the highest quality of results from which important treatment decisions are then implemented. Engaging leadership to develop mutually agreed-upon institutional best practices will help not only to standardize practices but also to improve the quality of microbiology results reported.

Perform or perish: laboratory optimization to avoid false negative blood cultures in pneumococcal bacteremia

We present the laboratory operations influencing the culture yield of pneumococci and suggest an alternate solution to the problem. Blood cultures of 136 adults and 19 pediatric patients were analyzed in two phases. In phase I, the laboratory operated only during weekdays but in phase II the laboratory provided 24-h services on all days. In phase I, successful bacterial isolation leading to testing of antimicrobial susceptibility was possible only in 51% of cases, while a significant 49% had failed to grow in subcultures due to autolysis resulting from delayed processing time. These false negative blood cultures were further confirmed as Streptococcus pneumoniae by commercial antigen tests. In phase II, we did not observe any false-negative results due to prompt subculturing protocols (p < 0.001). We also found that taking blood cultures on two occasions increases the yield by 46% among adults.

Best Practices of Blood Cultures in Low- and Middle-Income Countries

Bloodstream infections (BSI) have a substantial impact on morbidity and mortality worldwide. Despite scarcity of data from many low- and middle-income countries (LMICs), there is increasing awareness of the importance of BSI in these countries. For example, it is estimated that the global mortality of non-typhoidal Salmonella bloodstream infection in children under 5 already exceeds that of malaria. Reliable and accurate diagnosis of these infections is therefore of utmost importance. Blood cultures are the reference method for diagnosis of BSI. LMICs face many challenges when implementing blood cultures, due to financial, logistical, and infrastructure-related constraints. This review aims to provide an overview of the state-of-the-art of sampling and processing of blood cultures, with emphasis on its use in LMICs. Laboratory processing of blood cultures is relatively straightforward and can be done without the need for expensive and complicated equipment. Automates for incubation and growth monitoring have become the standard in high-income countries (HICs), but they are still too expensive and not sufficiently robust for imminent implementation in most LMICs. Therefore, this review focuses on "manual" methods of blood culture, not involving automated equipment. In manual blood cultures, a bottle consisting of a broth medium supporting bacterial growth is incubated in a normal incubator and inspected daily for signs of growth. The collection of blood for blood culture is a crucial step in the process, as the sensitivity of blood cultures depends on the volume sampled; furthermore, contamination of the blood culture (accidental inoculation of environmental and skin bacteria) can be avoided by appropriate antisepsis. In this review, we give recommendations regarding appropriate blood culture sampling and processing in LMICs. We present feasible methods to detect and speed up growth and discuss some challenges in implementing blood cultures in LMICs, such as the biosafety aspects, supply chain and waste management.

Improvement of blood culture contamination rate, blood volume, and true positive rate after introducing a dedicated phlebotomy team

The introduction of dedicated phlebotomy teams certified for blood collection has been reported to be highly cost-effective by reducing contamination rates. However, data on their effects on blood volume and true positive rate are limited. Therefore, we investigated the effect of replacing interns with a phlebotomy team on blood culture results. We performed a 24-month retrospective, quasi-experimental study before and after the introduction of a phlebotomy team dedicated to collecting blood cultures in a 2700-bed tertiary-care hospital. The microbiology laboratory database was used to identify adult patients with positive blood culture results. During the study period, there were no changes in blood collection method, blood culture tubes, and the application of antiseptic measures. Blood volume was measured by the BACTEC™ FX system based on red blood cell metabolism. A total of 162,207 blood cultures from 23,563 patients were analyzed, comprising 78,673 blood cultures during the intern period and 83,534 during the phlebotomy team period. Blood volume increased from a mean of 2.1 ml in the intern period to a mean of 5.6 ml in the phlebotomy team period (p < 0.001). Introduction of the phlebotomy team also reduced contamination rate (0.27% vs. 0.45%, p < 0.001) and led to a higher true positive rate (5.87% vs. 5.01%, p < 0.05). The increased true positive rate associated with the phlebotomy team involved both gram-positive and gram-negative bacteria. The introduction of a dedicated phlebotomy team can increase blood volumes, reduce blood culture contamination rate, and increase true positive rate.

Blood culture utilization at an academic hospital: Addressing a gap in benchmarking

OBJECTIVE

To describe the pattern of blood culture utilization in an academic university hospital setting.

DESIGN

Retrospective cohort study.

SETTING

A 789-bed tertiary-care university hospital that processes 40,000+blood cultures annually.

METHODS

We analyzed blood cultures collected from adult inpatients at the Hospital of the University of Pennsylvania between July 1, 2014, and June 30, 2015. Descriptive statistics and regression models were used to analyze patterns of blood culture utilization: frequency of blood cultures, use of repeat cultures following a true-positive culture, and number of sets drawn per day.

RESULTS

In total, 38,939 blood culture sets were drawn during 126,537 patient days (incidence rate, 307.7 sets per 1,000 patient days). The median number of blood culture sets drawn per hospital encounter was 2 (range, 1-76 sets). The median interval between blood cultures was 2 days (range, 1-71 days). Oncology services and cultures with gram-positive cocci were significantly associated with greater odds of having repeat blood cultures drawn the following day. Emergency services had the highest rate of drawing single blood-culture sets (16.9%), while oncology services had the highest frequency of drawing ≥5 blood culture sets within 24 hours (0.91%). Approximately 10% of encounters had at least 1 true-positive culture, and 89.2% of those encounters had repeat blood cultures drawn. The relative risk of a patient having repeat blood cultures was lower for those in emergency, surgery, and oncology services than for those in general medicine.

CONCLUSIONS

Ordering practices differed by service and culture results. Analyzing blood culture utilization can contribute to the development of guidelines and benchmarks for appropriate usage.

A national survey of interventions and practices in the prevention of blood culture contamination and associated adverse health care events

The scientific literature indicates that blood culture contamination often leads to inappropriate antimicrobial treatment, adverse patient occurrences, and potential reporting of false-positive central line-associated bloodstream infections. The findings of a national infection prevention survey of blood culture practices and related interventions in hospitals support the need for infection preventionists to expand their participation in the review of topics related to the ordering and collection of blood for culture.

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.

The antibiotic checklist: an observational study of the discrepancy between reported and actually performed checklist items

BACKGROUND

Checklists are increasingly used to measure quality of care. Recently we implemented an antibiotic checklist in nine Dutch hospitals and showed that use of the checklist resulted in more appropriate antibiotic use. While more appropriate antibiotic use was associated with a reduction in length of stay, use of the checklist in itself was not. In the current study we explored discrepancies between reported and actually performed checklist items at the patient level to test the validity of checklist answers, to evaluate whether discrepancies between reported and actually performed checklist items could explain the lack of effect of checklist use on length of stay, and to identify missed opportunities for performance per checklist item.

METHODS

Checklist answers represented reported performance. Actual performance was assessed by data from the patients' medical files. Reported and actually performed checklist items could be 'both YES'; 'both NO'; 'YES reported, NOT actually performed'; or 'NO reported, YES actually performed'. We determined an overall 'both YES' score per checklist, and used mixed models to evaluate whether an association existed between this overall score and patient's length of hospital stay. Finally, we analysed whether the items that were not actually performed, could have been performed.

RESULTS

Between January and October 2015 physicians filled in 1207 checklists. In total 7881 items were checked. Most items were 'both YES' (3392/7881, 43.0%) or 'both NO' (2601/7881, 33.0%). The number of 'YES reported, NOT actually performed' items was 1628/7881 (20.7%) compared to 260/7881 (3.3%) 'NO reported, YES actually performed' items. The level of discrepancy between reported and actually performed items differed per checklist item. The item 'prescribe antibiotic treatment according to the local guideline' had the highest percentage of 'YES reported, NOT actually performed' items, namely 45.1%. A higher overall 'both YES' score of the checklist was significantly associated with a shorter length of hospital stay. Of all checklist items 21.8% were not performed while they could have been performed.

CONCLUSIONS

Checklist answers do not accurately assess actual provided care. As actual performance of the antibiotic checklist items is associated with length of stay, efforts to increase actual performance appear to be justified.

Recent advances in the microbiological diagnosis of bloodstream infections

Rapid identification (ID) and antimicrobial susceptibility testing (AST) of the causative agent(s) of bloodstream infections (BSIs) are essential for the prompt administration of an effective antimicrobial therapy, which can result in clinical and financial benefits. Immediately after blood sampling, empirical antimicrobial therapy, chosen on clinical and epidemiological data, is administered. When ID and AST results are available, the clinician decides whether to continue or streamline the antimicrobial therapy, based on the results of the in vitro antimicrobial susceptibility profile of the pathogen. The aim of the present study is to review and discuss the experimental data, advantages, and drawbacks of recently developed technological advances of culture-based and molecular methods for the diagnosis of BSI (including mass spectrometry, magnetic resonance, PCR-based methods, direct inoculation methods, and peptide nucleic acid fluorescence in situ hybridization), the understanding of which could provide new perspectives to improve and fasten the diagnosis and treatment of septic patients. Although blood culture remains the gold standard to diagnose BSIs, newly developed methods can significantly shorten the turnaround time of reliable microbial ID and AST, thus substantially improving the diagnostic yield.

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.

Blood Culture Testing via a Mobile App That Uses a Mobile Phone Camera: A Feasibility Study

Background

To evaluate patients with fever of unknown origin or those with suspected bacteremia, the precision of blood culture tests is critical. An inappropriate step in the test process or error in a parameter could lead to a false-positive result, which could then affect the direction of treatment in critical conditions. Mobile health apps can be used to resolve problems with blood culture tests, and such apps can hence ensure that point-of-care guidelines are followed and processes are monitored for blood culture tests.

Objective

In this pilot project, we aimed to investigate the feasibility of using a mobile blood culture app to manage blood culture test quality. We implemented the app at a university hospital in South Korea to assess the potential for its utilization in a clinical environment by reviewing the usage data among a small group of users and by assessing their feedback and the data related to blood culture sampling.

Methods

We used an iOS-based blood culture app that uses an embedded camera to scan the patient identification and sample number bar codes. A total of 4 medical interns working at 2 medical intensive care units (MICUs) participated in this project, which spanned 3 weeks. App usage and blood culture sampling parameters (including sampler, sampling site, sampling time, and sample volume) were analyzed. The compliance of sampling parameter entry was also measured. In addition, the participants’ opinions regarding patient safety, timeliness, efficiency, and usability were recorded.

Results

In total, 356/644 (55.3%) of all blood culture samples obtained at the MICUs were examined using the app, including 254/356 (71.3%) with blood collection volumes of 5-7 mL and 256/356 (71.9%) with blood collection from the peripheral veins. The sampling volume differed among the participants. Sampling parameters were completely entered in 354/356 cases (99.4%). All the participants agreed that the app ensured good patient safety, disagreed on its timeliness, and did not believe that it was efficient. Although the bar code scanning speed was acceptable, the Wi-Fi environment required improvement. Moreover, the participants requested feedback regarding their sampling quality.

Conclusions

Although this app could be used in the clinical setting, improvements in the app functions, environment network, and internal policy of blood culture testing are needed to ensure hospital-wide use.

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.

Evaluation of the Septifast MGrade Test on Standard Care Wards--A Cohort Study

Background

The immediate need for appropriate antimicrobial therapy in septic patients requires the detection of the causative pathogen in a timely and reliable manner. In this study, the real-time PCR Septifast M^Grade test was evaluated in adult patients meeting the systemic inflammatory response syndrome (SIRS) criteria that were treated at standard care wards.

Methods

Patients with clinical suspected infection, drawn blood cultures (BC), the Septifast M^Grade test (SF) and sepsis biomarkers were prospectively screened for fulfillment of SIRS criteria and evaluated using the criteria of the European Centre of Disease Control (ECDC) for infection point prevalence studies.

Results

In total, 220 patients with SIRS were prospectively enrolled, including 56 patients with detection of bacteria in the blood (incidence: 25.5%). BC analysis resulted in 75.0% sensitivity (95% confidence interval, CI: 61.6%– 85.6%) with 97.6% specificity (CI: 93.9%– 99.3%) for detecting bacteria in the blood. In comparison to BC, SF presented with 80.4% sensitivity (CI: 67.6%– 89.8%) and with 97.6% specificity (CI: 93.9%– 99.3%). BC and SF analysis yielded comparable ROC-AUCs (0.86, 0.89), which did not differ significantly (p = 0.558). A trend of a shorter time-to-positivity of BC analysis was not seen in bacteremic patients with a positive SF test than those with a negative test result. Sepsis biomarkers, including PCT, IL-6 or CRP, did not help to explain discordant test results for BC and SF.

Conclusion

Since negative results do not exclude bacteremia, the Septifast M^Grade test is not suited to replacing BC, but it is a valuable tool with which to complement BC for faster detection of pathogens.

A Multicenter Evaluation of Blood Culture Practices, Contamination Rates, and the Distribution of Causative Bacteria

BACKGROUND

The prognostic value of blood culture testing in the diagnosis of bacteremia is limited by contamination.

OBJECTIVES

In this multicenter study, the aim was to evaluate the contamination rates of blood cultures as well as the parameters that affect the culture results.

MATERIALS AND METHODS

Sample collection practices and culture data obtained from 16 university/research hospitals were retrospectively evaluated. A total of 214,340 blood samples from 43,254 patients admitted to the centers in 2013 were included in this study. The blood culture results were evaluated based on the three phases of laboratory testing: the pre-analytic, the analytic, and the post-analytic phase.

RESULTS

Blood samples were obtained from the patients through either the peripheral venous route (64%) or an intravascular catheter (36%). Povidone-iodine (60%) or alcohol (40%) was applied to disinfect the skin. Of the 16 centers, 62.5% have no dedicated phlebotomy team, 68.7% employed a blood culture system, 86.7% conducted additional studies with pediatric bottles, and 43.7% with anaerobic bottles. One center maintained a blood culture quality control study. The average growth rate in the bottles of blood cultures during the defined period (1259 - 26,400/year) was 32.3%. Of the growing microorganisms, 67% were causative agents, while 33% were contaminants. The contamination rates of the centers ranged from 1% to 17%. The average growth time for the causative bacteria was 21.4 hours, while it was 36.3 hours for the contaminant bacteria. The most commonly isolated pathogens were Escherichia coli (22.45%) and coagulase-negative staphylococci (CoNS) (20.11%). Further, the most frequently identified contaminant bacteria were CoNS (44.04%).

CONCLUSIONS

The high contamination rates were remarkable in this study. We suggest that the hospitals' staff should be better trained in blood sample collection and processing. Sterile glove usage, alcohol usage for disinfection, the presence of a phlebotomy team, and quality control studies may all contribute to decreasing the contamination rates. Health policy makers should therefore provide the necessary financial support to obtain the required materials and equipment.

Multidisciplinary team review of best practices for collection and handling of blood cultures to determine effective interventions for increasing the yield of true-positive bacteremias, reducing contamination, and eliminating false-positive central line-associated bloodstream infections

BACKGROUND

A literature search was conducted using keywords for articles published in English from January 1990 to March 2015. Using criteria related to blood culture collection and handling, the search yielded 101 articles. References used also included Microbiology Laboratory standards, guidelines, and textbook information.

RESULTS

The literature identified diverse and complex issues surrounding blood culture practices, including the impact of false-positive results, laboratory definition of contamination, effect on central line-associated bloodstream infection (CLABSI) reporting, indications for collecting blood cultures, drawing from venipuncture sites versus intravascular catheters, selection of antiseptics, use of needleless connectors, inoculation of blood culture bottles, and optimizing program management in emergency departments, education, and implementation of bundled practice initiatives.

CONCLUSION

Hospitals should optimize best practice in the collection, handling, and management of blood culture specimens, an often overlooked but essential component in providing optimal care of patients in all settings and populations, reducing financial burdens, and increasing the accuracy of reportable CLABSI. Although universal concepts exist in blood culture practices, some issues require further research to determine benefit. Institutions undertaking a review of their blood culture programs are encouraged to use a checklist that addresses elements that encompass the research contained in this review.

Evaluation of the Broad-Range PCR/ESI-MS Technology in Blood Specimens for the Molecular Diagnosis of Bloodstream Infections

BACKGROUND

Rapid identification of the etiological agent in bloodstream infections is of vital importance for the early administration of the most appropriate antibiotic therapy. Molecular methods may offer an advantage to current culture-based microbiological diagnosis. The goal of this study was to evaluate the performance of IRIDICA, a platform based on universal genetic amplification followed by mass spectrometry (PCR/ESI-MS) for the molecular diagnosis of sepsis-related pathogens directly from the patient's blood.

METHODS

A total of 410 whole blood specimens from patients admitted to Emergency Room (ER) and Intensive Care Unit (ICU) with clinical suspicion of sepsis were tested with the IRIDICA BAC BSI Assay (broad identification of bacteria and Candida spp.). Microorganisms grown in culture and detected by IRIDICA were compared considering blood culture as gold standard. When discrepancies were found, clinical records and results from other cultures were taken into consideration (clinical infection criterion).

RESULTS

The overall positive and negative agreement of IRIDICA with blood culture in the analysis by specimen was 74.8% and 78.6%, respectively, rising to 76.9% and 87.2% respectively, when compared with the clinical infection criterion. Interestingly, IRIDICA detected 41 clinically significant microorganisms missed by culture, most of them from patients under antimicrobial treatment. Of special interest were the detections of one Mycoplasma hominis and two Mycobacterium simiae in immunocompromised patients. When ICU patients were analyzed separately, sensitivity, specificity, positive and negative predictive values compared with blood culture were 83.3%, 78.6%, 33.9% and 97.3% respectively, and 90.5%, 87.2%, 64.4% and 97.3% respectively, in comparison with the clinical infection criterion.

CONCLUSIONS

IRIDICA is a promising technology that offers an early and reliable identification of a wide variety of pathogens directly from the patient's blood within 6h, which brings the opportunity to improve management of septic patients, especially for those critically ill admitted to the ICU.

Evaluation of the BD BACTEC FX blood volume monitoring system as a continuous quality improvement measure

The yield of blood cultures is proportional to the volume of blood cultured. We evaluated an automatic blood volume monitoring system, recently developed by Becton Dickinson within its BACTEC EpiCenter module, that calculates mean volumes of negative aerobic bottles and generates boxplots and histograms. First, we evaluated the filling degree of 339 aerobic glass blood cultures by calculating the weight-based volume for each bottle. A substantial amount of the bottles (48.3%) were inadequately filled. Evaluation of the accuracy of the monitoring system showed a mean bias of -1.4 mL (-15.4%). Additional evaluation, using the amended software on 287 aerobic blood culture bottles, resulted in an acceptable mean deviation of -0.3 mL (-3.3%). The new software version was also tested on 200 of the recently introduced plastic bottles, which will replace the glass bottles in the near future, showing a mean deviation of +2.8 mL (+26.7%). In conclusion, the mean calculated volumes can be used for the training of a single phlebotomist. However, filling problems appear to be masked when using them for phlebotomist groups or on wards. Here, visual interpretation of boxplots and histograms can serve as a useful tool to observe the spread of the filling degrees and to develop a continuous improvement program. Re-adjustment of the software has proven to be necessary for use with plastic bottles. Due to our findings, BD has developed further adjustments to the software for validated use with plastic bottles, which will be released soon.

Quality assurance in blood culture: A retrospective study of blood culture contamination rate in a tertiary hospital in Nigeria

BACKGROUND

Blood culture is a critical tool for diagnosing septicaemia. Quite frequently, contamination of blood sample poses a great challenge to accurate diagnosis. This study evaluated the rate of blood culture contamination in our hospital over a one-year period.

MATERIALS AND METHODS

It was a retrospective study of 1032 blood cultures carried out in a clinical laboratory of a tertiary hospital in North Central part of Nigeria between 2010 and 2011.

RESULTS

There were 730 blood cultures from paediatric and 302 adult patients. The overall yield was 22%; 107 out of the 730 were contaminated giving a contamination rate of 10.4%. Contamination rate was higher in children than in adult (11% vs 8%) specimen. These rates were much higher than the acceptable benchmark of 2-3%. The main contaminants were coagulase negative Staphylococcus, Bacillus species, Diphtheroids and Enterococcus species.

CONCLUSION

Contamination rate is high, and mainly due to normal skin flora, suggesting aseptic collection challenges as the main cause. We recommend a review of the entire process of blood collection for culture and analysis with a view to instituting appropriate quality assurance measures to reduce the contamination rate.

Diagnostic utility of broad range bacterial 16S rRNA gene PCR with degradation of human and free bacterial DNA in bloodstream infection is more sensitive than an in-house developed PCR without degradation of human and free bacterial DNA

We compared a commercial broad range 16S rRNA gene PCR assay (SepsiTest) to an in-house developed assay (IHP). We assessed whether CD64 index, a biomarker of bacterial infection, can be used to exclude patients with a low probability of systemic bacterial infection. From January to March 2010, 23 patients with suspected sepsis were enrolled. CD64 index, procalcitonin, and C-reactive protein were measured on admission. Broad range 16S rRNA gene PCR was performed from whole blood (SepsiTest) or blood plasma (IHP) and compared to blood culture results. Blood samples spiked with Staphylococcus aureus were used to assess sensitivity of the molecular assays in vitro. CD64 index was lower in patients where possible sepsis was excluded than in patients with microbiologically confirmed sepsis (P = 0.004). SepsiTest identified more relevant pathogens than blood cultures (P = 0.008); in three patients (13%) results from blood culture and SepsiTest were congruent, whereas in four cases (17.4%) relevant pathogens were detected by SepsiTest only. In vitro spiking experiments suggested equal sensitivity of SepsiTest and IHP. A diagnostic algorithm using CD64 index as a decision maker to perform SepsiTest shows improved detection of pathogens in patients with suspected blood stream infection and may enable earlier targeted antibiotic therapy.

Evaluation of an intervention to improve blood culture practices: a cluster randomised trial

This study aimed to evaluate an intervention to improve blood culture practices. A cluster randomised trial in two parallel groups was performed at the Grenoble University Hospital, France. In October 2009, the results of a practices audit and the guidelines for the optimal use of blood cultures were disseminated to clinical departments. We compared two types of information dissemination: simple presentation or presentation associated with an infectious diseases (ID) specialist intervention. The principal endpoint was blood culture performance measured by the rate of patients having one positive blood culture and the rate of positive blood cultures. The cases of 130 patients in the "ID" group and 119 patients in the "simple presentation" group were audited during the second audit in April 2010. The rate of patients with one positive blood culture increased in both groups (13.62 % vs 9.89 % for the ID group, p = 0.002, 15.90 % vs 13.47 % for the simple presentation group, p = 0.009). The rate of positive blood cultures improved in both groups (6.68 % vs 5.96 % for the ID group, p = 0.003, 6.52 % vs 6.21 % for the simple presentation group, p = 0.017). The blood culture indication was significantly less often specified in the request form in the simple presentation group, while it remained stable in the ID group (p = 0.04). The rate of positive blood cultures and the rate of patients having one positive blood culture improved in both groups. The ID specialist intervention did not have more of an impact on practices than a simple presentation of audit feedback and guidelines.

Quality of blood culture testing - a survey in intensive care units and microbiological laboratories across four European countries

Introduction

Blood culture (BC) testing before initiation of antimicrobial therapy is recommended as a standard of care in international sepsis guidelines and has been shown to reduce intensive care unit (ICU) stay, antibiotic use, and costs in hospitalized patients. Whereas microbiological laboratory practice has been highly standardized, shortfalls in the preanalytic procedures in the ICU (that is indication, time-to-incubation, blood volume and numbers of BC sets) have a significant effect on the diagnostic yield. The objective of this study was to gain insights into current practices regarding BC testing in intensive care units.

Methods

Qualitative survey, data collection by 138 semi-structured telephone interviews in four European countries (Italy, UK, France and Germany) between September and November 2009 in 79 clinical microbiology laboratories (LABs) and 59 ICUs.

Results

Whereas BC testing is expected to remain the gold standard for sepsis diagnostics in all countries, there are substantial differences regarding preanalytic procedures. The decision to launch BC testing is carried out by physicians vs. ICU nurses in the UK in 92 vs. 8%, in France in 75 vs. 25%, in Italy in 88 vs. 12% and in Germany in 92 vs. 8%. Physicians vs. nurses collect BCs in the UK in 77 vs. 23%, in France in 0 vs. 100%, in Italy in 6 vs. 94% and in Germany in 54 vs. 46%. The mean time from blood collection to incubation in the UK is 2 h, in France 3 h, in Italy 4 h, but 20 h in German remote LABs (2 h in in-house LABs), due to the large number of remote nonresident microbiological laboratories in Germany. There were major differences between the perception of the quality of BC testing between ICUs and LABs. Among German ICU respondents, 62% reported that they have no problems with BC testing, 15% reported time constraints, 15% cost pressure, and only 8% too long time to incubation. However, the corresponding LABs of these German ICUs reported too many false positive results due to preanalytical contaminations (49%), insufficient numbers of incoming BC sets (47%), long transportation time (41%) or cost pressure (18%).

Conclusions

There are considerable differences in the quality of BC testing across European countries. In Germany, time to incubation is a considerable problem due to the increasing number of remote LABs. This is a major issue of concern to physicians aiming to implement sepsis guidelines in the ICUs.

Transport time for blood culture bottles: underlying factors and its consequences

In the present study we investigated transport times for blood cultures from three tertiary-care hospitals to Karolinska University Laboratory and identified predictors of long transport times. Concomitantly, consequences of delayed incubation on total detection time (TDT) were analyzed by in vitro sepsis models. A total of 909 blood cultures were studied. The median (interquartile range) transport time was 9 (3-15) h. The hospital accommodating the microbiology laboratory had the shortest transport time compared to the other two hospitals (P < 0.0001). Samples taken between 16:00-24:00 had longer transport times compared to samples taken between 8:00-16:00 and 24:00-08:00 (P < 0.0001). In vitro experiments showed that TDT was longer for samples pre-incubated at room temperature (RT) for 19 h compared to the ones pre-incubated for 2 h or 9.5 h (P < 0.0001). In conclusion, off-site location, time of sampling and number of transports per day were related to, and predictors of transport time.

Education of phlebotomy teams improves blood volume in blood culture bottles

The volume of blood sampled for blood culture determines its sensitivity. We measured low mean blood volumes in submitted aerobic (8.38 ± 3.88 ml) and anaerobic (7.16 ± 3.83 ml) blood culture bottles. Educational seminars were held for phlebotomy teams, and renewed measurements thereafter revealed significantly higher blood volumes in submitted aerobic (9.77 ± 4.42 ml) and anaerobic (8.30 ± 3.64 ml) bottles. Education of phlebotomy teams improves the blood volume in blood culture bottles and should be part of quality control procedures.