The effectiveness of interventions to reduce peripheral blood culture contamination in acute care: a systematic review protocol

A multi-pronged approach to improve blood culture diagnostics in different clinical departments: a single-centre experience

PURPOSE

Blood culture (BC) diagnostics are influenced by many factors. We performed a targeted interdisciplinary analysis to analyse effects of various measures on BC diagnostics performance.

METHODS

A diagnostic stewardship initiative was conducted at two intervention and two control wards in a German tertiary level hospital. The initiative comprised staff training on the correct indications and sampling for BC, implementation of information cards, labels to identify the collection site, regular BC bottle feedback including the number of bottles, filling volumes and identified pathogens; and the use of a specific sampling device (BD Vacutainer®). Before and after the interventions, two three-month measurement periods were performed, as well as a one-month follow-up period to assess the sustainability of the conducted measures.

RESULTS

In total, 9362 BC bottles from 787 patients were included in the analysis. The number of BCs obtained from peripheral venous puncture could be increased at both intervention wards (44.0 vs. 22.2%, 58.3 vs. 34.4%), while arterial sampling could be reduced (30.6 vs. 4.9%). A total of 134 staff members were fully trained. The intervention led to a considerable increase in BC knowledge (from 62.4 to 79.8% correct answers) with differences between the individual professional groups. Relevant reduced contamination rates could be detected at both intervention wards.

CONCLUSIONS

As knowledge on the correct BC sampling and strategies to reduce contamination varies considerably between clinical departments and healthcare professionals, a targeted training should be adapted to the specific needs of the individual professional groups. An additional filling device is not necessary.

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).

Blood culture contamination in a tertiary care hospital: a retrospective three-year study

BACKGROUND

Bloodstream infections (BSI) are a leading cause of morbidity and mortality in hospitalized patients worldwide. A blood culture is the primary tool for determining whether a patient has BSI and requires antimicrobial therapy, but it can result in an inappropriate outcome if the isolated microorganisms are deemed contaminants from the skin. Despite the development of medical equipment and technology, there is still a percentage of blood culture contamination. The aims of this study were to detect the blood culture contamination (BCC) rate in a tertiary care hospital in Palestine and to identify the departments with the highest rates along with the microorganisms isolated from the contaminated blood samples.

METHOD

Blood cultures that were taken at An-Najah National University Hospital between January 2019 and December 2021 were evaluated retrospectively. Positive blood cultures were classified as either true positives or false positives based on laboratory results and clinical pictures. Statistical analysis was performed using the Statistical Package for Social Sciences (SPSS) version 21. A p-value of less than 0.05 was considered statistically significant for all analyses.

RESULTS

Out of 10,930 blood cultures performed in the microbiology laboratory from 2019 to 2021, 1479 (13.6%) were identified as positive blood cultures that showed microbial growth. Of these, 453 were blood culture contaminations, representing 4.17% of total blood cultures and 30.63% of the positive blood culture samples. The highest rate of contamination was in the hemodialysis unit (26.49%), followed by the emergency department (15.89%). Staphylococcus epidermidis was the most prevalent (49.2%), followed by Staphylococcus hominis (20.8%) and Staphylococcus haemolyticus (13.2%). The highest annual contamination rate was observed in 2019 (4.78%) followed by 2020 (3.95%) and the lowest was in 2021 (3.79%). The rate of BCC was decreasing, although it did not reach statistically significant levels (P value = 0.085).

CONCLUSION

The rate of BCC is higher than recommended. The rates of BCC are different in different wards and over time. Continuous monitoring and performance improvement projects are needed to minimize blood culture contamination and unnecessary antibiotic use.

A Quality Improvement Initiative on Reducing Blood Culture Contamination in the Emergency Department

INTRODUCTION

Contaminated blood cultures may have detrimental effects on patients, the organization, and antimicrobial stewardship. Patients in the emergency department may need blood cultures collected before antimicrobial therapy. Contaminated blood culture samples may contribute to prolonged hospital stay and also are associated with delayed or unnecessary antimicrobial therapy. This initiative aims to improve the emergency department's blood culture contamination rate that will eventually benefit the patients who will receive timely and proper antimicrobial therapy, and benefit the organization fiscally.

METHODS

This quality improvement initiative used the Define-Measure-Analyze-Improve-Control (DMAIC) process. The organization targets blood culture contamination rate of ≤2.5%. Control charts were used to study how blood culture contamination rate changed over time. In 2018, a workgroup was formed to work on this initiative. Improved site disinfection using 2% Chlorhexidine gluconate cloth before the standard procedure of blood culture sample collection was initiated. Chi squared test of significance was used to compare blood culture contamination rates 6 months before and during feedback intervention as well as contamination rate from source of blood draw.

RESULTS

Blood culture contamination rates 6 months before and during feedback intervention showed significant decrease (3.52% before intervention and 2.95% after intervention; P < .05). Contamination rates differed significantly based on the source of blood culture draw (7.64% via line, 3.05% via percutaneous venipuncture, and 4.53% via other; P < .01).

DISCUSSION

Blood culture contamination rate continued to decrease with the use of a predisinfection process with 2% Chlorhexidine gluconate cloth before blood sample collection process. Practice improvement also was evident with effective feedback mechanism.

Implementation of Antibiotic Stewardship Improves the Quality of Blood Culture Diagnostics at an Intensive Care Unit of a University Hospital

Background: Bloodstream infections increase morbidity and mortality in hospitalized patients and pose a significant burden for health care systems worldwide. Optimal blood culture diagnostics are essential for early detection and specific treatment. After assessing the quality parameters at a surgical intensive care unit for six months, we implemented a diagnostic stewardship bundle (DSB) to optimize blood culture diagnostics and then reevaluated its effects after six months. Material and Methods: All patients ≥18 years old and on the ward were included: pre-DSB 137 and post-DSB 158. The standard quality parameters were defined as the number of blood culture sets per diagnostic episode (≥2), the rate of contamination (2–3%), the rate of positivity (5–15%), the collection site (≥1 venipuncture per episode) and the filling volume of the bottles (8–10 mL, only post-DSB). The DSB included an informational video, a standard operating procedure, and ready-to-use paper crates with three culture sets. Results: From pre- to post-interventional, the number of ≥2 culture sets per episode increased from 63.9% (257/402) to 81.3% (230/283), and venipunctures increased from 42.5% (171/402) to 77.4% (219/283). The positivity rate decreased from 15.1% (108/714) to 12.8% (83/650), as did the contamination rate (3.8% to 3.6%). The majority of the aerobic bottles were filled within the target range (255/471, 54.1%), but in 96.6%, the anaerobic bottles were overfilled (451/467). Conclusions: The implementation of DSB improved the quality parameters at the unit, thus optimizing the blood culture diagnostics. Further measures seem necessary to decrease the contamination rate and optimize bottle filling significantly.

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.

Prevalence and predictors of bacteremia in dairy calves with diarrhea

Gastrointestinal disease is the most common cause of mortality in dairy calves. Septicemia is an important sequela of diarrhea, and the possibility of bacteremia is the primary justification for empirical antimicrobial therapy. Prior reports estimate that approximately one-third of diarrheic calves are bacteremic; however, those estimates may not be representative of routine cases in heifer calves on commercial dairy operations early in the course of disease. We hypothesized that the prevalence of bacteremia in calves with diarrhea and systemic signs of illness is less than prior estimates (~31%), and that clinical signs or hematological values would be associated with the presence or absence of bacteremia. Female calves less than 21 d of age with and without diarrhea were enrolled from 2 commercial dairy farms over a 10-wk period. Diarrheic calves were enrolled if they were newly diagnosed, had loose to watery stool, had either dehydration (assessed by skin tent and eye position) or depression (assessed by suckle reflex and standing ability), and had no prior antimicrobial treatments. Complete health assessments were conducted at 0, 7, and 14 d following enrollment. An aseptic jugular venous sample was collected and cultured using aerobic and anaerobic methods, and bacterial species were identified using mass spectrometry. Poisson regression models were used to identify associations with bacteremia and compute adjusted prevalence ratios. The prevalence of bacteremia in diarrheic and healthy calves was 9.26% (10/108, 95% confidence interval: 4.5-16%) and 14.8% (4/27, 95% confidence interval: 1.4-28.2%), respectively. Among calves with diarrhea, those with a fever (>39.7°C) or depression were 4.8 and 6.5 times more likely, respectively, to have bacteremia. Only 1 of 47 calves (2%) without signs of depression was bacteremic. The prevalence of bacteremia in diarrheic calves with signs of systemic illness (depression or dehydration) was significantly lower than previous estimates, and bacteremia was rare among calves without observed depression. Antimicrobial therapy targeting bacteremia is not currently justified in routine cases of diarrhea in preweaning calves without signs of depression. These results suggest a substantial opportunity for more targeted antimicrobial therapy to improve antimicrobial stewardship.

Blood culture contamination rates at different level healthcare institutions in the Western Cape, South Africa

Sterile blood culture (BC) collection procedures are important to prevent the consequences of contamination, namely, prolonged patient hospitalisation, unnecessary antimicrobial exposure and an increase in hospital costs. Blood culture contamination rates were determined at different hospitals in the Cape Metropole over a 3-year period. Study findings showed that contaminated BCs have a financial impact on the healthcare system and contamination rates remain above accepted international standards, except in the presence of a phlebotomist team. High BC contamination rates might be reduced by the implementation of cost-effective educational intervention programmes, which reminds healthcare workers to collect BC samples aseptically.

Timing of Blood Cultures in the Setting of Febrile Neutropenia: An Australian Institutional Experience

Objective

Febrile neutropenia (FN) is a hematological emergency requiring urgent investigations to exclude infection and treatment with broad-spectrum antibiotics. Despite frequent blood cultures (BCs) being taking during episodes of FN, in the current literature BC positivity rates remain low in FN. This study aims to determine the BC positivity rate in FN hematology patients and determine the utility of collecting BCs beyond 24 h of commencing broad-spectrum antibiotics.

Materials and Methods

BC results between 2014 and 2016 from all FN hematology patients were analyzed. Patient episodes of FN (PEFNs) were defined as a continuous period of FN where the interval between BC samples was a maximum of two days. In total from 2014 to 2016, 379 patients experienced 914 PEFNs and had 4267 BCs collected.

Results

Overall BC positivity rates and BC-positive PEFN rates were 8.16% and 13.35%, respectively. Within the first 24 h, the positivity rate of the first BCs was 3.49%, while subsequent BC positivity within the first 24 h was 11.96%. BC positivity rates declined after 24 h to 2.18%.

Conclusion

It is likely that BCs beyond 24 h of commencing broad-spectrum antibiotics will rarely identify relevant microorganisms. Not collecting BCs after 24 h would likely reduce laboratory test costs, patient discomfort, and iatrogenic anemia.

Rapid and sensitive identification of pleural and peritoneal infections by droplet digital PCR

Pleural and peritoneal infections cause substantial morbidity and mortality. Traditional diagnostic methods rely on the cultivation of clinical samples, which usually takes days to obtain report and holds a low detection sensitivity. In this study, we evaluated a 5-fluorescent-channel droplet digital PCR (ddPCR) system and 5 assay panels for culture-independent rapid pathogen detections directly from pleural and peritoneal fluid samples. Traditional culture of the same sample was used as reference. A total of 40 pleural fluid samples and 19 peritoneal fluid samples were tested in this study. Twenty-five positives including 4 polymicrobial infections by culture and 26 positives including 11 polymicrobial infections by ddPCR were detected for pleural fluid samples; 14 positives including 2 polymicrobial infections by culture and 15 positives including 3 polymicrobial infections by ddPCR were detected for peritoneal fluid samples. Klebsiella pneumoniae was the most common bacterium detected both in pleural and in peritoneal fluid samples. The sensitivity of the ddPCR assay for pleural and peritoneal fluid samples was 96% (95% confidence interval (CI) = 79.65 to 99.90%) and 92.86% (95% CI = 66.13 to 99.82%), respectively. The turnaround time of the ddPCR assay was approximately 3 h comparing with 38.30 ± 22.44 h for culture-based identifications. Our results demonstrated that the ddPCR assay is a rapid and sensitive method for identifying pathogens responsible for pleural and peritoneal infections and would be a promising approach for early diagnosis and optimizing treatment of infections.

Analysis of the frequency of bacteraemia of dental origin implicated in infective endocarditis in patients requiring valve surgery

Understanding the frequency of bacteraemia of dental origin that is implicated in severe infective endocarditis (IE) will further our understanding of the disease's pathoaetiology and help us take steps to reduce its prevalence. A total of 78 patients from the Royal Papworth Hospital, Cambridge, who had valve surgery due to IE (as confirmed by the Modified Duke Criteria) were included. Case notes were retrospectively reviewed for microorganisms that were implicated in the bacteraemia and IE. Associated factors were also recorded to determine whether they were different if a dental or non-dental pathogen was inoculated. A dental pathogen was implicated in 24 of the patients with IE; 20 had non-dental pathogens, and 30 were culture negative. This was not deemed statistically significant (p=0.54). Of the associated factors, only smoking was statistically significant with a greater proportion of non-smokers having bacteraemia of dental origin (p=0.03). No other associated factor was appreciably different based on the aetiology of the microorganism. Our results indicate that dental pathogens are not more likely to cause severe IE. We therefore advocate the stance adopted by the current national guidance on the judicious prescription of antibiotic prophylaxis for IE with regard to dental procedures.

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.