Use Of Blood Cultures Research Articles

Risk factors for positive follow-up blood cultures in critically ill adults with Gram-negative bacteraemia.

To evaluate the utility of follow-up blood cultures (FUBCs) for Gram-negative bloodstream infection (BSI) in ICU patients and identify risk factors for repeat positive cultures. This was a single-centre, retrospective cohort study of critically ill adults with Gram-negative BSI between 1 January 2015 and 1 January 2020. Critically ill patients with one or more blood cultures positive for a Gram-negative organism were included. Descriptive and inferential statistics were performed with an alpha of 0.05. A total of 148 critically ill patients with Gram-negative BSI were included, with 42 patients (28.4%) having one or more positive FUBCs. The majority (66.2%) were admitted to a medical ICU. The most common organisms isolated were Escherichia coli (n = 56, 37.8%) and Klebsiella pneumoniae (n = 26, 17.6%). Significant patient risk factors associated with a positive FUBC on univariate regression included: MDR organisms, immunocompromised status, fever, vasopressor use at time of FUBC, lack of source control attainment, and higher quick Pitt bacteraemia score. Multivariable penalized logistic regression indicated that lack of source control containment and less time from index to FUBC remained significantly associated with repeat positive FUBC. This is the first study to investigate the use of FUBC for Gram-negative BSI in exclusively ICU patients. Risk factors for repeat positive FUBC in this population include lack of source control and less time between index and FUBC. Prospective studies are needed to fully elucidate the role of FUBCs in critically ill patients with Gram-negative BSI.

2024 Clinical Practice Guideline Update by the Infectious Diseases Society of America on Complicated Intra-abdominal Infections: Utility of Blood Cultures in Adults, Children, and Pregnant People.

This article is part of a clinical practice guideline update on the risk assessment, diagnostic imaging, and microbiological evaluation of complicated intra-abdominal infections in adults, children, and pregnant people, developed by the Infectious Diseases Society of America. In this guideline, the panel provides recommendations for obtaining blood cultures in patients with known or suspected intra-abdominal infection. The panel's recommendations are based on evidence derived from systematic literature reviews and adhere to a standardized methodology for rating the certainty of evidence and strength of recommendation according to the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach.

Reduced Blood Culture Use in High-Volume Lung Transplant MICU Following a Stewardship Program, Northern California, 2021–2023

Introduction: There is a need to optimize blood culture (BC) utilization among hospitalized adults. A previous study showed an evidence-based BC algorithm improved BC utilization in a medical intensive care unit (MICU) at a large academic center. Our aim is to evaluate the impact of an intervention based on this algorithm on blood culture utilization in the MICU at Stanford Health Care, a referral center known for its high volume of solid organ transplants. Methods: We conducted a before-after study evaluating the impact of a BC diagnostic stewardship program in the MICU at Stanford Health Care, a 20-bed unit with an average of 20% lung transplant patients per day. All patients ≥18 years of age admitted to the unit during the study period were included. We adopted a previously published evidence-based algorithm detailing syndromes with low and high risk for bacteremia, which was referenced during patient rounds. Additionally, education and feedback to providers about BC utilization and indication inappropriateness was performed during leadership meetings every other month. We performed an interrupted time series analysis using historical data 17 months before the implementation of the blood culture stewardship program on April 1, 2022 and 8 months after. We assessed changes on BC utilization adjusted to patient days and crude mortality rate during the same period as a balancing measure. Results: Before the implementation of the program, the median BC utilization was 216 per 1,000 patient days (range 150–250 per 1,000 patient days). Following the introduction of the program, there was a significant decrease in blood culture utilization by 5% (95% CI -10% to -1%, p=.02; Figure 1). Post-intervention, the blood culture stabilized, with no significant increase observed (0.09% increase, 95% CI -0.7% to 1%, p=.81). The mortality rate, prior to the implementation of the program, had shown a significant downward trend of 1.4% over time (95% CI -3% to -0.2%, p=.02). After the intervention, a nonsignificant decrease of 8% was observed (95% CI -44% to 27%, p=.62; Figure 2), followed by a nonsignificant upward trend of 6% (95% CI -1% to 13%, p=.10). Conclusion: We observed a significant reduction in BC utilization after implementing the BC diagnostic stewardship program in a MICU frequented by a high number of lung transplant patients.

Clinical Utility of Follow-Up Blood Cultures Among Adult Cancer Patients with Gram-Negative Bacilli Bacteremia

Background: Gram-negative bacilli (GNB) bacteremia is a common and potentially fatal infection with mortality rates estimated to be 14-34%, despite effective antimicrobial treatments. Follow-up blood cultures (FUBCs) are blood cultures that are repeated after an initial positive culture and are indicated in certain clinical scenarios, such as in candidemia or Staphylococcus aureus bacteremia to ensure clearance of the bloodstream infection. FUBCs are used in bacteremia to assess the appropriateness and duration of antimicrobial therapy. Currently, there are no guidelines in place regarding the use of FUBC for GNB bacteremia. Furthermore, the utility of FUBCs is not well-studied in adults living with cancer. The purpose of this study is to identify risk factors associated with persistent GNB bacteremia in adult patients with cancer. Methods: We conducted a single-center, retrospective study in patients aged ≥18 years, hospitalized during calendar year 2022, living with cancer, and with laboratory confirmed GNB bloodstream infection. FUBC was defined as a blood culture performed within 7 days of the initial positive blood culture. Patients were grouped as having the same organism on FUBC (+/same), FUBC with no growth (NG) (+/NG), and different organism on FUBC (+/Different). Patients with a different organism on FUBC were excluded from analysis. We gathered demographic information, suspected source of bacteremia, type of malignancy, identified organisms, presence of antimicrobial resistance, and comorbidities (eg. presence of central venous catheters, urinary catheters, end-stage renal disease). Categorical variables were compared using Chi-square or Fisher’s exact test. Continuous variables were compared using Wilcoxon rank sum tests. Logistic regression analysis was used to identify the independent predictors of persistent GNB bacteremia. Results: 356 unique patients with FUBC were identified after inclusion/exclusion criteria. 93/356 (26%) of patients had persistent GNB bacteremia (+/same). Multivariate analysis identified history of bacteremia within the preceding year (OR 2.95, 95% CI [1.6-5.6]) and Achromobacter spp. bacteremia (OR 10.03, 95% CI [1.59-63.23] as independent risk factors for persistence. Organisms with multidrug resistance such as extended-spectrum beta-lactamase (OR 2.47, 95% CI [1.21-5.07]) and carbapenem-resistant organisms (OR 3.35, 95% CI [1.04-10.81]) were also associated with persistent GNB bacteremia. Conclusions: This is the first study to specifically identify risk factors for persistent GNB bacteremia in patients living with cancer. FUBC may be useful in GNB bacteremia with less common organisms and/or if they exhibit multidrug resistance on susceptibility testing. The utility of FUBC should be further explored in patients with cancer with certain risk factors.

Follow-up blood cultures do not reduce mortality in hospitalized patients with Gram-negative bloodstream infection: a retrospective population-wide cohort study

ObjectivesThe utility of follow-up blood cultures (FUBCs) in patients with Gram-negative bloodstream infection (GN-BSI) is controversial. Observational studies have suggested significant mortality benefit but may be limited by single-centre designs, immortal time bias, and residual confounding. We examined the impact of FUBCs on mortality in patients with GN-BSI in a retrospective population-wide cohort study in Ontario, Canada. MethodsAdult patients with GN-BSI hospitalized between April 2017 and December 2021 were included. Primary outcome was all-cause mortality within 30 days. FUBC was treated as a time-varying exposure. Secondary outcomes were 90-day mortality, length of stay, and number of days alive and out of hospital at 30 and 90 days. ResultsThirty-four thousand one hundred patients were included; 8807 (25.8%) patients received FUBC, of which 966 (11.0%) were positive. Median proportion of patients receiving FUBC was 18.8% (interquartile range, 10.0–29.7%; range, 0–66.1%) across 101 hospitals; this correlated with positivity and contamination rate. Eight hundred ninety (10.1%) patients in the FUBC group and 2263 (8.9%) patients in the no FUBC group died within 30 days. In the fully adjusted model, there was no association between FUBC and mortality (hazard ratio, 0.97; 95% CI, 0.90–1.04). Patients with FUBC had significantly longer length of stay (median, 11 vs. 7 days; adjusted risk ratio, 1.18; 95% CI, 1.16–1.21) and fewer number of days alive and out of hospital at 30 and 90 days. DiscussionFUBC collection in patients with GN-BSI varies widely across hospitals and may be associated with prolonged hospitalization without clear survival benefit. Residual confounding may be present given the observational design. Clear benefit should be demonstrated in a randomized trial before widespread adoption of routine FUBC.

The impact of a blood-culture diagnostic stewardship intervention on utilization rates and antimicrobial stewardship.

Blood-culture overutilization is associated with increased cost and excessive antimicrobial use. We implemented an intervention in the adult intensive care unit (ICU), combining education based on the DISTRIBUTE algorithm and restriction to infectious diseases and ICU providers. Our intervention led to reduced blood-culture utilization without affecting safety metrics.

Implementation of a diagnostic stewardship intervention to improve blood-culture utilization in 2 surgical ICUs: Time for a blood-culture change.

We compared the number of blood-culture events before and after the introduction of a blood-culture algorithm and provider feedback. Secondary objectives were the comparison of blood-culture positivity and negative safety signals before and after the intervention. Prospective cohort design. Two surgical intensive care units (ICUs): general and trauma surgery and cardiothoracic surgery. Patients aged ≥18 years and admitted to the ICU at the time of the blood-culture event. We used an interrupted time series to compare rates of blood-culture events (ie, blood-culture events per 1,000 patient days) before and after the algorithm implementation with weekly provider feedback. The blood-culture event rate decreased from 100 to 55 blood-culture events per 1,000 patient days in the general surgery and trauma ICU (72% reduction; incidence rate ratio [IRR], 0.38; 95% confidence interval [CI], 0.32-0.46; P < .01) and from 102 to 77 blood-culture events per 1,000 patient days in the cardiothoracic surgery ICU (55% reduction; IRR, 0.45; 95% CI, 0.39-0.52; P < .01). We did not observe any differences in average monthly antibiotic days of therapy, mortality, or readmissions between the pre- and postintervention periods. We implemented a blood-culture algorithm with data feedback in 2 surgical ICUs, and we observed significant decreases in the rates of blood-culture events without an increase in negative safety signals, including ICU length of stay, mortality, antibiotic use, or readmissions.

Utility of Routine Blood Cultures for Upper Extremity Abscesses.

Patients with skin and soft tissue infections (SSTIs) are often admitted by the emergency department for intravenous antibiotic therapy and surgical drainage of abscesses if necessary. As part of the initial diagnostic workup, blood cultures are routinely drawn at our institution in patients with SSTIs. This study seeks to identify the utility of performing blood cultures in patients with upper extremity abscesses as it relates to the number of incision and drainage (I&D) procedures performed, patient readmission rates, and length of hospital stay. A retrospective chart review of 314 patients aged 18 to 89 years who underwent 1 or more I&D procedures of upper extremity abscesses were included in the study. Patient demographic data, comorbidities, laboratory values, wound and blood culture results, number of I&D procedures performed, length of stay, and readmission rates were evaluated. Increasing age and white blood count were associated with an increased number of I&Ds performed. Obtaining blood cultures, whether positive or negative, was associated with increased length of stay. There was no association between obtaining blood cultures and number of procedures performed on multivariable analysis. Positive blood cultures were associated with increased readmission rates. Routinely obtaining blood cultures in patients with upper extremity abscesses may not be beneficial. Obtaining blood cultures is not associated with an increased number of I&D procedures or readmission rates. Furthermore, obtaining blood cultures, regardless of positivity, is associated with increased lengths of hospital stay.

Utilization of Platelet-Rich Plasma (PRP) in the Performance of Blood Cultures

Sepsis is a leading cause of death and morbidity. A precise microbiologic diagnosis in these patients reduces mortality, morbidity, hospital length of stay and costs. Current blood culture technology is woefully inadequate in the detection of circulating bacteria, with detection rates in the range of only 32 to 71%. Platelets play a key role in innate immunity. Platelets interact directly with innate immune cells, exert important immunomodulatory effects, and promote leucocyte migration to sites of infection. During active bacterial infection, platelets release platelet factor -4 which binds onto a variety of bacterial surfaces, thus rendering bacteria more susceptible to opsonization by leucocytes. Platelet surface Toll-like receptors play a key role in regulating bacterial phagocytosis by leucocytes. FcgammaRllA mediates immune complex mediated platelet activation for killing of opsonized bacteria. Platelets also have been observed to “corral” circulating bacteria by forming hollow spheres around them. For these reasons, we performed a prospective pilot study involving 100 patients with suspected sepsis testing the hypothesis that BC performed with PRP is superior to traditional BC performed with whole blood in detecting circulating bacteria. PRP was prepared via centrifugation of blood contained in 3 cc CBC tubes containing EDTA obtained upon admission. PRP and whole blood were injected into separate and identical culture media bottles and cultures were incubated identically in our state-of-the art microbiology laboratory. PRP culture technique detected two patients with circulating bacteria in whom traditional blood cultures were negative: Enterobacter faecalis in an elderly woman with bilateral pneumonia and Burkolderia capecia in an immunocompromised elderly man with pneumonia. In two patients with urosepsis culture results were concordant with identification of E. coli in both techniques. In eight patients, traditional BC technique detected circulating bacteria, wherein PRP-generated cultures were negative: three with Klebsiella pneumoniae, two with Enterococcus faecalis, two with E. Coli, and one with anaerobic Bacteroides Theta-iota group. Three positive cultures generated by traditional methodology were deemed contaminants by I.D. consultation. No contaminants or false positives were detected by the PRP-generated technique. Thus, in this pilot study, evaluating the utility of blood cultures prepared from platelet-rich-plasma, two patients were detected to harbor pathogenic circulating bacteria which was undetected by standard state-of-the-art blood culture techniques. Two distinct disadvantages of BC prepared from PRP relative to traditional BC technique in this study were the time delay in preparing PRP from the patient's CBC tube: these had been stored in the lab for typically 4 to 48 hours before centrifugation and subsequent inoculation, and the dramatic difference in volume represented by PRP vs. traditional BC: typically .5 to 1.1 cc vs. 32 to 40 cc, respectively. An additional disadvantage was the presence of EDTA in CBC tubes, which is confirmed to exert antibacterial properties. The results of this pilot study are intriguing. Further studies comparing PRP-generated BC and traditional BC in the detection of circulating bacteria with emerging identification techniques such as metrogenomic analysis in detecting bacterial DNA, RNA or peptide signatures would be interesting.

Risk factors for positive follow-up blood cultures in Gram-negative bacteremia among immunocompromised patients with neutropenia.

Gram-negative bacillary bloodstream infection (GN-BSI) is a frequent clinical challenge among immunocompromised hosts and is associated with a high mortality. The utility of follow-up blood cultures (FUBCs) for GN-BSI in this population, particularly in the setting of neutropenia, is poorly defined. We conducted a single-center, retrospective cohort study between the period of July 2018 and April 2022 to investigate the utility of FUBCs and delineate risk factors for positive cultures among neutropenic patients with monomicrobial GN-BSI. Univariate logistic regression was performed to assess risk factors associated with positive FUBCs. Of 206 patients, 98% had FUBCs performed, and 9% were positive. Risk factors for positive FUBCs included multidrug-resistant GN infection (OR 3.26; 95% confidence interval [CI] 1.22-8.72) and vascular catheter source (OR 4.82; CI 1.76-13.17). Among patients lacking these risk factors, the prevalence of positive FUBCs was low (2.8%) and the negative predictive value was 92%. Those with positive and negative FUBCs had similar rates of all-cause mortality (16.7% vs. 16.6%; p=.942) and microbiologic relapse (11.1% vs. 6.0%; p=.401) within 90-days of treatment completion. However, positive FUBCs were associated with prolonged hospitalization and longer duration of antimicrobial therapy. Positive FUBCs were infrequent in neutropenic patients with GN-BSI, and their occurrence did not significantly impact mortality or microbiologic relapse. Risk factors for positive FUBCs included multidrug resistant Gram-negative infection and vascular catheter source. Prospective studies will be necessary to elucidate the benefits and risks of FUBCs when managing GN-BSI in patients with underlying immune compromise.

606. Clinical Utility of Fungal Blood Cultures for the Diagnosis of Candidemia

Abstract Background Candidemia is the most common invasive fungal infection in hospitalized children, and the third most common cause of pediatric nosocomial bloodstream infections. The gold standard for diagnosis of Candida bloodstream infections is with blood cultures, and clinicians can order aerobic or fungal blood cultures when suspecting fungemia. The objective of this study is to investigate the additional utility of fungal blood cultures (in addition to aerobic blood cultures) for detecting Candida bloodstream infections. Methods This retrospective cohort study analyzed all patients &amp;lt; 21 years of age, admitted to Children’s National Hospital between January 1, 2010, and December 31, 2020, and had a positive fungal blood culture (using BHI-CG plates) for Candida species on day 1 of fungemia (Table 1). Demographic data, Candida species, the concomitant positive aerobic blood cultures (using the bioMérieux BACT/ALERT blood culture system) were collected from the electronic health records through structured chart review. The time to detection of positive blood cultures was calculated for the fungal and aerobic cultures drawn on day 1 of fungemia. P-value &amp;lt; 0.05 was considered statistically significant.Table 1:Definitions Results Thirty-one episodes of Candida fungemia (29 patients) were included in this study, of which 28 episodes also had an aerobic blood culture drawn on day 1 of fungemia that was positive for Candida species. All 31 episodes had an aerobic blood culture positive for Candida species within the duration of fungemia (Figure 1). The mean age of patients in the cohort was 5.7 ± 6.0 years with mean duration of admission of 67.1 days ± 79.6. C. parapsilosis was the most frequently identified Candida species (14), followed by C. albicans (10), C. lusitaniae (Clavispora lusitaniae) (2), C. tropicalis (1), C. krusei (Pichia kudriavzevii) (1) (Table 2). The mean time to positivity for aerobic blood cultures and fungal blood cultures were 26.4 ± 11.7 hours and 76.2 ± 29.6 hours, respectively (p &amp;lt; 0.001).Figure 1:Patient Population and Analysis FlowchartTable 2:Episodes of Candida by Species Conclusion All episodes of Candida species that grew on fungal cultures also had at least one aerobic culture positive for Candida species within the duration of fungemia. Aerobic blood cultures had a statistically significant shorter time to positivity for Candida than fungal blood cultures. Disclosures Benjamin Hanisch, MD, American Society of Transplantation: Board Member|Astellas Pharma Global Development, Inc.: Support for the present publication|NIH: Site PI for International Pediatric Fungal Network- funds to institution Joseph M. Campos, PHD, Accelerate Diagnostics: Honoraria|GenMark Diagnosticd: Honoraria

Epidemiology and clinical significance of persistent bacteremia in severely burned patients

BackgroundThe utility of follow-up blood cultures (FUBC) for gram-negative bloodstream infections (BSIs) are controversial due to low rates of positivity. However, recent studies suggest higher rates of positivity in critically ill patients. The utility of FUBC in gram-negative BSI in patients with severe burn injuries is unknown. MethodsPatients ≥ 18 years old admitted to the US Army Institute of Surgical Research Burn Center for combat-related thermal burns from 1/2003–6/2014 with a monomicrobial BSI were included. FUBC were defined as repeat cultures 1–5 days from index BSI. Persistent BSI (pBSI) was defined as isolation of the same organism from initial and FUBC. The primary endpoint was all-cause in-hospital mortality in patients with gram-negative pBSI. ResultsOf 126 patients meeting inclusion criteria with BSI, 53 (42%) had pBSI. Compared to patients without persistence, patients with pBSI had more severe burns with median total body surface area (TBSA) burns of 47% ([IQR 34–63] vs. 35.3% [IQR 23.3–56.6], p = 0.02), increased mortality (38 vs. 11%, p = 0.001) compared to those with non-persistent BSI. On multivariate analysis, pBSI was associated with an odds ratio for mortality of 5.3 [95% CI 1.8–15.8, p = 0.003). Amongst gram-negative pathogens, persistence rates were high and associated with increased mortality (41% vs. 11%, p = 0.001) compared to patients without pBSI. ConclusionIn this cohort of military patients with combat-related severe burns, pBSI was more common than in other hospitalized populations and associated with increased mortality. Given this high frequency of persistence in patients with burn injuries and associated mortality, FUBC are an important diagnostic and prognostic study in this population.

Utility of Previous Culture Results for Guiding Empirical Treatment of Sepsis in The Emergency Department

Background: Sepsis is a serious medical condition and a major cause of morbidity and mortality, and poses challenges in terms of recognition and management. Although studies have investigated the early identification of sepsis and early use of broad-spectrum antibiotics, no clear criteria exist to identify those patients needing additional coverage for resistant organisms. Aims: This study aims to evaluate the utility of previous positive blood or urine culture results in predicting the presence of resistant organisms in septic patients in the emergency department (ED). Methods: This retrospective observational study was conducted at King Fahad Medical City (KFMC), a tertiary care centre in Riyadh, Saudi Arabia, between March and August 2021. Patients aged 18 years or older, who visited the ED at KFMC during the study period, were included if they had a positive blood or urine culture and met the sepsis definition. Result: A total of 133 patients were enrolled (mean age 61.6 [18.3] years), of whom approximately half were male (67, 50.4%). We found that previous colonisation with resistant organisms was more likely in patients with resistant organisms at the time of the enrolled visit (n = 17, 77.3%) than in patients with non-resistant organisms (n = 22, 19.8%, p &lt; .05). Therefore, one statically significant predictor of a current resistant organism is a prior colonisation with a resistant organism (OR = 13.8; 95% CIs 3.6, 51.9; p &lt; .05). Conclusion: Previous cultures, from within the last 12 months, are useful predictors of current resistant organisms, and are therefore essential in guiding empirical antibiotic treatment in septic patients in the ED. Further more extensive and prospective cohort studies on this subject are now needed to mitigate the burden of sepsis on healthcare systems worldwide.

Positive Rate and Utility of Blood Culture among Nursing and Healthcare-associated Pneumonia Inpatients: A Cross-sectional Study.

Objective Although blood cultures to identify the presence of bacteremia are recommended for nursing- and healthcare-associated pneumonia (NHCAP), the incidence of true bacteremia and the relationship between true bacteremia and the outcome remain unclear. Physicians can therefore sometimes be confused regarding whether or not blood cultures should be obtained for NHCAP patients. This study assessed the incidence of true bacteremia and the relationship between true bacteremia and the outcome of NHCAP in a Japanese hospital setting. Methods We retrospectively analyzed NHCAP patients hospitalized between April 2016 and March 2021. The primary outcome was the incidence of true bacteremia in blood cultures. The incidence of true bacteremia was also examined according to quick Sequential Organ Failure Assessment (qSOFA) and A-DROP scores. In addition, we compared the incidence of true bacteremia between survivors and non-survivors. Results In total, 205 patients were included in this study. Blood cultures were obtained from 150 of the 205 patients (73.2%). Positive blood cultures were detected in 26 patients (17.3%), of which only 8 cases (5.3%; 95% confidence interval, 2.3-10.2%) were considered true bacteremia. Trend analyses for the incidence of true bacteremia according to qSOFA and A-DROP scores did not show any statistically significant results (p=0.49 for qSOFA; p=0.14 for A-DROP). The proportion of true bacteremia cases did not differ significantly between survivors and non-survivors. Conclusions The incidence of true bacteremia among NHCAP patients was very low. A strategy for determining indications for obtaining blood cultures from NHCAP patients needs to be established.

The effect of follow-up blood cultures on mortality and antibiotic use in gram-negative bloodstream infections

BackgroundGram-negative bloodstream infections (GN-BSIs) are a significant clinical challenge. The utility of follow-up blood cultures (FUBCs) in GN-BSIs and their impact on mortality and antibiotic consumption are areas of debate. This study aimed to evaluate the effect of FUBCs on mortality and antibiotic consumption in patients with GN-BSIs.MethodsThis single-center, retrospective study was conducted in aged > 18 years of patients with GN-BSIs. FUBC was defined as a blood culture performed 2–7 days after the first blood culture. Patients were grouped as FUBC and no FUBC and compared. A 1:1 match analysis was performed between the groups according to the SOFA score. The matched subgroup was compared for mortality risk factors with logistic regression models. The two groups were compared for the duration of effective antibiotic therapy and total antibiotic consumption (days of therapy per 1000 patient days (DOT/1000 PD)).ResultsFUBC was performed in 564 (69.4%) of 812 patients. Persistent, positive and negative FUBC rates were 7.9%, 14%, and 78%, respectively. The frequency of persistent GN-BSI in patients with appropriate antibiotic therapy was 3.9%. SOFA score (OR:1.33; 95% CI, 1.23–1.44), Charlson comorbidity index score (OR:1.18; 95% CI, 1.08–1.28), hospital-acquired infections (OR:1.93; 95% CI, 1.08–3.46) and carbapenem-resistant GN-BSI (OR: 2.92; 95% CI, 1.72–4.96) were independent risk factors for mortality. No relationship was found between FUBC and mortality (p > 0.05). Duration of effective antibiotic therapy (10(4–16) vs. 15(9–20), p < 0.001) and DOT/1000 PD (1609 (1000–2178) vs. 2000 (1294–2769), p < 0.001) were longer in the FUBC group.ConclusionRoutine FUBC should not be recommended because of the low prevalence of persistent infections in patients under appropriate antibiotic therapy and FUBC increases antibiotic consumption.

The impact of a blood-culture diagnostic stewardship intervention on utilization rates and antimicrobial stewardship

Background: Blood cultures are often ordered when an infection is suspected; however, they have a low yield in most cases. The overuse of blood culture is associated with high contamination rates, resulting in excess diagnostics, unnecessary antibiotics, longer hospital stays, and higher hospital costs. We evaluated the safety of a multifaceted intervention, which encompassed education and blood-culture restriction, and its impact on blood-culture utilization and antibiotic use in adult intensive care unit (ICU) patients. Methods: The study was performed between October 2020 and October 2021 in the 12 general medicine and specialty ICUs of a quaternary academic care center. The intervention, implemented in April 2021, included providing education to ICU and infectious disease physicians based on an algorithm adapted from the Johns Hopkins DISTRIBUTE study in addition to restricting blood-culture ordering on these units to these providers. The month of April 2021 was excluded as a washout period. Study outcomes comprised blood-culture utilization, blood-culture positivity, days of therapy (DOT), and length of therapy (LOT), which were compared across the study periods using IRR or the Pearson χ2 test, as appropriate. In addition, 30-day mortality and 30-day ICU readmission were evaluated utilizing multiple COX regression models. Results: In total, 6,303 patients (2,087 MICU, 3,636 SICU, and 580 both) were included in the study, with a median age of 65 years (IQR, 21). Most participants were male (57.5%), with a median length of stay of 175 hours (IQR, 186). After the intervention, blood-culture utilization rates decreased from 15.4% to 12.4% (IRR 0.80, 95% CI, 0.76–0.85) (Fig. 1). There was no difference in blood-culture positivity between the preintervention period (11.05%) and the postintervention period (11.64%; P = .459). Days of therapy decreased from 1,180 to 1,130 per 1,000 patient days (IRR, 0.96; 95% CI, 0.95–0.98), and the length of therapy decreased from 602 to 579 per 1,000 patient days (IRR, 0.96; 95% CI, 0.94–0.99) (Fig. 2). There was no difference in 30-day mortality (P = .241) nor 30-day ICU readmission (P = .888) across the study periods after adjusting for potential confounders (Table 1). Conclusions: Our multifaceted intervention decreased blood-culture and antimicrobial utilization in the ICUs without significantly affecting the positivity rate, mortality, or readmission. This study suggests that educating providers on appropriate blood-culture use along with restriction could safely improve healthcare outcomes. Further studies are warranted to validate our results across various institutions and to evaluate the impact of blood-culture optimization in non-ICU patients.Disclosures: None

Utility of Blood Culture in Patients with Community-Acquired Pneumonia: A Propensity Score-Matched Analysis Based on a Japanese National Health Insurance Database.

Community-acquired pneumonia (CAP) is an acute pulmonary parenchymal infection acquired outside the hospital. The utility of blood cultures in inpatients with CAP to reduce mortality and length of hospital stay is controversial. This study aimed to determine the utility of blood cultures on the first day of hospitalization for CAP inpatients and its influence on mortality, length of hospital stay, and antibiotics use. We conducted a fact-finding survey on the implementation of blood culture in inpatients with CAP in Japan. A propensity score (PS)-matched analysis based on the National Database of Health Insurance Claims and Specific Health Check-ups of Japan database was conducted. Overall, 163173 patients were included in the analysis, and PS matching extracted 68104 pairs. The results of the comparison between the PS-matched blood culture group and PS-matched control group were as follows: mortality and length of hospital stay were significantly lower in the PS-matched blood culture group than in the control group. The adjusted odds ratio (OR) (95% confidence interval (CI)) for in-hospital mortality with blood culture test was 0.73 (0.68-0.79). Moreover, for days of antibiotic usage, number of antibiotics used were significantly higher in the PS-matched blood culture group than that in the control group. Our findings indicated that performing a blood culture on the first day of hospitalization for inpatients with CAP was associated with reduced mortality. To our knowledge, this is the largest epidemiological study to assess the utility of blood culture in Japanese inpatients with CAP. This testing method shows potential for application in clinical practice.

350. Clinical impact of positive fungal blood cultures for diagnosis and treatment of fungal infections.

Abstract Background Fungal blood cultures are usually ordered when sepsis secondary to disseminated fungal infection is suspected. We aimed to analyze whether positive fungal blood cultures had an added clinical impact over other conventional microbiological tests. Methods We performed a retrospective study of all patients for whom fungal blood cultures were performed for any indication at our institution from June 2018 to March 2022. We reviewed informatics database and medical records to assess the microbiological and clinical impact of positive fungal blood cultures during the initial admission. Assessment of clinical impact was analyzed using a list of predefined positive, negative, and no impact scenarios (Table 1) based by the treating team’s decisions. Results In total, 4447 fungal blood cultures were performed in 3648 admissions during our study period. The overall positivity rate of fungal blood cultures was 6.4% (n=284), of which only 130 (2.9%) were positive for fungi. The most common isolated fungi were Candida spp. (71, 55%), followed by Histoplasma spp. (16, 12%), Cryptococcus spp. (12, 9%), and unidentified mold (9, 7%) (Table 1). The median time to positivity was 106 hours (IQR 79-177). Only 21 (16%) fungal blood cultures resulted in a change in management. Positive fungal blood cultures for fungi led to a positive clinical impact in 17 (13%), negative clinical impact in 4 (3%), and no clinical impact in 109 (84%). Most fungal blood cultures confirmed other conventional microbiological diagnosis (71, 55%) or result was not acted upon (26, 20%). Organisms where fungal blood culture had a positive impact included C. albicans (n=4), and C. parapsilosis (n=3), while Cladosporium spp. (n=2) was the most frequent fungi with a negative clinical impact. Isolated fungi that had no clinical impact because of other confirmatory tests included Candida spp. (n=57), Histoplasma spp. (n=13) and Cryptococcus neoformans (n=10). Table 1.Microbiological characteristics and clinical impact of fungal blood cultures.Abbreviations: h hours; IQR, interquartile range.*Time to positivity was defined as the time from the fungal blood culture collection until growth and preliminary identification of a fungal organism on staining by the microbiology laboratory. **Time to identification was defined as the time from the fungal blood culture collection until identification of the fungal organism by the microbiology laboratory. Conclusion Most of positive fungal blood cultures for fungi resulted in no immediate clinical impact due to other microbiological tests available sooner or isolates thought to be non-clinically significant. Further studies should evaluate the long-term impact of fungemia and identify stewardship interventions to optimize clinical utility of fungal blood cultures. Disclosures All Authors: No reported disclosures.

47 A Host Protein Test Based on TRAIL, IP-10 and CRP for Differentiating Between Bacterial and Viral Infection Has Potential to Improve Patient Selection for Blood Culture Utilization

47 A Host Protein Test Based on TRAIL, IP-10 and CRP for Differentiating Between Bacterial and Viral Infection Has Potential to Improve Patient Selection for Blood Culture Utilization

The characteristics of bacteremia among patients with acute febrile illness requiring hospitalization in Indonesia.

Blood culturing remains the "gold standard" for bloodstream infection (BSI) diagnosis, but the method is inaccessible to many developing countries due to high costs and insufficient resources. To better understand the utility of blood cultures among patients in Indonesia, a country where blood cultures are not routinely performed, we evaluated data from a previous cohort study that included blood cultures for all participants. An acute febrile illness study was conducted from July 2013 to June 2016 at eight major hospitals in seven provincial capitals in Indonesia. All participants presented with a fever, and two-sided aerobic blood cultures were performed within 48 hours of hospital admission. Positive cultures were further assessed for antimicrobial resistance (AMR) patterns. Specimens from participants with negative culture results were screened by advanced molecular and serological methods for evidence of causal pathogens. Blood cultures were performed for 1,459 of 1,464 participants, and the 70.6% (1,030) participants that were negative by dengue NS1 antigen test were included in further analysis. Bacteremia was observed in 8.9% (92) participants, with the most frequent pathogens being Salmonella enterica serovar Typhi (41) and Paratyphi A (10), Escherichia coli (14), and Staphylococcus aureus (10). Two S. Paratyphi A cases had evidence of AMR, and several E. coli cases were multidrug resistant (42.9%, 6/14) or monoresistant (14.3%, 2/14). Culture contamination was observed in 3.6% (37) cases. Molecular and serological assays identified etiological agents in participants having negative cultures, with 23.1% to 90% of cases being missed by blood cultures. Blood cultures are a valuable diagnostic tool for hospitalized patients presenting with fever. In Indonesia, pre-screening patients for the most common viral infections, such as dengue, influenza, and chikungunya viruses, would maximize the benefit to the patient while also conserving resources. Blood cultures should also be supplemented with advanced laboratory tests when available.