Blood Culture Identification Research Articles

The clinical impact of early detection of ESBL-producing Enterobacterales with PCR-based blood culture assays

Starting January 4, 2021, our health system core microbiology laboratory changed blood culture identification (BCID) platforms to ePlex BCID from BioFire BCID1 with the additional capability to detect the blaCTX-M-Type gene of ESBL-producing organisms. Clinical outcomes of ESBL bloodstream infections (BSI) after implementing ePlex BCID were unknown. Patients with ESBL BSI were compared pre and postimplementation of ePlex BCID in this 11-hospital retrospective analysis (BioFire BCID1 in 2019 vs ePlex BCID in 2021). The primary outcome was time from the Gram stain result to escalation to a carbapenem. Secondary outcomes included in-hospital mortality, 30-day readmission rate, length of stay (LOS), and the duration of antimicrobial therapy. A total of 275 patients were analyzed. The median time of Gram stain result to escalation to carbapenem was reduced from 44.5hours with BioFire BCID1 to 7.9hours with ePlex BCID (P<.001). There were no significant differences in mortality, 30-day readmission, or LOS. The duration of antimicrobial therapy for ESBL BSI was lower in the ePlex BCID group (from 14.4 days to 12.7 days, P=.014). Timely detection of the blaCTX-M-Type gene by BCID provides valuable information for the early initiation of appropriate and effective antimicrobial therapy. Although it was not associated with lower mortality, 30-day readmission, or LOS, it may have benefits such as decreasing antimicrobial exposure to patients.

Microbiological Assessment of the FilmArray Blood Culture Identification 2 Panel: Potential Impact in Critically Ill Patients.

Rapid pathogen detection and characterization from positive blood cultures are crucial in the management of patients with bloodstream infections (BSI) and in achieving their improved outcomes. In this context, the FilmArray Blood Culture Identification (BCID2) panel is an FDA approved molecular test, which can quickly identify different species and resistance determinants, thus making an impact in antimicrobial practice. In this study, we analyzed 136 positive blood cultures collected from septic critically ill patients from April 2021 to March 2023 by using the FilmArray BCID2 panel, and results obtained by fast molecular analysis were compared to those obtained by routine protocols. Overall, the BCID2 panel showed a strong concordance with conventional methods, particularly in the case of monomicrobial samples, whereas some discrepancies were found in 10/32 polymicrobial samples. Of note, this technique allowed us to identify a significant number of yeasts (37/94 samples) and to unravel the presence of several resistance markers, including both Gram-positive and Gram-negative organisms. These findings strongly support the potential use of the BCID2 panel as an adjunct to the conventional microbiology methods for the management of critically ill septic patients, thus accelerating blood pathogen and resistance genes identification, focusing antibiotic therapy, and avoiding inappropriate and excessive use of drugs.

Clinical Impact of the BIOFIRE Blood Culture Identification 2 Panel in Adult Patients with Bloodstream Infection: A Multicentre Observational Study in the United Arab Emirates.

Rapid pathogen identification is key to the proper management of patients with bloodstream infections (BSIs), especially in the intensive care setting. This multicentre study compared the time to pathogen identification results in 185 patients admitted to intensive care with a confirmed BSI, using conventional methods (n = 99 patients) and upon implementation of the BIOFIRE® Blood Culture Identification 2 (BCID2) Panel, a rapid molecular test allowing for the simultaneous identification of 43 BSI-related nucleic acids targets (n = 86 patients). The median time to result informing optimal antibiotic therapy was significantly shorter following the implementation of the BCID2 Panel (92 vs. 28 h pre vs. post BCID2 implementation; p < 0.0001). BCID2 usage in addition to conventional methods led to the identification of at least one pathogen in 98.8% patients vs. 87.9% using conventional methods alone (p = 0.003) and was associated with a lower 30-day mortality (17.3% vs. 31.6%, respectively; p = 0.019). This study at three intensive care units in the United Arab Emirates therefore demonstrates that, in addition to conventional microbiological methods and an effective antimicrobial stewardship program, the BCID2 Panel could improve the clinical outcome of patients admitted to the intensive care unit with a confirmed BSI.

Implementation of diagnostic stewardship in blood culture laboratory: a large-scale interventional study in a tertiary care hospital, South India

Background: Laboratories with well-established diagnostic stewardship program for culture and antimicrobial susceptibility test (C-AST) play a key role in guiding the clinicians to institute specific targeted therapy. Methods: The study period was divided into three phases; pre-intervention phase, intervention phase and post- intervention phase. During the pre-intervention phase, the blood culture was performed by conventional methods. During the intervention phase, immense efforts were made for full-fledged implementation of all the components of intervention-educational intervention for microbiology and clinical team and automations for culture, workflow modifications for performing preliminary tests in parallel with reporting, enhanced reporting frequency and stage-wise communication of reports to the clinicians. Results: There was a significant improvement in the isolation rate in the post-intervention phase (from 10.3% to 15.5%). There has been a steady decrease in mean turnaround time (TAT) of positive culture reports (from 85 to 45 h), which was in turn due to faster blood culture positivity, identification time and AST time. There was also significant improvement in clinical team performance on various parameters such as % of samples sent in pair, % of specimens with appropriate blood volume collected and % culture drawn before the antibiotic start. Conclusions: Our observation shows significant improvement in the pathogen isolation rate as well as performance of both microbiology and the clinical team. Most patients with sepsis are critically ill, therefore, it is the responsibility of every clinical microbiologist to implement the highest standard of diagnostic stewardship in blood culture laboratory.

Influence of Multiplex PCR in the Management of Antibiotic Treatment in Patients with Bacteremia.

The multiplex PCR assay can be a helpful diagnostic tool for patients with bacteremia. Herein, we assessed the impact of a Blood Culture Identification Panel (BCID) on both the diagnosis and treatment of patients with bacteremia. We performed a retrospective study using laboratory and clinical data to evaluate the impact of syndromic testing using a multiplex PCR testing system (BioFire® FilmArray) for the management of patients with bloodstream infections. BCID detected the pathogen in 102 (87.9%) samples out of the 116 positive blood cultures tested. The average time from the blood culture collection to the communication of the molecular test result was 23.93 h (range: 10.67-69.27 h). The main pathogen detected was Klebsiella pneumoniae (17.6%). The antimicrobial therapy was changed in accordance with the BCID results in 28 (40.6%) out of the 69 cases, wherein the treatment could have been theoretically adjusted. This allowed the adjustment of the therapy to be performed 1305.1 h faster than it would have been possible if conventional diagnostic methods had been used; this was the case for only 35.1% of the time gained if treatment was adjusted for all patients with positive BCID. Thus, although molecular tests can make a difference in the management of bloodstream infections, there is room for improvement in the clinical application of BCID results.

Molecular technique for precise antibiotics administration in patients with cancer.

e18749 Background: Infectious diseases are the second most common cause of mortality in oncology patients. Multiple hospital admissions and previous exposure to antibiotics are risk factors for infection with microorganisms having antibiotic resistance gene in these patients.Molecular technique helps in targeted antibiotic administration at the earliest. Methods: This was a retrospective observational study over a period of one year from November 2021 to October 2022 in Tata Memorial Hospital, Mumbai, on oncology patients with blood stream infection (BSI) whose blood sample underwent film array assay. The BioFire Blood culture Identification 2 Panel (BCID2) which identifies Imipenemases (IMP), Klebsiella pneumoniae carbapenemases (KPC), New Delhi metallo beta-lactamases (NDM), oxacillinase-48 like (OXA-48), Verona integron-encoded metallo beta-lactamase (VIM), CTX M and methicillin resistance gene like mec A/C was used. BSI was categorised according to the resistance gene and recommended antibiotics of choice as per the Infectious Disease Society of America (IDSA). CTX-M - Carbapenem&amp;nbsp; OXA-48 like/ KPC - Ceftazidime-avibactam, Polymixin&amp;nbsp; Metallo beta-lactamase (MBL) i.e VIM, IMP, NDM - Ceftazidime-avibactam plus aztreonam, polymyxin, Cefiderocol&amp;nbsp; The impact of appropriate antibiotic administration on 30-day mortality was seen. Results: A total of 79 blood samples were submitted for film array assay during the study period. The mean age of the study population was 17± 4 years. 41(51.9%) patients had acute myeloid leukemia (AML), 29 (36.7%) had acute lymphocytic leukemia (ALL), 4 (5%) patients had lymphoma and 5 (6.3%) had other malignancies. 54(68.3%) BSI had microorganism with antibiotic resistance gene, 16 (20.3%) did not carry resistance gene and in 9 (11.4%), microorganism was not identified in film array assay, though conventional culture showed contaminants. Of the 54 BSI with microorganisms having antibiotic resistance gene, 37(68.5%) had MBL gene either alone or along with CTX-M or OXA-48 like genes, 12 (22.2%) had CTX-M and 5 (9.2%) had both CTX-M and OXA -48 like genes. Empirical antibiotic did not match the antibiotic resistance pattern in 40 (74.1%), antibiotic matched the resistance pattern in 14(22.9%). Antibiotic adjustment was done in 32 (86%) of MBL, 4 (80%) of OXA-48 like with CTX-M and 9 (75%) CTX-M. The 30-day mortality was significantly less (28% vs 80%, p = 0.042) in patients who received appropriate antibiotic versus those who continued inappropriate antibiotics in MBL BSI. Conclusions: Majority of the study population had BSI with antibiotic resistance gene and underwent a change in the antibiotic after the assay. There was lesser 30-day mortality in patients who received antibiotics appropriate for the identified resistance gene. Molecular technique is helpful for precise antibiotic administration in cancer patients who have a higher risk of infection with organisms having resistance gene.

Impact of the FilmArray Rapid Multiplex PCR Assay on Clinical Outcomes of Patients with Bacteremia.

Bacteremia is a serious disease with a reported mortality of 30%. Appropriate antibiotic use with a prompt blood culture can improve patient survival. However, when bacterial identification tests based on conventional biochemical properties are used, it takes 2 to 3 days from positive blood culture conversion to reporting the results, which makes early intervention difficult. Recently, FilmArray (FA) multiplex PCR panel for blood culture identification was introduced to the clinical setting. In this study, we investigated the clinical impact of the FA system on decision making for treating septic diseases and its association with patients' survival. Our hospital introduced the FA multiplex PCR panel in July 2018. In this study, blood-culture-positive cases submitted between January and October 2018 were unbiasedly included, and clinical outcomes before and after the introduction of FA were compared. The outcomes included (i) the duration of use of broad-spectrum antibiotics, (ii) the time until the start of anti-MRSA therapy to MRSA bacteremia, and (iii) sixty-day overall survival. In addition, multivariate analysis was used to identify prognostic factors. In the FA group, overall, 122 (87.8%) microorganisms were concordantly retrieved with the FA identification panel. The duration of ABPC/SBT use and the start-up time of anti-MRSA therapy to MRSA bacteremia were significantly shorter in the FA group. Sixty-day overall survival was significantly improved by utilizing FA compared with the control group. In addition, multivariate analysis identified Pitt score, Charlson score, and utilization of FA as prognostic factors. In conclusion, FA can lead to the prompt bacterial identification of bacteremia and its effective treatment, thus significantly improving survival in patients with bacteremia.

Algorithm for the selection of drugs for targeted antimicrobial therapy based on the results of molecular biological studies of positive blood cultures

Cardinal changes in approaches to the choice of antimicrobial therapy for severe infections have occurred in recent years. They are associated with the growth of antibiotic resistance of nosocomial pathogens and the lack of sufficiently effective «universal» schemes of empirical antibiotic therapy. Recent international and domestic recommendations focus on a «pathogen-specific» approach aimed at the treatment of infections caused by specific problematic resistant pathogens. The application of such «pathogen-specific» recommendations is not possible without the availability of appropriate quality microbiological data. The further evolution of diagnostic methods is directed creating test systems that allow detecting the main pathogens of infection and the most important antibiotic resistance genes, allowing to reduce the time from the moment of taking clinical material for microbiological examination to obtaining the result that affects the choice of antibiotic therapy regimen. The review contains practical recommendations on the choice of drugs for targeted antimicrobial therapy based on the clinical interpretation of the results obtained using the «hyperplex» panel BioFire BCID2 (Blood Culture Identification 2BCID2), taking into account the statements set out in the guidelines «Diagnosis and antimicrobial therapy for infections caused by polyresistant strains of microorganisms».

Usefulness of the FilmArray blood culture identification panel for identifying causative pathogens of bone and joint infections

As bone and joint infections (BJIs) require long-term treatment, identifying their causative pathogens is vital. However, the detection rate of conventional culturing remains inadequate. This study aimed to evaluate the usefulness of the FilmArray blood culture identification (BCID) panel for identifying causative pathogens in patients with BJIs. We tested a BCID panel using collected samples, in addition to conventional cultures. The primary outcome was to evaluate the diagnostic performance of the BCID panel, calculated using conventional culturing methods. A total of 44 patients who underwent BJI-related specimen collection were enrolled. Of the 44 patients, 22 were diagnosed with a BJI. Conventional culture identified 15 of 22 organisms (68.2%), whereas the BCID panel identified 14 of 22 organisms (63.4%). The overall sensitivity and specificity of the BCID panel were 73.3% and 57.1%, respectively, compared to those of the conventional culture. However, the sensitivity reached 100% when only pathogens included in the BCID panel were considered. In seven culture-negative cases, the BCID panel identified three organisms (42.9%). The BCID panel also indicated the appropriate therapy against a BJI caused by methicillin-resistant Staphylococcus aureus by detecting the mecA gene. This study demonstrated that the BCID panel has the potential for early and accurate diagnosis of the causative organism of BJI using specimens such as joint fluid and bone tissue. Our results suggest that BCID panels, in addition to routine culture, may improve our ability to diagnose the causative microorganisms of BJI in clinical practice, thereby contributing to the selection of appropriate antimicrobial agents.

Impact of Adding a Rapid PCR-Based Blood Culture Identification Panel to the Antimicrobial Stewardship Program of Patients with Febrile Neutropenia in a Peruvian Referral Hospital.

The addition of Biofire® FilmArray® Blood Culture Identification panel 2 (BCID2) to the antimicrobial stewardship program (ASP) could improve outcomes in bloodstream infections (BSI) of patients with febrile neutropenia (FN). A pre- and post-quasi-experimental single-center study was conducted at a reference hospital in Peru. Three groups were considered: patients with BSI before ASP intervention (control group), patients with BSI after ASP intervention (group 1), and patients with BSI after ASP intervention plus BCID2 PCR Panel implementation (group 2). Overall, 93 patients were identified (32 control, 30 group 1, 31 group 2). The median time to effective therapy was significantly shorter in group 2 compared to group 1 and control group, respectively (3.75 vs. 10 h, p = 0.004; 3.75 vs. 19 h, p < 0.001). No significant differences in terms of relapse of bacteremia, in-hospital mortality (all cause), and 30-day-all-cause hospital readmission between the three study periods were found. The appropriateness of empirical antimicrobial use, adding or change, and the following de-escalation or discontinuation was significant when the two intervention periods were compared with the control group (p < 0.001). In addition to the lack of local studies documenting the microbiological profile of FN episodes, adding syndromic panels-based testing could allow for the consolidation of ASP strategies.

Clinical outcomes associated with blood-culture contamination are not affected by utilization of a rapid blood-culture identification system.

Contaminated blood cultures result in extended hospital stays and extended durations of antibiotic therapy. Rapid molecular-based blood culture testing can speed positive culture detection and improve clinical outcomes, particularly when combined with an antimicrobial stewardship program. We investigated the impact of a multiplex polymerase chain reaction (PCR) FilmArray Blood Culture Identification (BCID) system on clinical outcomes associated with contaminated blood cultures. We conducted a retrospective cohort study involving secondary data analysis at a single institution. In this before-and-after study, patients with contaminated blood cultures in the period before PCR BCID was implemented (ie, the pre-PCR period; n = 305) were compared to patients with contaminated blood cultures during the period after PCR BCID was implemented (ie, the post-PCR implementation period; n = 464). The primary exposure was PCR status and the main outcomes of the study were length of hospital stay and days of antibiotic therapy. We did not detect a significant difference in adjusted mean length of hospital stay before (10.8 days; 95% confidence interval [CI], 9.8-11.9) and after (11.2 days; 95% CI, 10.2-12.3) the implementation of the rapid BCID panel in patients with contaminated blood cultures (P = .413). Likewise, adjusted mean days of antibiotic therapy between patients in pre-PCR group (5.1 days; 95% CI, 4.5-5.7) did not significantly differ from patients in post-PCR group (5.3 days; 95% CI, 4.8-5.9; P = .543). The introduction of a rapid PCR-based blood culture identification system did not improve clinical outcomes, such as length of hospital stay and duration of antibiotic therapy, in patients with contaminated blood cultures.

Large-Scale Clinical Evaluation of Rapid Blood Culture Identification Panels for Bloodstream Infections at a Tertiary Hospital

The prompt implementation of optimal antibacterial therapy through the rapid identification of the causative organisms is essential for improving outcomes for critically ill patients with bloodstream infections. We evaluated the clinical performance of the FilmArray blood culture identification (BCID) panel for rapidly identifying causative pathogens in the bloodstream using large-scale clinical samples. We analyzed the results of identification using a BCID panel performed on 2005 positive blood culture bottles from September 2019 to June 2022. Pathogen detection efficiency and interval from Gram staining to identification using the BCID panel were compared to those of conventional identification systems-VITEK MS MALDI-TOF Mass Spectrometer and Vitek2-and antibiotic susceptibility testing-Vitek2. We detected 2167 isolates from 2005 positive blood culture bottles. In these isolates, the BCID panel showed 93% full agreement-both organisms and antimicrobial resistance genes were matched, and no off-target organisms were detected. Species-level discordance was found in 0.6% of tests. Sixty-five isolates (3.0%) were only detected by BCID, whereas 22 isolates (1.0%) from the on-target panel were not detected by BCID. This large-scale study demonstrated that the BCID panel was a reliable and rapid identification method for directly identifying bloodstream pathogens in a positive blood culture.

Clinical Utility of the FilmArray® Blood Culture Identification (BCID) Panel for the Diagnosis of Neonatal Sepsis.

This prospective single-center study was designed to assess the clinical utility of the FilmArray® blood culture identification (BCID) panel for improving the diagnostic accuracy in neonatal sepsis. Results obtained using the FilmArray® BCID panel were correlated with results of blood culture in all consecutive neonates with suspicion of early-onset (EOS) and late-onset sepsis (LOS) attended in our service over a two-year period. A total of 102 blood cultures from 92 neonates were included, 69 (67.5%) in cases of EOS and 33 (32.3%) in LOS. The FilmArray® BCID panel was performed in negative culture bottles at a median of 10 h of blood culture incubation (IQR 8-20), without differences by the type of sepsis. The FilmArray® BCID panel showed a 66.7% sensitivity, 100% specificity, 100% positive predictive value, and 95.7% negative predictive value. There were four false-negative cases, three of which were Streptococcus epidermidis in neonates with LOS, and there was one case of Granulicatella adiacens in one neonate with EOS. We conclude that the use of the FilmArray® BCID panel in negative blood cultures from neonates with clinical suspicion of sepsis is useful in decision-making of starting or early withdrawal of empirical antimicrobials because of the high specificity and negative predictive values of this assay.

SG-APSIC1101: Virulence factors and antimicrobial resistance in coagulase-negative staphylococci isolated from blood of neonates

Objectives: To determine virulence genes and sensitivity to antibacterial drugs of Staphylococcus epidermidis isolated from blood cultures of newborns. Methods: A study of сoagulase-negative Staphylococcus (CoNS) from newborns with sepsis was conducted in the regional perinatal center in Karaganda, Kazakhstan. Blood-culture identification was performed using MALDI-TOF MS. Virulence factors were determined on primers (sdrG, sdrG, atl, lip, nuc, ebh, hlb, sspA, sspB, and gehD) with PCR (Bio-Rad CFX 96). Susceptibility to antibiotics determination was carried out using the disc-diffusion method. Testing with cefoxitin was used to detect methicillin resistance in staphylococci. Results: Overall, 18 Staphylococcus epidermidis isolates from blood cultures of newborns with sepsis were investigated from January to December 2021. The frequency of detection of virulence genes was distributed as follows: atl (94.5%), sspB (94.5%), sspA (89%), gehD (89%), ebh (89%), hlb (72%), sdrG (39%), sdrF (28%), nuc (28%), and lip (13%). Also, 10 isolates (55%) were resistant to cefoxitin (MRSE). Furthermore, 72% of S. epidermidis isolates showed resistance to azithromycin and 33% were resistant to clindamycin and gentamicin. Also, 39% of strains were resistant to fluorchinolones. All isolates were susceptible to vancomycin, linezolid, and fusidic acid. Conclusions:S. epidermidis strains isolated from blood cultures had high rates of exoenzymes sspB, sspA, gehD, autolysin (atl), β-hemolysin (hlb), and cell-wall–associated fibronectin-binding protein (ebh). Among 18 neonatal sepsis pathogens, 10 (55%) were MRSE, so it is necessary to pay attention to antibiotic therapy adjustment.

Test Performance and Potential Clinical Utility of the GenMark Dx ePlex Blood Culture Identification Gram-Negative Panel.

The test performance and potential clinical utility of the ePlex blood culture identification Gram-negative (BCID-GN) panel was evaluated relative to matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry on bacterial isolates and conventional antimicrobial susceptibility testing. The majority (106/108, 98.1%) of GN bacteria identified by MALDI were on the BCID-GN panel, and valid tests (107/108, 99.1%) yielded results on average 26.7 h earlier. For all valid tests with on-panel organisms, the positive percent agreement was 102/105 (97.2%) with 3 false negatives and the negative percent agreement was 105/105. Chart review (n = 98) showed that in conjunction with Gram stain results, negative pan-Gram-positive (GP) markers provided the opportunity to discontinue GP antibiotic coverage in 63/98 (64.3%) cases on average 26.2 h earlier. Only 8/12 (66.7%) Enterobacterales isolates with resistance to third-generation cephalosporins harbored the CTX-M gene. In contrast, 8/8 CTX-M+ samples yielded a resistant isolate. Detection of 1 Stenotrophomonas maltophilia (18 h), 1 OXA23/48+ Acinetobacter baumannii (52.4 h), and 3 CTX-M+ Enterobacterales isolates on ineffective treatment (47.1 h) and 1 on suboptimal therapy (72.6 h) would have additionally enabled early antimicrobial optimization in 6/98 (6.1%) patients. IMPORTANCE The GenMark Dx ePlex rapid blood culture diagnostic system enables earlier time to identification of antimicrobial-resistant Gram-negative bacteria causing bloodstream infections. Its ability to rule out Gram-positive bacteria enabled early discontinuation of unnecessary antibiotics in 63/98 (64.3%) cases on average 26.2 h earlier. Detection of bacteria harboring the CTX-M gene as well as early identification of highly resistant bacteria such as Stenotrophomonas maltophilia and Acinetobacter baumannii enabled optimization of ineffective therapy in 6/98 (6.1%) patients. Its implementation in clinical microbiology laboratories optimizes therapy and improves patient care.

Direct inoculation method for identification and antimicrobial susceptibility testing using matrix-assisted laser desorption ionization-time of flight mass spectrometry and both the Vitek 2 and MicroScan Walkaway 96 Plus systems

The aim of our study was to evaluate a protocol utilizing serum separator tubes (SST) to facilitate a faster, cost-effective, direct method for rapid sensitivity testing and identification of positive blood cultures. Spiked cultures were inoculated into either Becton Dickinson (BD) BACTECTM Aerobic Plus or Anaerobic/F bottles containing sterile human blood. Bottles were immediately processed when positive. A parallel study using patient isolates was used in which bacteria were pelleted by SST from positive blood cultures. For identification, a portion of the pellet was tested by matrix-assisted laser desorption/ionization as described by the manufacturer. MicroScan panels and Vitek 2 results were compared. Categorical agreement was used as comparison to standard subculture and/or polymerase chain reaction methods. No discordant identifications were observed, and 86% generated a successful identification when compared to subculture methods. For the Vitek 2, we observed a 99% essential agreement when compared to the subculture method. For the MicroScan Walkaway, we observed 94.9%, 97.4%, and 100% categorical agreement for MIC panels 53, 38, and MICroSTREP Plus 2, respectively. Turnaround times were reduced from 4 hours for identification and 11 hours for antimicrobial sensitivity testing. We conclude that the SST method results in timelier, actionable results for antimicrobial stewardship initiatives.

Antimicrobial stewardship, procalcitonin testing, and rapid blood-culture identification to optimize sepsis care in critically ill adult patients: A quality improvement initiative.

We examined the effect of an antimicrobial stewardship program (ASP), procalcitonin testing and rapid blood-culture identification on hospital mortality in a prospective quality improvement project in critically ill septic adults. Secondarily, we have reported antimicrobial guideline concordance, acceptance of ASP interventions, and antimicrobial and health-resource utilization.

197. The Clinical Impact of Early Detection of ESBL-Producing Enterobacterales with PCR-Based Blood Culture Assays

Abstract Background Bloodstream infections (BSIs) due to extended spectrum beta-lactamase (ESBL) producing Enterobacterales can cause significant morbidity and mortality. The first-line treatment for these is a carbapenem. ESBL-encoding genes such as blactx-m can be detected by ePlex® Blood Culture Identification (BCID) panels by utilizing polymerase chain reaction (PCR)-based techniques. Our primary objective was to assess the impact of BCID on time to appropriate therapy; secondary objectives were to assess the clinical impact on mortality, 30-day readmission, and length of stay (LOS). Methods This study was a retrospective multicenter observational study of hospitalized patients with ESBL-producing Enterobacterales positive blood cultures. Patients with ESBLs identified in the final blood culture by conventional methods pre-ePlex® BCID (Jan 1 to Sep 30, 2019) were compared to patients with ESBLs identified by ePlex® BCID (Jan 1 to Sep 30, 2021). Patients who expired or were discharged prior to Gram stain results were excluded. Time to appropriate therapy was defined as the time from Gram stain result to ordering a carbapenem. In-hospital mortality, 30-day readmission rate, and LOS were analyzed for each cohort. T-test and Chi-square test were performed. Inclusion and exclusion criteria for pre-ePlex BICD (2019) and post-ePlex BCID (2021) groups Results ESBL BSIs in 503 patients across 11 hospitals were identified and a total of 281 patients (pre-ePlex® BCID n=130; ePlex® BCID n=151) were included. A significant decrease in the median time to carbapenem order was observed (44.5 hours in the pre-ePlex® BCID group vs. 8 hours in the ePlex® BCID group (p&amp;lt; 0.001)). No significant difference was observed in in-hospital mortality, 30-day readmissions, or LOS. The mortality rates were 6.9% and 6.6%, the 30-day readmission rates were 7.7% and 12.6%, and the LOS were 8 days and 10 days, respectively in the pre- and post-ePlex® BCID groups. Comparison of outcome measure results between the pre-ePlex BICD (2019) and post-ePlex BCID (2021) groups. Box and whisker graphs for time from Gram stain result to ordering carbapenems (hours) Conclusion Implementing ePlex® BCID to detect ESBL BSIs decreased the median time to escalation to carbapenems by 36 hours. Despite the decrease in time to appropriate therapy, no change in in-hospital mortality, 30-day readmission, and LOS was observed. Disclosures All Authors: No reported disclosures.

331. Blood Culture Identification (BCID) Performance in Polymicrobial Bacteremia

Abstract Background The rapid multiplex PCR (rmPCR)-based FilmArray® blood culture identification (BCID) assay reduces time from positive blood culture to organism identification. Polymicrobial bacteremia is a known area of reduced diagnostic fidelity for BCID and remains incompletely characterized. Methods All cases of clinically confirmed polymicrobial bacteremia at a large academic single center from a 23-month period were evaluated in a retrospective cohort analysis (figure 1). Samples were assorted into BCID/blood culture concordant and BCID/blood culture discordant groups. Clinical characteristics of the two groups were compared, missed organisms were characterized, and changes in antimicrobial regimen in response to BCID results were characterized. Figure 1. Screening and exclusion process. 207 cultures were included in final analysis from a number screened of 2750 (constituting all positive blood cultures over a 23-month period from February 2019 to January 2021). Microbiologic inclusion criteria were as follows: evidence on final phenotypic culture of at least two separate microorganisms from the same blood culture specimen as long as both organisms were species other than coagulase negative staphylococci. Results A total of 207 samples were identified and studied. Overall, 49.3% (N=102) of polymicrobial cultures were incompletely identified by FilmArray® result. There were no significant group differences in comorbidity status, length of stay, mortality, or source between patients with polymicrobial bacteremia who had complete versus incomplete BCID identification (see table 1). Some 29.9% (38 of 127 total) of species identified corresponded to an organism potentially requiring time-sensitive treatment (relative numbers of each shown in table 2). De-escalation from adequate empiric to inadequate step-down antibiotic coverage following incomplete BCID result occurred in only 8.8% (N=9) of cases (shown in table 3). Table 1. Comparison of the characteristics of the BCID/blood culture (BCx) concordant and BCID/BCx discordant groups. Abbreviations: BCx, blood culture; IQR, interquartile range; ICU, intensive care unit; ER, emergency room; TPN, total parenteral nutrition. Table 2. Discrepant organisms typically requiring timely treatment identified on blood culture phenotyping but not on BCID. A complete list can be found in supplemental table S1. Table 3. Among patients with inaccurate BCIDs, antimicrobial changes and outcomes following return of BCID result are shown below. P-values comparing the four groups are shown. There was no significant association that could be seen in mortality and time to discharge and patient’s empiric therapy and de-escalation therapy status. Abbreviations: IQR, interquartile range; N/A, not applicable. Conclusion BCID frequently results in incomplete identification of blood culture results in patients with polymicrobial bacteremia, but clinical characteristics and outcomes were similar to those of patients with accurate BCID identification. Clinical team de-escalation to inappropriate antibiotic coverage following return the BCID assay was uncommon and was not clearly associated with inferior outcomes. Disclosures All Authors: No reported disclosures.

174. Evaluation of FilmArray® Blood Culture Identification and TheraDoc® Utilization at a Veterans Affairs Health Care System

Abstract Background Bacteremia is associated with significant morbidity and mortality, with each hour of delay initiating antibiotics associated with a 7.6% decrease in survival rate. At the Salisbury Veterans Affairs Health Care System (VA HCS), FilmArray® Blood Culture Identification (BCID) is used along with TheraDoc® to assist with selection of antimicrobial regimens as an antimicrobial stewardship practice at the site. The purpose of this study is to evaluate the time to appropriate antibiotic therapy based on positive BCID results. Methods This study is a retrospective, quality assurance project conducted at a 284-bed VA medical center from May 2018 through December 2020 of Veterans with positive BCID results identified on TheraDoc®. The primary endpoint is to identify the mean time for initiation of appropriate antimicrobial therapy defined as at least 80% susceptibility on local antibiogram to the resulting BCID organism for Veterans not on antibiotics or on inappropriate therapy from the time of BCID positivity. Secondary endpoints include comparing time to appropriate therapy with or without Infectious Diseases (ID) and Antimicrobial Stewardship Program (ASP) coverage, time to de-escalation, and contributors to time delays. Results A total of 168 Veterans were included in the study with 138 Veterans (82%) receiving appropriate antibiotic therapy at the time of BCID results and 30 Veterans (18%) on inappropriate or no empiric antibiotics. The mean time to appropriate therapy of the 30 Veterans on inappropriate or no antibiotics at the time of BCID positivity was 13 hours and 54 minutes with provider order entry being the largest factor in time delays. Of these 30 Veterans, BCID positivity occurred in 6 Veterans during business hours with onsite availability to ID and ASP to which the mean time to appropriate therapy was 3 hours and 29 minutes compared to 16 hours and 30 minutes for the 24 Veterans with results outside of business hours. For the 138 Veterans on appropriate therapy, the average time to de-escalation was about 43 hours and 52 minutes. Percentage of ID and/or ASP involvement. This pie chart shows the percentages of Veterans with ID and/or ASP involvement. Time to de-escalation. This graph demonstrates the time to de-escalation for Veterans on appropriate therapy at the time of BCID positivity. Inappropriate Therapy Group. This graph compares time to appropriate therapy between results occurring during business hours or outside of business hours for Veterans on no initial antibiotics or inappropriate therapy. Conclusion BCID and TheraDoc® are helpful antimicrobial stewardship tools to assist with reducing time to appropriate therapy when consistently monitored. Additional resources and education may be of benefit to providers covering outside of business hours. Example of BCID Algorithm Creation of a local BCID algorithm has been started as a result of this study. The goal of this resource is to be a tool for providers to help guide therapeutic decisions when ID and/or ASP are not readily available. Disclosures All Authors: No reported disclosures.