scholarly journals 89. Follow-Up Blood Cultures (FUBC) in the Management of Gram-Negative Bacilli (GNB) Bloodstream Infections (BSIs): Frequently Obtained and Rarely Helpful

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S160-S160
Author(s):  
Evan D Robinson ◽  
Heather Cox ◽  
Amy J Mathers
Keyword(s):  
Antimicrobial Susceptibility ◽  
Positive Culture ◽  
Bloodstream Infections ◽  
Blood Cultures ◽  
Severe Neutropenia ◽  
Gram Stain ◽  
Exclusion Criteria ◽  
Persistent Bacteremia ◽  
Unnecessary Testing

Abstract Background While GNB BSIs remain a major cause of morbidity and mortality, no clear guidelines exist on the utilization of FUBCs to guide management. Despite the recognition of persistent bacteremia as a risk factor for increased mortality, early studies suggested FUBCs were low yield in this setting, and thus had low utility. More recently, some controversy has arisen with multivariate analyses suggesting FUBC acquisition may be associated with lower mortality. We sought to characterize the utilization and yield of FUBCs for GNB BSIs at our institution. Methods We performed a retrospective review of 514 episodes of consecutive blood cultures from unique adult inpatients with GNB BSI between July 2017-July 2019. Exclusion criteria included prior positive culture, polymicrobial Gram stain, or discharge, death, or comfort measures only within 24 hours of Gram stain. FUBCs were defined as blood cultures collected between 24 hours to 7 days after the index blood culture. Baseline clinical and microbiologic characteristics were compared between groups, as well as clinical outcomes. Results Of 514 episodes, 338 (66%) had FUBCs performed, with a median of 2 FUBCs/episode. The majority of FUBCs (322/338; 95%) were negative, with 9 (3%) yielding the same organism and 9 (3%) yielding a different organism. Most initial FUBCs were obtained prior to index antimicrobial susceptibility results (227/338; 67%). Patients with FUBCs performed had a higher median Pitt bacteremia score (2 vs 1; p = 0.015) and were more likely to have hospital onset (36% vs 22%; p = 0.002), severe neutropenia (16% vs 4%; p < 0.001) and a catheter-associated source (13% vs 4%; p = 0.001). 30-day mortality did not differ between patients with or without FUBCs (10% vs 11%; p = 0.84). Conclusion FUBCs were frequently obtained, but were of low yield even in comparison to recent similar studies. Though FUBCs were performed in more severe cases, a difference in mortality was not observed. Delaying the decision of whether to obtain FUBCs until after index antimicrobial susceptibility results are available would reduce unnecessary testing in most cases. Further study could better define where FUBCs after antimicrobial susceptibility testing would be most helpful. Disclosures All Authors: No reported disclosures

Evaluation of standardized automated rapid antimicrobial susceptibility testing of Enterobacterales-containing blood cultures: a proof-of-principle study

2020 ◽  
Vol 75 (11) ◽  
pp. 3218-3229
Author(s):  
Stefano Mancini ◽  
Elias Bodendoerfer ◽  
Natalia Kolensnik-Goldmann ◽  
Sebastian Herren ◽  
Kim Röthlin ◽  
...  
Keyword(s):  
Standard Method ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Bloodstream Infections ◽  
Inhibition Zone ◽  
Blood Cultures ◽  
Antimicrobial Susceptibility Testing ◽  
Disc Diffusion ◽  
Inhibition Zones ◽  
Reading System

Abstract Background Rapid antimicrobial susceptibility testing (RAST) of bacteria causing bloodstream infections is critical for implementation of appropriate antibiotic regimens. Objectives We have established a procedure to prepare standardized bacterial inocula for Enterobacterales-containing clinical blood cultures and assessed antimicrobial susceptibility testing (AST) data generated with the WASPLabTM automated reading system. Methods A total of 258 blood cultures containing Enterobacterales were examined. Bacteria were enumerated by flow cytometry using the UF-4000 system and adjusted to an inoculum of 106 cfu/mL. Disc diffusion plates were automatically streaked, incubated for 6, 8 and 18 h and imaged using the fully automated WASPLabTM system. Growth inhibition zones were compared with those obtained with inocula prepared from primary subcultures following the EUCAST standard method. Due to time-dependent variations of the inhibition zone diameters, early AST readings were interpreted using time-adjusted tentative breakpoints and areas of technical uncertainty. Results and conclusions Inhibition zones obtained after 18 h incubation using an inoculum of 106 cfu/mL prepared directly from blood cultures were highly concordant with those of the EUCAST standard method based on primary subcultures, with categorical agreement (CA) of 95.8%. After 6 and 8 h incubation, 89.5% and 93.0% of the isolates produced interpretable results, respectively, with CA of >98.5% and very low numbers of clinical categorization errors for both the 6 h and 8 h readings. Overall, with the standardized and automated RAST method, consistent AST data from blood cultures containing Enterobacterales can be generated after 6–8 h of incubation and subsequently confirmed by standard reading of the same plate after 18 h.

scholarly journals Evaluation of the Accelerate Pheno System for Fast Identification and Antimicrobial Susceptibility Testing from Positive Blood Cultures in Bloodstream Infections Caused by Gram-Negative Pathogens

2017 ◽  
Vol 55 (7) ◽  
pp. 2116-2126 ◽  
Author(s):  
Matthias Marschal ◽  
Johanna Bachmaier ◽  
Ingo Autenrieth ◽  
Philipp Oberhettinger ◽  
Matthias Willmann ◽  
...  
Keyword(s):  
Blood Culture ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Bloodstream Infections ◽  
Test System ◽  
Blood Cultures ◽  
Antimicrobial Susceptibility Testing ◽  
Diagnostic Tools ◽  
Gram Negative ◽  
Content Type

ABSTRACT Bloodstream infections (BSI) are an important cause of morbidity and mortality. Increasing rates of antimicrobial-resistant pathogens limit treatment options, prompting an empirical use of broad-range antibiotics. Fast and reliable diagnostic tools are needed to provide adequate therapy in a timely manner and to enable a de-escalation of treatment. The Accelerate Pheno system (Accelerate Diagnostics, USA) is a fully automated test system that performs both identification and antimicrobial susceptibility testing (AST) directly from positive blood cultures within approximately 7 h. In total, 115 episodes of BSI with Gram-negative bacteria were included in our study and compared to conventional culture-based methods. The Accelerate Pheno system correctly identified 88.7% (102 of 115) of all BSI episodes and 97.1% (102 of 105) of isolates that are covered by the system's identification panel. The Accelerate Pheno system generated an AST result for 91.3% (95 of 104) samples in which the Accelerate Pheno system identified a Gram-negative pathogen. The overall category agreement between the Accelerate Pheno system and culture-based AST was 96.4%, the rates for minor discrepancies 1.4%, major discrepancies 2.3%, and very major discrepancies 1.0%. Of note, ceftriaxone, piperacillin-tazobactam, and carbapenem resistance was correctly detected in blood culture specimens with extended-spectrum beta-lactamase-producing Escherichia coli ( n = 7) and multidrug-resistant Pseudomonas aeruginosa ( n = 3) strains. The utilization of the Accelerate Pheno system reduced the time to result for identification by 27.49 h ( P < 0.0001) and for AST by 40.39 h ( P < 0.0001) compared to culture-based methods in our laboratory setting. In conclusion, the Accelerate Pheno system provided fast, reliable results while significantly improving turnaround time in blood culture diagnostics of Gram-negative BSI.

scholarly journals Microbiological aspects of peritonitis associated with continuous ambulatory peritoneal dialysis.

1992 ◽  
Vol 5 (1) ◽  
pp. 36-48 ◽  
Author(s):  
A von Graevenitz ◽  
D Amsterdam
Keyword(s):  
Peritoneal Dialysis ◽  
Continuous Ambulatory Peritoneal Dialysis ◽  
Antimicrobial Agents ◽  
Positive Culture ◽  
Bloodstream Infections ◽  
Peritoneal Macrophages ◽  
Gram Stain ◽  
Coagulase Negative Staphylococci ◽  
Safe Alternative ◽  
Skin Flora

The process of continuous ambulatory peritoneal dialysis has provided a useful, relatively inexpensive, and safe alternative for patients with end-stage renal disease. Infectious peritonitis, however, has limited a more widespread acceptance of this technique. The definition of peritonitis in this patient population is not universally accepted and does not always include the laboratory support of a positive culture (or Gram stain). In part, the omission of clinical microbiological findings stems from the lack of sensitivity of earlier microbiological efforts. Peritonitis results from decreased host phagocytic efficiency with depressed phagocytosis and bactericidal capacity of peritoneal macrophages. During episodes of peritonitis, fluid movement is reversed, away from the lymphatics and peritoneal membrane and toward the cavity. As a result, bloodstream infections are rare. Most peritonitis episodes are caused by bacteria. Coagulase-negative staphylococci are the most frequently isolated organisms, usually originating from the skin flora, but a wide array of microbial species have been documented as agents of peritonitis. Clinical microbiology laboratories need to be cognizant of the diverse agents so that appropriate primary media can be used. The quantity of dialysate fluid that is prepared for culture is critical and should constitute at least 10 ml. The sensitivity of the cultural approach depends on the volume of dialysate, its pretreatment (lysis or centrifugation), the media used, and the mode of incubation. The low concentration of microorganisms in dialysate fluids accounts for negative Gram stain results. Prevention of infection in continuous ambulatory peritoneal dialysis patients is associated with the socioeconomic status of the patient, advances in equipment (catheter) technology, and, probably least important, the application of prophylactic antimicrobial agents.

scholarly journals Evaluation of the Accelerate Pheno™ system to identify bacteria and determine antimicrobial susceptibility in positive blood cultures

2019 ◽  
Author(s):  
Mariana J. Fernandez-Pittol ◽  
Javier Morales ◽  
Elisa Rubio ◽  
Assumpta Fasanella ◽  
Izaskun Alejo-Cancho ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Antibiotic Susceptibility ◽  
Susceptibility Testing ◽  
Standard Procedure ◽  
Bloodstream Infections ◽  
Blood Cultures ◽  
Bacterial Isolates ◽  
Minimal Inhibitory Concentrations ◽  
Maldi Tof ◽  
The Mean

AbstractIntroductionNew platforms have recently been developed to reduce response time of identification and antimicrobial susceptibility of bacterial isolates in positive blood cultures from patients with bloodstream infections. The Accelerate Pheno™ system (Accelerate Diagnostics, Inc.) provides information on pathogen identification and antibiotic susceptibility in approximately 1.5 and 7 hours, respectively.MethodsIn this study we compared the Accelerate Pheno™ system with the standard procedure used in our laboratory. A total of 41 blood cultures were prospectively analysed with the Accelerate Pheno™ system and our standard methods, which include identification by MALDI-TOF mass spectrometry and antibiotic susceptibility testing (AST) by BD Phoenix system and E-test.ResultsThe correlation between the two methods using Cohen’s kappa coefficient was 0.82; mean (sd) time of identification for MALDI-TOF MS was 0.7 (0.22) hours and 1.43 (0.14) hours for the Accelerate Pheno™ system. The mean (sd) time of AST with the BD Phoenix system was 15.85 (2.57) hours and with the Accelerate Pheno™ system 6.7 (0.12) hours. AST results showed an overall essential agreement of 92% for the minimal inhibitory concentrations (MIC) and an overall category agreement of 96%. Among Gram positive isolates, essential and category agreements of 100% were observed. In Gram negative isolates 10 discrepancies were detected, which were classified as 7 major and 3 minor errors. Discrepancies in the Accelerate Pheno™ system were observed particularly for P. aeruginosa.ConclusionThe Accelerate Pheno™ system can improve turn-around time in the management of patients with bloodstream infections.

scholarly journals 185. Trends in Clinical Presentation and Antibiotic Resistance of Viridans Group Streptococci Bloodstream Infections in Immunocompromised Children

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S112-S113
Author(s):  
Ana M Quintero ◽  
Diego A Cruz Vidal ◽  
Monica I Ardura ◽  
Sophonie Jean
Keyword(s):  
High Risk ◽  
Antimicrobial Susceptibility ◽  
Bloodstream Infections ◽  
Severe Neutropenia ◽  
Underlying Malignancy ◽  
Significant Difference ◽  
Viridans Group Streptococci ◽  
The Impact ◽  
Over Time ◽  
High Risk Children

Abstract Background Levofloxacin prophylaxis (LVXp) is recommended in children with severe neutropenia from underlying malignancy or hematopoietic cell transplantation (HCT). The impact of LVXp on the epidemiology of viridans group streptococcus bloodstream infections (VGS-BSI) is unknown. At our center, LVXp was prescribed to high-risk children with expected prolonged neutropenia (ANC &lt; 100, &gt; 7 days) as part of a clinical trial (2013-17) and routinely since November 2018. We aim to describe our local epidemiology, antibiotic susceptibilities, and clinical outcomes of VGS-BSI over time. Methods VGS-BSI from 1/1/10-1/31/21 were identified via the laboratory database. Clinical data of patients followed at NCH with underlying malignancy, severe neutropenia, or HCT were extracted from the electronic health record. Available VGS isolates were subcultured, species identification confirmed by MALDI-ToF or 16s rDNA sequencing and susceptibility to penicillin (PCN), cefepime (CEF), vancomycin (VAN), and LVX performed via Etest per CLSI M100 guidelines. Non-parametric descriptive statistics were applied. Results Over a 10-yr period, 111 VGS-BSI occurred in 93 patients (Table 1); 15 (16%) patients had ≥ 2 VGS-BSI. 80 (86%) patients had fever and neutropenia (F&N); 26 (28%) required ICU care for vasopressors (N=17, 18%) or mechanical ventilation (N=10, 11%). Most VGS isolates were S. mitis/oralis group. In total, 15 (16%) patients received LVXp ≤ 6 months before VGS-BSI; 9 (10%) had breakthrough VGS-BSI while receiving LVXp and all isolates were LVX resistant. Figure 1 shows susceptibilities: overall, 24% of isolates had frank resistance to PCN, 19% CEF, 13% LVX; all were VAN susceptible. When evaluating for changes in susceptibilities over time, there was a significant difference in the proportion of LVX-resistant isolates (p=0.009, Cochran-Armitage χ 2), but not CEF (p=0.08) or PCN (p=0.86). Table 1. Demographic and Clinical Characteristics of Immunocompromised Children with Viridans Group Streptococci Bloodstream Infections (VGS-BSI) Figure 1. Antimicrobial Susceptibility Profile of Viridans Group Streptococci Bloodstream Isolates from Immunocompromised children, 2010-2021. Of 111 VGS-BSI reported during the study period from immunocompromised children, 83 (75%) were available for further testing. Antimicrobial susceptibility testing was performed by Etest and interpreted per CLSI M100. Susceptibility profiles to penicillin (PCN), cefepime (CEP) and, levofloxacin (LVX) are shown. Abbreviations: S—susceptible, I—intermediate, R—resistant. Conclusion Breakthrough, LVX-resistant VGS-BSI occurred in 10% of patients, most frequently in children with AML or HCT. Over time, there was a trend towards increased LVX resistance in the cohort. Routine antimicrobial testing and ongoing monitoring for emergence of resistance are warranted to inform local prophylaxis and empirical antibiotic strategies for high-risk children with F&N. Disclosures Monica I. Ardura, DO, MSCS, Shire (Grant/Research Support)

scholarly journals Use of the Accelerate Pheno System for Identification and Antimicrobial Susceptibility Testing of Pathogens in Positive Blood Cultures and Impact on Time to Results and Workflow

2017 ◽  
Vol 56 (1) ◽  
Author(s):  
Angella Charnot-Katsikas ◽  
Vera Tesic ◽  
Nedra Love ◽  
Brandy Hill ◽  
Cindy Bethel ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Bloodstream Infections ◽  
Standard Of Care ◽  
Blood Cultures ◽  
Antimicrobial Susceptibility Testing ◽  
Clinical Microbiology Laboratory ◽  
Current Standard ◽  
Cellular Analysis ◽  
Hands On

ABSTRACT The Accelerate Pheno system uses automated fluorescence in situ hybridization technology with morphokinetic cellular analysis to provide rapid species identification (ID) and antimicrobial susceptibility testing (AST) results for the most commonly identified organisms in bloodstream infections. The objective was to evaluate the accuracy and workflow of bacterial and yeast ID and bacterial AST using the Accelerate Pheno system in the clinical microbiology laboratory. The consecutive fresh blood cultures received in the laboratory were analyzed by the Accelerate Pheno system within 0 to 8 h of growth detection. ID/AST performance, the average times to results, and workflow were compared to those of the routine standard of care. Of the 232 blood cultures evaluated (223 monomicrobial and 9 polymicrobial) comprising 241 organisms, the overall sensitivity and specificity for the identification of organisms were 95.6% and 99.5%, respectively. For antimicrobial susceptibility, the overall essential agreement was 95.1% and categorical agreement was 95.5% compared to routine methods. There was one very major error and 3 major errors. The time to identification and the time to susceptibility using the Accelerate Pheno system were decreased by 23.47 and 41.86 h, respectively, compared to those for the standard of care. The reduction in hands on time was 25.5 min per culture. The Accelerate Pheno system provides rapid and accurate ID/AST results for most of the organisms found routinely in blood cultures. It is easy to use, reduces hands on time for ID/AST of common blood pathogens, and enables clinically actionable results to be released much earlier than with the current standard of care.

scholarly journals Limited Clinical Utility of Follow-up Blood Cultures in Patients With Streptococcal Bacteremia: An Opportunity for Blood Culture Stewardship

2020 ◽  
Vol 7 (12) ◽  
Author(s):  
Emily A Siegrist ◽  
Minkey Wungwattana ◽  
Leyla Azis ◽  
Patricia Stogsdill ◽  
Wendy Y Craig ◽  
...  
Keyword(s):  
Blood Culture ◽  
Clinical Utility ◽  
Epidural Abscess ◽  
Vertebral Osteomyelitis ◽  
Blood Cultures ◽  
Inclusion Criteria ◽  
Streptococcal Species ◽  
Persistent Bacteremia ◽  
Polymicrobial Bacteremia

Abstract Background The value of positive follow-up blood cultures (FUBCs) in streptococcal bacteremia has not been well defined. Therefore, we explored the frequency of and risk factors for positive FUBC in a retrospective cohort of patients with streptococcal bacteremia. Methods Adults ≥18 years of age, admitted with at least 1 positive blood culture for Streptococcus spp between 2013 and 2018 followed by at least 1 FUBC, were potentially eligible. Positive FUBCs were defined as cultures positive for the same streptococcal species drawn &gt;24 hours after the index culture. We excluded patients with polymicrobial bacteremia. We compared the characteristics of patients with and without a positive FUBC. Results In our single-center cohort, we identified 590 patients with streptococcal bacteremia, and 314 patients met inclusion criteria. Ten patients had FUBC with Streptococcus spp (3.2%), 4 (1.3%) had a contaminant identified, and 3 (1.0%) had a new pathogen isolated. Endocarditis (5 of 10 [50.0%] vs 35 of 304 [11.5%]), epidural abscess (2 of 10 [20%] vs 4 of 304 [1.3%]), and discitis or vertebral osteomyelitis (3 of 10 [30.0%] vs 14 of 304 [4.6%]) were associated with positive FUBC. Patients with positive FUBC had a longer median length of stay (12.9 vs 7.1 days, P = .004) and longer duration of antibiotic treatment (14.9 vs 43.2 days, P = .03). Conclusions Follow-up blood cultures among patients with streptococcal BSI are rarely positive. Clinicians could consider limiting follow-up blood cultures in patients at low risk for deep-seated streptococcal infections, persistent bacteremia, or endovascular infection.

scholarly journals 1360. Variation in Duration of Antibiotic Therapy for Central-line Associated Blood Stream Infections Caused by Gram Negative Bacilli in Hospitalized Children

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S691-S691
Author(s):  
Grant R Whitmer ◽  
Tonya Scardina ◽  
Shan Sun ◽  
Xiaotian Zheng ◽  
Sameer Patel
Keyword(s):  
Antibiotic Therapy ◽  
Median Duration ◽  
Positive Culture ◽  
Bloodstream Infections ◽  
Venous Catheter ◽  
Central Line ◽  
Effective Therapy ◽  
Severe Neutropenia ◽  
Solid Organ ◽  
Gram Negative

Abstract Background Central-line associated bloodstream infections (CLABSIs) are associated with increased morbidity, mortality, and duration of hospitalization in children. Existing guidelines recommend a broad range (7-14 days) for duration of antibiotic therapy. Unnecessarily prolonged therapy may be associated with emergence of antibiotic resistance and adverse events. Methods We performed a retrospective review of all patients diagnosed with CLABSIs caused by Gram negative bacilli (GNB) at our institution from August 2009 to April 2019. CLABSI was defined as isolation of a GNB from the blood &gt;48 hours after hospital admission with presence of a central venous catheter. Children who died before completion of treatment were excluded. Data collection variables included severe neutropenia (defined as absolute neutrophil count &lt; 500), immunocompromised status (defined as receipt of bone marrow transplant, solid organ transplant, or immunosuppressive medication), and catheter removal. The duration of effective antibiotic therapy was calculated from the date of last positive culture to discontinuation. Effective therapy was defined as use of an agent to which the isolated organism was susceptible by antimicrobial susceptibility testing. The primary outcome was microbiological recurrence of the same organism and/or all-cause mortality within 30 days of discontinuation. Results Overall, 95 CLABSIs were included. Of 92 patients, 46 (50%) were immunocompromised. For patients with catheters removed prior to the end of therapy (n=48), the median duration of effective therapy was 13.5 days (IQR: 8.75-16 days). For patients who retained catheters throughout treatment (n=47), the median duration of effective therapy was 13 days (IQR: 9-15 days). Of these 95 CLABSIs, one patient (retained catheter) had microbiological recurrence within 30 days. Seven patients died (without microbiological recurrence), with range of duration of therapy of 6-14 days. Conclusion There was a wide variation in length of therapy for CLABSIs caused by GNB in children. Microbiological recurrence was rare, and mortality was unrelated to microbiological recurrence. Future studies should evaluate standardization of shorter duration therapy to avoid unnecessarily prolonged antibiotic exposure. Disclosures Sameer Patel, MD MPH, Merck (Grant/Research Support)Nexogen (Consultant)

scholarly journals Rapid Antimicrobial Susceptibility Testing Methods for Blood Cultures and Their Clinical Impact

2021 ◽  
Vol 8 ◽  
Author(s):  
Ritu Banerjee ◽  
Romney Humphries
Keyword(s):  
Clinical Outcomes ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Bloodstream Infections ◽  
Blood Cultures ◽  
Clinical Impact ◽  
Antimicrobial Susceptibility Testing ◽  
Optimal Management ◽  
Testing Methods

Antimicrobial susceptibility testing (AST) of bacteria isolated in blood cultures is critical for optimal management of patients with sepsis. This review describes new and emerging phenotypic and genotypic AST methods and summarizes the evidence that implementation of these methods can impact clinical outcomes of patients with bloodstream infections.

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