Qualitative versus quantitative blood cultures in the diagnosis of catheter-related bloodstream infections in children with malignancy

Abstract Background Blood cultures have high sensitivity to detect bacteremia in septic neonates when >=1 ml of blood is collected. Neonatologists often cite low confidence in microbiologic sampling as rationale for continuing antibiotics without a focus of infection despite negative blood cultures, resulting in prolonged antimicrobial therapy. We aim to describe the blood culture sample volumes in NICU patients, to identify factors associated with sample volumes < 1ml, and to compare the sample volumes of patients treated for culture-negative sepsis with those with bloodstream infections and those treated for a ≤72-hour sepsis rule-out Methods Data from this observational cohort study were collected retrospectively and prospectively from NICU patients with blood cultures obtained from September 2018 to February 2019. Clinical data were collected through chart review. All inoculated culture bottles were weighed for volume calculation. We determined the association of age, weight, sample source, and time of collection with volume < 1mL. Continuous variables were analyzed using Wilcoxon-Mann-Whitney, and categorical variables using chi-squared test. For aim 3, the volumes of the groups were compared using analysis of variance. Results A total of 310 blood cultures were identified, corresponding to 159 patients. Of these, 49 (16%) were positive. Among the negative blood cultures, 86% were collected in patients who subsequently received antibiotics (Figure 1). Median inoculated volume was 0.6 ml (IQR: 0.1-2.4). Weight and age at time of culture collection, source of sample, and time of collection were not significantly associated with the inoculation of < 1ml of blood. Median volume of blood was 0.6ml (0.3-0.6) for sepsis rule-out, 0.6ml (0.2-0.6) for bloodstream infection, and 0.6ml (0.6-1.4) for culture-negative sepsis. No difference was found among the three groups (p=0.54) Figure 1. Classification of blood cultures identified during study period Conclusion The blood volume collected for cultures in the NICU is lower than recommended. Clinical and environmental characteristics are not significantly associated with the inoculated volume. The volume of blood sampled does not differ in patients with culture-negative sepsis, bloodstream infection and sepsis rule-out, and should not be a justification for longer duration of antibiotic therapy Disclosures All Authors: No reported disclosures

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

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dkaa336 ◽

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.

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Scanning Electron Microscope: A New Potential Tool to Replace Gram Staining for Microbe Identification in Blood Cultures

Microorganisms ◽

10.3390/microorganisms9061170 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1170

Author(s):

Gabriel Haddad ◽

Sara Bellali ◽

Tatsuki Takakura ◽

Anthony Fontanini ◽

Yusuke Ominami ◽

...

Keyword(s):

Electron Microscope ◽

Blood Culture ◽

Scanning Electron Microscope ◽

Sample Preparation ◽

Bloodstream Infections ◽

Blood Cultures ◽

Preliminary Identification ◽

Gram Staining ◽

Micro Organisms ◽

Scanning Electron

Blood culture is currently the most commonly used method for diagnosing sepsis and bloodstream infections. However, the long turn-around-time to achieve microbe identification remains a major concern for clinical microbiology laboratories. Gram staining for preliminary identification remains the gold standard. We developed a new rapid strategy using a tabletop scanning electron microscope (SEM) and compared its performance with Gram staining for the detection of micro-organisms and preliminary identification directly from blood cultures. We first optimised the sample preparation for twelve samples simultaneously, saving time on imaging. In this work, SEM proved its ability to identify bacteria and yeasts in morphotypes up to the genus level in some cases. We blindly tested 1075 blood cultures and compared our results to the Gram staining preliminary identification, with MALDI-TOF/MS as a reference. This method presents major advantages such as a fast microbe identification, within an hour of the blood culture being detected positive, low preparation costs, and data traceability. This SEM identification strategy can be developed into an automated assay from the sample preparation, micrograph acquisition, and identification process. This strategy could revolutionise urgent microbiological diagnosis of infectious diseases.

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53. Incidence of Bloodstream Infections and Outcomes in Patients with Severe COVID-19 Pneumonia

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.363 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S156-S157

Author(s):

Aikaterini Papamanoli ◽

Jeanwoo Yoo ◽

Azad Mojahedi ◽

Robin Jacob ◽

Prabhjot Grewal ◽

...

Keyword(s):

Length Of Stay ◽

Medical Records ◽

Bloodstream Infections ◽

Blood Stream ◽

Blood Cultures ◽

High Flow ◽

University Hospital ◽

Skin Microbiota ◽

Prolonged Recovery ◽

The Impact

Abstract Background Coronavirus disease 19 (COVID-19) leading to acute respiratory distress syndrome is associated with need for intensive care (IC), mechanical ventilation (MV), and prolonged recovery. These patients are thus predisposed to blood stream infections which can worsen outcomes. This risk may be aggravated by adjunctive therapies. Methods We reviewed the medical records of all adults admitted to Stony Brook University Hospital, NY, from March 1 to April 15, 2020 with severe COVID-19 pneumonia (requiring high-ﬂow O2). Patients who received MV or died within 24h were excluded. Patients were followed until death or hospital discharge. We reviewed positive blood cultures (PBC) for pathogenic microorganisms, and calculated the incidence of bacteremia, rates of infective endocarditis (IE), and impact on mortality. Microbes isolated only once and belonging to groups defined as commensal skin microbiota were labelled as contaminants. We also examined the impact of adjunctive therapies with immunosuppressive potential (steroids and tocilizumab), on bacteremia. Results A total of 469 patients with severe COVID-19 pneumonia were included (Table 1). Of these, 199 (42.4%) required IC and 172 (36.7%) MV. Median length of stay was 13 days (8–22) and 94 (20.0%) had PBC. Of these, 43 were considered true pathogens (bacteremia), with predominance of E. faecalis and S. epidermidis, and 51 were considered contaminants (Table 2). The incidence of bacteremia (43/469, 9.2%) was 5.1 per 1000 patient-days (95%CI 3.8–6.4). An echocardiogram was performed in 21 patients, 1 had an aortic valve vegetation (IE) by methicillin sensitive S. aureus. Bacteremia rates were nonsignificantly higher with steroids (5.9 vs 3.7 per 1000 patient-days; P=0.057). Use of tocilizumab was not associated with bacteremia (5.8 vs 4.8 per 1000 patient-days; P=0.28). Mortality was nonsignificantly higher in patients with (15/43, 34.9%) vs. without (108/426, 25.4%) bacteremia (P=0.20). Length of stay was the strongest predictor of bacteremia, with risk increasing by 7% (95%CI 6%-9%, P< 0.001) per additional day. Cohort Characteristics of Patients with Severe COVID-19 Pneumonia on High-Flow O2 (N= 469) All Microorganisms Isolated from Blood Cultures Conclusion The incidence of bacteremia was relatively low and IE was uncommon in this study of severe COVID-19 patients. Risk of bacteremia increased with longer hospital stay and with steroids use, but not with tocilizumab. Disclosures All Authors: No reported disclosures

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Molecular epidemiology of catheter-related bloodstream infections caused by coagulase-negative staphylococci in haematological patients with neutropenia

Epidemiology and Infection ◽

10.1017/s0950268804002584 ◽

2004 ◽

Vol 132 (5) ◽

pp. 921-925 ◽

Cited By ~ 9

Author(s):

M. MÜLLER-PREMRU ◽

P. ČERNELČ

Keyword(s):

Blood Culture ◽

Staphylococcus Epidermidis ◽

Clinical Signs ◽

Bloodstream Infections ◽

Venous Catheter ◽

Blood Cultures ◽

Peripheral Vein ◽

Central Venous ◽

Coagulase Negative Staphylococci ◽

Haematological Patients

Catheter-related bloodstream infection (CRBSI) caused by coagulase-negative staphylococci (CNS) is common in haematological patients with febrile neutropenia. As the clinical signs of CRBSI are usually scarce and it is difficult to differentiate from blood culture contamination, we tried to confirm CRBSI by molecular typing of CNS isolated from paired blood cultures (one from a peripheral vein and another from the central venous catheter hub). Blood cultures were positive in 59 (36%) out of 163 patients. CNS were isolated in 24 (40%) patients; in 14 from paired blood cultures (28 isolates) and in 10 from a single blood culture. CNS from paired blood cultures were identified as Staphylococcus epidermidis. Antimicrobial susceptibility was determined and bacteria were typed by pulsed-field gel electrophoresis (PFGE) of bacterial genomic DNA. In 13 patients, the antibiotic susceptibility of isolates was identical. The PFGE patterns from paired blood cultures were identical or closely related in 10 patients, thus confirming the presence of CRBSI. In the remaining four patients they were unrelated, and suggested a mixed infection or contamination. Since CNS isolates from three patients had identical PFGE patterns, they were probably nosocomially spread amongst them.

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Clinical Evaluation of the iCubate iC-GPC Assay for Detection of Gram-Positive Bacteria and Resistance Markers from Positive Blood Cultures

Journal of Clinical Microbiology ◽

10.1128/jcm.00485-18 ◽

2018 ◽

Vol 56 (9) ◽

Cited By ~ 5

Author(s):

Paul A. Granato ◽

Melissa M. Unz ◽

Raymond H. Widen ◽

Suzane Silbert ◽

Stephen Young ◽

...

Keyword(s):

Blood Culture ◽

Staphylococcus Epidermidis ◽

Bloodstream Infections ◽

Blood Cultures ◽

Gram Positive ◽

Content Type ◽

Gram Positive Bacteria ◽

Sequencing Method ◽

Resistance Markers ◽

Gram Positive Cocci

ABSTRACT The iC-GPC Assay (iCubate, Huntsville, AL) is a qualitative multiplex test for the detection of five of the most common Gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Enterococcus faecalis, and Enterococcus faecium) responsible for bacterial bloodstream infections, performed directly from positive blood cultures. The assay also detects the presence of the mecA, vanA, and vanB resistance determinants. This study comparatively evaluated the performance of the iC-GPC Assay against the Verigene Gram-positive blood culture (BC-GP) assay (Luminex Corp., Austin, TX) for 1,134 patient blood culture specimens positive for Gram-positive cocci. The iC-GPC Assay had an overall percent agreement with the BC-GP assay of 95.5%. Discordant specimens were further analyzed by PCR and a bidirectional sequencing method. The results indicate that the iC-GPC Assay together with the iCubate system is an accurate and reliable tool for the detection of the five most common Gram-positive bacteria and their resistance markers responsible for bloodstream infections.

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Systematic Comparison of Four Methods for Detection of Carbapenemase-Producing Enterobacterales Directly from Blood Cultures

Journal of Clinical Microbiology ◽

10.1128/jcm.00709-19 ◽

2019 ◽

Vol 57 (11) ◽

Cited By ~ 13

Author(s):

Maria Meier ◽

Axel Hamprecht

Keyword(s):

Rapid Detection ◽

Clinical Microbiology ◽

Bloodstream Infections ◽

Blood Cultures ◽

Patient Treatment ◽

Clinical Microbiology Laboratory ◽

Microbiology Laboratory ◽

Study Protocols ◽

Sensitivity Specificity ◽

Good Detection

ABSTRACT Early identification of infections caused by carbapenemase-producing Enterobacterales (CPE) can help to optimize patient treatment and improve outcome. In this study, protocols for rapid detection of carbapenemase production directly from positive blood cultures were developed applying a concentration and hemolysis step before a test for carbapenemase production was performed. Four different methods (three modified colorimetric assays [β-Carba, bcCarba NP, and NeoRapid Carb] and a variation of the carbapenem inactivation method [CIM] test with blood cultures [bcCIM]) were assessed on blood cultures spiked with 185 different molecularly characterized Enterobacterales isolates. The challenge collection included 81 carbapenemase-negative isolates and 104 CPEs (OXA-48 [n = 25], NDM [n = 20], KPC [n = 18], VIM [n = 25], GIM [n = 5], OXA-48-like [n = 9], and OXA-48-like plus NDM [n = 2]). The sensitivity/specificity was 99.0%/95.1% for bcCarba NP, 99.0%/91.4% for NeoRapid Carb, 100%/95.1% for β-Carba and 100%/100% for bcCIM. Weakly hydrolyzing carbapenemases (e.g., OXA-48-like) were also well detected by the assays. The time to result was 20 to 45 min for β-Carba, 2 to 3 h for bcCarba NP, 2.5 to 2 h for NeoRapid Carb, and 18 to 24 h for bcCIM. In conclusion, all assays demonstrated good detection of CPE. The protocols can be easily implemented in any clinical microbiology laboratory and could help to optimize therapy early in bloodstream infections by CPE.

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2143. Attempting to Add Clarity to “Indeterminates” on a Deployed Rapid Diagnostic with Antimicrobial Stewardship Program (ASP) Intervention

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.1823 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S726-S726

Author(s):

Heather L Cox ◽

April E Attai ◽

Allison M Stilwell ◽

Kasi B Vegesana ◽

Frankie Brewster ◽

...

Keyword(s):

Pasteurella Multocida ◽

Diagnostic Testing ◽

Bloodstream Infections ◽

Empiric Therapy ◽

Central Line ◽

Blood Cultures ◽

University Hospital ◽

Salmonella Spp ◽

Gram Negative ◽

Stewardship Program

Abstract Background Rapid diagnostic testing paired with ASP intervention optimizes therapy and improves outcomes but few data guide ASP response in the absence of organism identification (ID). We describe the microbiology for organisms unidentified by Accelerate Pheno™ Gram-negative platform (AXDX) in order to inform ASP-provider team communication (PTC). Methods Consecutive, non-duplicate inpatient blood cultures with Gram-negative bacilli (GNB) following AXDX implementation at a single university hospital between April 2018 and March 2019 were included. Standard of care (SOC) ID and susceptibility followed AXDX. Clinical Microbiology emailed AXDX results to the ASP in real time; results were released into the EMR paired with telephone PTC or withheld after ASP review. Bloodstream Infections (BSIs) and patient outcomes for organisms labeled no/indeterminate ID by the AXDX were characterized. Results AXDX was performed on 351 blood cultures. Among 52 (15%) labeled no/indeterminate ID, SOC methods revealed: Enterobacteriaceae (40%; 9 monomicrobial with AXDX targets), anaerobes (21%), non-lactose fermenters (NLFs) other than Pseudomonas aeruginosa (21%), and fastidious GNB (10%). Frequent organisms without AXDX targets included: Raoultella planticola (4); Bacteroides fragilis, Cupriavidus spp., Haemophilus spp., Prevotella spp., Providencia spp., non-aeruginosa Pseudomonas spp., Salmonella spp. (3 each); Pasteurella multocida, Stenotrophomonas maltophilia (2 each). BSI sources were most commonly intra-abdominal (21%), central line-associated (17%), or unknown (17%). CLABSIs were associated with immune suppression and/or substance abuse in all but 1 case. BSIs without active empiric therapy included: NDM-producing Providencia stuartii SSSI; OXA-48-producing R. planticola intraabdominal infection (IAI); Pandoraea spp. CLABSI after liver transplant; enteric fever; B. fragilis, Leptotrichia wadei, and S. maltophilia, each of unknown source. In-hospital mortality occurred in 4 of these cases. Conclusion When AXDX yields no/indeterminate ID, ASP chart review for possible anaerobic/IAI, unique environmental exposures, and travel history may assist in guiding empiric therapy. GNB with AXDX targets are not excluded. Disclosures All authors: No reported disclosures.

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The Efficacy of Blood Culture in Postoperative Patients

The American Surgeon ◽

10.1177/000313481007601035 ◽

2010 ◽

Vol 76 (10) ◽

pp. 1172-1175 ◽

Cited By ~ 1

Author(s):

Jenny J. Lee ◽

David R. Martin

Keyword(s):

National Research Council ◽

Bloodstream Infections ◽

Central Line ◽

Blood Cultures ◽

Blood Cell Count ◽

Blood Draw ◽

Suspected Sepsis ◽

Wound Classification ◽

Preoperative Antibiotics ◽

Rule Out

Blood cultures are often obtained in postoperative patients to rule out bloodstream infections. Our study objectives were to determine the efficacy of blood cultures in postoperative patients with suspected sepsis and to determine variables predisposing patients to positive cultures. This was a retrospective study including patients with blood cultures drawn from January to March 2009 at our institution. We recorded demographics, presence of fever (temperature 101.5°F or higher), elevated white blood cell count (12,000/μL or greater), central line, diabetes, intensive care unit admission, postoperative day of blood draw, National Research Council surgical wound classification, and pre- or postoperative antibiotics. Blood cultures were drawn from 150 patients undergoing surgery within 30 days prior. Sixteen had positive cultures and nine were true-positives (6.3%). There was no statistical difference ( P > 0.05) between patients with positive and negative cultures except that those with negative cultures were more likely to have received preoperative antibiotics ( P = 0.0186). Blood cultures are invasive, expensive tests with low yield. We recommend that blood cultures be drawn in patients not receiving preoperative antibiotics who have undergone surgery more than 4 days before culture.

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Rapid Diagnostics for Blood Cultures: Supporting Decisions for Antimicrobial Therapy and Value-Based Care

The Journal of Applied Laboratory Medicine ◽

10.1373/jalm.2018.028159 ◽

2019 ◽

Vol 3 (4) ◽

pp. 686-697 ◽

Cited By ~ 3

Author(s):

Donna M Wolk ◽

J Kristie Johnson

Keyword(s):

Critical Care ◽

Antibiotic Therapy ◽

Bloodstream Infections ◽

Blood Cultures ◽

Rapid Diagnostics ◽

Clinical Practices ◽

Critical Care Units ◽

The Us ◽

Causes Of Mortality ◽

Value Based Care

Abstract Bacteremia and sepsis are critically important syndromes with high mortality, morbidity, and associated costs. Bloodstream infections and sepsis are among the top causes of mortality in the US, with >600 deaths each day. Most septic patients can be found in emergency medicine departments or critical care units, settings in which rapid administration of targeted antibiotic therapy can reduce mortality. Unfortunately, routine blood cultures are not rapid enough to aid in the decision of therapeutic intervention at the onset of bacteremia. As a result, empiric, broad-spectrum treatment is common—a costly approach that may fail to target the correct microbe effectively, may inadvertently harm patients via antimicrobial toxicity, and may contribute to the evolution of drug-resistant microbes. To overcome these challenges, laboratorians must understand the complexity of diagnosing and treating septic patients, focus on creating algorithms that rapidly support decisions for targeted antibiotic therapy, and synergize with existing emergency department and critical care clinical practices put forth in the Surviving Sepsis Guidelines.

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