scholarly journals Clinical comparison of aerobic, hypertonic, and anaerobic culture media for the radiometric detection of bacteremia

1976 ◽  
Vol 3 (3) ◽  
pp. 281-286
Author(s):  
R M Coleman ◽  
W W Laslie ◽  
D W Lambe
Keyword(s):  
False Positive ◽  
Culture Media ◽  
Growth Index ◽  
False Positives ◽  
Blood Cultures ◽  
Anaerobic Culture ◽  
Hypertonic Medium ◽  
Positive Growth ◽  
Radiometric Detection ◽  
Anaerobic Medium

The BACTEC 225 was used to test 5,811 routine blood cultures over a 20-month period. Aerobic, anaerobic, and hypertonic media were employed. The BACTEC 225 detected 511 positive cultures; 407 of these were considered significant organisms, and 104 were presumed contaminants. Of the significant positive cultures, 15% were detected within the first 12 h of incubation, 52% within 24 h, 82% within 48 h and 92% within 72 h. Aerobic, anaerobic, and hypertonic media are recommended for each venipuncture since 56 cultures were isolated from the aerobic medium only, 110 from the anaerobic medium only, and 94 from the hypertonic medium only. There were 16 patients who had multiple venipunctures from which organisms were repeatedly isolated from only one medium: two from the aerobic medium, four from the anaerobic medium, and ten from the hypertonic medium only. Detection times were not significantly different for the aerobic and hypertonic media. However, there were five patients with multiple venipunctures in which growth was detected radiometrically at least 48 h earlier in the hypertonic than in the aerobic medium. False-positive growth index readings were noted in 1,085 (19%) of the aerobic vial, 11 (0.19%) of the anaerobic vials, microorganisms were isolated from at least one of the companion vials. Using 5% co2 to flush the aerobic vials. With some false-positive aerobic and hypertonic vials decreased the number of false positives to about 6% of the total.

scholarly journals 118. Eliminating Blood Culture Contamination with an Initial-specimen Diversion Device

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S187-S187
Author(s):  
Lucy S Tompkins ◽  
Alexandra Madison ◽  
Tammy Schaffner ◽  
Jenny Tran ◽  
Pablito Ang
Keyword(s):  
Health Care ◽  
Blood Culture ◽  
Nursing Staff ◽  
False Positive ◽  
Blood Cultures ◽  
Traditional Methods ◽  
Standard Methods ◽  
Candida Sp ◽  
Initial Specimen ◽  
Skin Flora

Abstract Background Blood samples obtained via traditional venipuncture can become contaminated by superficial and deeply embedded skin flora. We evaluated the hospital-wide use of an initial-specimen diversion device (ISDD) designed to shunt these microorganisms away from the culture bottle to reduce blood culture contamination (BCC) and sequelae: false-positive central line-associated bloodstream infections (CLABSIs), repeat blood culture draws, inappropriate antibiotic usage, increased patient length-of-stay and misdiagnosis. The study aimed to show the proportion of blood cultures containing contaminants drawn by phlebotomy staff using the ISDD versus those drawn using traditional methods. Nursing staff continued to use traditional methods to draw blood cultures in the emergency department (ED) and from inpatients. Methods Over a four-month trial at Stanford Health Care (SHC), 4,462 blood cultures were drawn by phlebotomy staff using the ISDD (Steripath Gen2, Magnolia Medical Technologies) in the ED and from inpatients; 922 blood cultures were obtained by phlebotomy staff using standard methods. Additionally, 1,413 blood cultures were drawn by nursing staff using standard methods. The number of matched sets (2 bottles [aerobic/anaerobic] plus 2 bottles [aerobic/anaerobic], with total volume 40 ml) obtained through traditional methods and by the ISDD were recorded. Contaminants were defined by the National Healthcare Safety Network (NHSN). In addition, sets in which 1 out of 4 bottles contained vancomycin-resistant Enterococcus (VRE) or Candida sp. were also recorded, even though these are not considered contaminants by the NHSN. Results Of 4,462 blood cultures obtained using the ISDD there were zero contaminants found (BCC rate 0%) versus 29 contaminated sets using traditional methods (BCC rate 3.15%). Twenty-eight contaminants were observed from nursing staff blood culture draws (BCC rate 1.98%). Zero false-positive CLABSIs were associated with use of the ISDD for the trial period. No matched sets containing 1 of 4 bottles with VRE or Candida sp. were observed. Table Stanford Health Care blood culture collection methods and contamination events (March 15, 2019 - July 21, 2019) Conclusion The trial results encourage adoption of the ISDD as standard practice for blood culture at SHC. Disclosures All Authors: No reported disclosures

scholarly journals Train Fast While Reducing False Positives: Improving Animal Classification Performance Using Convolutional Neural Networks

Geomatics ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 34-49
Author(s):  
Mael Moreni ◽  
Jerome Theau ◽  
Samuel Foucher
Keyword(s):  
False Positive ◽  
Classification Performance ◽  
Large Datasets ◽  
False Positives ◽  
Fine Tuning ◽  
Training Time ◽  
In The Wild ◽  
Test Sets ◽  
High Level ◽  
Time Decrease

The combination of unmanned aerial vehicles (UAV) with deep learning models has the capacity to replace manned aircrafts for wildlife surveys. However, the scarcity of animals in the wild often leads to highly unbalanced, large datasets for which even a good detection method can return a large amount of false detections. Our objectives in this paper were to design a training method that would reduce training time, decrease the number of false positives and alleviate the fine-tuning effort of an image classifier in a context of animal surveys. We acquired two highly unbalanced datasets of deer images with a UAV and trained a Resnet-18 classifier using hard-negative mining and a series of recent techniques. Our method achieved sub-decimal false positive rates on two test sets (1 false positive per 19,162 and 213,312 negatives respectively), while training on small but relevant fractions of the data. The resulting training times were therefore significantly shorter than they would have been using the whole datasets. This high level of efficiency was achieved with little tuning effort and using simple techniques. We believe this parsimonious approach to dealing with highly unbalanced, large datasets could be particularly useful to projects with either limited resources or extremely large datasets.

Evaluation of Positive T- and B-Cell Gene Rearrangement Studies Among Patients Without a Definitive Diagnosis by Other Assays

2019 ◽  
Vol 152 (Supplement_1) ◽  
pp. S35-S36
Author(s):  
Hadrian Mendoza ◽  
Christopher Tormey ◽  
Alexa Siddon
Keyword(s):  
T Cell ◽  
False Positive ◽  
Gene Rearrangement ◽  
Hematologic Malignancy ◽  
False Negative ◽  
False Positives ◽  
False Negatives ◽  
True Negative ◽  
Flow Cytometric ◽  
Pathology Reports

Abstract In the evaluation of bone marrow (BM) and peripheral blood (PB) for hematologic malignancy, positive immunoglobulin heavy chain (IG) or T-cell receptor (TCR) gene rearrangement results may be detected despite unrevealing results from morphologic, flow cytometric, immunohistochemical (IHC), and/or cytogenetic studies. The significance of positive rearrangement studies in the context of otherwise normal ancillary findings is unknown, and as such, we hypothesized that gene rearrangement studies may be predictive of an emerging B- or T-cell clone in the absence of other abnormal laboratory tests. Data from all patients who underwent IG or TCR gene rearrangement testing at the authors’ affiliated VA hospital between January 1, 2013, and July 6, 2018, were extracted from the electronic medical record. Date of testing; specimen source; and morphologic, flow cytometric, IHC, and cytogenetic characterization of the tissue source were recorded from pathology reports. Gene rearrangement results were categorized as true positive, false positive, false negative, or true negative. Lastly, patient records were reviewed for subsequent diagnosis of hematologic malignancy in patients with positive gene rearrangement results with negative ancillary testing. A total of 136 patients, who had 203 gene rearrangement studies (50 PB and 153 BM), were analyzed. In TCR studies, there were 2 false positives and 1 false negative in 47 PB assays, as well as 7 false positives and 1 false negative in 54 BM assays. Regarding IG studies, 3 false positives and 12 false negatives in 99 BM studies were identified. Sensitivity and specificity, respectively, were calculated for PB TCR studies (94% and 93%), BM IG studies (71% and 95%), and BM TCR studies (92% and 83%). Analysis of PB IG gene rearrangement studies was not performed due to the small number of tests (3; all true negative). None of the 12 patients with false-positive IG/TCR gene rearrangement studies later developed a lymphoproliferative disorder, although 2 patients were later diagnosed with acute myeloid leukemia. Of the 14 false negatives, 10 (71%) were related to a diagnosis of plasma cell neoplasms. Results from the present study suggest that positive IG/TCR gene rearrangement studies are not predictive of lymphoproliferative disorders in the context of otherwise negative BM or PB findings. As such, when faced with equivocal pathology reports, clinicians can be practically advised that isolated positive IG/TCR gene rearrangement results may not indicate the need for closer surveillance.

scholarly journals Analysis of 281,797 Consecutive Blood Cultures Performed over an Eight-Year Period: Trends in Microorganisms Isolated and the Value of Anaerobic Culture of Blood

1997 ◽  
Vol 24 (3) ◽  
pp. 403-418 ◽  
Author(s):  
F. R. Cockerill ◽  
J. G. Hughes ◽  
E. A. Vetter ◽  
R. A. Mueller ◽  
A. L. Weaver ◽  
...  
Keyword(s):  
Blood Cultures ◽  
Anaerobic Culture

scholarly journals A Sterile Collection Bundle Intervention Reduces the Recovery of Bacteria from Neonatal Blood Culture

2018 ◽  
Vol 3 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Linze F. Hamilton ◽  
Helen E. Gillett ◽  
Adam Smith-Collins ◽  
Jonathan W. Davis
Keyword(s):  
Intensive Care ◽  
Blood Culture ◽  
False Positive ◽  
Neonatal Intensive Care ◽  
Intervention Group ◽  
Group Versus ◽  
Antibiotic Use ◽  
Culture Collection ◽  
Blood Cultures ◽  
Before And After

Background: In neonatal intensive care, coagulase-negative Staphylococcus species can be both blood culture contaminants and pathogens. False-positive cultures can result in clinical uncertainty and unnecessary antibiotic use. Objective: This study sought to assess whether a sterile blood culture collection bundle would reduce the incidence of false-positive blood cultures in a regional neonatal intensive care unit. Method: Clinical data was collected from all infants who had blood cultures taken before and after the introduction of the sterile blood culture collection bundle intervention. This intervention required 2% chlorhexidine and full sterile precautions for blood culture collection. False-positive blood culture rates (presence of skin commensals and ≥3 clinical infection signs) were compared before and after the intervention. The number of days of unnecessary antibiotics associated with false-positive blood cultures was also analysed. Results: In the pre-intervention group (PRE) 197 cultures were taken from 161 babies. In the post-intervention group (POST) 170 cultures from 133 babies were acquired. Baseline demographics were similar in both groups. The rate of false-positive cultures in the PRE group versus the POST group was 9/197 (4.6%) compared to 1/170 (0.6%) (p < 0.05). Unnecessary antibiotic exposure was reduced in the PRE group in comparison to the POST group (27 vs. 0 days, p < 0.01). Conclusions: Implementation of sterile blood culture collection intervention reduced the number of false-positive results. This has potential benefit in reducing unnecessary antibiotic use.

scholarly journals The KELT Follow-up Network and Transit False-positive Catalog: Pre-vetted False Positives for TESS

2018 ◽  
Vol 156 (5) ◽  
pp. 234 ◽  
Author(s):  
Karen A. Collins ◽  
Kevin I. Collins ◽  
Joshua Pepper ◽  
Jonathan Labadie-Bartz ◽  
Keivan G. Stassun ◽  
...  
Keyword(s):  
False Positive ◽  
False Positives

The Study of the Ontology and Context Verification Based Intrusion Detection Model

2014 ◽  
Vol 644-650 ◽  
pp. 3338-3341 ◽  
Author(s):  
Guang Feng Guo
Keyword(s):  
Intrusion Detection ◽  
Knowledge Base ◽  
False Positive ◽  
Intrusion Detection System ◽  
Detection System ◽  
False Positive Rate ◽  
False Positives ◽  
The Real ◽  
Detection Model ◽  
Positive Rate

During the 30-year development of the Intrusion Detection System, the problems such as the high false-positive rate have always plagued the users. Therefore, the ontology and context verification based intrusion detection model (OCVIDM) was put forward to connect the description of attack’s signatures and context effectively. The OCVIDM established the knowledge base of the intrusion detection ontology that was regarded as the center of efficient filtering platform of the false alerts to realize the automatic validation of the alarm and self-acting judgment of the real attacks, so as to achieve the goal of filtering the non-relevant positives alerts and reduce false positives.

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