scholarly journals Evaluation of Verigene Blood Culture Test Systems for Rapid Identification of Positive Blood Cultures

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Jae-Seok Kim ◽  
Go-Eun Kang ◽  
Han-Sung Kim ◽  
Hyun Soo Kim ◽  
Wonkeun Song ◽  
...  

The performance of molecular tests using the Verigene Gram-Positive and Gram-Negative Blood Culture nucleic acid tests (BC-GP and BC-GN, resp.; Naosphere, Northbrook, IL, USA) was evaluated for the identification of microorganisms detected from blood cultures. Ninety-nine blood cultures containing Gram-positive bacteria and 150 containing Gram-negative bacteria were analyzed using the BC-GP and BC-GN assays, respectively. Blood cultures were performed using the Bactec blood culture system (BD Diagnostic Systems, Franklin Lakes, NJ, USA) and conventional identification and antibiotic-susceptibility tests were performed using a MicroScan system (Siemens, West Sacramento, CA, USA). When a single strain of bacteria was isolated from the blood culture, Verigene assays correctly identified 97.9% (94/96) of Gram-positive bacteria and 93.8% (137/146) of Gram-negative bacteria. Resistance genesmecAandvanAwere correctly detected by the BC-GP assay, while the extended-spectrumβ-lactamase CTX-M and the carbapenemase OXA resistance gene were detected from 30 cases cultures by the BC-GN assay. The BC-GP and BC-GN assays showed high agreement with conventional identification and susceptibility tests. These tests are useful for rapid identification of microorganisms and the detection of clinically important resistance genes from positive Bactec blood cultures.

2021 ◽  
Vol 8 (2) ◽  
pp. 128-131
Author(s):  
Asmabanu Shaikh ◽  
Rachana Patel ◽  
Anant Marathe

The symptomatology and severity of covid-19 ranges widely depending on stage of infection. Most of the patients with mild to moderate disease can be managed without hospitalization. The patients with risk factors are likely to progress to severe disease. Patients developing secondary blood stream infections require longer hospital stay and are likely to develop fatal disease. The antibiotic selection is key to successful treatment of secondary BSI. This is cross-sectional study of 166 COVID 19 patients admitted to ICU of Parul Sevashram Hospital who developed sepsis like syndrome and were subjected to blood culture.Blood cultures were performed of all the patients developing sepsis like syndrome. IDSA guidelines were followed during blood collection for culture. Blood cultures were monitored on automated blood culture system. ID and susceptibility of all the isolates were performed on automated system (VITEK 2).A total of 1915 patients were reported RT-PCR positive for SARS nCoV2 during the period of 1st March2020 to 30 October 2020. 452 patients needed hospitalization based on their Oxygen saturation and co-morbidities. Out of 452, 166 patients developed sepsis like syndrome and were subjected to blood culture. The Blood culture positivity was 37/166 (22.28%). Gram positive bacteria were found in 48.64% while gram negative bacteria were 43.24%. The Enterococcus was the most common Gram positive bacterial isolates in patients. Candida was isolated in 2/37 positive blood cultures. Gram negative bacteria were isolated mostly amongst those patients who were on Ventilator. Most of the Gram positive bacteria were sensitive to Clindamycin, Linezolid, Vancomycin, Daptomycin and Teicoplanin.The incidence rate of BSI was high. Early secondary blood stream infections were mostly endogenous. Enterococcus was the most common amongst Gram positive bacteria. Gram negative secondary bacterial infections were more common with patients on ventilator. The susceptibility pattern would help in decision making of empiric antibiotic therapy. Interestingly as described by some authors earlier the relationship between SARS nCoV 2 and Enterococci needs to be studied further.


Author(s):  
Venere Cortazzo ◽  
Tiziana D’Inzeo ◽  
Liliana Giordano ◽  
Giulia Menchinelli ◽  
Flora Marzia Liotti ◽  
...  

Among molecular assays currently developed for detection and identification of pathogens (and their antimicrobial resistance genes) in positive blood cultures (BCs) (1), the BioFire FilmArray blood culture identification (BCID) panel (bioMérieux, Marcy l’Étoile, France)—a multiplex PCR assay with less than 2 minutes of hands-on time and a ∼1-hour turnaround time—allows syndromic diagnosis of bloodstream infection (BSI) (2, 3). Previously, the panel could identify 24 etiological agents of BSI (11 Gram-negative bacteria, 8 Gram-positive bacteria, and 5 yeast species), as well as three antimicrobial resistance genes (mecA, vanA/B, and blaKPC, which encodes Klebsiella pneumoniae carbapenemase). Now, the BioFire FilmArray BCID2 panel encompasses 43 molecular targets associated with BSI, including 15 Gram-negative bacteria, 11 Gram-positive bacteria, 7 yeast species, and 10 antimicrobial resistance genes (https://www.biomerieux-diagnostics.com/biofire-bcid-panel). The last targets include genes encoding for carbapenemases (IMP, KPC, OXA-48-like, NDM, and VIM), colistin resistance (mcr-1), ESBL (CTX-M), methicillin-resistance (mecA/C and, specifically for methicillin-resistant Staphylococcus aureus [MRSA], mecA/C and MREJ [mec right-extremity junction]), or vancomycin resistance (vanA/B). Unlike BCID, no published studies to date reported on the BCID2 performance. This study evaluated and compared the accuracy of BCID2 with that of BCID to identify bacterial species and relative antimicrobial resistance genes directly from positive BCs.


Author(s):  
Jacob S. Hanker ◽  
Paul R. Gross ◽  
Beverly L. Giammara

Blood cultures are positive in approximately only 50 per cent of the patients with nongonococcal bacterial infectious arthritis and about 20 per cent of those with gonococcal arthritis. But the concept that gram-negative bacteria could be involved even in chronic arthritis is well-supported. Gram stains are more definitive in staphylococcal arthritis caused by gram-positive bacteria than in bacterial arthritis due to gram-negative bacteria. In the latter situation where gram-negative bacilli are the problem, Gram stains are helpful for 50% of the patients; they are only helpful for 25% of the patients, however, where gram-negative gonococci are the problem. In arthritis due to gram-positive Staphylococci. Gramstained smears are positive for 75% of the patients.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4564-4564
Author(s):  
Marek Seweryn ◽  
Urszula Jarosz ◽  
Malgorzata Krawczyk-Kulis ◽  
Miroslaw Markiewicz ◽  
Grzegorz Helbig ◽  
...  

Abstract Abstract 4564 Background: Infectious complications remain an important cause of morbidity and mortality in the early phase after hematopoietic stem cell transplantation (HSCT). Aim: The aim of this study was to assess the frequency of positive blood cultures and its potential correlation with different studied parameters in large patient population studied in the first 30 days after HSCT. Material and methods: 431 patients at median age of 47 years (range 18–85) transplanted between 2009–2011 for hematological and non-hematological malignancies were included in our analysis. There were 242 males and 189 females. Results: The indications for autologous and allogeneic HSCT were following: AML – 105 (24%), NHL – 86 (20%), MM – 75 (17,5%), HL – 48 (11%), ALL – 40 (9%), MDS – 17 (4%), AA – 15 (3,5%), CML – 12 (2,8%), PNH – 11 (2,6%), connective tissue diseases – 5 (1,2%), CLL – 3 (0,7%) and other – 14 (3,2%). The following transplant procedures were performed: ABCT – 213 (49%), ABMT – 3 (0,7%), alloBCT – 56 (13%), alloBMT – 21 (5%), URDBCT – 87 (20%), URDBMT – 51 (12%). Pre-transplant ATG and anti-CD52 antibody were used in 142 (33%) and 5 (1.2%) patients, respectively. Amongst 431 transplanted patients, 495 blood cultures were collected; range 0–8 (median 1). Eighty seven blood samples were positive (17,6%). The following pathogens were detected: gram-positive bacteria in 48% (n=42), gram-negative bacteria in 38% (n=33), fungi in 1% (n=1) and both G(+) and G(−) bacteria in 13%(n=11). The gram-positive bacteria included: Staphylococcus epidermidis: 21 (50%), Micrococcus spp: 4 (9%), Enterococcus faecium: 3 (7%), Enterococcus faecalis: 3 (7%), Streptococcus haemolyticus: 3 (7%). The following gram-negative bacteria were found: Enterobacter cloacae: 10 (30%), Escherichia coli: 7 (21%), Pseudomonas aeruginosa: 5 (15%), Klebsiella pneumonia: 5 (15%). Candida albicans was detected only in one case. The use of ATG was associated with higher number of total blood draw and positive blood cultures. No significant correlation was found between the specific pathogen and the use of ATG. Male gender was associated with significantly higher number of blood sampling and with tendency to higher number of positive blood cultures. The type of conditioning regimen, the source of stem cell and the donor origin (auto vs sibling vs unrelated) did not influence the number of positive blood culture. There was tendency to higher number of blood intake, but not positive blood culture in patients transplanted in NR if compared to PR or CR. Conclusions: Positive blood cultures were positive in about 20% of patients after HSCT. Only pre-transplant ATG use was associated with the higher number of positive blood culture. Disclosures: No relevant conflicts of interest to declare.


2016 ◽  
Vol 70 (4) ◽  
pp. 361-366 ◽  
Author(s):  
Manjula Meda ◽  
James Clayton ◽  
Reela Varghese ◽  
Jayakeerthi Rangaiah ◽  
Clive Grundy ◽  
...  

AimsTo assess current procedures of processing positive blood cultures against national standards with an aim to evaluate its clinical impact and to determine the utility of currently available rapid identification and susceptibility tests in processing of blood cultures.MethodsBlood cultures from three secondary care hospitals, processed at a centralised laboratory, were prospectively audited. Data regarding processing times, communication with prescribers, changes to patient management and mortality within 30 days of a significant blood culture were collected in a preplanned pro forma for a 4-week period.ResultsOf 2206 blood cultures, 211 positive blood cultures flagged positive. Sixty-nine (3.1%) of all cultures were considered to be contaminated. Fifty per cent of blood cultures that flagged positive had a Gram stain reported within 2 hours. Two (0.99%) patients with a significant bacteraemia had escalation of antimicrobial treatment at the point of reporting the Gram stain that was subsequently deemed necessary once sensitivity results were known. Most common intervention was de-escalation of therapy for Gram-positive organisms at the point of availability of pathogen identification (25.6% in Gram positive vs 10% in Gram negative; p=0.012). For Gram-negative organisms, the most common intervention was de-escalation of therapy at the point of availability of sensitivity results (43% in Gram negatives vs 17.9% in Gram positive; p=0.0097). Overall mortality within 30 days of a positive blood culture was 10.9% (23/211). Antibiotic resistance may have contributed to mortality in four of these patients (three Gram negative and one Gram positive).ConclusionGram stain result had the least impact on antibiotic treatment interventions (escalation or de-escalation). Tests that improve identification time for Gram-positive pathogens and sensitivity time for Gram-negative pathogens had the greatest impact in making significant changes to antimicrobial treatment.


2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Cesira Giordano ◽  
Elena Piccoli ◽  
Veronica Brucculeri ◽  
Simona Barnini

Rapid identification of bloodstream pathogens by MALDI-TOF MS and the recently introduced rapid antimicrobial susceptibility testing (rAST) directly from positive blood cultures allow clinicians to promptly achieve a targeted therapy, especially for multidrug resistant microorganisms. In the present study, we propose a comparison between phenotypical rASTs performed in light-scattering technology (Alfred 60AST, Alifax®) and fluorescencein situhybridization (Pheno™, Accelerate) directly from positive blood cultures, providing results in 4–7 hours. Blood samples from 67 patients admitted to the Azienda Ospedaliero-Universitaria Pisana were analyzed. After the direct MALDI-TOF MS identification, the rAST was performed at the same time both on Alfred 60AST and Pheno. Alfred 60AST provided qualitative results, interpreted in terms of clinical categories (SIR). Pheno provided identification and MIC values for each antibiotic tested. Results were compared to the broth microdilution assay (SensiTitre™, Thermo Fisher Scientific), according to EUCAST rules. Using Alfred 60AST, an agreement was reached, 91.1% for Gram-negative and 95.7% for Gram-positive bacteria, while using Pheno, the agreement was 90.6% for Gram-negative and 100% for Gram-positive bacteria. Both methods provided reliable results; Alfred 60AST combined with MALDI-TOF MS proved itself faster and cheaper. Pheno provided identification and MIC determination in a single test and, although more expensive, may be useful whenever MIC value is necessary and where MALDI-TOF MS is not present.


Author(s):  
A Morin ◽  
N Poirier ◽  
S Vallee ◽  
A Porter

AbstractBacillusis a predominant genus of bacteria isolated from tobacco. The Gram stain is the most commonly used and most important of all diagnostic staining techniques in microbiology. In order to help confirm the Gram positivity ofBacillusisolates from tobacco, three methods using the chemical differences of the cell wall and membrane of Gram-positive and Gram-negative bacteria were investigated: the KOH (potassium hydroxide), the LANA (L-alanine-4-nitroanilide), and the vancomycin susceptibility tests. When colonies of Gram-negative bacteria are treated with 3% KOH solution, a slimy suspension is produced, probably due to destruction of the cell wall and liberation of deoxyribonucleic acid (DNA). Gram-positive cell walls resist KOH treatment. The LANA test reveals the presence of a cell wall aminopeptidase that hydrolyzes the L-alanine-4-nitroanilide in Gram-negative bacteria. This enzyme is absent in Gram-positive bacteria. Vancomycin is a glycopeptide antibiotic inhibiting the cell wall peptido-glycan synthesis of Gram-positive microorganisms. Absence of lysis with KOH, absence of hydrolysis of LANA, and susceptibility to vancomycin were used with the Gram reaction to confirm the Gram positivity of variousBacillusspecies isolated from tobacco.B. laevolacticusexcepted, all Bacillus species tested showed negative reactions to KOH and LANA tests, and all species were susceptible to vancomycin (5 and 30 µg).


2020 ◽  
Vol 11 (18) ◽  
pp. 4730-4740 ◽  
Author(s):  
Chengcheng Zhou ◽  
Meijuan Jiang ◽  
Jian Du ◽  
Haotian Bai ◽  
Guogang Shan ◽  
...  

A simple AIEgen with three emission colors achieves rapid identification of Gram-negative bacteria, Gram-positive bacteria and fungi.


Author(s):  
Måns Ullberg ◽  
Volkan Özenci

Abstract Rapid identification and antimicrobial susceptibility testing remain a crucial step for early efficient therapy of bloodstream infections. Traditional methods require turnaround times of at least 2 days, while rapid procedures are often associated with extended hands-on time. The Accelerate Pheno™ System provides microbial identification results within 90 min and susceptibility data in approximately 7 h directly from positive blood cultures with only few minutes of hands-on time. The aim of this study was, therefore, to evaluate the performance of the Accelerate Pheno™ System in identification and antimicrobial susceptibility testing of both Gram-positive and Gram-negative bacteria directly from clinical blood culture samples. We analyzed 108 and 67 blood culture bottles using the Accelerate PhenoTest™ BC kit with software version v1.0 and the FDA-cleared version v1.2, respectively. Reliable identification was achieved for Enterobacteriaceae, staphylococci, and enterococci, with 76/80 (95%), 42/46 (91%), and 10/11 (91%) correct identifications. Limitations were observed in the identification of streptococci, including Streptococcus pneumoniae and Streptococcus pyogenes, and coagulase-negative staphylococci. Antimicrobial susceptibility results for Enterobacteriaceae, for amikacin, ertapenem, ciprofloxacin, gentamicin, meropenem, and piperacillin-tazobactam ranged between 86 and 100% categorical agreement. Using v1.2, results for ceftazidime showed 100% concordance with the reference method. For staphylococci, the overall performance reached 92% using v1.2. Qualitative tests for detection of methicillin or macrolide-lincosamide-streptogramin B (MLSB) resistance caused major and very major errors for isolates. Overall, the present data show that the Accelerate Pheno™ system can, in combination with Gram stain, be used as a rapid complementation to standard microbial diagnosis of bloodstream infections.


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