scholarly journals Identification and antimicrobial susceptibility testing of Gram-positive and Gram-negative bacteria from positive blood cultures using the Accelerate Pheno™ system

2019 ◽  
Vol 39 (1) ◽  
pp. 139-149 ◽  
Author(s):  
Måns Ullberg ◽  
Volkan Özenci
Keyword(s):  
Blood Culture ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Bloodstream Infections ◽  
Blood Cultures ◽  
Antimicrobial Susceptibility Testing ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Hands On

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.

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 Direct antimicrobial susceptibility testing of Gram-negative bacteria from positive blood cultures

2014 ◽  
Vol 28 (3) ◽  
Author(s):  
Andrea Zappavigna ◽  
Enrica Cavatorta ◽  
Rossana Chiarabini ◽  
Roberta Schiavo ◽  
Daniela Padrini ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Blood Cultures ◽  
Antimicrobial Susceptibility Testing ◽  
Gram Negative Bacteria ◽  
Gram Negative

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 Rapid antimicrobial susceptibility testing on positive blood cultures through an innovative light scattering technology: performances and turnaround time evaluation

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Lidvine Boland ◽  
Corentin Streel ◽  
Hélène De Wolf ◽  
Hector Rodriguez ◽  
Alexia Verroken
Keyword(s):  
Light Scattering ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Turnaround Time ◽  
Blood Cultures ◽  
Antimicrobial Susceptibility Testing ◽  
Resistant Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Cocci

Abstract Background A bacteremia diagnosis with speeded-up identification and antimicrobial susceptibility testing (AST) is mandatory to adjust empirical broad-spectrum antibiotherapy and avoid the emergence of multi-resistant bacteria. Alfred 60AST (Alifax, Polverara, PD, Italy) is an innovative automated system based on light scattering measurements allowing direct AST from positive blood cultures with rapid results. In this study we aimed to evaluate the system’s performances and turnaround time (TAT) compared to routine AST. Methods The study was conducted during 2 non-consecutive 3-month periods at the microbiology laboratory of the Cliniques universitaires Saint-Luc. All blood cultures detected positive in the 0 AM–10 AM time frame with a pure Gram-positive cocci or Gram-negative bacilli stain were included for Alfred 60AST testing. Two customized EUCAST antibiotic panels were set up composed of 1) a “Gram-negative” panel including cefuroxime, ceftazidime Enterobacteriaceae, piperacillin-tazobactam Enterobacteriaceae, ciprofloxacine, and ceftazidime Pseudomonas 2) a “Gram-positive” panel including cefoxitin Staphylococcus aureus, cefoxitin coagulase-negative (CNS) Staphylococci and ampicillin Enterococci. Categorical agreement (CA), very major errors (VME), major errors (ME), minor errors (mE) and TAT to Alfred 60AST results were calculated in comparison with AST results obtained from direct testing on positive blood cultures with the Phoenix system (Becton Dickinson, Franklin Lakes, NJ, USA). Results Five hundred seventy and one hundred nine antibiotics were evaluated on respectively 166 Gram-negative bacilli and 109 Gram-positive cocci included in the studied population. During the first study period regarding Gram-negative strains a CA of 89.5% was obtained with a high rate of VME (19 and 15.4% respectively) for cefuroxime and piperacillin-tazobactam Enterobacteriaceae. Considering this, Alifax reviewed these antibiotics’ formulations improving Gram-negative bacilli total CA to 92.2% with no VME during the second study period. For Gram-positive cocci, total CA was 88.1% with 2.3% VME, 13.8% ME (mainly cefoxitin CNS) and 12% mE rates both study periods combined. Median TAT to AST results was 5 h with Alfred versus 12 h34 with Phoenix. Conclusion The Alfred 60AST system shows correct yet improvable microbiological performances and a major TAT reduction compared to direct automated AST testing. Clinical studies measuring the impact of the approach on antibiotic management of patients with bacteremia are recommended.

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 &gt;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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