A Rapid Procedure for Bacterial Identification and Antimicrobial Susceptibility Testing Directly from Positive Blood Cultures

The Analyst ◽  
2021 ◽  
Author(s):  
Bo Sun ◽  
Weili Hong ◽  
Pu Wang ◽  
Guang-Hui Zheng ◽  
Xixiong Kang ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Blood Cultures ◽  
Antimicrobial Susceptibility Testing ◽  
Bacterial Identification ◽  
Rapid Procedure

There is an urgent need to develop a rapid procedure that can rapidly identify and obtain antimicrobial susceptibility testing (AST) results directly from positive blood cultures. Here, we report a...

scholarly journals Integrating Bacterial Identification and Susceptibility Testing: A Simple and Rapid Approach to Reduce the Turnaround Time in the Management of Blood Cultures

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Dariane C. Pereira ◽  
Luciano Z. Goldani
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Bloodstream Infections ◽  
Turnaround Time ◽  
Blood Cultures ◽  
Antimicrobial Susceptibility Testing ◽  
Bacterial Identification ◽  
Current Standard ◽  
Short Period ◽  
Infection Diagnostics

We evaluated a rapid bacterial identification (rID) and a rapid antimicrobial susceptibility testing by disk diffusion (rAST) from positive blood culture to overcome the limitations of the conventional methods and reduce the turnaround time in bloodstream infection diagnostics. The study included hemocultures flagged as positive by bacT/ALERT®, identification by MALDI-TOF MS, and rAST. The results were compared to identification and antimicrobial susceptibility testing (AST) results by current standard methods, after 24 h incubation. For rAST categorical agreement (CA), very major errors (VME), major errors (ME), and minor errors (mE) were calculated. A total of 524 bacterial samples isolated from blood cultures were obtained, including 246 Gram-negative (GN) and 278 Gram-positive (GP) aerobes. The overall concordance of rID was 88.6%, and it was highest among GN (96%). A total of 2196 and 1476 antimicrobial agent comparisons were obtained for GN and GP, respectively. Evaluation of rAST, CA, VME, ME, and mE disclosed 97.7, 0.7, 0.5, and 1.1% for GN and 98.0, 0.5, 0.7, and 0.8% for GP, respectively. Meropenem CA, VME, and ME were 98.3, 0.5, and 0.5%, respectively; mE was not observed. Oxacillin CA, ME, and mE were 97.4, 1.6, and 0.6%, respectively; VME was not observed. Overall, kappa scores of the results of the comparisons demonstrated the high agreement between rAST and the standard method. Identification and AST of aerobic bacteria from positive blood cultures after a short period of incubation on solid blood agar is a fast and reliable method that may improve the management of bloodstream infections.

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 Clinical and Financial Benefits of Rapid Bacterial Identification and Antimicrobial Susceptibility Testing

1999 ◽  
Vol 37 (5) ◽  
pp. 1415-1418 ◽  
Author(s):  
Joan Barenfanger ◽  
Cheryl Drake ◽  
Gail Kacich
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Average Length ◽  
Antimicrobial Susceptibility Testing ◽  
Variable Cost ◽  
Bacterial Identification ◽  
Time Period ◽  
Normal Manner ◽  
Financial Benefits ◽  
Evening Shift

To assess the expected clinical and financial benefits of rapid reporting of microbiology results, we compared patients whose cultured samples were processed in the normal manner to patients whose samples were processed more rapidly due to a minor change in work flow. For the samples tested in the rapid-reporting time period, the vast majority of bacterial identification and antimicrobial susceptibility testing (AST) results were verified with the Vitek system on the same day that they were available. This time period was called rapid AST (RAST). For RAST, a technologist on the evening shift verified the data that became available during that shift. For the control time period, cultures were processed in the normal manner (normal AST [NAST]), which did not include evening-shift verification. For NAST, the results for approximately half of the cultures were verified on the first day that the result was available. The average turnaround time for the reporting of AST results was 39.2 h for RAST and 44.4 h for NAST (5.2 h faster for RAST [P = 0.001]). Subsequently, physicians were able to initiate appropriate antimicrobial therapy sooner for patients whose samples were tested as part of RAST (P = 0.006). The mortality rates were 7.9 and 9.6% for patients whose samples were tested as part of RAST and NAST, respectively (P = 0.45). The average length of stay was 10.7 days per patient for RAST and 12.6 days for NAST, a difference of 2.0 days less for RAST (P = 0.006). The average variable cost was $4,927 per patient for RAST and $6,677 for NAST, a difference of $1,750 less per patient for RAST (P = 0.001). This results in over $4 million in savings in variable costs per year in our hospital.

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