A prospective study to reduce turnaround time of microbiologically positive blood cultures in patients with sepsis in intensive care unit.

PURPOSE

To determine the accuracy of direct microbial identification (dID) and antimicrobial susceptibility testing by EUCAST rapid antimicrobial susceptibility testing (rAST) methodology from positively flagged blood culture bottles (BCBs) as well as reduction in turnaround time (TAT) compared to standard methodology.

METHODS

It was a hospital based, prospective cohort study conducted over a period of 21 months from March 2020 to November 2021 in which positively flagged blood culture bottles were simultaneously processed by dID ​+ ​rAST and by VITEK®-2 Compact system or Kirby-Bauer disk diffusion method. TAT was calculated as the time (hours) taken from receipt of sample in bacteriology laboratory to release of clinical reports with complete identification and susceptibility testing results in both methods.

RESULTS

Of 301 dID ​+ ​rAST performed in study, 125 (41.5%) BCBs were identified as having one of the 8 reportable micro-organisms by EUCAST rAST standard. Amongst VITEK concordant BCBs with gram-negatives, mean reduction in TAT by dID ​+ ​rAST methodology was 23 ​± ​1.4 ​h. Amongst VITEK concordant gram-negatives, Categorical Agreement (CA) rates for any drug-bug combination were 94.4%, 94.5% and 93.6% and Very Major Error (VME) rates were 3.1%, 3.4% and 3.9% at 4-, 6- and 8-h reading time, respectively.

CONCLUSIONS

EUCAST rAST methodology can generate susceptibility testing reports a day earlier if incorporated into the laboratory workflow. For resource-limited settings, implementing EUCAST rAST approach can be used effectively in early reporting, which can reduce antimicrobial use and improve patient outcomes by promoting timely escalation or de-escalation of empirical antibiotic therapy.