Time to clinical response in sepsis associated with an algorithm for blood-culture pathogen identification using matrix-assisted laser desorption ionization time-of-flight mass spectroscopy

Faster infection diagnostics for intensive care unit (ICU) patients

INTRODUCTION

: The patient admitted to intensive care units (ICU) is critically ill, to some extent immunosuppressed, with a high risk of infection, sometimes by multidrug-resistant microorganisms. In this context, the intensivist expects from the microbiology service quick and understandable information so that appropriate antimicrobial treatment for that particular patient and infection can be initiated.

AREAS COVERED

: In this review of recent literature (2015-2021), we identified diagnostic methods for the most prevalent infections in these patients through a search of the databases Pubmed, evidence-based medicine online, York University reviewers group, Cochrane, MBE-Trip, and Sumsearch using the terms: adult, clinical laboratory techniques, critical care, early diagnosis, microbiology, molecular diagnostic techniques, spectrometry and metagenomics.

EXPERT OPINION

: There has been an exponential surge in diagnostic systems used directly on blood and other samples to expedite microbial identification and antimicrobial susceptibility testing of pathogens. Few studies have thus far assessed their clinical impact; final outcomes will also depend on preanalytical and post-analytical factors. Besides, many of the resistance mechanisms cannot yet be detected with molecular techniques, which impairs the prediction of the actual resistance phenotype.

Nonetheless, this is an exciting field with much yet to explore.

Impact of Accelerate Pheno and BacT/Alert Virtuo on Clinical Processes and Outcomes in Patients with Sepsis and Concurrent Gram-Negative Bacteremia

The Accelerate Pheno and BacT/Alert Virtuo systems may improve bacteremia management. Here, we evaluated the impact of both devices on outcomes in patients with sepsis and concurrent Gram-negative bacteremia. This quasiexperimental study included a retrospective preimplementation and a prospective postimplementation group. Patients ≥18 years old with Gram-negative bacteremia were included. Patients with neutropenia, pregnant patients, those who were transferred from an outside hospital with active bloodstream infections, and those with polymicrobial bacteremia were excluded. Blood culture incubation in the BacT/Alert 3D device and microdilution antimicrobial susceptibility testing from culture plate growth were used prior to implementation of the BacT/Alert Virtuo and Accelerate Pheno systems. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) identification directly from blood culture was used pre- and postimplementation. Time to Gram stain results, identification, susceptibility reporting, initiation of narrow-spectrum Gram-negative therapy at 72 h, 30-day inpatient mortality, sepsis resolution, and length of hospital stay were evaluated. A total of 116 patients were included (63 preimplementation, 53 postimplementation). Median times to Gram stain and susceptibility results were significantly shorter postimplementation (P < 0.001). The postimplementation group had an improved hazard ratio for narrow-spectrum Gram-negative therapy at 72 h (hazard ratio [HR], 2.685 [95% confidence interval {CI}, 1.348 to 5.349]), a reduced hazard ratio for 30-day inpatient mortality (adjusted HR [aHR], 0.150 [95% CI, 0.026 to 0.846]), and improved sepsis resolution (92.5% versus 77.8% [P = 0.030]). The length of hospital stay was unchanged after implementation. We conclude that implementation of the BacT/Alert Virtuo and Accelerate Pheno systems improved microbiology laboratory processes, antibiotic utilization processes, and clinical outcomes. These data support the use of rapid diagnostics in sepsis with concurrent Gram-negative bacteremia.