Recent advances in rapid antimicrobial susceptibility testing systems

ABSTRACT

Introduction

Until recently antimicrobial susceptibility testing (AST) methods based on the demonstration of phenotypic susceptibility in 16–24 h remained largely unchanged.

Areas covered

Advances in rapid phenotypic and molecular-based AST systems.

Expert opinion

AST has changed over the past decade, with many rapid phenotypic and molecular methods developed to demonstrate phenotypic or genotypic resistance, or biochemical markers of resistance such as β-lactamases associated with carbapenem resistance. Most methods still require isolation of bacteria from specimens before both legacy and newer methods can be used. Bacterial identification by MALDI-TOF mass spectroscopy is now widely used and is often key to the interpretation of rapid AST results. Several PCR arrays are available to detect the most frequent pathogens associated with bloodstream infections and their major antimicrobial resistance genes. Many advances in whole-genome sequencing of bacteria and fungi isolated by culture as well as directly from clinical specimens have been made but are not yet widely available. High cost and limited throughput are the major obstacles to uptake of rapid methods, but targeted use, continued development and decreasing costs are expected to result in more extensive use of these increasingly useful methods.

KEYWORDS:

• Antimicrobial susceptibility testing
• β-lactamase
• bloodstream infections
• genotype
• lateral flow assay
• maldi-tof ms
• MIC
• pcr
• phenotype
• whole-genome sequencing

Declaration of interest

MR Jacobs has received grant support from bioMerieux and OpGen. DD Rhoads has received grant support from bioMerieux, Beckton Dickinson, BioFire, BioRad, Cepheid, Cleveland Dx, Luminex, OpGen and Qiagen, and consulting fees from Talis. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Article highlights

• Turnaround time of legacy AST methods can be improved.

• Several rapid phenotypic AST methods are available.

• Many molecular methods are available to demonstrate genotypic resistance or biochemical markers of resistance.

• MALDI-TOF MS identification of bacteria is often key to interpreting rapid AST results.

• WGS is not ready for routine use.

• High cost and limited throughput limit use of new technologies.

• These limitations are expected to be overcome in the future.

Additional information

Funding

This paper was not funded.