Progress on the development of rapid methods for antimicrobial susceptibility testing

Abstract

Antimicrobial susceptibility testing is essential for guiding the treatment of many types of bacterial infections, especially in the current context of rising rates of antibiotic resistance. The most commonly employed methods rely on the detection of phenotypic resistance by measuring bacterial growth in the presence of the antibiotic being tested. Although these methods are highly sensitive for the detection of resistance, they require that the bacterial pathogen is isolated from the clinical sample before testing and must employ incubation times that are sufficient for differentiating resistant from susceptible isolates. Knowledge regarding the molecular determinants of antibiotic resistance has facilitated the development of novel approaches for the rapid detection of resistance in bacterial pathogens. PCR-based techniques, mass spectrometry, microarrays, microfluidics, cell lysis-based approaches and whole-genome sequencing have all demonstrated the ability to detect resistance in various bacterial species. However, it remains to be determined whether these methods can achieve sufficient sensitivity and specificity compared with standard phenotypic resistance testing to justify their use in routine clinical practice. In the present review, we discuss recent progress in the development of methods for rapid antimicrobial susceptibility testing and highlight the limitations of each approach that still remain be addressed.

Clinical and laboratory considerations for the rapid detection of carbapenem-resistant Enterobacteriaceae

“…41,42 Accelerate Diagnostics, Inc. is the only of these in clinical trials for direct, phenotypic susceptibility testing of bacteria in positive blood culture broths. The Accelerate method utilizes digital microscopy of immobilized live bacteria present in blood cultures to both identify (via fluorescent in-situ hybridization probes) and perform susceptibility (via observation of bacteria growth or inhibition in the presence of antimicrobials).…”

Clinical Evaluation of QMAC-dRAST for Direct and Rapid Antimicrobial Susceptibility Test with Gram-Positive Cocci from Positive Blood Culture Bottles

“…The other strategy is the application of novel techniques such as MALDI-TOF mass spectrometry, PCR-based techniques, microarrays, and microfluidics [7]. The QMAC-dRAST system detects the response of individual bacteria to antimicrobials by time-lapse microscopic observation and image analysis of micro-colony formation at the various concentrations of antimicrobial agents [13].…”

“…In most of These conventional AST methods require relatively longer turnaround time (TAT) due to preceding preparation procedures including blood culture, Gram stain and overnight subculture onto solid medium of flagged positive culture samples [6]. For reducing TAT, various researchers have tried to directly process the positive blood culture (PBC) samples without subculture involving overnight culture [7]. AST methods utilizing direct inoculation from PBC had previously been reported with significant agreement rates compared to reference methods [8,9].…”

Rapid Antimicrobial Susceptibility Testing Using Forward Laser Light Scatter Technology

“…Several methods for rapid AST have been described in the literature (22)(23)(24)(25). Those in clinical use are primarily genotypic and sensitive and offer a rapid TAT.…”

“…The goal of ASPs is to optimize appropriate antimicrobial treatment, thereby reducing adverse outcomes (19)(20)(21) and preventing further antimicrobial resistance. Technologies have evolved to address these needs, and they include not only molecular methods but also methods based on the use of microfluidics, cell lysis detection, mass spectrometry, rapid cytometry, isothermal microcalorimetry, and magnetic bead rotation, among others (22)(23)(24)(25). Forward laser light scatter (FLLS) is another promising emerging technology that depends on electro-optical technology to measure bacterial growth prior to visual assessment.…”