Antibiotic Testing

Susceptibility Testing: From Days to Minutes

Introduction

Each year, millions suffer and die from illnesses that are primarily transmitted by bacterial pathogens.  The magnitude of disease incidence and prevalence is compounded by the emergence of antibiotic-resistant and opportunistic strains.

These factors contribute to the daunting challenge researchers face quickly, easily, and efficiently isolating new and potentially dangerous strains. 

Bacterial isolation, identification, and susceptibility testing are crucial to understanding how resistance evolves and the best means of combatting it with new treatments and methods. Current cell-separation processes are time-consuming, require highly skilled technicians using sophisticated laboratory equipment, and involve delicately complex sample preparation procedures that unnecessarily place the target cells under a lot of stress. 

A seemingly small mishap can lead to a disastrous and costly (in time, resources, and funds) assay failure. Consequently, there is a tremendous demand for a reliable, fast, simple, cost-effective, and replicable process for bacterial isolation from a variety of samples that will shorten the antibiotic susceptibility testing timeline and allow researchers to isolate even the rarest resistance inheriting mutations.

The LeviCellTM system explicitly meets this demand.

The LeviCellTM Solution

The LeviCellTM is an innovative cell separating platform with multiple applications in bacteria isolation, including antibiotic susceptibility testing. The LeviCellTM’s simple three-step workflow gently isolates viable cell populations from dirty, complex, or contaminated samples without the need for markers, labels, pre-processing, calibrating, or cleanup. 
Simply pipette the sample directly into the single-use consumable, load the cartridge into the LeviCell system, wait 30 minutes, analyze and collect your cells of interest.

Results

Enrichment of bacteria from mammalian cells and contaminants

The LeviCell system is ideally suited for isolating infectious pathogens. The completely sterile environment of the single-use consumable “cartridge” and the absence of interface between chip and instrument eliminates the risk for cross-contamination and aerosolization of particles.  The LeviCell system’s high run-to-run reproducibility removes the need for calibration, improving reliability, and simplifying the experiments.

The large diameter of the cartridge channels removed the need for pre-filtering samples to prevent clogging. If the sample can be pipetted into the consumable loading receptacle, the LeviCell can process it.  The LeviCell system’s gentle separation process (<1 psi versus the conventional 70-100 psi) enables maximum isolation and enrichment of viable bacteria from dead, debris, soil, and other cell types without inflicting needless stress on the cells.

Isolation of infected vs. un-infected cells

The levitation height of infected cells is significantly different from that of uninfected cells.  Uninfected cells levitate at a much lower height than infected ones, making it easy to collect and study for downstream analysis.

Antibiotic resistance testing

A similar characteristic is apparent in antibiotic-treated samples. Live or antibiotic-resistant bacteria levitate in a tight group and at a lower height than non-resistant (dead) bacteria. This characteristic holds for all other cells tested on the LeviCell system to date. This distinguishing feature eliminates the need for plating, which decreases the antibiotic resistance testing timeline from a few days to a few minutes. Cells of interest are simply collected and used for downstream analysis to identify resistance genes or mutations.

Antibiotic resistance testing

 Additionally, the bacterial samples can be rapidly and easily enriched directly from swabs or other collection sources such as soil as shown on the left.     

Conclusion

With most infectious diseases being bacterial in origin, determining the sensitivity and resistance of specific bacterial pathogens to a range of antimicrobial agents is a vital component of developing new treatments.  The LeviCellTM enables fast and direct response testing and a highly efficient collection of responding vs. none responsive populations for downstream analysis.