ASTar technology

The fully automated ASTar system provides robust and consistent inoculum preparation for AST, with high-speed time-lapse microscopy imaging of bacteria in broth for MIC determination.

Add positive blood culture and load disposables

The process begins with the user transferring an aliquot of the patient sample to the sample preparation cartridge.

The user then choses a suitable AST panel disc that is loaded in the instrument, the barcode on the disk is scanned automatically during loading.

The cartridge barcodes, for the patient sample and cartridge respectively, are scanned by a reader after which the cartridge is loaded in the instrument.

After this all required steps are carried out automatically by ASTar.

Automated sample preparation

The instrument automatically isolates intact and viable bacteria from the sample and the isolated bacteria are placed in a suitable growth medium for subsequent AST.
The system then measures the concentration of the isolated bacteria. Based on this  measurement, bacteria are diluted in a suitable growth medium to produce an appropriate inoculum for AST. A controlled inoculum is an important prerequisite for obtaining stable data, the risk otherwise is that the MIC value could be affected by the bacteria concentration, producing incorrect results.
A subset of the sample is also diluted in a separately enriched growth medium to facilitate AST of organisms that require special growth conditions (fastidious organisms). The capacity to simultaneously handle both types of organisms means that the analysis can begin without knowing bacterial ID, which saves time. The two different inoccula are loaded into culturing chambers prefilled with antibiotics,  through centralized filling ports in the disc by the instrument’s pipetting robot.

AST analysis

The AST disc is incubated in a temperature-controlled part of the instrument and the culturing chambers are read at even intervals by a high-speed, high-resolution optical detection system.

An image analysis algorithm continuously evaluates the collected images to quantify the accumulated bacterial biomass in the culturing chambers. When the incubation is completed, time-dependent bacterial biomass curves are compiled for each antibiotic type and concentration.
The analysis can continue without knowing the bacterial ID up until this point. When the ID is available, MIC is calculated for each antibiotic by a separate algorithm that also weighs in information about the bacterial ID. Using this value as the basis, bacteria are classified as susceptible (S), intermediate (I) or resistant (R) in terms of the current antibiotics.
ASTar facilitates a wide concentration range for each antibiotic, which ensures sufficient coverage around the breakpoints, even if they are updated.

Works with any ID solution

Several approaches for rapid pathogen identification (ID) e.g. molecular techniques and MALDI-TOF mass spectrometry, are available today. Our phenotypic AST solution can be combined with any of these rapid ID technologies, which augments current laboratory capabilities and meets the clinical need for more rapid results.

Thanks to the broad ASTar panel, positive blood culture may be directly analyzed in the ASTar instrument without waiting for pathogen ID, delivering a comprehensive answer in just one test. Pathogen ID is only needed to create the final MIC results report.

The AST technology has been extensively tested on clinically relevant pathogens in correct sample matrix

 

✓ Over 239 different strains including several challenge strains

 

– 25 different species

– Gram positive and Gram negative bacteria

– Fastidious pathogens

 

✓ 30 different antibiotics

 

✓ In total over 3300 bug-drug combinations to date – steadily increasing

The AST technology has been extensively tested on clinically relevant pathogens in correct sample matrix

 

✓ Over 239 different strains including several challenge strains

 

– 25 different species

– Gram positive and Gram negative bacteria

– Fastidious pathogens

 

✓ 30 different antibiotics

 

✓ In total over 3300 bug-drug combinations to date – steadily increasing

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Designed to simplify

Flexible solution enables future panel extensions

Designed to simplify

Flexible solution enables future panel extensions