Clinical Laboratory Assessment of Urine Cultures by an Image Analysis Device

9 January 2015

The Automated Plate Assessment System (APAS®, LBT Innovations, South Australia) is a novel device dedicated to screening agar plates. Using image analysis technology, it is able to detect colony growth, enumerate the various colony types detected and apply standard microbiological rule sets to sort each plate into categories suitable for further processing.

It then stratifies cases by the need for further action such as manual review or additional work for identification and antibiotic susceptibility testing.

The purpose of this study was to evaluate the diagnostic performance of an agar plate reading device in screening urine cultures at a busy clinical laboratory.

A total of 1861 clean catch and catheter urines submitted for routine culture to a diagnostic laboratory (SA Pathology, South Australia) were assessed.

1µL of left-over urine samples were inoculated onto TSA sheep blood agar and MacConkey with CV agar (Remel, Lenexa, USA) and incubated in air at 35C for 18h. The plates were read by two microbiologists and separately compared with the results produced by the APAS® instrument.

This study demonstrated the ability of APAS® to read and interpret urine cultures on two agars commonly used in the diagnosis of urinary tract infection with a diagnostic sensitivity of 96.7% and specificity of 97%.

The device was able to detect and enumerate colonies and provided a preliminary identification for the primary isolates on the different agars.

The application of an expert system with standard interpretive rules further enhanced the usefulness of the system.

To read the full article click here

Poster 1493, 1 June
American Society of Microbiology
New Orleans, 2015