Customer testimonial : Ludwig Maximilian University of Munich (LMU)

Logo LMU

The good image quality on the screen and the ability, in real time, to see the dish on the Scan 4000, provide a reliable setup. Even more difficult functions, such as evaluating low growth and detecting Streptococci hemolíticos on blood agar, are easy.

Dr Georg WOLF, Bacteriologist, Central Laboratory for Bacteriological Diagnostics (LCDB) at Ludwig Maximilian University of Munich (LMU) Veterinary Faculty, Munich
GERMANY

The Central Laboratory for Bacteriological Diagnostics (LCDB) at Munich’s Ludwig Maximilian University of Munich (LMU) veterinary faculty carries out around 6,000 analyses using patient samples from nearby clinics and pathology departments, and to a limited extent, submissions from veterinary practices.


Location: Munich, GERMANY

Works with : Scan 4000

Scan 4000, Germany’s first device for antibiotic resistance according to CLSI VET01 standard

Interview with Dr Georg WOLF, Bacteriologist at LMU’s LCDB:

Why did you need an automatic inhibition zone reader?

For a long time, we were looking for a measurement and analysis technology for agar diffusion tests with a high level of flexibility and user-friendliness for disk configuration and qualitative evaluation of antibiotics.

What was your procedure without using a PLC?

Manual evaluation of templates and gauges is done in accordance with the four-eye principle, where high concentration and flexibility are required. Data are qualified as resistant, intermediate or sensitive for reporting. In the event of implausible results, Petri dishes are stored for a week.

What were your expectations?

We wanted a device that could automatically or semi-automatically measure low-contrast bacterial colonies after adjusting the inhibition zones. For our blood agar applications, we needed reliable identification of minimal growth and hemolyzing bacterial colonies. We wanted simple clinical reporting and statistical evaluation, without any programming effort. For this, we needed simple, transformable files with original images, inhibition zones, as well as qualitative antibiotic assessments.

At the end of 2015, we became aware of the development of a new LED lighting technology for Interscience automatic counters that matched our expectations.

What are your first impressions of the Scan 4000 in your laboratory?

The user interface is simple and intuitive to use. Immediately after inserting a plate into the Scan 4000, the image zooms in on the area to be analyzed and automatically adjusts the brightness. From time to time, it may be necessary to change the lighting with a click of the mouse, particularly on blood agar plates. Automatic measurement of the inhibition zone is precise, and readjustment is very easy to manage the size of the inhibition zone, as well as the position of the antibiotic disc.

Good image quality on the screen and its capacity, in real time, to see the dish on the Scan 4000, provide reliable adjustment. Even more difficult functions, such as evaluating low growth and detecting hemolytic Streptococci on blood agar, are easy.

What do you think of the processing of the data files?

All images with measurements and results can be stored in files (sessions) that allow easy access and possible later correction. Sessions are expandable, and measurements can be reactivated at a later date.

In addition to session storage, in our laboratory we use PDF files for internal communication of our reports, which include plate images and tables as MS-ExcelTM files.

Each file type can be created via a button for a complete session. We will use the MS-ExcelTM file records as the basis for clinical reports and for statistical analysis of all resistance test results with our standard software.

Have you used the colony counter function?

So far, we haven’t investigated the suitability of Scan 4000 as a colony counter, since we carry out semi-quantitative studies for the routine diagnosis of bacterial infections. This function was not a decisive factor in our decision to buy.

Judging by our impressions of the optical quality and the counter software, there are virtually no limitations for colony detection. The definition of measurement zones can be easily modified by means of exclusion or inclusion zones. The software’s counting function is intuitive, the work is simple and distinct counts according to the pigmentation of different colonies on chromogenic media is child’s play.

How did you make your choice?

We tested several devices. The devices we found so far were not selected after inspection of the specifications or after a telephone conversation with another user. One device, which we had tested, was eliminated due to insufficient detection quality of low-contrast colonies. Measurement of zones of inhibition on agar plates was also inadequate. In addition, there was insufficient flexibility in the choice of antibiotic discs.

Why did you choose Interscience?

The one-week trial of Interscience’s Scan 4000 completely dispelled our previous scepticism about automated evaluation of inhibition zones. The glare-free visualization of bacterial cultures and other technical specifications of the Scan 4000 specified by the manufacturer, motivated us to benefit from a demonstration in our Institute.

In a very competent, pleasant and brief presentation, the staff of a local distributor, in collaboration with the Interscience representative, explained the technical potential of the device and software for colony counting and for reading inhibition zones. Without even reading the user manual, our test reports were created and easy to apply, in our routine tests for automated evaluation of resistance profiles.

ANALYSES PROTOCOL

Type of samples: veterinary samples for bacterial isolation and evaluation of
antibiotic resistance.
Number of analyses: 6000/year.
Bacteria: the full spectrum of fast-growing bacteria.
Culture media: Mueller-Hinton media with or without blood for agar diffusion tests.
Detection of inhibition zones: automatic.
Resistance assessment of relevant isolates is carried out by agar diffusion testing, using up to up to 16 antibiotics per isolate. Reports are species-specific, and the evaluation of diffusion according to CLSI VET01 for animal species and bacteria, available in the standard. Otherwise, specific human and manufacturers’ standards are used.