AMS Laboratories - Organism Identification


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Organism Identification

BACKGROUND:

The Qualicon RiboPrinter™ provides an automated system for the identification and characterization of bacterial isolates. It allows for the comparison between different bacterial isolates at the sub-species or strain taxonomic level. Genotypic comparison gives much greater certainty in determining sources of contamination than traditional methods and also allows tracking or characterization of commercially useful strains.

PRINCIPLE OF TEST:

The Qualicon RiboPrinter™ operates on the principle that the bacterial ribosomal DNA is relatively stable within a given strain. Unlike traditional biochemical tests, identification is not reliant on the expression of certain genes, which may be affected by the conditions in which the bacteria grow.

By breaking up the DNA strand using specific restriction enzymes, different sized fragments will be produced. These fragments are then separated by electrophoresis and an image of the resulting pattern is recorded. Differences in the size and number of fragments will give each strain a distinct pattern.

Comparison of the resulting DNA fingerprint to the DuPont database allows the identification of a wide variety of different genera, species and strains. At present there are over 6000 patterns to which an isolate can be compared.

Highly similar patterns are assigned to specific Ribogroups. Comparison between these allows you to analyze results in far greater detail than traditional biochemical tests as isolates are being compared at the strain rather than just species level. Contaminants can be compared to environmental isolates, or those from other samples, both current and historical, to determine where problems are originating. Additionally changes in the predominant strain over time can be observed allowing for changes in cleaning and disinfection protocols. New cultures can be compared to reference strains.

Note: The enzyme and specific setup requirements do vary between different bacterial types. Most bacterial can be identified and characterized using the EcoR1 enzyme. The more commonly encountered exceptions to this are Salmonella and Micrococcus species which require PvuII and Campylobacter which needs PstI. Lactobacillus spp. require the addition of an additional reagent.

Only 1 enzyme can be used per batch. The system utilizes a batch of 8 samples per each machine run.

SAMPLE REQUIREMENTS:

A submission form should be completed detailing the sample(s) to be examined and any comparisons required. Any additional information that you have regarding identification, will help us to minimize turnaround time e.g. growth conditions, API results etc

Pure isolates can be submitted as broth or agar cultures. Once received these will be streaked onto the appropriate agar, checked for purity and processed. Plate cultures less than 24 hours old can be set up immediately provided we are advised in advance and there are sufficient samples to justify the run.

A batch for the Qualicon RiboPrinter™ consists of 8 samples. If you are submitting samples in lots of 8, these can be run straight away. Single samples will be grouped with others as they become available. Urgent samples can be processed without needing to wait for a full run - additional costs will apply.

Each run takes 8 hours to complete. Multiple runs can be commenced on the same day - up to a maximum of 4 batches (32 samples).

TEST PROTOCOLS:

Test description

Test Code

Turnaround time

Qualicon RiboPrinter™

TMI 001

see above

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