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Updated: Feb 27, 2026
A High-throughput Platform for the Screening of Salmonella spp./Shigella spp.
Published on: November 7, 2018
Comparison of classical serotyping and PremiTest assay for routine identification of common Salmonella enterica
Pierre Wattiau1, Mieke Van Hessche, Christine Schlicker
1Department of Bacteriology and Immunology, Veterinary and Agrochemical Research Centre, Brussels, Belgium. Pierre.Wattiau@var.fgov.be
Abstract:
The commercial PremiTest Salmonella kit uses a multiplexed DNA typing test aimed at identifying common serovars of Salmonella enterica. It was used in assays over a 9-month period in the Belgian reference laboratory that performs the routine identification of Salmonella strains of animal origin. A blind analysis of 754 strains was conducted in parallel by classical serotyping and the PremiTest assay. Full results were available for 685 strains (90.8%) by serotyping, while the remaining 69 strains were found to be nontypeable due to either a lack of surface antigen expression or autoagglutination properties. When the PremiTest assay (version 4.2) was performed with crude bacterial extracts, it identified 658 strains (87.3%), including most strains found to be nontypeable by serotyping. In contrast, it gave no, wrong, dual, or noninterpretable results for 96 strains, for which 23 were caused by assay failures. When purified DNA instead of crude extracts were tested, the number of strains successfully identified to the serovar level increased to 714 (94.7%), while all assay failures were cleared. Our conclusion is that, in its actual development stage, the application of the investigated kit to purified DNA samples offers a valuable alternative to classical serotyping for laboratories performing the routine identification of Salmonella strains belonging to commonly encountered serovars and isolated from a given geographical area, assuming that the system has been validated beforehand with a significant number of strains originating from that particular area.
Insights
The PremiTest Salmonella kit offers a valuable alternative for identifying common Salmonella serovars. Using purified DNA with the kit significantly improves accuracy compared to classical serotyping, especially for difficult-to-type strains.
Area of Science:
- Microbiology
- Molecular Biology
- Food Safety
Background:
- Classical serotyping is the standard for Salmonella identification but can be time-consuming and yield non-typeable results.
- The PremiTest Salmonella kit offers a multiplexed DNA typing approach for identifying common Salmonella enterica serovars.
Purpose of the Study:
- To evaluate the performance of the PremiTest Salmonella kit in a routine reference laboratory setting.
- To compare the efficacy of the PremiTest assay using crude bacterial extracts versus purified DNA against classical serotyping.
Main Methods:
- A blind analysis of 754 Salmonella strains of animal origin was conducted using both classical serotyping and the PremiTest assay (version 4.2).
- The PremiTest assay was performed using both crude bacterial extracts and purified DNA for comparison.
- Results were compared to identify Salmonella enterica serovars and assess assay reliability.
Main Results:
- Classical serotyping provided full results for 90.8% of strains; 9.2% were non-typeable.
- Using crude extracts, PremiTest identified 87.3% of strains, with 12.7% yielding no, wrong, dual, or noninterpretable results.
- Employing purified DNA increased successful identification to 94.7% and eliminated assay failures.
Conclusions:
- The PremiTest Salmonella kit, when applied to purified DNA, is a valuable alternative to classical serotyping for routine identification of common Salmonella serovars.
- Pre-validation with local strains is recommended for laboratories implementing this DNA-based typing method.
