Molecular detection of Salmonella serovars Enteritidis, Heidelberg and Typhimurium directly from pre-enriched poultry samples

ABSTRACT

1. Salmonella is one of the most important pathogens in public health and it is usually associated with food-borne diseases. Salmonella serovars Enteritidis and Typhimurium are widespread in the world with outbreaks frequently associated with consumption of poultry products; furthermore, there is an increasing public health concern with the wide dissemination of the serovar Heidelberg in poultry flocks.

2. The aim of the experiment was to develop and to validate rapid methods to detect Salmonella serovars Enteritidis, Typhimurium, and Heidelberg by real-time PCRs and test isolates from pre-enriched poultry samples.

3. Three real-time PCRs were developed and used in combination to detect the serovars Enteritidis, Typhimurium and Heidelberg. These assays were validated by the analysis of 126 Salmonella isolates, eight other enteric bacterial species and 34 naturally contaminated poultry samples after pre-enrichment with buffered peptone water (BPW).

4. Real-time PCRs detected the isolates of the most important poultry serovars (Enteritidis, Typhimurium and Heidelberg) with 100% inclusivity and exclusivity in each assay. The PCR identified monophasic variants of the serovars Typhimurium and Heidelberg. All PCRs were validated in detecting these specific serovars directly from pre-enriched poultry samples. The whole analytical procedure was performed in less than 24 h in a veterinary diagnostic laboratory.

KEYWORDS:

• Bacteriological analysis
• chicken
• foodborne diseases
• outbreaks
• salmonellosis

Acknowledgments

The authors thank the staff of Simbios Biotecnologia and Molecular Diagnosis Laboratory of ULBRA for technical support and the laboratories Porto Belo and Simbios Biotecnologia for providing the samples.

Disclosure statement

No potential conflict of interest was reported by the authors.

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Funding

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. This study was also financed by Simbios Biotecnologia, FAPERGS (Fundação de Amparo à Pesquisa do Rio Grande do Sul) and FINEP (Financiadora de Estudos e Projetos). NI and VRL were also financially supported by the National Council for Scientific and Technological Development from Brazil (CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico; process numbers 331 313564/2014-0; 311010/2017-2).