Journal of Microbial & Biochemical Technology

Rapid detection of viable pathogenic Yersinia spp. by fluorescence in situ hybridization

World Congress and Expo on Applied Microbiology

August 18-20, 2015 Frankfurt, Germany

Alexander Rohde, Jens Andre Hammerl, Bernd Appel, Ralf Dieckmann and Sascha Al Dahouk

Federal Institute of Risk Assessment, Germany

Posters-Accepted Abstracts: J Microb Biochem Technol

Abstract:

Yersinia enterocolitica, the causative agent of yersiniosis, is the third most frequent bacterial zoonosis of foodborne origin in the European Union, after Salmonella enterica and Campylobacter spp. Apart from Y. enterocolitica, Y. pseudotuberculosis and Y. pestis are also important human pathogens. Despite their clinical significance, the detection of pathogenic Yersinia spp. by traditional cultivation techniques is slow and often hampered by the presence of excessive amounts of accompanying bacterial flora. Fluorescence in situ hybridization (FISH), which targets ribosomal RNAs, represents a promising alternative for a more rapid detection of viable Yersinia spp. In this study, highly specific fluorophore-labelled oligonucleotide probes were designed for each of the three target species, Y. enterocolitica, Y. pseudotuberculosis and Y. pestis. Additionally, a genus-specific probe, which binds to the rRNAs of all Yersinia spp., was used as an internal control and a eubacterial probe was employed to enumerate other viable bacteria. Strong FISH signals were observed in rapidly growing as well as in resting cells. By coupling FISH with a direct viable count approach (DVC), a reliable live/dead differentiation was possible. The suitability of FISH for the detection of Yersinia in food was assessed in comparison to ISO 10273:2003. After selective enrichment in Irgasan-Tircacillin- Potassium-Chlorate (ITC) bouillon for 24 hours 1 CFU/g in spiked minced pork meat could be detected with FISH, whereas the detection by ISO 10273:2003 took at least four days. In conclusion, these results demonstrate the potential of FISH as a rapid and sensitive detection method for viable Yersinia spp.

Biography :

Alexander Rohde is a PhD student at the Freie Universität Berlin and is employed by the Federal Institute for Risk Assessment (BfR) in Berlin since 2013. In his work at the Department of Biological Safety, he examines the applicability of novel rapid detection methods like fluorescence in situ hybridization (FISH) for the detection of foodborne pathogens in food.