5th ASM - Orals Molecular Epidemiology

Session 1: Friday 5 June, 09.30

Geraldine Smith, from the Health Protection Agency Centre for Infections, London, UK, showed the application of the “variable number tandem repeat” (VNTR) analysis as a rapid sequence‑based typing method for VTEC O157. VNTR may represent an alternative or a complement to pulsed field gel electrophoresis (PFGE) in the identification of potentially linked cases of VTEC O157.

Marie Bugarel, from the AFSSA, Maisons-Alfort, France, presented a multi-parametric PCR test targeting virulence-related genes located on genomic pathogenicity islands other then the Locus for Enterocyte Effacement (LEE). These non-LEE effectors could represent a tool for evaluating the virulence of VTEC strains from non-human sources and contribute to a sort of molecular risk assessment of their potential pathogenicity to humans.

For Salmonella, Giorgia Borriello, from the Istituto Zooprofilattico Sperimentale del Mezzogiorno, Portici (NA), Italy, presented novel data on the characterization of salmonella isolates from water buffaloes by PCR detection of multiple prophage genes and virulence-associated genes. Strains belonging to the same serotype often showed different PCR prophage profiles, suggesting the potential usefulness of this typing method.

Finally Aurora Echeita, Centro Nacional de Microbiología, ISCIII, Majadahonda-Madrid, Spain, presented a study on the evolution of a monophasic variant of Salmonella identified as S. enterica serotype 4,5,12:i:-, which is spreading in many European countries. A combination of molecular techniques (microarrays, PCR and sequencing of the operon fljAB deletion, PFGE, and MLVA) confirmed the theory that S. Typhimurium U302 is the ancestor of S. 4,5,12: i:- and that the the fljAB deletion had occurred on at least in two different occasions.

All the presentations stimulated lively discussion and the session represented a good example of the contribution of molecular epidemiology to public health.

Chairs: Alfredo Caprioli (ISSA) & Alvaro San Millan (UCM)

Session 2: Friday 5 June, 11.00

István Tóth: A PCR Phage Typing System Based on Detecting Enterohaemorrhagic Escherichia coli O157 (EHEC) Specific Phages.

Hendrik-Jan Roest: Geographical distribution of MLVA types of Coxiella burnettii isolates from goats in The Netherlands.

Simone M Cacciò: Polymorphisms in the CpA135 gene of Cryptosporidium and development of a PCR-RFLP genotyping assay.

Wioletta Rozej: Application of Multitemperature Single Stand Conformation Polymorphism (MSSCP) technique for the differentiation of Cryptosporidum species – preliminary results.

Fraser Gormley: Campylobacter jejuni – the advantages of combined phenotyping and genotyping in outbreak investigation.

A common theme stressed by all speakers was the necessity of developing and testing appropriate molecular methods to answer questions related to pathogen identification, transmission routes and epidemiologic investigations. The presented approaches varied from analysis of microsatellites, to the use of sophisticated electrophoretic techniques to define genetic variants, to a combination of genotype and phenotype analyses to trace infection sources. Progresses and future challenges were discussed by the speakers, and the heterogeneous nature of the subjects presented enriched the session. All the presentations were followed by short but lively discussion, with questions from the chairpersons and from the audience. The high quality of the scientific works has triggered more discussion during poster sessions.

Chairs: Dr. Simone M Cacciò (ISS) & Dr. Grzegorz Madajczak (PZH)