Mammina C

Use of pulsed field gel electrophoresis (PFGE) and single-enzyme amplified fragment length polymorphism(SE-AFLP) to subtype isolates of Salmonella entericaserotype enteritidis

Serotype Enteritidis is still the main serotype infecting humans and poultry worldwide. Subtyping of isolates belonging to this serotype is difficult, because of the wide clonal circulation of a few bacterial clones. This study presents the results of the characterization of 49 isolates of S. Enteritidis identified at the southern Italy Centre for Enteric Pathogens (CEPIM) during the years 2002-2003 by the methods of Pulsed Field Gel Electrophoresis (PFGE) and Single-Enzyme Amplified Fragment Length Polymorphism (SE-AFLP). Clustering of the strains by SE-AFLP and PFGE is very similar, but the first technique is more rapid and user-friendly and does not require sophisticated equipment. Further work is needed for a more accurate assessment of SEAFLP, but preliminary results suggest it could be a promising support to epidemiological investigations.

Salmonella enterica serotype Infantis in southern Italy from 2000-2005: molecular typing of isolates from human and non human sources

Serotype Infantis ranks within the top-five Salmonella serotypes in many European countries. An association between this serotype and the poultry ecosystem is apparent in some geographic areas and could account for its persistent or emergent role as causative agent of human salmonellosis. Recently, in southern Italy isolation from eggs and poultry has become increasingly frequent, and in one case the egg yolk also cultured positive. Molecular typing was performed to assess the possible relationship among isolates from human, food and animal sources. Isolates of serotype Infantis identified in southern Italy between 2000 and 2005 rom various sources were submitted to pulsed field gel electrophoresis (PFGE) by a CHEF-Mapper apparatus fter endonuclease digestion of DNA by XbaI. PFGE patterns of isolates from swine and poultry reservoirs showed distinctive PFGE profiles and human solates shared pulsotypes with isolates from both sources. Moreover, egg isolates from different farms ppeared very similar to each other. Epidemiological investigation and risk assessment can obtain reliable and useful pointers from he pplication of molecular epidemiology techniques.