Background: In November 2005, a large outbreak due to Salmonella enterica serotype Enteritidis(S. Enteritidis) was observed within children who had eaten their meals at 53 school cafeterias inFlorence and the surrounding area. A total of 154 isolates of S. Enteritidis were recovered fromhuman cases between November 2005 and January 2006. All strains were assigned phage type 8(PT8) and a common XbaI pulsotype.This paper reports the findings of a molecular epidemiological investigation performed on 124strains of S. Enteritidis isolated in the years 2005 and 2006 in Florence and the surrounding area,including the epidemic isolates.Methods: One hundred twenty-four human isolates of S. Enteritidis identified in the periodJanuary 2005 – December 2006 were submitted to molecular typing by single enzyme – amplifiedfragment length polymorphism (SE-AFLP).Results: Molecular subtyping by SE-AFLP yielded five different profiles. In the pre-epidemic phase,type A included 78.4% of isolates, whereas only three (8.1%) belonged to type C. All isolates, butone, of the epidemic phase were indistinguishable and attributed to type C. In the post-epidemicperiod, a polymorphic pattern of SE-AFLP types was again recognized but type C accounted for73.3% of the isolates during the first six months of 2006, whereas during the remaining six monthstype A regained the first place, including 52.0% of the isolates.Conclusion: The epidemic event was attributed to the emergence and clonal expansion of a strainof S. Enteritidis PT8-SE-AFLP type C. Circulation of the epidemic clone was much more extensivethan the surveillance and traditional laboratory data demonstrated.
|Numero di pagine||6|
|Rivista||BMC Public Health|
|Stato di pubblicazione||Published - 2007|
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