Listeria monocytogenes serotypes in human infections (Italy, 2000-2010)

Background. In developed countries invasive listeriosis is an infection of great concern to public health to due its clinical severity and high fatality rate, despite its low incidence. In Europe, statistically significant increasing trends in listeriosis notification rates from 2005 to 2009 were noted in Austria, Denmark, Hungary, Italy, Spain and Sweden. Materials and methods. The standardized techniques based on phenotype to typing Listeria monocytogenes is the serotyping. In Europe, as elsewhere in the world, about 95% of L. monocytogenes strains isolated from clinical and food samples belongs to serovars 1/2a, 1/2b, 1/2c and 4b. Results. The target of this work is to draw attention to this important and atypical foodborne disease, reporting epidemiological data and serotypes distribution of 251 human L. monocytogenes isolates reported during 2000-2010 to Veterinary Public Health and Food Safety Department of Istituto Superiore di Sanità, focusing on epidemiological trend of invasive listeriosis in Lombardia, a North Italian Region. The serotypes most frequently identified are 1/2a, 4b, 1/2b (in total 92%), but the detection of uncommon serotypes is not missing (1/2c, 3a, 3b, 4d). Conclusions. In Italy the surveillance laboratory network, as well as the foodborne disease network (ENTER-NET), has revealed in the last 11 years an increase trend of listeriosis cases reported likewise with results of Notificable National Infectious Disease surveillance System. This is probably due to a real increase of listeriosis, even if there is a greater sensitivity of the network in some regions.