[Tuberculosis surveillance in Sicily, Italy]

Abstract

Objective: To describe the epidemiology of tuberculosis (TB) in Sicily in the years 2010-2013.

Design and participants: Observational study of the TB notifications in the years 2010-2013 by analyzing the Sistema informative delle malattie infettive (SIMI) database and carrying out a molecular epidemiological analysis by spoligo- e 24-loci mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) typing of the Mycobacterium tuberculosis complex (MTBC) isolates identified in Palermo, Italy, in the years 2012-2013.

Results: In the four-year period under study 876 TB cases were notified in Sicily with a mean annual notification rate of 4.4 cases per 100,000 inhabitants. The proportion of TB cases in the foreign-born individuals was increasing and higher than the proportion in Italian-born in the period 2010-2013. The median age of foreign-born patients was significantly lower than the Italian-born (30.5 vs. 51.2 years, p <0,001). Moreover, the distribution by age class was also significantly different, with the largest proportion of TB cases among the foreign-born sub-population in the 15-44 age class, whereas the Italian-born cases were equally distributed in the 15-44, 45-64 and >64 age classes. Eighty-two percent of cases were pulmonary TB. Molecular typing of 151 MTBC isolates identified in Palermo in 2012 and 2013 detected14 lineages and 33 subline ages showing a different distribution among the two patients sub-populations. Only nine MTBC isolates (6.2%) were grouped in four clusters. Two multidrug resistant (MDR) MTBC isolates were identified from an Italian born elderly patient and an Eritrean young patient (Beijing lineage), respectively.

Conclusions: TB epidemiology in Sicily is complex and is rapidly changing. The most striking features are the increasing proportion of cases in the foreign-born population and the wide heterogeneity of MTBC isolates. An integrated approach using both conventional and molecular tools is necessary to accurately assess and monitor TB epidemiology in this Region.