MOLECULAR EPIDEMIOLOGY OF MYCOBACTERIUMTUBERCULOSIS COMPLEX IN PALERMO, ITALY

Background: We aimed to investigate the molecularepidemiology of Mycobacterium tuberculosiscomplex (MTBC) in the province ofPalermo, Italy, by characterizing 183 isolatesidentified in the years 2004-2012. A comparisonwith 104 MTBC strains identified in thesame geographic area in the years 1994-2000was also carried out.Methods: MTBC isolates were analyzed byspoligotyping and the 24 mycobacterial interspersedrepetitive unit (MIRU)-variablenumbertandem-repeat (VNTR) method typing.Susceptibility testing to streptomycin,isoniazid, rifampin and ethambutol was alsocarried out. Furthermore, the spoligotypingdataset obtained from 104 MTBC isolates identifiedin the years 1994-2000 in the same geographicarea was reanalyzed. Distribution intolineages and clustering of isolates in the twoperiods was compared.Results: Out of the 177 isolates of MTBC submittedto molecular typing, 108 were fromItalian-born and 69 from foreign-born individuals.Eleven different lineages were identifiedwith the most represented being Haarlem,T, LAM and S. Except for the Haarlem lineage,where isolates from foreign-born patients wereoverrepresented, the distribution of isolates inthe families belonging to the Euro-Americanphylogeographical clone reflected the proportionsof the two subpopulations. A total of 27strains (15.2%) were clustered and three clusterwere mixed. 25% of the isolates proved to beresistant to at least one anti-TB drug, with only three isolates being categorized as multidrugresistant (MDR). When MTBC isolates identifiedin the years 1994-2000 were reanalyzed,lineages T, LAM, Haarlem and S proved alsoto be predominant. No MTBC isolates belongingto CAM, U, CAS, Turkish and Ural lineageswere identified in this set of isolates. Moreover,the proportion of clustered isolates was similar,but all the clustered isolates were from Italianpatients.Conclusions: A wide heterogeneity (11 lineagesand 35 families-subfamilies) was detectedamong the MTBC strains isolated inthe years 2004-2012. Ten clusters were identified,of which three mixed and four involvingnewly identified lineages. Compared with isolatesfrom 1994-2000, six new lineages weredetected. Comparison between distribution oflineages and the characteristics of isolates inthe two consecutive periods depicts rapid anddeep changes in the tuberculosis epidemiologyin Palermo, Italy.