Molecular epidemiology of tuberculosis in Sicily, Italy: what has changed after a decade?

Abstract

BackgroundWe aimed to investigate the molecular epidemiology of Mycobacterium tuberculosis complex (MTBC) isolates in the province of Palermo, Sicily, Italy, by characterizing 183 isolates identified in the years 2004-2012. A comparison with 104 MTBC strains identified in the same geographic area in the years 1994-2000 was also carried out.MethodsOne hundred eighty-three MTBC isolates identified in Palermo, Italy, in the years 2004-2012 were analyzed by spoligotyping and the 24 mycobacterial interspersed repetitive unit (MIRU)-variable-number tandem-repeat (VNTR) method typing. Susceptibility testing to streptomycin, isoniazid, rifampin and ethambutol was also performed. Furthermore, the spoligotyping dataset obtained from 104 MTBC isolates identified from 1994 to 2000 was reanalyzed. Distribution into lineages and clustering of isolates in the two periods was compared.ResultsOne hundred seventy-seven out of the 183 isolates of MTBC submitted to molecular typing were fully characterized. Of these, 108 were from Italian-born and 69 from foreign-born individuals. Eleven different lineages and 35 families-subfamilies were identified with the most represented lineages being Haarlem (26.5%), T (19.2%), LAM (13.6%) and S (8.5%). Except for the Haarlem lineage, where isolates from foreign-born patients were overrepresented, the distribution of isolates in the families belonging to the Euro-American clone reflected the proportions of the two subpopulations. A total of 27 (15.2%) strains were clustered and three clusters were mixed. Approximately 25% of the 183 MTBC isolates under study proved to be resistant to at least one antiTB drug, with only three isolates categorized as multidrug resistant (MDR). When MTBC isolates identified in the years 1994-2000 were reanalyzed, lineages T (30.8%), LAM (29.8%), Haarlem (16.3%) and S (13.5%) proved to be predominant. No MTBC isolates belonging to CAM, U, CAS, Turkish and Ural lineages were identified.ConclusionsA wide heterogeneity was detected among the MTBC strains isolated in the years 2004-2012. Six lineages were not present among the isolates of the period 1994-2000. Comparison between distribution of lineages in the two consecutive periods depicts rapid and deep changes in the TB epidemiology in Palermo, Italy. An universal and continued laboratory-based surveillance of TB in Sicily is required.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-014-0602-4) contains supplementary material, which is available to authorized users.

Rifampicin-resistant <em>Mycobacterium tuberculosis</em> among tuberculosis-presumptive cases at University of Gondar Hospital, northwest Ethiopia

“…Other studies have reported an association between previous history of TB treatment and anti-TB-drug resistance 48,49. In addition, a study in Palermo, Italy reported a wide heterogeneity among the MTB strains observed, which illustrates rapid changes in TB epidemiology 50. This indicates the existence of ongoing transmission of DR strains, and could indicate weakness in TB prevention and control measures, as it is convoyed by resistance to rifampicin in new cases as well.…”

Molecular epidemiology of Mycobacterium tuberculosis complex strains isolated from livestock and wild animals in Italy suggests the need for a different eradication strategy for bovine tuberculosis

“…In Sicily, an average of 4.4 human cases/100,000 inhabitants was reported until 2013, and the proportion of cases was higher in foreign‐born individuals (Mammina et al., ). A genetic study on MTBC isolates from native and foreign population in the province of Palermo showed a wide genetic heterogeneity of the isolates and four M. bovis strains (3.7%) was identified only from Sicilian‐born patients (Bonura et al., ). The province of Palermo together with Messina and Enna is the ones with the highest prevalence of bTB in cattle so it is possible that human cases are also present.…”

Genetic diversity and molecular epidemiology of multidrug-resistant Mycobacterium tuberculosis in Minas Gerais State, Brazil

“…The standard 24 MIRU-VNTR loci method [ 18 ] was performed based on agarose gel electrophoresis. The simplex PCR product size was determined as previously reported [ 43 ].…”