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A Cannas,1 O Butera,1 G Gualano,2 MP Parracino,3 C Venditti,1 A Mazzarelli,1 F Palmieri,2 E Girardi,3,* A Di Caro1,* 1Microbiology and Bio-Repository Unit, National Institute for Infectious Diseases “L. Spallanzani” IRCCS, Rome, Italy; 2Respiratory Infectious Diseases Unit, National Institute for Infectious Diseases “L. Spallanzani” IRCCS, Rome, Italy; 3Clinical Epidemiology Unit, National Institute for Infectious Diseases “L. Spallanzani” IRCCS, Rome, Italy*These authors contributed equally to this workCorrespondence: A CannasNational Institute for Infectious Diseases “L. Spallanzani” IRCCS, Via Portuense 292, Rome 00149, ItalyTel +39 06 5517 0905Email angela.cannas@inmi.itPurpose: Multidrug-resistant tuberculosis (MDR-TB) is a major burden to public health in low incidence countries in Europe. The aim of this study was to attempt to have a better insight into the trends of MDR-TB in the metropolitan area of Rome, within the Italian and the foreign-born population, based on microbiological and demographic data.Patients and methods: We performed a prospective study, collecting microbiological data based on phenotypic drug-resistant testing (DST) of TB strains consecutively isolated in a referral hospital in Rome, the capital city of a low TB incidence country, over a 6-year period, and correlated them to the geographical origin of patients. This study was carried out in a referral hospital for patients with drug-resistant TB from the whole region.Results: Drug-resistance data from 926 patients with a microbiological diagnosis of TB from 2011 to 2016 show a 5.5% rate of MDR-TB, mostly occurring in patients born in a single East European country, that has a high incidence of MDR-TB. The strains isolated from these patients frequently carry additional resistances, leading to an increased risk of developing extensively drug-resistant (XDR) TB.Conclusion: In the great metropolitan area of Rom

Background: The presence in a geographic area of Mycobacterium tuberculosis (Mtb) strains belonging to different phylogeographic lineages and showing different drug susceptibility patterns may suggest recent transmission, with implications in terms of patient clinical management and disease control. The aim of this study was to carry out a preliminary epidemiological investigation of tuberculosis (TB) cases in Rome. Methods: A total of 232 Mtb isolates, collected from new or previously treated patients, admitted between 2008 and 2014 at 2 hospital settings in Rome with a diagnosis of TB, were analyzed by spoligotyping and analyzing 24 variable-number tandem repeats (VNTR) mycobacterial interspersed repetitive-unit (MIRU) loci. The SITVIT2 database and the MIRU-VNTRplus web applications were used to identify the strain genotypes and to generate phylogenetic trees. Results: Based on the position on the phylogenetic tree, 97.4% of the strains were associated with 1 of the 7 main lineages. The Euro-American lineage was the most commonly represented (81.9%) within both Italian and foreign-born populations, although all main lineages were present. The highest frequency of drug-resistant strains was found among the East-Asian lineage (Beijing genotype) isolated from foreign-born patients. Conclusions: Dynamics of TB transmission in Rome indicate recent spread of Mtb strains belonging to phylogeographic lineages and clades usually found in countries and geographic areas with a high incidence of TB, similarly to what is observed in most metropolitan areas in Western Europe. Knowledge from molecular and classical epidemiology provides an important tool for disease control.

The evaluation of diagnostic accuracy of new in vitro diagnostic assays for tuberculosis infection has been hampered by the lack of a standard reference test. The aim of this study was to compare sensitivity and specificity of interferon gamma assays for latent tuberculosis infection by assessing the association of test results with tuberculosis occupational exposure and by using latent class analysis. We analysed data from 115 healthcare workers on whom tuberculin skin test (TST) and the following in vitro tests were performed: in-house ELISPOT for RD1 proteins, T.SPOT-TB and Quantiferon-TB Gold. Results of all tests were associated with increased occupational risk of exposure to Mycobacterium tuberculosis, but only TST was associated with Bacillus Calmette-Guerin (BCG) vaccination. Sensitivity/specificity (95% confidence intervals) estimated by a latent class model were: 99.9%/64.2% (53.0-74.1) for TST, 95.3% (61.8-99.6)/87.5% (78.0-93.2) for in-house ELISPOT, 96.7% (69.3-99.7)/85.6%(75.3-92.0) for T.SPOT-TB, and 76.3% (55.9-89.1)/93.6% (85.4-97.3) for Quantiferon. The estimated specificity of in vitro assays was higher than that of TST also among individuals who were not BCG-vaccinated. In conclusion, when used in healthcare workers, in vitro assays may provide a significant increase of specificity for tuberculosis infection compared to TST, even among non vaccinated individuals, at the cost of some sensitivity.