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We used DNA fingerprinting to analyse tuberculosis (TB) epidemiology in immigrant patients living in two major northern Italian urban areas. The study population included 1999 TB patients (1500 Italian-born and 499 immigrants). Univariate and multivariate logistic regression models were used to identify risk factors related to clustering similar proportions of immigrant and Italian-born patients (46%) had infection with TB strains that belonged to genetic clusters. This supports the hypothesis that the disease in foreign patients is more likely to have arisen from reactivation of latent infection acquired in the country of origin than from recent transmission. Gender, age, human immunodeficiency virus infection and drug resistance were not significantly linked to TB clustering. Risk factors associated with strain clustering were country of origin (Somalia, adjusted OR (AOR) 3.19, p 0.017; Peru, AOR 2.86, p 0.014; and Senegal, AOR 2.60, p 0.045) and city of residence. Immigrant status in the larger urban area was an independent risk factor for infection with clustered TB, as reinforced by a subanalysis of the Senegalese group. In conclusion, variations in TB transmission were observed among immigrants from different countries and even within national groups, where living conditions have been found to exert a profound impact. These results emphasize the importance of improving social integration of immigrant subjects in order to limit risks of TB transmission in developed countries.

Background: Correct identification of individuals with latent tuberculosis infection (LTBI) is a crucial element of the elimination strategy, allowing their adequate treatment. In addition to tuberculin skin test (TST), the Quantiferon test (QFT, based on whole blood gamma-interferon release) had been recently proposed. Aim of the study is to compare this test to TST for identification of LTBI in a non-selected population, in order to verify their value in identifying truly infected individuals (entitled to receive preventive chemotherapy), and to exclude from treatment those having a positive TST for other reasons (e.g. after BCG vaccination)., Methods: 136 consecutive persons (78 males, mean age 34 +/- 9 years) referred to the clinic for TST were recruited (78 born in low--or middle--income countries). Based on their history, the cases were divided into 4 groups: 1) recently traced contacts of whom 18 TST negative and 28 TST positive; 2) 22 screening subjects, all TST negative; 3) BCG vaccinated subjects (14); and 4) 54 subjects already undergoing treatment of LTBI for exposure to TB., Results: The overall agreement between TST and QFT was 72% (64% in TST positive and 88.4% in TST negative subjects). The proportion of TST positive/QFT negative BCG vaccinated individuals was 23.1%. The K coefficient was 0.474 in recently traced contacts, 0.366 in BCG vaccinated individuals and 0.451 overall., Conclusions: The study results suggest that agreement between TST and QFT is lower in TST positive than in negative subjects, being lower in individuals treated for LTBI. Quantiferon does not seem to have brought significant improvement in the diagnosis of LTBI.

A mycobacterium isolated form a cultured snakehead with nodular lesions was identified on the basis of high performance liquid chromatography (HPLC) profile of cell wall mycolic acids, and confirmed by conventional tests, as Mycobacterium poriferae, a species previously isolated only from a marine sponge. The profiles of M. poriferae, Mycobacterium aurum and Mycobacterium parafortuitum are here reported for the first time.