Genotyping analyses of tuberculosis transmission among immigrant residents in Italy

Abstract

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.

Methodological and Clinical Aspects of the Molecular Epidemiology of Mycobacterium tuberculosis and Other Mycobacteria

“…In general, TB in immigrant populations in lowendemicity settings is thought to result mostly from reactivation of infection acquired prior to or shortly after immigration (435,(437)(438)(439). Also, the studies described above have shown that urban settings are a risk factor for TB transmission (445).…”

“…Here too, the clustering rate was significantly higher among the homeless population; by multivariate analysis, homelessness, male sex, an age of Ͻ40 years, the presence of pulmonary TB, work as a day laborer or unemployment, and being born in Japan were all associated with clustering, as was disease caused by Beijing genotype strains (438). In two urban areas in Northern Italy (Milan and Brescia), a 7-year population-based study showed that risk factors for strain clustering included an immigrant status, particular nationalities (Somali, Senegalese, or Peruvian), and city of residence: clustering was more frequent among immigrants with TB in Milan than in Brescia (49% versus 31%) (439). In Alabama, risk factors for clustering on the basis of recent transmission were young age, homelessness, alcohol abuse, urban residency, history of imprisonment, and black race but not HIV infection (440); HIV infection was a risk factor for recent transmission in an earlier study in San Francisco, along with being born in the United States, substance abuse, and homelessness.…”

Regional transport and its association with tuberculosis in the Shandong province of China, 2009–2011

“…The importance of TB contact locations such as community drop-in centers, bars, and parks, and social networks have been explored to great effect (Cook et al, 2007;Carter et al, 2009). Indeed, the movements of people in space and migrants, in particular, have contributed to the spread of TB in both developing (Long et al, 2008;Wei et al, 2009;PaceAsciak et al, 2013) and developed countries (Haase et al, 2007;McPherson et al, 2008;Franzetti et al, 2010;Edelson and Phypers, 2011). An earlier study by Jia et al (2008) reported a higher rate of TB prevalence in migrants than the local residents of Beijing.…”

The Impact of Tuberculosis among Immigrants: Epidemiology and Strategies of Control in High-Income Countries—Current Data and Literature Review

“…Given that the majority of active TB in foreign-born persons in low-incidence countries arises from reactivation of LTBI, acquired many years previously in the country of origin, as also demonstrated by epidemiological studies based on M. tuberculosis strain isolates by molecular genotyping that found that 55-90% of TB cases in foreign-born persons are due to LTBI reactivation [40][41]. Screening new entrants for LTBI remains the cornerstone for controlling imported TB.…”