Drug Resistant Tuberculosis Among Foreigners and Natives in a City of Northern Italy. A Retrospective Study Period of Eight Years.

Background: Drug-resistant tuberculosis (TB) represents a threat in TB control, because of cumbersome clinical management, toxicity and prolonged treatment. Drug resistance trend in Emilia-Romagna, a region of Northern Italy, is not increasing and in 2016 is even decreased. The present study describes the TB epidemiological and anti-TB drug resistance trend among natives and foreign-born cases between 2009 and 2017, in a low TB burden and high immigrant receiving setting (Ferrara, a city of Northern Italy, Emilia-Romagna region). Methods: We retrospectively identified all bacteriologically confirmed TB cases (confirmed by NAAT or culture) diagnosed in Ferrara University-Hospital from 2009 to 2017. We recorded gender, age, country of birth, site of disease, smear positivity, sensitivity or resistance toward one (mono-resistant), two or more first-line anti-TB drug (poly-resistant), MDR, and XDR-TB. Results: 109 out of the 167 TB cases (65.3%) were foreign-born and 58 natives, 95 males and 72 females, 120 pulmonary (PTB) and 47 extra-pulmonary (EPTB) cases. Among PTB cases, a positive smear was recorded in 56.6 % of foreign-born subjects and 45.5 % of natives. Foreign-born cases were significantly younger than natives (33.9 vs 62.2 years, p<0.01). The proportion of foreign-born cases increased from 57.1% to 78.9% over the study period (2009-2017). Antibiotic resistance profile was available in 134 cases (80.2%). 32/96 foreign-born and 14/38 native subjects presented drug resistant TB (p > 0.05). All multidrug-resistant (MDR) (2/134) and extensively-resistant (XDR) (1/134) cases were East-European and smear negative cases. We did not observe any increasing or decreasing trend in drug resistance profile over the 8 year study period (Figure 1). However, even if not statistically significant, we found an association with the country of birth: East-Europeans presented the higher rate of drug resistant cases (44.1%), Asians, the lower (23.8%). Conclusions: In a low TB burden setting, TB cases cluster mostly among foreign-born subjects and are generally sensitive to first-line drugs. In our series, most of drug-resistant cases, all MDR and XDR cases were recorded among East-Europeans. Drug-resistance rate is not increasing and its profile reflects those of the country of birth and may vary with the variation of immigration flows.