Recent transmission of pulmonary tuberculosis and its influencing factors in Jing'an district, Shanghai, 2010-2015

Abstract

Objective: To understand the recent transmission of Mycobacterium tuberculosis (MTB), and to identify the influencing factors of recent transmission among pulmonary tuberculosis (TB) patients in Jing'an district, Shanghai. Methods: The genotypes and drug resistances of MTB isolated from TB patients registered in the TB designated hospitals in Jing'an district during 2010-2015 were analyzed through 12-loci Mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR)(QUB11b, QUB18, Mtub21, Miru26, QUB26, Mtub04, Miru31, Miru40, VNTR2372, VNTR3820, 3232, 4120), and tested for drug susceptibility as well. With the results of field epidemiological investigation, univariate and multivariate analyses were performed to analyze the distribution of the clusters and influencing factors on recent transmission. Results: This study enrolled 80 TB patients, 23 (28.75%) had a resistance to at least one anti-TB drug, and the prevalence of multidrug-resistant tuberculosis (MDR-TB) was 16.25%. A total of 65 genotypes were identified with 58 (72.50%, 58/80) being unique and 7 clusters with 2-10 isolated in each cluster. The proportion of clustering was 27.50% (22/80). Results from the multivariate analysis revealed that multidrug- resistance (OR=35.799, 95%CI: 4.239-302.346) and having comorbidity with TB (OR=7.695, 95%CI: 1.421-41.658) were independently associated with the clustering, which suggesting a recent transmission. The field investigation to the clustered cases proved that the patients in two clusters had epidemiological links, one was between family members, and the other contained 10 MDR-TB patients with 9 knowing each other which have a definite connection and 1 having the possible connection with them. Conclusion: Recent transmission of tuberculosis happened among TB patients in Jing'an district, with high risks among the MDR-TB patients.