An outbreak of Mycobacterium tuberculosis infection associated with acupuncture in a private clinic of Zhejiang Province, China, 2012

Background: Acupuncture carries the potential risk of transmission of pathogenic microorganisms from the environment to the patient, and from one patient to another. An outbreak of tuberculosis at a private clinic in eastern China was investigated to identify the source of infection, mode of transmission, and risk factors for infection. Methods: A probable case was one who had the onset of unexplained pain, swelling, or abscess in the area of invasive treatment between January 1, 2011 and February 23, 2012. A confirmed case was a probable case with positive laboratory test results for Mycobacterium tuberculosis. Patient history and the frequency of invasive treatment were compared between 56 probable and confirmed cases and 98 controls in a case-control study. Results: Fifty-six of 2561 patients (2.2%) who had visited the clinic developed tuberculosis. The odds ratio (OR) of M. tuberculosis infection increased with the frequency of clinic visits (Chi-square for trend = 28.943, p = 0.000). Multivariate analysis showed that the frequency of acupuncture (Chi-square = 24.258, adjusted p-value = 0.000) and sharing acupuncture needles (Chi-square = 8.936, adjusted p-value = 0.003) were risk factors for M. tuberculosis infection. Thirty-two pus sample and nine sputum sample cultures were M. tuberculosis-positive. Conclusions: This outbreak was caused by acupuncture and was transmitted through sharing acupuncture needles contaminated with M. tuberculosis. (C) 2014 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.