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.