Increased risk of Mycobacterium tuberculosis infection related to the occupational exposures of health care workers in Chiang Rai, Thailand.

SETTING

Chiang Rai, the northernmost province of Thailand.

OBJECTIVE

To evaluate the occupational risk for tuberculous infection of health care workers (HCWs) and the utility of tuberculin skin test (TST) in a developing country setting.

DESIGN

A cross-sectional TST survey, including a risk assessment questionnaire, of Chiang Rai Hospital HCWs.

RESULTS

Of 911 HCWs tested, 623 (68%) had indurations of > or = 10 mm and 322 (35%) indurations of > or = 15 mm. Factors most predictive for TST positivity, using either cut-off, were employment > 1 year, frequent direct patient contact, and male sex. Moreover, having a bacillus Calmette-Guérin (BCG) scar was predictive of a > or = 10 mm, but not a > or = 15 mm, reaction.

CONCLUSIONS

Chiang Rai Hospital HCWs had an increased risk for Mycobacterium tuberculosis infection, which was significantly associated with occupational exposure. Where BCG coverage is high, a TST cut-off of > or = 15 mm may correlate better with M. tuberculosis infection than does a cut-off of > or = 10 mm. Effective, affordable infection control measures are needed for health care facilities in developing countries such as Thailand, where HCWs may be at increased risk for M. tuberculosis infection from occupational exposures.