Liss G M, Khan R, Koven E, Simor A E
Health and Safety Studies Unit, Ontario Ministry of Labour, Toronto, Canada.
Infect Control Hosp Epidemiol. 1996 Jan;17(1):29-35. doi: 10.1086/647185.
To determine risks for tuberculin skin-test conversion among employees of a community hospital in Ontario, Canada.
Cohort morbidity study.
Of 14 metropolitan Toronto area hospitals surveyed for data on tuberculin skin-test conversions, only one provided tuberculosis (TB) test data on all employees. Between 1991 and June 1994, 24 patients were treated at this hospital for pulmonary TB.
The population at risk included those on staff from January 1991 through December 1993 who previously were skin-test negative; they were followed until the end of June 1994. Exposure was estimated (a) based on ranking departments according to an estimate of the number of hours of direct patient contact during a typical day, and (b) based on location of sputum-positive patients.
Risks of skin-test conversion among hospital employees with documented prior negative skin tests.
A total of 809 skin-test negative employees were followed for 2,084 person-years; 18 employees with skin-test conversions were identified. The overall conversion rate was 0.9% per year (0.86 per 100 person-years). After excluding two conversions attributed to contact with coworkers, the relative risk of conversion was 4.5 (5.5 after adjusting for age and gender) among those in the highest exposure category (> or = 4 hours per day), compared to those in departments ranked as having the lowest exposure (< 2 hours per day). Among those working in wards in which sputum-positive patients were treated, 2.4% converted; the risk of conversion was over six times greater than among those working on wards with no TB patients or in departments with no patient contact, of whom 0.4% converted. Among the emergency room staff, the department in which the greatest number of sputum-positive patients were treated, at least 5% of staff converted. In those instances in which conversions were associated with exposure to a specific TB patient, the involved patients had been in the hospital for at least 4 days prior to being isolated.
These results indicate that even in a hospital with few admissions due to tuberculosis, skin-test conversions associated with occupational exposure may occur (Infect Control Hosp Epidemiol 1996; 17:29-35).
确定加拿大安大略省一家社区医院员工结核菌素皮肤试验转阳的风险。
队列发病率研究。
在对多伦多市14家医院进行的关于结核菌素皮肤试验转阳数据的调查中，只有一家提供了所有员工的结核病（TB）检测数据。1991年至1994年6月期间，该医院有24例肺结核患者接受治疗。
风险人群包括1991年1月至1993年12月期间入职且之前皮肤试验呈阴性的员工；对他们进行随访直至1994年6月底。暴露情况的评估方法如下：（a）根据各科室在典型工作日中与患者直接接触的小时数估计进行排名；（b）根据痰涂片阳性患者的所在位置进行评估。
记录在案的先前皮肤试验阴性的医院员工中皮肤试验转阳的风险。
总共对809名皮肤试验阴性的员工进行了2084人年的随访；确定有18名员工皮肤试验转阳。总体转阳率为每年0.9%（每100人年0.86例）。在排除因与同事接触导致的2例转阳病例后，与每天接触时间最短（<2小时）的科室员工相比，最高暴露类别（每天≥4小时）的员工转阳的相对风险为4.5（调整年龄和性别后为5.5）。在收治痰涂片阳性患者的病房工作的员工中，2.4%出现转阳；其转阳风险比在没有结核病患者的病房或不接触患者的科室工作的员工（转阳率为0.4%）高出6倍多。在急诊室工作人员中，该科室收治的痰涂片阳性患者数量最多，至少5%的员工出现转阳。在那些转阳与接触特定结核病患者有关的病例中，相关患者在被隔离前已在医院至少待了4天。
这些结果表明，即使在一家因结核病入院患者较少的医院，与职业暴露相关的皮肤试验转阳情况仍可能发生（《感染控制与医院流行病学》1996年；17:29 - 35）。
